Correlation of polymerization conditions with thermal and mechanical properties of polyethylenes...

Research ArticleCorrelation of Polymerization Conditions withThermal and Mechanical Properties of Polyethylenes Made withZiegler-Natta Catalysts

M Anwar Parvez1 Mostafizur Rahaman1 M A Suleiman1

J B P Soares2 and I A Hussein1

1 Department of Chemical Engineering King Fahd University of Petroleum and Minerals Dhahran 31261 Saudi Arabia2Department of Chemical Engineering University of Waterloo Waterloo ON Canada N2L 3G1

Correspondence should be addressed to I A Hussein ihusseinkfupmedusa

Received 14 October 2013 Revised 23 December 2013 Accepted 25 December 2013 Published 11 February 2014

Academic Editor Giridhar Madras

Copyright copy 2014 M Anwar Parvez et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

In this study the synthesis of polyethylenes has been carried out with titanium-magnesium supported Ziegler-Natta catalystsin laboratory-scale reactors A correlation of different polymerization conditions with thermal and mechanical properties ofpolyethylenes has been established It is seen that there is lowering of molecular weight (Mw) polymer yield and catalyst activityat high hydrogen pressure and high temperature The Mw polymer yield and catalyst activity are improved with the increasein ethylene pressure Dynamic mechanical analysis (DMA) results show that the increase in temperature and hydrogen pressuredecreases storage modulus The samples with higher Mw showed high activation energy The melting point decreases with theincrease in hydrogen pressure but increases slightly with the increase in ethylene pressure It is seen that the increase in reactiontemperature ethylene pressure and hydrogen pressure leads to an increase in crystallinity The tensile modulus increases with theincrease in hydrogen pressure and can be correlated with the crystallinity of polymer The Mw has a major influence on the flowactivation energy and tensile strength But the other mechanical and thermal properties depend onMw as well as other parameters

1 Introduction

Polyolefins are prepared commercially using different ini-tiator and catalysts like free radical initiators Phillips typecatalysts and Ziegler-Natta catalysts Among these the het-erogeneous Ziegler-Natta catalysts remain the main indus-trial catalysts of choice because of their remarkable abilityto affect the polymerization of olefins to produce polymersof high molecular weight and ordered structure [1 2] Aunique feature of these catalysts is the presence of more thanone active site type which leads to polyolefins with broadmolecular weight distributions (MWD) and stereoregularityThese distributions influence the physical properties of poly-olefins and are responsible for their performance and finalapplications Heterogeneous Ziegler-Natta resins dominatethe polyolefin market now and will still be a major fraction

of the polyolefin market in the next decade because of theirversatility and low cost

Ziegler-Natta catalysts have been used to synthesizepolyethylene and polypropylene [3 4] There are two typesof Ziegler-Natta catalysts one is supported type and theother is nonsupported type [5 6] Among the supportedtype Ziegler-Natta catalysts titanium-magnesium supportedZiegler-Natta catalysts are mostly used to synthesize poly-olefins [7 8] The final properties of synthetic polyolefinsare affected by different polymerization parameters Thereare many literatures where the molecular weight (Mw)molecular weight distribution (MWD) melting temperatureand crystallinity of polyolefins are strongly dependent onpolymerization parameters like hydrogen pressure ethylenepressure polymerization temperature and polymerizationtime [9ndash13] However systematic discussions about the

Hindawi Publishing CorporationInternational Journal of Polymer ScienceVolume 2014 Article ID 549031 10 pageshttpdxdoiorg1011552014549031

2 International Journal of Polymer Science

1 MgCl2 3C8H17OH + 5 TiCl430

∘C hexane

700 rpmMgCl2 C8H17O TiCl4

Ti(C8H17O)xCl4minusx

HClCl3TiOTiCl3

+

Solid productLiquid solution

Side product filtered off

middot middot middot

Scheme 1 Synthesis of the magnesium supported Ziegler-Natta catalyst

effect of these polymerization parameters on the polyolefinsfinal properties like dynamic mechanical properties thermalproperties and mechanical properties are really scanty

The objectives of this study are to produce polyethy-lene with heterogeneous Ziegler-Natta catalysts in controlledlaboratory-scale reactors and correlate themacroscopic prop-erties to polymerization conditions The effect of differentpolymerization conditions like hydrogen pressure ethylenepressure polymerization temperature and polymerizationtime on molecular weight (Mw) molecular weight distri-bution (MWD) dynamic mechanical properties thermalproperties and mechanical properties have been studiedMoreover some correlations of Mw with dynamic mechan-ical thermal and tensile properties has been made and theirfittings have been discussed

2 Materials Methods andExperimental Techniques

21 Materials All operations were performed under ultra-high purity nitrogen (99999 purchased from Praxair)using standard Schlenk techniques or inside the glove boxPolymer grade ethylene (999 purchased from Praxair) andultrahigh purity nitrogen were purified by passing throughcolumns packed with R3-11 copper catalyst activated alu-mina and 3A4A mixed molecular sieves Materials for cat-alyst synthesis such as magnesium chloride (MgCl

2 power-

325 mesh) and titanium (IV) chloride (TiCl4 99) were

purchased from Aldrich and 2-ethyl-1-hexanol (99) wasprocured fromAlfa AesarThese materials were used withoutfurther purification The activator triethyl aluminium (TEA1M in hexane) was purchased from Aldrich The reactiondiluent hexane (HPLC grade 95 n-hexane) used forsynthesis of the catalyst and polymerization was purchasedfrom J T Baker and purified by passing through columnspacked with activated alumina andmolecular sieves (ZeolumType F-9 Tosoh Co) Purified solvent was stored in Schlenkflasks with 3A4A mixed molecular sieves

