Thermal and mechanical characterisation of Phormium tenax-reinforced polypropylene composites

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published online 20 February 2013Journal of Thermoplastic Composite MaterialsD. Puglia, C. Santulli, F. Sarasini, J.M. Kenny and T. Valente

polypropylene compositesThermal and mechanical characterisation of Phormium tenax-reinforced

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Article

Thermal and mechanicalcharacterisation ofPhormium tenax-reinforcedpolypropylene composites

D. Puglia1, C. Santulli2, F. Sarasini2,J.M. Kenny1 and T. Valente2

AbstractComposites including short and randomly arranged Phormium tenax fibres in a poly-propylene (PP) matrix (fibre content of 20, 30 and 40 wt%) were produced by twin-screwcompounding and injection moulding. They have been characterised by tensile testing,scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differentialscanning calorimetry (DSC). The results indicated that tensile modulus has been increasedby reinforcing the matrix with growing amounts of fibres, whilst the effect on tensilestrength had lower evidence. Fracture surface characterisation by SEM indicated thatdebonding and pull-out are prevalent, which suggests the need to optimise the interfacialbonding. Thermal characterisation results have shown that the main degradation peak forPP was slightly shifted to higher temperatures with the increasing fibre contents, thusimproving the thermal stability of the composites. The introduction of fibres did not resultin a significant variation in the position of the peaks for calorimetric analysis, except for themelting peak, which appeared lower for the composites with respect to the neat matrix.A slight increase in crystallinity was also measured.

KeywordsThermoplastic composite materials, mechanical properties, thermal characterisation,natural fibres, Phormium tenax

1 Materials Science and Technology, Civil and Environmental Engineering Department, Universita di Perugia,

Terni, Italy2 Department of Chemical Engineering Materials Environment, Sapienza – Universita di Roma, Roma, Italy

Corresponding author:

C. Santulli, Department of Chemical Engineering Materials Environment, Sapienza – Universita di Roma, Via

Eudossiana 18, Roma 00184, Italy.

Email: [email protected]

Journal of Thermoplastic Composite

Materials

1–11

ª The Author(s) 2013

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Introduction

The depletion of petroleum resources coupled with the adoption of stricter environ-

mental regulations is stimulating the search for materials and products with the lowest

possible environmental ‘footprint’. In this regard, biocomposites made from natural

fibres and oil-derived thermoplastic polymers, for example, polypropylene (PP) and

polyethylene (PE), can represent a suitable alternative to glass fibre-reinforced compo-

sites, providing potential value-added source of income to the agricultural community,

without extensively modifying the fabrication processes for the composites.1,2 In this

field, the use of thermoplastic composites offers several advantages compared with

that of thermosetting ones, normally including high impact resistance, damage toler-

ance, low price and easier recyclability of the polymer matrix. Currently, the main

areas of application of thermoplastic natural fibre composites are packaging, transpor-

tation and building industries. The use of non-biodegradable thermoplastic polymers as

matrix for natural fibre composites can also be intended as a step towards the applica-

tion of natural and biodegradable polymers, such as poly(lactic acid),3 polycaprolac-

tone4,5 and poly(b-hydroxybutyrate-co-valerate),6 which are being considered as

matrices for the next generation of ‘green’ composites.

PP is perhaps the most commonly used polymer to produce thermoplastic natural

fibre composites, even though other synthetic polymers, such as PE, polystyrene and

polyamides, are also common in natural fibre composites. Of all thermoplastics, PP

shows the highest potential benefits when combined with natural fibres for making

composites of industrial value.7 Several types of natural fibres have been investigated in

PP, including bast fibres such as flax,8 hemp,9 kenaf,10 jute,11 ramie,12 abaca,13 vetiver,14

leaf fibres (sisal,15 date palm16 and pineapple17) and coconut fruit skin fibres (coir18).

The resulting composites and properties have also been recently reviewed.19 Amongst

natural fibres, leaf fibres appear promising for obtaining long stretches of aligned fibres.

