THE EFFECT OF TRANS-POLYOCTYLENE RUBBER (TOR) AS COMPATIBILIZER ON RECYCLED NITRILE GLOVE (NBRr) FILLED

NATURAL RUBBER COMPOUND: TENSILE TEST AND MORPHOLOGY STUDIES

M.H.Fatin1,a, N.Z.Noriman1,2,c, S. T. Sam1. d , M.Z.Salihin1,e, Z. Norhafizah1,b,

N.Z. Nik Yahya1f

1 Center of Excellence Geopolymer and Green Technology (CEGeoGTech), School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), Kompleks Pengajian Jejawi 2, 02600 Arau,

Perlis, Malaysia.

2 Faculty Engineering Technology (FETech), Engineering Center and Innovasion, Universiti Malaysia Perlis (UniMAP), Aras 1, Bangunan Pentadbiran. Kampus Pauh Putra, 02600 Arau,

Perlis, MALAYSIA.

anurfatinmohdhaniff@gmail.com,bhafizah909@gmail.com cniknoriman@unimap.edu.my, dsam.sunting@gmail.com esalihin@unimap.edu.my , fnikzakariany90@gmail.com,

Keywords: Recycled Nitrile glove (NBRr) and ENR 50 compounds, Trans-polyoctylene Rubber (TOR),Tensile Properties, morphology

ABSTRACT: Tensile test and morphology studies were performed to determine the influences of

Trans-polyoctylene Rubber (TOR) as compatibilizer of NBRr filled ENR 50 with composition of 15

phr. Fine size (300µm-700µm) of NBRr was used as fillers. Both uncompatibilized and

compatibilized NBRr/ENR 50 were prepared using two roll mill at room temperature with different

php of 1.0, 1.5, 2.0, 2.5 and 3.0. It can be observed that tensile strength and modulus of elasticity

were decreased as increased in TOR loading before started to increased at 1.5 up to 3.0. Meanwhile,

the increment in the value of elongation at break when increased in the addition of TOR. The

scanning electron microscopy (SEM) of the tensile surface fracture of increased TOR loading

illustrated a better adhesion and dispersion in comparison of low amount of TOR loading.

1.0 INTRODUCTION

Rubber waste appeared to have a low percentage by weight in urban waste streams in both

industrialized and less-industrialized area. The part of the rubber waste is usually collected

separately, directly from generators such as petrol station, garages and junkyards, and it seen to

have a limited number of items and materials. The data concerning about the specific composition

of rubber waste is limited and the production data of for the rubber product had gave an idea of

product dominate. Recycling is the process of reduction, reuse, recyclable, recovery and reclaim the

materials. The process is such a way that will save the nature and hence added the value of the

product [1].

Compatibilizer is an agent which will perform the blending as it criteria to compatibilize the

two components. Most polymers blends are often undergo phase separation, with poor adhesion

between the matrix and dispersed phase. A blend can be technologically compatible, if the two

polymers have similar intermolecular forces or if they interact or react at the phase interface. Hence,

compatibilization may be described as a process that reduces the enthalpy of mixing or making it

negative. This is best accomplished either by adding a third component, called a compatibilizer, or

Applied Mechanics and Materials Vol. 679 (2014) pp 305-310 Submitted: 13.08.2014© (2014) Trans Tech Publications, Switzerland Accepted: 13.08.2014doi:10.4028/www.scientific.net/AMM.679.305

All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,www.ttp.net. (ID: 14.1.198.52-04/10/14,15:29:07)

by enhancing the interaction of the two component polymers, chemically or mechanically. This is

an importance step to develop a stable morphology that will facilitate smooth stress transfer from

one phase to the other and allow the product to resist failure under multiple stresses [2].

In this project, waste of nitrile glove obtained in medical industry is used as recycled rubber

to fill in natural rubber compounds. The recycled nitrile glove filled natural rubber compound is

study on the effect of tensile test and morphology in different formulations of TOR in order to

improve the properties of the compounds.

2.0 EXPERIMENTAL

2.1 Materials

Some of the raw material that commonly used in mixing and compounding of rubber listed in the

Table 1. Raw materials function and supplier stated.

Table 1: List of raw materials, their functions and suppliers.

Raw material Function Supplier

ENR 50 Elastomer RRIM Guthrie Group Sdn. Bhd.

NBRr Elastomer Top Glove (M) Sdn. Bhd

Sulphur Vulcanizing agent Anchor Chemical Co (M) Ltd.

Zinc oxide Activator Anchor Chemical Co (M) Ltd.

Stearic acid Accelerator Anchor Chemical Co (M) Ltd.