22 Synthesis of Magnesium Supported Ziegler-Natta CatalystThe catalyst preparation has been carried out through atypical procedure mentioned in the literature [14] In thismethod magnesium chloride (762 g 008mol) 2-ethyl-1-hexanol (375mL 024mol) and 200mL hexane as solventwere added to a 500mL round flask The mixture was stirredand refluxed for 24 hours and then a clear solution wasobtained 05mol of titanium (IV) chloride was slowly addeddrop wise at 30∘C under a stirring rate of 700 rpm and themixture was additionally reacted for 2 hoursThe precipitatedproduct was filtered washed three times with hexane and

then dried under nitrogen flow A dried white powder wasisolated at the end of the reactionThe synthetic route for thecatalyst synthesis is shown in Scheme 1

23 Ethylene Polymerization Ethylene polymerizationsusing the magnesium supported Ziegler-Natta catalyst wereconducted under various reaction conditions Polymeriza-tions were carried out in a 300mL semibatch autoclavereactor equipped with a mass flow meter and a temperaturecontrol unit consisting of a cooling coil and an electric heaterThe polymerization temperature was maintained withinplusmn02∘C of the set point Prior to each reaction the reactorwas purged five times with nitrogen then heated to 140∘Cunder vacuum and purged again to the set point temperatureunder nitrogen flow A volume of 200mL solvent and thetriethyl aluminium activator were transferred to the reactorand stirred for 5 minutes The amount of triethyl aluminiumwas fixed at 20mmol Catalyst slurry with hexane wasinjected into the reactor and stirred for 10 minutesThe poly-merization was performed with a continuous ethylene flowto meet the desired ethylene pressure under a stirring rate of500 rpm At the end of polymerization time the reactor wasrapidly vented and the obtained polymer was precipitated in200mL ethanol and then filtered and dried under vacuum

24 Gel Permeation Chromatography (GPC) Molecularweight and molecular weight distribution were determinedby gel permeation chromatography (GPC-IR Polymer Char)Samples were dissolved at 160∘C in 124-trichlorobenzeneand passed through three linear Polymer Laboratoriescolumns which were calibrated with polystyrene standardsand operated with a flow rate of 1mLmin Details of GPCand NMR characterization procedure have been reportedelsewhere [15]

25 Differential Scanning Calorimetry (DSC) The meltingtemperature of the polymerwas determined using differentialscanning calorimetry (DSC TA InstrumentsDSC 2920) Twoscans were performed The first melting scan was used toerase the thermal history of the sample followed by coolingwith air The second scan was done at a heating rate of10∘Cmin and used to characterize the sample

26 Dynamic Mechanical Analysis (DMA) Dynamic mech-anical analysis is a method that measures the stiffness andmechanical damping (ie storage and loss moduli in thesolid state) of a cyclically deformed material as a functionof temperature strain and frequency The combination ofstiffness and damping properties is a reflection of the uniqueviscoelastic nature of polymers The Q800 DMA from TA

International Journal of Polymer Science 3

Table 1 Ethylene polymerization using Ziegler-Natta catalyst

SnoPolymerization Results

Catalyst 119875C2119875H2

Temp Time Yield Activity Mn Mw PDI(mg) (atm) (atm) (∘C) (hour) (g) (kg PEG catsdoth) (kgmol) (kgmol) MwMn

1 30 5 0 60 05 90 83 88 325 3692 31 5 0 60 1 201 65 83 340 4103 34 5 0 80 05 83 49 78 310 3974 34 5 0 80 1 96 28 80 317 3965 29 5 2 60 05 81 66 30 111 3706 30 5 2 60 1 174 58 25 112 4487 30 5 2 80 05 48 32 19 89 4688 30 5 2 80 1 78 26 23 102 4439 30 5 5 60 05 49 33 19 103 54210 30 5 5 60 1 77 26 14 92 65711 33 5 5 80 05 31 19 10 57 57012 30 5 5 80 1 35 10 12 66 55013 34 10 0 60 05 385 226 167 662 39614 35 10 0 60 1 458 131 158 655 41515 33 10 0 80 05 265 161 162 617 38116 31 10 0 80 1 285 92 154 625 40617 33 10 2 60 05 239 145 35 176 50318 33 10 2 60 1 436 132 30 161 53719 31 10 2 80 05 229 148 25 127 50820 32 10 2 80 1 391 122 68 267 39321 30 10 5 60 05 202 135 40 226 56522 32 10 5 60 1 321 103 49 239 48823 30 10 5 80 05 154 103 39 169 43324 32 10 5 80 1 251 78 41 178 434

Instruments was used to get the dynamic mechanical proper-ties of the polymer samples Single cantilever of 8mm lengthfixture was used to run the DMA testsThe sample specimenswere prepared in carver press using the fixed size mold Thespecimen dimension was 8mm length 101mm width anda thickness between 065 and 075mm Temperature stepfrequency sweep test was run in strain controlled mode Thefrequency range was 01ndash100Hz and the strain was 15 micronThe temperature was varied in the range 40ndash80∘C with a stepof 10∘C per each frequency sweep The experimental datawere then exported in time temperature superposition (TTS)mode to get the flow activation energy

27 Mechanical Testing The sample specimen formechanicaltest was prepared using a dog-bone mold in carver pressThespecimen used for the tensile tests was prepared according toASTMD638 (TypeV)The tensile tests were performed usingan Instron 5567 tensile testing machine at room temperatureThe gauge length was kept at 25mm with a crosshead speedof 50mmmin

3 Results and Discussion

31 Effect of Polymerization Conditions on Molecular Weight(Mw) and Molecular Weight Distribution (MWD) of Poly-ethylenes The effects of polymerization conditions on Mw

and MWD of polyethylenes have been presented in Table1 The effect of hydrogen pressure (0 2 and 5 bar) on Mwand MWD has been reported at two different ethylene pres-sures (5 and 10 bar) polymerization temperatures (60 and80∘C) and polymerization times (30 and 60min) As thehydrogen pressure is increased while maintaining a constantpolymerization temperature (60 or 80∘C) polymerizationtime (30 or 60min) and ethylene pressure (5 or 10 bar) it isobserved that the Mw of polyethylene decreases whereas theMWD(PDI) increases It has beenmentioned in the literaturethat hydrogen acts as an efficient chain transfer agent [910] Thus an increase in hydrogen pressure leads to thetermination of the polymerization reaction resulting in thelowering of molecular weight and broadening of molecularweight distribution Our observation is in good agreementwith the findings made by Moballegh and Hakim [10] wherethe effect of hydrogen pressure on Mw and MWD hasbeen reported for ethylene1-butene copolymer [10] Both thepolymer yield and catalyst activity decrease with the increasein hydrogen pressure As mentioned earlier hydrogen actsas chain transfer agent for the reaction thus an increase inhydrogen pressure leads to an increase in its concentrationat the catalyst active sites This results in a decrease in theavailability of ethylene at the active catalyst sites and favoursthe termination of polymerization reaction Hence both thepolymer yield and catalyst activity are reduced