In case of the most used leaf-extracted fibres, that is sisal, PP matrix resulted particularly

suitable to the fabrication of composites: a number of aspects were investigated in the

literature, which included mechanical properties and effects of fire retardants20 and rheo-

logical behaviour.21

In recent years, a renewed interest has been shown for fibres extracted from the leaves

of the Phormium tenax,22,23 commonly known as harakeke or New Zealand flax, a

monocotyledonous plant which is endemic to New Zealand. Harakeke is a significant

source of fibre that has a traditional use by the Maori people as a fibre for weaving mats

and ropes.24 The use of Phormium fibres as reinforcing system in plastics has often been

proposed, in thermosets,25–28 thermoplastics29 and biodegradable thermoplastics.30–32

Thermoset-based composites are well characterised; however, limited data are still avail-

able on non-biodegradable thermoplastic-reinforced composites. In order to extend the

potential applications of P. tenax fibres, a detailed mechanical and thermal characterisa-

tion of these composites is needed.

To this purpose, this experimental work is aimed at investigating the use of untreated P.

tenax fibres as reinforcement in PP matrix. This is considered preliminary to the appli-

cation of possible compatibilisation treatments, such as maleic anhydride, to the matrix

2 Journal of Thermoplastic Composite Materials

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and is aimed in particular at the comparison of the composite properties with what has been

obtained using untreated P. tenax fibres in thermosetting matrices.28 Several properties

including mechanical and thermal properties were studied. The morphologies of the

fractured specimens were also investigated using a scanning electron microscope (SEM).

Materials and testing methods

Materials

PP homopolymer (Moplen HP 501-L) was supplied by Lyondell Basell (Ferrara, Italy).

As per supplier’s data, HP 501-L has the following properties: melt flow rate is 6 g/

10 min (230�C/2.16 kg), density is 0.9 g/cm3, tensile stress at yield is 34.0 MPa, tensile

modulus is 1500 MPa and tensile strain at break exceeds 50%. P. tenax fibres were col-

lected from New Zealand. Leaves were stripped and the hanks of fibres were washed and

then paddocked and scutched, according to the typical procedure followed for these

fibres.23 The fibres were cut to a length of 2–3 mm.

Composites manufacturing

PP composites were manufactured using a twin-screw microextruder (DSM Explore

5&15 CC Micro Compounder), and the mixing process parameters (100 r/min screw

speed, 1 min mixing time and the temperature profile would be: 170–180–190�C) were

modulated in order to optimise the final properties of material. To obtain the desired spe-

cimens for the characterisation, the molten composite samples were transferred after

extrusion through a preheated cylinder to a mini injection mould (Tmould ¼ 25�C,

Pinjection ¼ 8 bar). Composites were prepared with different amount of Phormium fibres:

specifically, a masterbatch containing 40 wt% of Phormium fibres was prepared

(PP40PH), whilst the other compositions (20 and 30 wt%, designed as PP20PH and

PP30PH, respectively) were obtained diluting the master with neat PP.

Tensile tests

Tensile tests were performed in accordance with the UNI EN ISO standard 527/2: the

type IBA (ISO 527-2 type 1BA tensile test specimens) sample was used for tensile

testing with an initial grip length of 5 mm. Loading was applied in displacement control,

using a load cell of 30 kN by means of a digital Lloyd Instrument LR 30K (Segensworth

West, Foreham, UK) with a crosshead speed of 5 mm/min. Average tensile strength,

percentage deformation at break and elastic modulus were calculated from the resulting

stress–strain curves. The measurements were performed at room temperature and at least

five samples were tested, expressing the results as mean value and SD.

Thermal and morphological characterisation

Thermogravimetric analysis (TGA) was performed on a 10-mg sample on a Seiko Exstar

6000 TGA quartz rod microbalance (Seiko Instruments, Inc., Chiba, Japan). The tests

Puglia et al. 3

3



were carried out in nitrogen flow (250 ml/min) from 30 to 900�C with a 10�C/min heat-

ing ramp.