N-cyclohexyl-2-

benzothiazole

sulphonamide (CBS)

Accelerator Anchor Chemical Co(M) Ltd.

Talc Filler Anchor Chemical Co(M) Ltd.

TOR Compatibilizer Eronik, Germany.

2.2 Compounding, Cure Characteristics and Vulcanization

2.2.1 Effect of NBRr filled ENR 50

Compounding ratio between NBRr glove and ENR 50 vulcanizate was shown in the Table

2. The properties of tensile and morphology on tensile fracture surface was examined.

Table 2: Formulation of NBRr filled ENR 50.

Material phr

rN0 rN05 rN15 rN25 rN35 rN50

ENR 50 100 100 100 100 100 100

NBRr 0 5 15 25 35 50

Talc 20 20 20 20 20 20

ZnO 5 5 5 5 5 5

Stearic acid 2 2 2 2 2 2

Sulphur 2 2 2 2 2 2

CBS 1 1 1 1 1 1

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2.2.2 Effect of TOR as a compatibilizer on NBRr filled ENR 50

Addition of compatibilizer TOR in the compounding of NBRr glove and ENR 50

vulcanizate is shown in the Table 3. The properties of tensile and morphology on tensile fracture

surface were been examined.

Table 3: Formulation of TOR on NBRr filled ENR 50

Material Phr

rN05 rN15 rN25 rN35 rN50

ENR 50 100 100 100 100 100

NBRr Optimum ratio of 15 phr

Talc 20 20 20 20 20

ZnO 5 5 5 5 5

Stearic acid 2 2 2 2 2

Sulphur 2 2 2 2 2

CBS 1 1 1 1 1

TOR 1 1.5 2 2.5 3

2.3 Tensile test

After the rubber compound has undergo compression molding, a flat sheet of 2 mm thick is

used for a tensile test based on ASTM D412-93. Rubber compound in a shape of dumbbell is cut

using Wallace die cutter according to ASTM D638 [3].

2.5 Morphology of tensile fracture surface by Scanning Electron Microscope (SEM)

Samples that had already undergone tensile test were collected and subjected to the scanning

electron microscope (SEM) model JEOL JFC6460LA. The dumbbell shape samples were cut and

coated with a thin layer (1.5 – 3.0 nm) of gold or gold-palladium inside a “sputter coater” machine.

3.0 RESULTS AND DISCUSSIONS

3.1 Tensile Properties.

Tensile strength of the compound in addition of TOR increases gradually from 1 phr to 3 phr

TOR loading showed in the Figure 1. The addition of TOR enhanced the tensile strength due to

ability of TOR to crosslink and provide a rubberised matrix in the compound that prevent premature

cracking, rutting and shoving. TOR acting as a processing aid and rubber component itself was

incorporated into NBRr filled ENR 50. The highly flexible and liable S-S linkages area capable of

withstanding high stresses [4]. The addition of TOR also increased the adhesion at the interface of

NBRr filled ENR 50. From the figure, it also showed that NBRr filled ENR 50 without the addition

of TOR exhibited higher tensile strength than the compound with 1 to 1.5 phr TOR loading but low

tensile strength than the compound with 2 to 3 phr TOR loading. The lower tensile strength at low

TOR loading because of the fracture point occurred at the part with no presence of TOR. This was

due to the poor distribution of TOR at all part of compound when added with low quantity.

Applied Mechanics and Materials Vol. 679 307

Figure 1: Tensile strength (TS) on the effect of compatibilizer (TOR) on NBRr filled ENR 50.

Modulus (M100) of the vulcanizate with addition of TOR range from 1 to 3 phr TOR loading

increase continuously showed in the Figure 2. Addition of the compatibilizer TOR improved the

modulus (M100) respectively. It believed that TOR added has contributed to an efficient stress

transfer in the compound. This was due to the incorporation of NBRr in ENR 50/NBRr compound

that enhanced the crosslinking density properties of the compound. At low TOR loading of 1 phr to

1.5 phr, modulus (M100) of NBRr filled ENR 50 showed a lower value compared to the NBRr

filled ENR 50 without TOR loading. This was due to the decreasing ENR 50 content and small

quantity of TOR in the compound that contributed to the low modulus. The low TOR loading

cannot react homogenously in the compound. Thus, unstable dispersion of TOR happened in the

compound.

Figure 2: Modulus (M100) on the effect of compatibilizer (TOR) on NBRr filled ENR 50.