The impact of ethylene pressure (5 and 10 bar) onMw andMWD has been reported at three different hydrogen pres-sures (0 2 and 5 bar) two polymerization temperature (60and 80∘C) and two polymerization times (30 and 60min) ascan be seen from Table 1 It is seen that with the increase inethylene pressure from 5 to 10 bar an increase in molecularweight is observed This result is found to be similar withprevious investigations [9] where an increase in molecularweight was reportedThe effect of ethylene pressure onMWDis not systematic It has been mentioned in the literature thatthe monomer ethylene acts as an activator for the catalystfor the polymerization reaction [9] Hence with the increasein ethylene pressure an increase in Mw is observed Theincrease in ethylene pressure leads to the improvement inpolymer yield and catalyst activity as observed in Table 1Theincrease in ethylene pressure increases its availability at theactive catalyst sites Thus catalyst activity increases whichimproves the polymer yield

The polymerization temperature also effects the Mw ofpolyethylene homopolymers It is observed from Table 1 thatthe increase in polymerization temperature from 60 to 80∘Cthere is the decrease in Mw of the resulting polymer whenethylene pressure is maintained at both 5 and 10 bar Thisdecrease in Mw at higher polymerization temperature is dueto stronger chain transfer reaction during polymerizationTheMWD(PDI) of ethylene homopolymers are not in properorder with polymerization temperature It is seen from thetable that both the polymer yield and catalyst activity decreasewith the increase in polymerization temperature

The results in Table 1 show that the increase in reactiontime from 30min to 1 hour has less impact onMw andMWD(PDI) when the experiments are carried out at 5-bar ethylenepressure In this case the Mw and MWD (PDI) are irregularin nature The irregularity in the effect of reaction time onMw is also observed when the experiments are carried out at10-bar ethylene pressure These results are in agreement withthe findings reported elsewhere [11] However the increase inpolymerization time improves the polymer yield but reducesthe catalyst activity as observed in Table 1 The reason is thatthe monomers get more time for the formation of polymerhence polymer yield increases As the time increases theconcentration of ethylenemonomer at the catalyst active sitesdecreases Hence the catalyst activity is reduced

32 DynamicMechanical Analysis (DMA) Dynamic temper-ature stepfrequency sweep tests produce solid state dynamicmechanical properties of polymeric samples as a function ofboth temperature and frequency Figure 1 shows the variationof storage modulus (1198661015840) with respect to frequency at differenttemperature for sample 5 that is at hydrogen pressure =2 bar ethylene pressure = 5 bar polymerization temperature(119879) = 60

∘C and polymerization time (119905) = 30min Itis observed from this figure that the increase in frequencyincreases the 1198661015840 of the polymer almost linearly However theprogressive increase in temperature leads to the decrease instorage modulus Actually the molecular motion in polymerchanges with the increase in temperature This makes thepolymer sample softer which results in lowering of storageenergyThe tan 120575 versus frequency plots for sample 5 has been

T = 60∘C

t = 30min

PC2H4= 5bar

PH2= 2bar

Temperature = 50∘C




01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)

Figure 1 Dynamic temperature stepfrequency sweep for polyethy-lene sample 5 synthesized at 119875C2H4 = 5 bar 119875H2 = 2 bar 119879polymerizationtemperature = 60∘C and 119905polymerization time = 30min

T = 60∘C

t = 30min

PC2H4=

PH2=

004

008

012

016

020

024

028





01 1 10 100Frequency (Hz)

tan120575

5bar

2bar

Figure 2 Dynamic temperature stepfrequency sweep (tan 120575) forpolyethylene sample 5 synthesized at 119875C2H4 = 5 bar 119875H2 = 2 bar119879polymerization temperature = 60∘C and 119905polymerization time = 30min

presented in Figure 2 which shows the decrease in tan 120575withthe increase in frequency On the contrary tan 120575 increaseswith the increase in temperature This increase in tan 120575 isdue to the decrease in 1198661015840 of the sample with the increase intemperature

Figure 3 shows the effect of frequency on 1198661015840 at hydrogenpressure (0 2 and 5 bar) for samples 1 5 and 9 that isat ethylene pressure = 5 bar polymerization temperature =60∘C and polymerization time = 30min where themeasure-ment temperature was maintained at 60∘C It is seen from thefigure that the increase in hydrogen pressure reduces the1198661015840 It


T = 60∘C

t = 30min

PC2H4=

PH2=

PH2=

PH2=

01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)

∘CIsothermal conditioned at 60

5bar

2bar0bar

5bar

Figure 3 Storage modulus of polyethylene synthesized at 119875C2H4 =5 bar 119879polymerization temperature = 60∘C and 119905polymerization time = 30minutes (samples 1 5 and 9)