Differential scanning calorimetric (DSC TA Q200,TA Instruments, Vimodrone,

Italy) measurements were performed in the temperature range from �25 to 250�C, at

10�C/min, performing two heating and one cooling scans. The peak temperatures for

melting and crystallisation were evaluated and the degree of crystallinity of the sample

was calculated taking as reference 191.3 J/g as heat of melting of the fully crystalline

sample according to the following equation33

Xc ¼�Hm

�H0mð1� wfibreÞ ð1Þ

where �Hm is the enthalpy of melting (Joules per grams (J/g)), �H0m is the enthalpy of

melting for 100% crystalline PP (J/g) and wfibre is the weight fraction of Phormium

fibres.

A Philips XL40 SEM (Eindhoven, The Netherlands) was used to investigate the

fracture surfaces of the composites. Prior to observation, the specimens were gold coated.

Results and discussion

To allow a sound comparison with strength and stiffness of the composites, it is note-

worthy recalling the values obtained elsewhere in a study on the tensile properties of

Phormium fibres.22 To summarise the results obtained in De Rosa et al.’s study,22 average

strength was progressively reduced, passing from 20 to 40 mm grip length, from a value of

770.68 to 465.96 MPa, whilst average Young’s modulus increased from 23.89 to

27.59 GPa, in both the cases with substantial coefficients of variation, in the region of 40%.

Figure 1 and Table 1 show typical tensile curves and properties for neat PP and PP/

Phormium composites, respectively. The results indicate that Young’s modulus

increases with increasing Phormium content. Tensile modulus has been consistently

increased by reinforcing the composite with growing amounts of fibres, whilst the effect

on tensile strength is less evident, as is the case in a large number of lignocellulosic fibre

composites. This increment in the modulus is in agreement with the findings from the

literature,26,27 where adding fibres to a thermoplastic polymer restrains the movement of

its chains, thereby increasing the stiffness. The addition of Phormium fibres did not

largely improve the tensile strength: this is also a common trend for natural fibre-

reinforced composites. It needs to be noted, however, that the addition of a 20% of short

untreated Phormium fibres to a thermosetting matrix resulted elsewhere in a consider-

able reduction in tensile strength.28

This behaviour is usually an indication of poor adhesion between natural fibres and

polymers and, as a consequence, of not very effective stress transfer across the interface.

Generally, tensile strength is much more dependent on the interfacial adhesion than the

Young’s modulus is.27

The morphology of the fracture surface of the injection-moulded specimens resulting

from the tensile tests was investigated using SEM to characterise the fracture behaviour

of PP/Phormium composites (Figure 2(a) to (f)).


4



From micrographs, it is evident that debonding and pull-out (Figure 2(a), (b), (e) and

(f)) dominate the fracture surface, thus confirming the poor interfacial bonding as pro-

posed in the discussion. Phormium fibres show a surface with no clear signs of resin

or resin particles adhering to it (Figure 2(a)) and finite gaps near the interfacial region

are present (Figure 2(b), (e) and (f)): both these evidences indicate a poor adhesion

between filler and matrix. It is also to be noted that a number of lumens appear to be

completely filled (Figure 2(d)) and the occurrence of some fibre breakage in the plane

of fracture (Figure 2(c) and (d)) suggest that some degree of adhesion has been achieved.

Despite this, as a general comment, the interface would need to be optimised for a more

effective use of the composite.

Table 1. Summary of mechanical properties of neat PP and PP/Phormium composites.

Materials Tensile strength (MPa) Young’s modulus (GPa)

PP 35.24 + 0.26 1.94 + 0.17PP20PH 36.13 + 0.50 2.94 + 0.25PP30PH 35.80 + 0.48 3.22 + 0.38PP40PH 36.45 + 0.54 4.19 + 0.36

PP: polypropylene.

Figure 1. Typical tensile curves for neat PP and PP/Phormium composites. PP: polypropylene.

Puglia et al. 5

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This is also a common trend of PP composites including lignocellulosic fibres, which

was also revealed using aspen fibres,34 using jute fibres35 and using coir fibres36; the

effect of poor wettability of the fibres36 becomes more severe for higher fibre contents.

In this respect, the results obtained with untreated Phormium fibres in PP do appear quite

promising for the further application of a limited amount of chemical treatments.

