MAH grafted EPM is a highly potential compatibiliser in EPDM based blend. This studyjs

focusing on synthesizing peroxide-initiated MAH-g-EPM via melt grafting using a Haake

intemal mixer at high shear rate. The effect of MAH and dicumyl (DCP) percentage on the

grafting efficiency of MAH onto EPM chains was carried out through a 2-level factorial

experimental design using the Design Expert 6.0.5 software. The MAH and DCP content

were varied in the range of 1-5 phr and 0.1-0.3 phr, respectively. The grafting parameters

were fixed at temperature of 180°C, rotor speed of 60 rpm for 5 minutes. The grafting

efficiency was determined by Fourier Transform Infrared spectroscopy analysis based on

cumulative absorbance of anhydrides characteristic peaks. It was observed to be highly

'j 'f influenced by the amount of MAH and DCP and the optimum funtionalisation was achieved

at 5 phr MAH and 0.3 phr peroxide additio

Abdul Razak, Jeefferie

Kasim, Mohd Shahir

Mahamood, Mazlin Aida

Mohamad, Noraiham

Mohd Abid, Mohd Asyadi Azam

Muchtar, Andanastuti

Mustafa, Nuzaimah

Qumrul, Ahsan

Shueb, Mohammed Iqbal

Toibah, Abd Rahim

Yaakob, Mohd Yuhazri

Yaakub, Juliana

English

Universiti Teknikal Malaysia Melaka (UTeM) Repository

rj_....L....LKeywords: Ethylene-Propylene Copolymer (EPM), melt functionalisation, maleic anhydride,grafting parameters, rubber blends incompatibility.GetMAH grafted EPM is a highly potential compatibiliser in EPDM based blend. This studyjsfocusing on synthesizing peroxide-initiated MAH-g-EPM via melt grafting using a Haakeintemal mixer at high shear rate. The effect of MAH and dicumyl (DCP) percentage on thegrafting efficiency of MAH onto EPM chains was carried out through a 2-level factorialexperimental design using the Design Expert 6.0.5 software. The MAH and DCP contentwere varied in the range of 1-5 phr and 0.1-0.3 phr, respectively. The grafting parameterswere fixed at temperature of 180°C, rotor speed of 60 rpm for 5 minutes. The graftingefficiency was determined by Fourier Transform Infrared spectroscopy analysis based oncumulative absorbance of anhydrides characteristic peaks. It was observed to be highly~~/', ~'j 'f influenced by the amount of MAH and DCP and the optimum funtionalisation was achievedat 5 phr MAH and 0.3 phr peroxide addition.Corresponding author: noraiham((i),utem.edu.my4RadiationProcessing Technology Division, Malaysia Nuclear Agency, 43600 Bangi,Selangor, MalaysiaUniversiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia3Facultyof Engineering & Built Environment,Universiti Teknikal Malaysia Melaka, Durian Tunggal, 76100 Melaka, Malaysia2Faculty of Science& Technology, fVIv\ l "'.t't'~L' ?1Faculty of Manufacturing Engineering,N. Mohamad, M.A. Mahamood', Y. Juliana', A.R. Jeefferie<, A. Muchtar', M.l. Shueb",M.S. Kassim', M.A. Azam', Y. Mohd Yuhazri', N. Mustafa', A.R. Toibah!, T.R. Sahroni', Q.Ahsan'FUNCTIONALISATIONOF ETHYLENE-PROPYLENE COPOLYMER(EPM) BY MELT GRAFTING OF MALEIC ANHYDRIDE (MAH) USINGHIGH SHEAR INTERNAL MIXER..Lj_Blending of two or more polymers produces material with improved properties, better'r nprocessibility and superiorj-ompared to its original phases at/very minimal cost1,2,3.Forinstance, rubber blends are widely utilised in automobile parts like springs and snubbers, hoseand belting, seals and bearing 4, engine mounts", gears gaskets, pneumatic tires and tubes",Previous research works have reported some attractive elastomers blends such asNRJEPDM6,7, BRJEPDM8, NBRJEPDM7,8, NRJBRJEPDM9, NRJENRlO, NRJSBRJBR11,NRJIIR12 and NRJEPM1,13,14. Among these blends, NRJEPDM shows great potential IIIoutdoor-application due to excellent thermal, chemical and ozone resistance, as well asattractive dynamic properties'v':'. For example, poor outdoor properties of high unsaturatedrubbers such as NR can be significantly improved by the incorporation of EPDM withoutsacrificing their unique mechanical properties".According to Kothandararnarr , a successful NRJSBR blend may exhibits discreteareas of each elastomers in the range of ~O.5 microns'. However, in most cases elastomersare immiscible due to their high molecular weight chains, viscosity mismatch, differences incure rate, different saturation level, and polarity mismatch/-':'. Immiscibility produce blendswith poor mechanical properties. Due to that, compatibilisation is required to improvecompatibility of the blends'<. In El-Sabbagh" and Zhang9 findings, the incorporation of asmall amount of compatibiliser reduces the domain size of the dispersed phase, and thusenhances the compatibility and rheological