T = 60∘C

t = 30min

PC2H4=


004

008

012

016

020

024


tan120575

PH2=

PH2=

PH2=

2bar0bar

5bar

5bar

Figure 4 tan120575 of polyethylene synthesized at 119875C2H4 = 5 bar119879polymerization temperature = 60∘C and 119905polymerization time = 30 minutes(samples 1 5 and 9)

has been mentioned earlier that hydrogen acts as an efficientchain transfer agent for the reactionThus the incorporationof hydrogen leads to the formation of polymer with shortchain length This results in lowering the molecular weightand consequently reducing storage modulus tan120575 versusfrequency plots at different hydrogen pressure for the samples1 5 and 9 has been shown in Figure 4 It is found that thetan 120575 value increases with the increase in hydrogen pressureat all frequency ranges Actually the molecular movementin low Mw polymer is higher compared to high molecular

weight polymer As tan 120575 (damping factor) is a measure ofmolecularmovement (structural transformation) in polymerhence the increase in molecular movement in polymer willresult in a higher value of tan 120575This is why the lowmolecularweight polymer (short chain length polymer) will have highervalue of tan 120575 compared to the polymer with a long chainThe trends in variation in the effects of ethylene pressure andpolymerization temperature on storage modulus and tan 120575of the polymer have been found almost similar (not shownin the figure) the only difference is in their magnitude Acorrelation of Mwwith1198661015840 and tan 120575 has been established andshown in Figures 5(a) and 5(b) It is seen from the figure that1198661015840 increases but tan 120575 decreases with the increase in MwThe

coefficients of correlation (1198772) of linear fit for1198661015840 and tan 120575 are090 and 089 respectively a little bit away from unity Thisindicates that 1198661015840 and tan 120575 also depend on other parameterslike polymer crystallinity

The activation energy (Δ119864) for all the samples has beenextracted from the DMA data using the time temperaturesuperposition technique (TTS) The results are presented inTable 2 It is found that the Δ119864 for all samples is in the range1983plusmn43ndash2942plusmn57 kJmolΔ119864 is found to increasewith theincrease in ethylene pressure but decrease with the increasein hydrogen pressure and polymerization temperature Therelation between Δ119864 and Mw has been presented in Figure5(c) The samples with higher Mw exhibit high values of Δ119864The value of 1198772 is 093This suggests that the similarity of thestructure resulted in similar values for Δ119864

33 Differential Scanning Calorimeter (DSC) The results ofcrystallization temperature (119879

119888) melting temperature (119879

119898)

and crystallinity ( 119883119888) have been extracted from the

DSC experiments and are presented in Table 3 for thepolyethylene samples It is observed from the table that the119879119888of polyethylenes is not affected somuch by polymerization

parameters that is the 119879119888remains in between 11737 plusmn

143ndash11998 plusmn 218∘C However there is impact of polymer-ization parameters on 119879

119898and crystallinity

It is seen from the table that the increase in hydrogenpressure decreases the melting point due to the decrease inMw A polymer with lower Mw will have lower surface areathat means lower physical attraction between the polymerchains and low 119879

119898[16] On the other hand melting point

is slightly increased with the increase in ethylene pressureAt 5-bar ethylene pressure the 119879

119898is in between 14154 plusmn

159ndash1345plusmn186∘C whereas at 10-bar ethylene pressure therange is 14293 plusmn 208ndash13587 plusmn 215∘C With the increase inpolymerization temperature the 119879

119898of polyethylene is found

to decrease slightly This is likely due to the decrease in Mwwith the increase in polymerization temperature as shown inTable 1 However the polymerization time has no effect on119879

119898

of the polyethylene homopolymerThe effect of hydrogen pressure on polymer crystallinity

has also been reported in Table 3 It is seen that the increase inhydrogen pressure increases the crystallinity of the polymerIn coordination polymerization successive polymerizationand crystallization take place [12] The increase in hydrogenpressure blocks the active sites of polymerization becausehydrogen acts as chain transfer agent for the reaction Thus


0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)

Figure 5 Correlation of Mw with (a) 1198661015840 (b) tan 120575 and (c) Δ119864

Table 2 Activation energy for polyethylene samples

Sample 119875C2H4119875H2

Temp Time Mw Activation energy Δ119864(bar) (bar) (∘C) (hour) (kgmol) (kJmol)

1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43


Table 3 DSC analysis for polyethylene samples

Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898

crystallinity(bar) (bar) (∘C) (hour) (∘C) (∘C) (Cooling)

1 5 0 60 05 11901 plusmn 236 14154 plusmn 159 5200 plusmn 212
























the polymerization rate is reduced and crystallization rate isincreased This leads to the higher value of crystallinity withthe increase in hydrogen pressure [13] It is also observedfrom the table that the increase in ethylene pressure from 5to 10 bar increases the polymer crystallinity For sample 5 andsample 17 where the polymerization has been carried outat ethylene pressure 5 and 10 bar (constant polymerizationconditions are hydrogen pressure = 2 bar polymerizationtemperature = 60∘C and polymerization time = 30min) the crystallinity is found to be 5739 plusmn 241 and 7485 plusmn 241respectively Thus the increase in crystallinity in this case isaround 30 This increment in crystallinity has been foundto vary according to polymerization condition The increasein crystallinity with the increase in ethylene pressure has alsobeen reported elsewhere though the effect is less significant[11] In the same table it can be seen that the increase inpolymerization temperature leads to increase in crystallinityThe increase in crystallinity with respect to polymerizationtemperature at 5-bar ethylene pressure and 0-bar hydrogenpressure (for samples 1 and 3) is around 9 whereas at5-bar ethylene and hydrogen pressure (samples 9 and 11)the increment in crystallinity is around 23 However at10-bar ethylene pressure and 5-bar hydrogen pressure (forthe sample sets 21 and 23) the effect of polymerizationtemperature on crystallinity is very marginal Thus it canbe said that the effect of polymerization temperature oncrystallinity is more significant at low ethylene pressure and

high hydrogen pressure The polymerization time has nosignificant effect on crystallinity as can be seen from the datapresented in the same table

An effort has been made to correlate Mw with polymerproperties such as119879

119898119879119888 and119883

119888as shown in Figures 6(a)ndash

6(c) It is observed from the figure that 119879119898increases with the

increase inMw but 119879119888and 119883

119888decreaseThe 1198772 of linear fits

for 119879119898 119879119888 and 119883

119888are 052 049 and 046 respectively far

away from unityThis suggests that these parameters not onlydepend on Mw but also on other parameters