Figure 3 indicated the elongation at break (Eb) on the effect of compatibilizer on NBRr

filled ENR 50. The result illustrates an increment in the value of elongation at break (Eb) when

increased in addition of compatibilizer TOR in the compound. The addition of TOR provided high

elasticity and flexibility to the compound. NBRr filled ENR 50 with 3 phr TOR loading has an

optimum elongation at break (Eb). TOR has said to be effective especially in case of lower level

acrylonitrile. The molecular motion of NBRr droplet phase was suppress by encapsulation action of

TOR [5]. From the figure, NBRr filled ENR 50 without the addition of TOR exhibited the lowest

0,0

1,0

2,0

3,0

4,0

5,0

6,0

control 1.0 1.5 2.0 2.5 3

Te

nsi

le S

tre

ng

th (

Mp

a)

TOR Loading (phr)

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

control 1.0 1.5 2.0 2.5 3.0

M1

00

(Mp

a)

TOR Loading (phr)

308 Engineering and Technology Research

value of elongation at break (Eb). Eventhough both ENR 50 and NBRr are polar rubber, they seem

to have low compatibility between each other. Thus, this causes a low elongation at break (Eb) in

the absence of TOR.

Figure 3: Elongation at break (Eb) on the effect of compatibilizer (TOR) on NBRr filled ENR 50.

3.4 Morphological Properties

Figure 4 showed SEM micrograph of tensile fracture surface of NBRr filled ENR 50 with

x100 magnification at (a) 1 phr TOR loading and (b) 3 phr TOR loading. For figure (a), it showed

small holes caused by the detachment of NBRr filler. This was due to the poor dispersion of NBRr

filler with ENR 50. For Figure (b) NBRr contributed to the rough surface due to the high addition

of TOR in NBRr filler inside the rubber matrix. Meanwhile, Figure 5 showed SEM micrograph of

tensile fracture surface of NBRr filled ENR 50 with x1000 magnification at (a) 1 phr TOR loading

and (b) 3 phr TOR loading. In figure (a) showed the formation of holes inside the rubber matrix.

This was due to the detachment of NBRr filler respectively. Figure (b) showed that fine size NBRr

filler gave a rougher surface and well bonded inside the rubber matrix. Therefore, it prove that

NBRr filled ENR 50 at higher TOR loading at (3 phr TOR) required more energy to break the

sample.

(a) (b)

Figure 4: SEM micrograph of tensile fracture surface of NBRr filled ENR 50 with x100

magnification (a) 1 phr TOR and (b) 3 phr TOR

0

100

200

300

400

500

600

700

800

900

1 000

control 1.0 1.5 2.0 2.5 3.0

Elo

ng

ati

on

at

bre

ak

(%

)

TOR Loading (phr)

Applied Mechanics and Materials Vol. 679 309

(a) (b)

Figure 5: SEM micrograph of tensile fracture surface of NBRr filled ENR 50 with x1000

magnification at (a) 1 phr TOR (b) 3 phr TOR

4.0 CONCLUSIONS

Addition of compatibilizer TOR in NBRr filled ENR 50 improved the tensile properties of

the vulcanizate. The role of TOR as a compatibilizer increases the tensile strength of the vulcanizate

respectively. The increment in addition of TOR increases the tensile properties. Therefore, the

vulcanizate required high energy to break the bond.

The Scanning Electron Microscopic (SEM) observed a rough surface and large increases in

formation of matrix tear line at high addition of TOR. The surface also seems to have no

detachment and NBRr embedded tightly inside the ENR 50 vulcanizate.

As a conclusion, the addition of TOR enhanced the properties of vulcanizate. It tends to

form a good compatibility between the rubber matrixes of different phase. Thus, TOR is a suitable

compatibilizer between NBRr and ENR 50 vulcanizate.

5.0 REFERENCES

[1] A. Rehan, V.D.K. Arnold, K. Inge, Rubber Waste : Urban Solid Waste Series 3,pp.15-

16,Gouda, Netherland. (1996).

[2] K.D. Sadhan, Handbook of Rubber Recycling: Rubber Recycling by Blending with

Plastics, Taylor & Francis Group. (2005).

[3] R. Ahmed, Klundert, V.D. Arnold, I. Lardinois, Rubber Waste, Options for Small-scale

Resources Recovery, TOOL Publications and WASTE, A book at small-scale rubber

recyclers in developing countries. (1996).

[4] M. Awang, H. Ismail, M.A. Hazizan, Polypropylene-based blends containing waste tire

dust: Effects of trans-polyoctylene rubber (TOR) and dynamic vulcanization, Polymer

Testing, 26 (6), (2007). pp.779-787.

[5] N. Changwoon, Effects of trans-polyoctylene rubber on rheological and green tensile

properties of natural rubber/acrylonitrile-butadiene rubber blends, Polymer International,

Vol 51, (2002). pp.245-252.

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