properties of the blend.Generally, compatibilisation can be conducted either physically or chemically.Physical compatibilisation is achieved by the addition of third polymer into the elastomersblends to form a block or grafted copolymers'', The third polymer acts as surfactant where thehigh polar component of the blend will attract to the high polar part of the compatibiliser andvice versa. The third polymer can be polybutadiene rubber (BR)6, chlorinated rubber or SBR6and ENRI6,17. d~e-to MohamadJ6, ENR is frequently used as compatibilizer in producingnatural rubber nanocomposites due to its high polarity. On the other hand, chemicalcompatibilisation is achieved by addition of reactive or functional compound into the blendsin order to induce in-situ chemical reaction between the blends cornponents'", For chemicalcompatibilisation, maleic anhydride (MAH) from vinyl monomers group is often used to begrafted onto a polymer either through free radical copolymerisation or melt grafting. Theanhydride group will grafted to polar polymer and form functionalised compound=' 4,15.(According to Stuartl9 and Segneanu et a1.20,MAH grafting is identified by a distinctive\Introduction1.3 gil 0 min, and density of 0.862 g/cm' was supplied by Exxon Mobil Chemical. Maleicanhydride (C4H203) with purity of 99% and weight average molecular weight, M; of 98.06g/mol was supplied by Scharlau. Bis(a,a-dimethylbenzyl)peroxide (DCP) as free radicalExperiments"Ethylene Propylene Copolymer (EPM) with propylene content of 80%, melt flow index ofIIJJMelt compounding VIa internal mixer is a widely used technique to prepare forpolymer compounds and blends'". Uniform compounding is achieved when the materials aresheared between two rotors that are circulating in an opposite manner in the mixer chamber.High shear forces are needed for a blending process in order to overcome the high viscosityof melted elastomers'. Nevertheless, melt grafting via internal mixer is a rarely use techniqueto produce MAH-g-EPM compatibiliser.This study is an effort to measure the efficiency of melt grafting through high shearmelts compounding using a Haake internal mixer. It is aimed to prepare MAH-g-EPM viaperoxide-initiated melt grafting of anhydride onto EPM backbone as well as to detect theoptimum formulation of MAH-g-EPM using a mathematical and statistical technique.Response Surface Methodology is selected due to less time consuming and has the ability ofdetecting the true optimum of the factor". Incorporation of low molecular weight peroxide isexpected to activate the inert polyolefin and thus induce functionalisation ofEPM with MAH.carbonyl band region at several characteristic infrared bands; (1840-1800), (1780-1740) and(1300-11 00) cm-I which correspond to anhydrides stretching regions (-CO-O-CO-). Inaddition, a strong C-O stretching band of open-chain and cyclic anhydrides structures may beobserved near 1150 cm-I or ranging around 1150-1300 cm-I, respectively. Furthermore,based on Ismail et al.21, the grafting of MAH is also indicated by the presence of band at(1710-1719) and (1770-1792) cm-1 which attributed to C=O symmetric stretching bonds.Examples of functionalised compatibiliser for EPDM based blend are EPDM-g-PVAcI4,MMA-g-EPDM13, EVA-g-MAH, mercapto-functionalised EVA, mercapto-modified EPDMand MAH-g-EPDM9,22.MAH-g-EPM is a potential compatibiliser and similar with MAH-g-EPDM in term ofstructure except for the double bond. Refering to Zhang9, addition of MAH-g-EPM inNRlBRlEPDM blends increases the chemical reactivity of the blends due to the increase inpolarity of the EPDM. This is due to the presence of maleic anhydride group which providesextra polarity to the EPDM and be well linked to high polar double bond of NR diene rubberphase.I__j_MAH grafting efficiency characterisation through FTIR spectroscopyMAH-g-EPM thin films of 200-250 urn thickness were prepared by compression mouldingusing a laboratory hydraulic hot moulding. Machine parameters for hot pressing were set at150°C temperature, 5MPa (or equivalent to 51 kg/em.') pressure and 10 min. The films werethen dried in an air drying oven for 10 hours at 75°C in order to draw off the umeacted MAHfrom the thin films. The possible interaction of MAH with EPM was determined usingJASCO FTIR 6100 Spectrometer machine through thin film-FTIR approach. The FTIRspectra were collected from the MAH-g-EPM thin films in the transmission mode, and wererecorded in a range of between 2000-400 em" with a 4cm-1 resolution and 50 scans. Differentfunctional groups and structural features which present in the molecules of