34 Mechanical Properties Mechanical testing results forall the samples have been presented in Table 4 The resultsof mechanical testing of polyethylene can be correlatedwith hydrogen pressure It is observed from the table thatthe tensile modulus (TM) of polyethylene increases withthe increase in hydrogen pressure The modulus at 0-barhydrogen pressure is in the range 454 plusmn 22ndash515 plusmn 31MPaat 2-bar hydrogen pressure is in the range 573 plusmn 35ndash663 plusmn29MPa and at 5-bar hydrogen pressure is in the range 628 plusmn31ndash856 plusmn 27MPa when polymerization is conditioned at5-bar ethylene pressure Similarly when polymerization isconditioned at 10-bar ethylene pressure themodulus at 0-barhydrogen pressure is in the range 535 plusmn 38ndash622 plusmn 33MPaat 2-bar hydrogen pressure is in the range 758 plusmn 31ndash879 plusmn41MPa and at 5-bar hydrogen pressure is in the range873 plusmn 38ndash1019 plusmn 51MPa Thus the modulus value is higher


Table 4 Results of mechanical testing for polyethylene samples

Sample 119875C2H4119875H2

Temp Time Modulus Yield stress Yield strain Strain at break Tensile strength(bar) (bar) (∘C) (hour) (MPa) (MPa) () () (MPa)

1 5 0 60 05 454 plusmn 22 1632 plusmn 121 4 395 plusmn 19 5208 plusmn 632
























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)

Figure 6 Correlation of Mw with (a) 119879119898 (b) 119879

119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)

Figure 7 Correlation of Mw with (a) TM (b) TS (c) SB and (d) YS

when the polymerization is conditioned at higher ethylenepressure This increase in tensile modulus can be correlatedwith crystallinity results shown in Table 3 It is observed thathigher crystallinity leads to higher value of tensile modulus

The effect of hydrogen pressure on strain at break (SB) has been reported in the same Table 4The strain at break() is in between 395plusmn19ndash467plusmn18 at 0 bar hydrogen pressure(samples 1ndash4) 433 plusmn 23ndash563 plusmn 29 at 2 bar hydrogen pressure(samples 5ndash8) and 515 plusmn 21ndash669 plusmn 24 at 5 bar hydrogenpressure (samples 9ndash12) Similarly the strain at break () at0 bar hydrogen pressure (samples 13ndash16) is in the range 447 plusmn18ndash591 plusmn 23 at 2 bar hydrogen pressure (samples 17ndash20) is inthe range 542 plusmn 29ndash632 plusmn 27 and at 5 bar hydrogen pressure(samples 21ndash24) is in the range 682 plusmn 41ndash784 plusmn 39 Thusthere is the increase in strain at break () with the increase inhydrogen and ethylene pressure The strain at the yield pointhas remained in the range 3-4 as seen from the table

The yield stress (YS) results presented in the table showsome variation with hydrogen pressure It is seen that at 0 bar(samples 1ndash4) 2 bar (samples 5ndash8) and 5 bar (samples 9ndash12) hydrogen pressure the yield stress ranges are 1632 plusmn121ndash1698 plusmn 124MPa 1954 plusmn 136ndash2215 plusmn 127MPaand 2347 plusmn 129ndash2630 plusmn 123MPa respectively Thus anincrement in yield stress is observed with the increase inhydrogen pressure Almost similar type of results is obtainedfor the sample sets 13ndash16 (0-bar hydrogen pressure) 17ndash20 (2-bar hydrogen pressure) and 21ndash24 (5-bar hydrogen pressure)The effect of ethylene pressure on yield stress is less significantcompared to hydrogen pressure as is observed from the tableHowever the effects of polymerization temperature and timeon yield stress are marginal The tensile strength (TS) resultsreported in the table show that the strength has improvedwith the increase in ethylene pressure But TS decreased withthe increase in hydrogen pressure polymerization tempera-ture and polymerization time

The influences of Mw on TM TS SB and YS havebeen shown in Figures 7(a)ndash7(d) The data points are morerandom for TM SB and YS but less random for TS Thereis sufficient overall improvement of TS with the increasein Mw But overall the other properties decrease with theincrease in Mw and this decrement is marginal The 1198772 oflinear fits for TM TS SB and YS are 059 097 056and 054 respectively The 1198772 value for TS is almost closeto unity whereas for other parameters it is far away fromunity Thus it can be said that TS is more dependent on Mwcompared to other tensile properties In a similar way it canbe inferred that other than Mw these tensile properties alsodepend on some other parameters like polymer crystallinitybranch chain length branch chain content and so forthThus establishment of perfect correlation of these propertieswith Mw is really very difficult

4 Conclusions

A decrease in Mw is observed with the increase in hydrogenpressure and polymerization temperature The role of hydro-gen as chain transfer agent is responsible for this decrease inMw There is improvement in Mw with the increase in ethy-lene pressure However the effect of reaction time on Mw ismarginalTheMWDis irregular in naturewith the increase inethylene pressure polymerization temperature and reactiontime The storage modulus value decreases but tan 120575 valueincreases with the increase in polymerization parametersThe activation energy for polyethylenes was in the range1983 plusmn 43ndash2942 plusmn 57 kJmol regardless of the differencesin reaction parameters The higher the Mw is the higher theactivation energy is The increase in reaction temperaturehydrogen pressure and ethylene pressure leads to increasein polymer crystallinity tensile modulus elongation atbreak and yield stress The tensile strength has improved


with the increase in ethylene pressure but reduced withthe increase in other polymerization parameters Howeverthe effect of pressure is more pronounced compared to thereaction temperature The results for the tensile modulus ofpolyethylene have been correlated with crystallinity resultsThe results show that higher crystallinity of polyethyleneleads to higher modulus Overall strong correlations of thepolymerization parameters with thermal and mechanicalproperties of polyethylene have been observed The Mw ofthe polymers has been correlated with their thermal andmechanical propertiesThe fittings reveal that Mw influencesmore 1198661015840 tan 120575 Δ119864 and TS and less the other thermal (119879