The thermal stability of neat PP- and PP-based composites was investigated in terms

of weight loss as a function of temperature by TGA. In Figure 3(a), TGA thermograms

and in Figure 3(b) DTG curves are reported for PP and PP/Phormium composites. An

enlarged view of TGA of the Phormium fibres is also provided between 150 and

Figure 2. Scanning electron micrographs of (a–d) PP 40 wt% Phormium composites; (e and f) PP30 wt% Phormium composites. PP: polypropylene.


6



200�C (Figure 3(c)), which indicates that the mass decrease is very limited, so as to show

that the fabrication of the composite, involving the application of a 190�C heating pro-

cess for 1 min, does not lead to a substantial degradation of the Phormium fibres.

In P. tenax fibres, the decomposition occurs in two main stage processes as shown in

Figure 3(b).11 The first stage process (200–305�C) is the thermal depolymerisation of

hemicellulose, pectin and the cleavage of glycosidic linkages of cellulose;11 the second

stage process (305–370�C) is attributed to the decomposition of the a-cellulose,11 whilst

the decomposition of lignin occurred slowly within the whole temperature range. This

(a) (b)

0

20

40

60

80

100

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

100 200

150 160 170 180 190 200

300 400 500 600 700 800 900

TG

DTG

Res

idua

l mas

s (%

) DT

G (µ

g/µgi m

in)

Temperature (°C)

85

85,2

85,4

85,6

85,8

86

Untreated phormium

Res

idua

l m

ass

(%)

Temperature (°C)

(c)

Figure 3. Residual mass (a) and differential residual mass (b) obtained from the TGA analysis forneat PP and PP–Phormium composites and (c) Phormium fibres. TGA: thermogravimetric analysis;PP: polypropylene.

Puglia et al. 7

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was attributed to the complex structure of lignin. According to the TGA curve of the

fibre and not considering the moisture loss at the beginning of the test, the char residue at

600�C of the fibre is approximately 33 wt%. Neat PP has the degradation peak at 460�C:

this was shifted to higher temperatures for the 20, 30 and 40 wt% PP/Phormium com-

posites (Figure 3(c)). Therefore, the system fibre–matrix degrades later than the neat

resin. As a consequence, the thermal stability of the composite is slightly higher than that

of fibre and matrix. It is also evident from Figure 3(a) that residual mass at the end of the

test increases with the fibre content, since the char residue of the Phormium-based

composites at 600�C is higher for the PP40PH system with higher fibre content. The char

value at this temperature for the composites is comparable with the theoretical char

residue obtained from the combustion of the fibre at different weight contents in the

same test condition.

From the point of view of DSC characterisation, the introduction of fibres did not

result in a significant variation in the position of the peaks, except for the melting peak,

which appears lower for the composites with respect to the pure matrix. A slight

increase in crystallinity was also measured, as detected from the measurements of

crystallinity in the second heating scan (Xc ranged from 47.3% to 58.4% for the neat

resin and PP 40 wt% Phormium composites, respectively). In Figure 4, which shows

DSC thermograms obtained from the cooling scan, the nucleating effect of fibres is

evident.

In general, the introduction of short-untreated P. tenax fibres in PP composites does

compare well with that of other lignocellulosic fibres in non-biodegradable thermoplas-

tic matrices, which indicates some potential for their use in semi-structural large volume

Figure 4. Heat flow for the second heating (a) and the cooling cycle (b) obtained from the DSC forneat PP- and PP-based composites. DSC: differential scanning calorimetry. PP: polypropylene.


8



applications. This is suggested by the fact that the mechanical properties of the compo-

site do not decrease with respect to the neat polymer, despite the fibres are not compa-

tibilised to provide a sound interface with PP.

Conclusions

This work on composites obtained introducing P. tenax fibres in a PP matrix gives

promising results for the applicability of these composites, where a larger stiffness and

increased thermal stability are required. In general, using short Phormium fibres in a

randomly oriented arrangement did result in a highly positive effect on composite tensile

modulus and thermal stability and in a limited modification of tensile strength and of the

thermal profile of PP. The main area of concern for these composites appears to be

represented by the need to improve the interface strength, since at higher fibre content, a

weak fibre–matrix link leads to diffuse fibre pull-out and debonding. Future studies will

involve a comparison of these results with those obtained by compatibilising the matrix

with the fibre, for example, by maleic anhydride grafting.