MAH-g-EPMabsorbed energy at the characteristic frequencies. The intensity of absorption is the indicationof the bond strength and structural geometry in the molecules24• In this experiment, FTIRspectra were used to identify the functional groups present on EPM backbone after theAll the three components were initially dry mixed in a weighing tray before immediatelybeing introduced into the mixing chamber. The mixing was performed until 5 minutes for acomplete peroxide reaction and to produce homogenous blend. The generated compoundswere then conditioned for FTIR analysis.The experiment for this study implemented 2-level factorial design using DesignExpert software. The 2-level factorial design for two independent variables, with threereplications at centre point leads to a total of seven set of experiments. In this experiment, thecontents of MAH and DCP were varied in the range of 1-5 phr and 0.1-0.3 phr, respectively;whereas content of EPM was kept constant.I ~\ ."----------------- Equation 1mtota'= p x V chamber X 0.7 fill factor/"Iingredients capable by the mixing chamber;initiator and crosslinking agent with purity of 98%, , M;of 27037 g/mol and density of 102g/cnr' was supplied by Merck.MAH grafted EPM compounds were prepared by blending 100 phr EPM, 1-5 phrvaried amount of MAH and 0.1-0.3 phr varied amount of DCP in a Haake internal mixer attemperature of 180°C, rotor speed of 60 rpm and mixing period of 5 minutes. The internalmixer used was equipped with a Banbury-type rotor blade and a mixing chamber capable of78 crrr' volume, with fill factor of 0.70. Equation 1was applied to calculate the total mass ofwere obvious differences between infrared spectrum of MAH-g-EPM if compared to pureEPM as well as pure MAH. The MAH-g-EPM spectrum shows the presence of few newpeaks, increase absorbance in few MAH characteristic peaks and strong peaks identificationto ethylene propylene structure except for minor broadening due to peaks overlapping. Bytaking into consideration the increment of absorbance at typical anhydride characteristicpeaks; (1840-1800), (1780-1740), (1300-1100), (1710-1719) and (1770-1792i1,l9,20, the,~grafting of MAH onto EPM backbones was confirmed. However, it is important to ensurethat the peak height of absorbance values for each selected band were measured byemploying an appropriate baseline in order to get a reliable and accurate infrared datall.Based on the FTIR peak absorbance intensity data of each MAH-g-EPM samples, allsamples exhibit an increment in intensity of anhydrides characteristic peaks as compared tothe peak intensity of pure MAH. Itwas proven when cumulative intensity of anhydride of allMAH-g-EPM samples increases in comparison with the absorbance intensity of control/pureEPM sample. The increment demonstrated that all samples had experienced chemicalmodification and alteration in its functional group. Due to the utilisation of absorbance ratioFigure 1 shows the FTIR spectra of pure EPM (spectrum 12,maleic anhydride (spectrum B)and MAH-g-EPM (spectrum C) in the region of 20001400cm-I.Refering to Figure1, there.:»FTIR-quantitative analysis ofMAH-g-EPMResult and DiscussionPrevious research on anhydride grafting efficiency analysis was conducted throughqualitative approach, which is based on the presence or occurrence of new characteristicpeaks2S.2I.However for this study, the FTIR analysis has been conducted quantitatively bywhich the internal standard method was applied on the recovered spectra in order to build anequation that can be used to quantify anhydride through standard calculation. The approach isbased on Lambert-Beer law theoryll.After the grafting efficiency was confirmed and quantified by FTIR, the next("evaluation on statistical reliability was then performedlbyDesign Expert Statistical software.Then, ANOVA was applied to show the statistical significance of the MAH grafting to theEPM. From the experimental findings, the effect of independent variables on the graftingefficiency was studied using a half-normal graph, effect-list and regression model.grafting. At least five different spectra were generated for every sample to ensure highconfident level.