119898

119879119888 and 119883

119888) and mechanical (TM SB and YS) properties

because these properties are not only influenced by Mw butalso depend on other parameters

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The research team acknowledges the support provided byKing Abdul Aziz City for Science and Technology for thisresearch project under research Grant no AR-27-67 Theresearch team also acknowledges the facilities and supportprovided by KFUPM The authors are also thankful toKACST project no AR-30-291 for providing partial funding

References

[1] P Pokasermsong and P Praserthdam ldquoComparison of activityof Ziegler-Natta catalysts prepared by recrystallization andchemical reaction methods towards polymerization of ethy-lenerdquo Engineering Journal vol 13 no 1 pp 57ndash64 2009

[2] J X Wong S N Gan and M J Aishah ldquoChromium(III)based Ziegler-Natta catalysts for olefin polymerizationrdquo SainsMalaysiana vol 40 no 7 pp 771ndash779 2011

[3] E Magni and G A Somorjai ldquoEthylene and propylene poly-merization catalyzed by amodel Ziegler-Natta catalyst preparedby gas phase deposition of magnesium chloride and titaniumchloride thin filmsrdquo Catalysis Letters vol 35 no 3-4 pp 205ndash214 1995

[4] I A Hussein and T Hameed ldquoInfluence of branching charac-teristics on thermal and mechanical properties of Ziegler-Nattaandmetallocene hexene linear low-density polyethylene blendswith low-density polyethylenerdquo Journal of Applied PolymerScience vol 97 no 6 pp 2488ndash2498 2005

[5] T B Mikenas V A Zakharov L G Echevskaya and M AMatsko ldquoKinetic features of ethylene polymerization over sup-ported catalysts [26-Bis(imino)pyridyl iron dichloridemagne-sium dichloride] with AlR 3 as an activatorrdquo Journal of PolymerScience A vol 45 no 22 pp 5057ndash5066 2007

[6] J B P Soares and A E Hamielec ldquoKinetics of propylene poly-merization with a non-supported heterogeneous Ziegler-Nattacatalystmdasheffect of hydrogen on rate of polymerization stereo-regularity and molecular weight distributionrdquo Polymer vol 37no 20 pp 4607ndash4614 1996

[7] M I Nikolaeva M A Matsko T B Mikenas L G Echevskayaand V A Zakharov ldquoCopolymerization of ethylene with 120572-ole-fins over supported titanium-magnesium catalysts I Effect ofpolymerization duration on comonomer content and the mole-cular weight distribution of copolymersrdquo Journal of AppliedPolymer Science vol 125 no 3 pp 2034ndash2041 2012

[8] V Zakharov M Matsko L Echevskaya and T MikenasldquoEthylene polymerization over supported titanium-magnesiumcatalysts heterogeneity of active centers and effect of catalystcomposition on the molecular mass distribution of polymerrdquoMacromolecular Symposia vol 260 pp 184ndash188 2007

[9] M I Nikolaeva T B Mikenas M A Matsko L G Echevskayaand V A Zakharov ldquoEthylene polymerization over supportedtitanium-magnesium catalysts effect of polymerization param-eters on the molecular weight distribution of polyethylenerdquoJournal of Applied Polymer Science vol 122 no 5 pp 3092ndash31012011

[10] L Moballegh and S Hakim ldquoMolecularweight bimodality ofethylene1-butene in a two-step polymerization process effectsof polymerization conditionsrdquo Iranian Polymer Journal vol 20no 6 pp 513ndash521 2011

[11] Y J Shin H X Zhang K B Yoon and D H Lee ldquoPreparationof ultra high molecular weight polyethylene with MgCl

2TiCl4

catalysts effect of temperature and pressurerdquo MacromolecularResearch vol 18 no 10 pp 951ndash955 2010

[12] B Wunderlich ldquoCrystallization during polymerizationrdquo Ad-vances in Polymer Science vol 5 pp 568ndash619 1968

[13] A Munoz-Escalona and A Parada ldquoFactors affecting thenascent structure and morphology of polyethylene obtainedby heterogeneous Ziegler-Natta catalysts 2 Crystallinity andmelting behaviourrdquo Polymer vol 20 no 7 pp 859ndash866 1979

[14] M C Forte and F M B Coutinho ldquoHighly active magnesiumchloride supported Ziegler-Natta catalysts with controlledmor-phologyrdquo European Polymer Journal vol 32 no 2 pp 223ndash2311996

[15] T Hameed and I A Hussein ldquoRheological study of theinfluence of MW and comonomer type on the miscibility of m-LLDPE and LDPE blendsrdquo Polymer vol 43 no 25 pp 6911ndash6929 2002

[16] L H Sperling Introduction to Physical Polymer Science Wiley-Interscience New York NY USA 4th edition 2006

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Polymer ScienceInternational Journal of


CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of


thinspInternationalthinspJournalthinspof

BiomaterialsHindawithinspPublishingthinspCorporationhttpwwwhindawicom Volumethinsp2014


NaNoscieNceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

CrystallographyJournal of

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of

BioMed Research International



Volume 2014

MaterialsJournal of

Nano

materials


Journal ofNanomaterials


1 MgCl2 3C8H17OH + 5 TiCl430

∘C hexane

700 rpmMgCl2 C8H17O TiCl4

Ti(C8H17O)xCl4minusx

HClCl3TiOTiCl3

+

Solid productLiquid solution

Side product filtered off

middot middot middot

Scheme 1 Synthesis of the magnesium supported Ziegler-Natta catalyst

effect of these polymerization parameters on the polyolefinsfinal properties like dynamic mechanical properties thermalproperties and mechanical properties are really scanty

The objectives of this study are to produce polyethy-lene with heterogeneous Ziegler-Natta catalysts in controlledlaboratory-scale reactors and correlate themacroscopic prop-erties to polymerization conditions The effect of differentpolymerization conditions like hydrogen pressure ethylenepressure polymerization temperature and polymerizationtime on molecular weight (Mw) molecular weight distri-bution (MWD) dynamic mechanical properties thermalproperties and mechanical properties have been studiedMoreover some correlations of Mw with dynamic mechan-ical thermal and tensile properties has been made and theirfittings have been discussed