Funding

This research received no specific grant from any funding agency in the public, com-

mercial, or not-for-profit sectors.

Acknowledgement

The authors acknowledge the contribution of Dr Antonio Iannoni to the manufacturing of

the composites tested in this work.

References

1. Mohanty AK, Misra M and Hinrichsen G. Biofibers biodegradable polymers and biocompo-

sites: an overview. Macromol Mater Eng 2000; 276/277: 1–25.

2. Bismarck A, Baltazar-Y-Jimenez A and Sarikakis K. Green composites as panacea? Socio-

economic aspects of green materials. Environ Dev Sust 2006; 8: 445–463.

3. Graupner N, Herrmann AS and Mussig J. Natural and man-made cellulose fibre-reinforced

poly(lactic acid) (PLA) composites: an overview about mechanical characteristics and appli-

cation areas. Composites A 2009; 40: 810–821.

4. Cyras VP, Martucci JF, Iannace S and Vazquez A. Influence of the fiber content and the pro-

cessing conditions on the flexural creep behavior of sisal–PCL–starch composites. J Thermo-

plas Compos Mater 2002; 15: 253–265.

5. Arbelaiz A, Fernandez B, Valea A and Mondragon I. Mechanical properties of short flax fibre

bundle/poly("-caprolactone) composites: influence of matrix modification and fibre content.

Carbohyd Polym 2006; 64: 224–232.

6. Singh S, Mohanty AK, Sugie T, Takai Y and Hamada H. Renewable resource based biocom-

posites from natural fiber and polyhydroxybutyrate-co-valerate (PHBV) bioplastic. Compo-

sites A 2008; 39: 875–886.

7. Pickering KL Properties and performance of natural-fibre composites. Cambridge, UK:

Woodhead Publishing Ltd, 2008.

Puglia et al. 9

9



8. Cantero G, Arbelaiz A, Llano-Ponte R and Mondragon I. Effects of fibre treatment on

wettability and mechanical behaviour of flax/polypropylene composites. Compos Sci Technol

2003; 63: 1247–1254.

9. Pracella M, Chionna D, Anguillesi I, Kulinski Z and Piorkowska E. Functionalization,

compatibilization and properties of polypropylene composites with hemp fibres. Compos Sci

Technol 2006; 66: 2218–2230.

10. Zampaloni M, Pourboghrat F, Yankovich SA, Rodgers BN, Moore J, Drzal LT, et al. Kenaf

natural fiber reinforced polypropylene composites: a discussion on manufacturing problems

and solutions. Composites A 2007; 38: 1569–1580.

11. Gassan J and Bledzki AK. Possibilities to improve the properties of natural fiber reinforced plas-

tics by fiber modification jute polypropylene composites. Appl Compos Mater 2000; 7: 373–385.

12. He LP, Tian Y and Wang LL. Study on ramie fiber reinforced polypropylene composites (RF-

PP) and its mechanical properties. Adv Mater Res 2008; 41–42: 313–316.

13. Rahman MR, Huque MM, Islam MN and Hasan M. Mechanical properties of polypropylene

composites reinforced with chemically treated abaca. Composites A 2009; 40: 511–517.

14. Ruksakulpiwat Y, Suppakarn N, Sutapun W and Thomthong W. Vetiver–polypropylene com-

posites: physical and mechanical properties. Composites A 2007; 38: 590–601.

15. Jayaraman K. Manufacturing sisal–polypropylene composites with minimum fibre degrada-

tion. Compos Sci Technol 2003; 63: 367–374.

16. Abu-Sharkh BF and Hamid H. Degradation study of date palm fibre/polypropylene compo-

sites in natural and artificial weathering: mechanical and thermal analysis. Polym Degrad

Stabil 2004; 85: 967–973.

17. Arib RMN, Sapuan SM, Ahmad MMHM, Paridah MT and Khairul Zaman HMD. Mechanical

properties of pineapple leaf fibre reinforced polypropylene composites. Mater Des 2006; 27:

391–396.