-The anhydride content of MAH-g-EPM was then determined from the ratio of peaksheights of the absorbance peaks at 1712.48 to 1456.96 cm-I,which correspond to anhydridesand polyethylene/polypropylene functional groups, respectively. Anhydride characteristicI 5peak at the 1712.48cm-1 region were selected for the absorbance ratio approach due to itshigh confirmation of anhydride grafting based on the presence of a new peak on MAH-g-EPM spectrum as compared to the pure EPM spectrum. Finally, a calibration curve ofabsorbance ratio (1712.4811456.96cm-1) versus MAH in phr was built and generated anexponential curve with R2=0.900 (Figure 2).There were only three points selected torepresent the contribution of various MAH addition during the grafting process with EPM.1 FTIR spectra of A) pure EPM, B) pure MAH, and C) MAH-g-EPM1HIt) J(~~,"",,_, i'J~! -oo ;~"l'J';.''''1\':,.''H~aHt'><r!":Trl"')Japproach for quantitative grafting efficiency analysis, the internal standard is required toperform quantification process; this approach follows the Lambert-Beer law theoryll.Decision on internal standard was referred at a selected range in between 1456-1460 cm-1(6.85 urn) where the intensity is at maximum ~99.00, which referring to strong band ofpolyethylene and polypropylene monomers of EPM rubber.ANOVA produces value such as mean of square (MS), sum of square (SS), F value, Pvalue and coefficient of multiple determinations (R2). Variables B and interaction point ABwere selected as significant model terms because their P values were lower than 0.05.Table 2 Effect List of all model terms for the screening experimentsTerm Sum of F-value P-value Percentage ofSquare contribution(SS) (%)A 0.078 1.92 0.3002 0.37B 18.40 452.19 0.0022 88.02AB 1.56 38.28 0.0251 7.45Y = 2.91 -0.14 A + 2.14 B + 0.62 ABJRegression model of the functionalisation of MAH into EPM using RSMThe experimental result was further proved by RSM statistical tools. In the generated halfnormal plot, it shows that variable A (MAH content), B (DCP content) and interaction pointof AB were positioned away from the straight line. These plots show that all variables, A andB were significant model terms. However, variable B was distance away from the straightline when compared to variable A and interaction point AB. This indicates that variable Bwas the most significant term. By selecting significant model term in half normal plot, aregression model for grafting yield, Y (Equation 3) and an effect list were generated. Byusing the Equation 3, the predicted grafting yield at each experimental point was obtained.This result was supported by the effect list which stated that the variable B to be the mostsignificant factor with 88.02% contribution to grafting yield than 0.37% contribution byvariable A.2 3 0.2 3.82 2.383 3 0.2 3.81 2.324 1 0.3 4.54 4.575 3 0.2 3.66 2.006 1 0.1 3.59 1.537 5 0.1 1.33 0.00"Relative to that of the 1456.96cm peak9. H. Zhang, R. N. Datta, A G. Talma and J. W. M. Noordermeer: 'Maleic-anhydridegrafted EPM as compatibilising agent in NRlBRlEPDM blends', Eur. Polym. J, 2010,46, 754-766.8. M. Kharazmkia, G. Naderi, M. H. R. Ghoreishy and S. Shokoohi. 'ElastomerNanocomposites Based on BRlEPDM/Organoclay', Rubber Chern. and Technol., 2013,86,299-312.7. B.G. Soares, AS. Sirqueira, M.G. Oleveira, M. S. M. Almeida & R. D. Janeiro. thereactive compatibilization of EPDM-based elastomer blends. raw materials andapplications 55, 454--459 (2002).6. S.H. El-Sabbagh. Compatibility study of natural rubber and ethylene-propylene dienerubber blends. Polymer Testing 22,93-100 (2003).5. J.G. Sommer. Engineered rubber products: Introduction to design, manufacture, andtesting. (Hanser, 2009).4. A N. Gent. Engineering with rubber: how to design rubber components. (Hanser,2001).3. W.D. Callister. material science and engineering: an introduction. (john wiley andsons, 2007).2. B. Kothandaraman: 'Rubber Materials', 2008, Ane Books.1. M. Arroyo, M. Lopezmanchado, J. Valentin & 1. Carretero: 'Morphology/behaviourrelationship of nanocomposites based on natural rubber/epoxidized natural rubberblends', Compo Sci. and Technol., 2007,67,1330-1339.Referencesunder thS Fundamental Research Grant Scheme (FRGS/2012/FKP/TK04/02/1 F00132). Wewish to sincerely thank the Universiti Teknikal Malaysia Melaka (UTeM) and Malaysia.--Nuclear Agency (MNA) for providing the research facilities and technical assistance toconduct the experiments.( ,VvL>101.1 ~ )C? •The authors would like to thank the Ministry of Education Malaysia for financial supportAcknowledgementsNuclear Agency (MNA) for providing the research facilities and technical assistance toconduct the experiments.

FUNCTIONALISATION OF ETHYLENE-PROPYLENE COPOLYMER

(EPM) BY MELT GRAFTING OF MALEIC ANHYDRIDE (MAH) USING

HIGH SHEAR INTERNAL MIXER

http://eprints.utem.edu.my/id/eprint/10998/1/ICoSEM.pdf

FUNCTIONALISATION OF ETHYLENE-PROPYLENE COPOLYMER (EPM) BY MELT GRAFTING OF MALEIC ANHYDRIDE (MAH) USING HIGH SHEAR INTERNAL MIXER

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