2 Materials Methods andExperimental Techniques

21 Materials All operations were performed under ultra-high purity nitrogen (99999 purchased from Praxair)using standard Schlenk techniques or inside the glove boxPolymer grade ethylene (999 purchased from Praxair) andultrahigh purity nitrogen were purified by passing throughcolumns packed with R3-11 copper catalyst activated alu-mina and 3A4A mixed molecular sieves Materials for cat-alyst synthesis such as magnesium chloride (MgCl

2 power-

325 mesh) and titanium (IV) chloride (TiCl4 99) were

purchased from Aldrich and 2-ethyl-1-hexanol (99) wasprocured fromAlfa AesarThese materials were used withoutfurther purification The activator triethyl aluminium (TEA1M in hexane) was purchased from Aldrich The reactiondiluent hexane (HPLC grade 95 n-hexane) used forsynthesis of the catalyst and polymerization was purchasedfrom J T Baker and purified by passing through columnspacked with activated alumina andmolecular sieves (ZeolumType F-9 Tosoh Co) Purified solvent was stored in Schlenkflasks with 3A4A mixed molecular sieves

22 Synthesis of Magnesium Supported Ziegler-Natta CatalystThe catalyst preparation has been carried out through atypical procedure mentioned in the literature [14] In thismethod magnesium chloride (762 g 008mol) 2-ethyl-1-hexanol (375mL 024mol) and 200mL hexane as solventwere added to a 500mL round flask The mixture was stirredand refluxed for 24 hours and then a clear solution wasobtained 05mol of titanium (IV) chloride was slowly addeddrop wise at 30∘C under a stirring rate of 700 rpm and themixture was additionally reacted for 2 hoursThe precipitatedproduct was filtered washed three times with hexane and

then dried under nitrogen flow A dried white powder wasisolated at the end of the reactionThe synthetic route for thecatalyst synthesis is shown in Scheme 1

23 Ethylene Polymerization Ethylene polymerizationsusing the magnesium supported Ziegler-Natta catalyst wereconducted under various reaction conditions Polymeriza-tions were carried out in a 300mL semibatch autoclavereactor equipped with a mass flow meter and a temperaturecontrol unit consisting of a cooling coil and an electric heaterThe polymerization temperature was maintained withinplusmn02∘C of the set point Prior to each reaction the reactorwas purged five times with nitrogen then heated to 140∘Cunder vacuum and purged again to the set point temperatureunder nitrogen flow A volume of 200mL solvent and thetriethyl aluminium activator were transferred to the reactorand stirred for 5 minutes The amount of triethyl aluminiumwas fixed at 20mmol Catalyst slurry with hexane wasinjected into the reactor and stirred for 10 minutesThe poly-merization was performed with a continuous ethylene flowto meet the desired ethylene pressure under a stirring rate of500 rpm At the end of polymerization time the reactor wasrapidly vented and the obtained polymer was precipitated in200mL ethanol and then filtered and dried under vacuum

24 Gel Permeation Chromatography (GPC) Molecularweight and molecular weight distribution were determinedby gel permeation chromatography (GPC-IR Polymer Char)Samples were dissolved at 160∘C in 124-trichlorobenzeneand passed through three linear Polymer Laboratoriescolumns which were calibrated with polystyrene standardsand operated with a flow rate of 1mLmin Details of GPCand NMR characterization procedure have been reportedelsewhere [15]

25 Differential Scanning Calorimetry (DSC) The meltingtemperature of the polymerwas determined using differentialscanning calorimetry (DSC TA InstrumentsDSC 2920) Twoscans were performed The first melting scan was used toerase the thermal history of the sample followed by coolingwith air The second scan was done at a heating rate of10∘Cmin and used to characterize the sample

26 Dynamic Mechanical Analysis (DMA) Dynamic mech-anical analysis is a method that measures the stiffness andmechanical damping (ie storage and loss moduli in thesolid state) of a cyclically deformed material as a functionof temperature strain and frequency The combination ofstiffness and damping properties is a reflection of the uniqueviscoelastic nature of polymers The Q800 DMA from TA






1 30 5 0 60 05 90 83 88 325 3692 31 5 0 60 1 201 65 83 340 4103 34 5 0 80 05 83 49 78 310 3974 34 5 0 80 1 96 28 80 317 3965 29 5 2 60 05 81 66 30 111 3706 30 5 2 60 1 174 58 25 112 4487 30 5 2 80 05 48 32 19 89 4688 30 5 2 80 1 78 26 23 102 4439 30 5 5 60 05 49 33 19 103 54210 30 5 5 60 1 77 26 14 92 65711 33 5 5 80 05 31 19 10 57 57012 30 5 5 80 1 35 10 12 66 55013 34 10 0 60 05 385 226 167 662 39614 35 10 0 60 1 458 131 158 655 41515 33 10 0 80 05 265 161 162 617 38116 31 10 0 80 1 285 92 154 625 40617 33 10 2 60 05 239 145 35 176 50318 33 10 2 60 1 436 132 30 161 53719 31 10 2 80 05 229 148 25 127 50820 32 10 2 80 1 391 122 68 267 39321 30 10 5 60 05 202 135 40 226 56522 32 10 5 60 1 321 103 49 239 48823 30 10 5 80 05 154 103 39 169 43324 32 10 5 80 1 251 78 41 178 434












T = 60∘C

t = 30min

PC2H4= 5bar

PH2= 2bar





01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


T = 60∘C

t = 30min

PC2H4=

PH2=

004

008

012

016

020

024

028






tan120575

5bar

2bar





T = 60∘C

t = 30min

PC2H4=

PH2=

PH2=

PH2=

01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


5bar

2bar0bar

5bar


T = 60∘C

t = 30min

PC2H4=


004

008

012

016

020

024


tan120575

PH2=

PH2=

PH2=

2bar0bar

5bar

5bar








119898)













119898




0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)