18. Lai CY, Sapuan SM, Ahmad M, Yahya N and Dahlan KZHM. Mechanical and electrical prop-

erties of coconut coir fiber-reinforced polypropylene composites. Polym Plast Technol Eng

2005; 44: 619–632.

19. Malkapuram R, Kumar V and Negi YS. Recent development in natural fiber reinforced poly-

propylene composites. J Reinf Plast Compos 2009; 28: 1169–1189.

20. Suppakarn N and Jarukumjorn K. Mechanical properties and flammability of sisal/PP compo-

sites: effect of flame retardant type and content. Composites B 2009; 40: 613–618.

21. Joseph PV, Oommen Z, Joseph K and Thomas S. Melt rheological behaviour of short

sisal fibre reinforced polypropylene composites. J Thermoplas Compos Mater 2002;

15: 89–114.

22. De Rosa IM, Kenny JM, Puglia D, Santulli C and Sarasini F. Tensile behavior of New Zealand

flax (Phormium tenax) fibers. J Reinf Plast Compos 2010; 29: 3450–3454.

23. Krause Sammartino LM, Aranguren MI and Reboredo M. Chemical and mechanical charac-

terization of two South American plant fibers for polymer reinforcement caranday palm and

Phormium. J Appl Polym Sci 2010; 115: 2236–2245.

24. Cruthers NM, Carr DJ, Laing RM and Niven BE. Structural differences among fibers from six

cultivars of harakeke (Phormium tenax, New Zealand flax). Text Res J 2006; 76: 601–606.

25. Le Guen MJ and Newman RH. Pulped Phormium tenax leaf fibres as reinforcement for epoxy

composites. Composites A 2007; 38: 2109–2115.

26. Newman RH, Clauss EC, Carpenter JEP and Thumm A. Epoxy composites reinforced with

deacetylated Phormium tenax leaf fibres. Composites A 2007; 38: 2164–2170.

27. Newman RH, Le Guen MJ, Battley MA and Carpenter JEP. Failure mechanisms in composites

reinforced with unidirectional Phormium leaf fibre. Composites A 2010; 41: 353–359.


10



28. De Rosa IM, Santulli C and Sarasini F. Mechanical and thermal characterization of epoxy

composites reinforced with random and quasi-unidirectional untreated Phormium tenax leaf

fibers. Mater Des 2010; 31: 2397–2405.

29. Jayaraman K and Halliwell R. Harakeke (Phormium tenax) fibre–waste plastics blend compo-

sites processed by screwless extrusion. Composites B 2009; 40: 645–649.

30. De Rosa IM, Iannoni A, Kenny JM, Puglia D, Santulli C, Sarasini F, et al. Poly(lactic acid)/

Phormium tenax composites: morphology and thermo-mechanical behaviour. Polym Compos

2011; 32(9): 1362–1368.

31. Fortunati E, Puglia D, Santulli C, Sarasini F and Kenny JM. Biodegradation of Phormium

tenax/poly/lactic acid) composites. J Appl Polym Sci 2012; 125: E562–E572.

32. Duchemin B, Van Luijk K and Staiger MP. New Zealand flax (Phormium tenax) reinforced

eco-composites. In: Proceedings of the 2nd international conference on eco-composites,

Queen Mary, University of London, London, UK, 2003.

33. Wunderlich B. Macromolecular physics, vol. 3: crystal melting. New York, NY: Academic

Press, 1980.

34. Xue Y, Veazie DR, Glinsey C, Horstemeyer MF and Rowell RM. Environmental effects on

the mechanical and thermomechanical properties of aspen fiber polypropylene composites.

Composites B 2007; 38: 152–158.

35. Rashed HMMA, Islam MA and Rizvi FB. Effects of process parameters on tensile strength of

jute fiber reinforced thermoplastic composites. J Naval Architect Mar Eng 2006; 3: 1–6.

36. Asad Akhter MD, Nazrul Islam MD and Gafur MA. PP-coir composites–its fabrication, pro-

cess parameters and properties. In: Proceedings of the 3rd BSME-ASME international confer-

ence on thermal engineering, Dhaka, Bangladesh, 20–22 December 2006.

Puglia et al. 11

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