Sample 119875C2H4119875H2


1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43



Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials








1 30 5 0 60 05 90 83 88 325 3692 31 5 0 60 1 201 65 83 340 4103 34 5 0 80 05 83 49 78 310 3974 34 5 0 80 1 96 28 80 317 3965 29 5 2 60 05 81 66 30 111 3706 30 5 2 60 1 174 58 25 112 4487 30 5 2 80 05 48 32 19 89 4688 30 5 2 80 1 78 26 23 102 4439 30 5 5 60 05 49 33 19 103 54210 30 5 5 60 1 77 26 14 92 65711 33 5 5 80 05 31 19 10 57 57012 30 5 5 80 1 35 10 12 66 55013 34 10 0 60 05 385 226 167 662 39614 35 10 0 60 1 458 131 158 655 41515 33 10 0 80 05 265 161 162 617 38116 31 10 0 80 1 285 92 154 625 40617 33 10 2 60 05 239 145 35 176 50318 33 10 2 60 1 436 132 30 161 53719 31 10 2 80 05 229 148 25 127 50820 32 10 2 80 1 391 122 68 267 39321 30 10 5 60 05 202 135 40 226 56522 32 10 5 60 1 321 103 49 239 48823 30 10 5 80 05 154 103 39 169 43324 32 10 5 80 1 251 78 41 178 434












T = 60∘C

t = 30min

PC2H4= 5bar

PH2= 2bar





01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


T = 60∘C

t = 30min

PC2H4=

PH2=

004

008

012

016

020

024

028






tan120575

5bar

2bar





T = 60∘C

t = 30min

PC2H4=

PH2=

PH2=

PH2=

01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


5bar

2bar0bar

5bar


T = 60∘C

t = 30min

PC2H4=


004

008

012

016

020

024


tan120575

PH2=

PH2=

PH2=

2bar0bar

5bar

5bar








119898)













119898




0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)



Sample 119875C2H4119875H2


1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43



Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials









T = 60∘C

t = 30min

PC2H4= 5bar

PH2= 2bar





01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


T = 60∘C

t = 30min

PC2H4=

PH2=

004

008

012

016

020

024

028






tan120575

5bar

2bar





T = 60∘C

t = 30min

PC2H4=

PH2=

PH2=

PH2=

01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


5bar

2bar0bar

5bar


T = 60∘C

t = 30min

PC2H4=


004

008

012

016

020

024


tan120575

PH2=

PH2=

PH2=

2bar0bar

5bar

5bar








119898)













119898




0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)



Sample 119875C2H4119875H2


1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43



Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




T = 60∘C

t = 30min

PC2H4=

PH2=

PH2=

PH2=

01 1 10 100100

200

300

400

500

600

700

800

Stor

age m

odul

us (M

Pa)

Frequency (Hz)


5bar

2bar0bar

5bar


T = 60∘C

t = 30min

PC2H4=


004

008

012

016

020

024


tan120575

PH2=

PH2=

PH2=

2bar0bar

5bar

5bar








119898)













119898




0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)



Sample 119875C2H4119875H2


1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43



Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




0

400

800

0 150 300 450 600 750Mw (kgmol)

G998400

(MPa

)

R2= 090

(a)

01

02

03

0 150 300 450 600 750Mw (kgmol)

tan120575

R2= 089

(b)

0 150 300 450 600 750

200

300

Mw (kgmol)

R2= 093

ΔE

(kJm

ol)

(c)



Sample 119875C2H4119875H2


1 5 0 60 05 325 2581 plusmn 63

2 5 0 60 1 340 2614 plusmn 85

3 5 0 80 05 310 2475 plusmn 85

4 5 0 80 1 317 2516 plusmn 94

5 5 2 60 05 111 2206 plusmn 49

6 5 2 60 1 112 2219 plusmn 95

7 5 2 80 05 89 2038 plusmn 56

8 5 2 80 1 102 2102 plusmn 69

9 5 5 60 05 103 2125 plusmn 74

10 5 5 60 1 92 2056 plusmn 78

11 5 5 80 05 57 1983 plusmn 43

12 5 5 80 1 66 2008 plusmn 52

13 10 0 60 05 662 2942 plusmn 57

14 10 0 60 1 655 2876 plusmn 32

15 10 0 80 05 617 2704 plusmn 87

16 10 0 80 1 625 2759 plusmn 54

17 10 2 60 05 176 2298 plusmn 64

18 10 2 60 1 161 2261 plusmn 56

19 10 2 80 05 127 2257 plusmn 95

20 10 2 80 1 267 2423 plusmn 57

21 10 5 60 05 226 2337 plusmn 49

22 10 5 60 1 239 2369 plusmn 46

23 10 5 80 05 169 2287 plusmn 68

24 10 5 80 1 178 2313 plusmn 43



Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials





Sample 119875C2H4119875H2

Temp Time 119879119888

119879119898





























119898119879119888 and119883





for 119879119898 119879119888 and 119883






Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials





Sample 119875C2H4119875H2


























128

136

144

0 150 300 450 600 750Mw (kgmol)

R2= 052

Tm

(∘C)

(a)

115

120

0 150 300 450 600 750Mw (kgmol)

R2= 049

Tc

(∘C)

(b)

30

60

90

0 150 300 450 600 750Mw (kgmol)

R2= 046

Xc

()

(c)


119888 and (c)119883

119888


400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials




400

800

1200

TM (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 059

(a)

50

60

TS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 097

(b)

400

800

SB (

)

0 150 300 450 600 750Mw (kgmol)

R2= 056

(c)

20

40

YS (M

Pa)

0 150 300 450 600 750Mw (kgmol)

R2= 054

(d)






4 Conclusions




119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials





119898

119879119888 and 119883





Acknowledgments


References












2TiCl4














CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials










CeramicsJournal of










Journal of


Journal of


Volume 2014




CoatingsJournal of

Advances in









Volume 2014

MaterialsJournal of

Nano

materials



Correlation of polymerization conditions with thermal and mechanical properties of polyethylenes...

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