Characterization of irradiation-induced crosslink of epoxidised natural rubber/ethylene vinyl acetate (ENR-50/EVA) blend (original) (raw)
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Electron beam irradiation of EVA/ENR blend
Polymer - Plastics Technology and Engineering, 2006
The influence of small amount of crude palm oil (CPO) content on the physical properties of high density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) was investigated. The HDPE and LLDPE containing 2%, 3%, and 5% CPO were prepared in a twin-screw extruder. Then films of 0.2 mm thickness were produced by using blown film technique. The improvement in tensile strength and elongation at break with a concurrent decline in density implied the enhancement in toughness of the polymers by the addition of CPO. A gradual increase in impact strength of HDPE with the CPO content further supported the previous notation. The enhancement in the physical properties in the presence of CPO is believed to be attributed to the increased chain mobility of the polymer along with improved orientation strengthening in HDPE and LLDPE. Evidence from scanning electron micrographs was also used to support this contention. The decline in impact strength of LLDPE with the addition of CPO is associated with the formation of defects in the amorphous phase of LLDPE.
European Polymer Journal, 2001
The eect of irradiation on the tensile and dynamic mechanical properties of ENR50 (ENR: epoxidized natural rubber) was investigated. ENR50 was irradiated using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. The in¯uence of several additives such as trimethylolpropane triacrylate (TMPTA), Irganox1010 and tribasic lead sulfate (TBLS) on the irradiation-induced changes of ENR50 was investigated. The general improvement on the tensile, as well as dynamic mechanical properties with irradiation indicates the formation of irradiation-induced crosslinks. An appreciable increase in T g is observed with irradiation while the enhancement in stress at break is found to be marginal. This observation agrees well with the relatively small increase in storage modulus occurred beyond the T g of the irradiated ENR. This in return reveals that only a small degree of crosslinking is achieved through irradiation. Based on these factors it can be inferred that the gradual increase in T g upon irradiation of ENR50 could be associated with the occurrence of irradiation-induced ring opening side chain reaction of the oxirane group and irradiationinduced oxidation at the cis double bond along with the irradiation-induced crosslinking. From the observation in the properties studied it con®rms that TMPTA is ecient in enhancing the irradiation-induced crosslinking of ENR50. The addition of Irganox1010 and TBLS are found to impart considerable stability to ENR50, although the antioxidant did cause some inhibition of crosslinking. The acceleration of crosslinking by the TMPTA as well as the inhibition of crosslinking the added stabilizing additives were further con®rmed by using gel fraction data. However, the studies did not reveal the exact nature of irradiation-induced reactions involved in ENR. Ó
Journal of Applied Polymer Science, 2011
Linear low-density polyethylene/soya powder blends were prepared by using an internal mixer at 150 C. The soya powder content ranged from 5 to 40 wt %. Epoxidized natural rubber with 50 mol % epoxidation (ENR 50) was added as a compatibilizer. The blends were irradiated by electron beam (EB) at a constant dose of 30 kGy. The changes in gel fraction, tensile properties, morphological and thermal properties of the samples were investigated. The gel content increased after EB irradiation. However, the increment of gel content was hindered by increasing soya powder content. The tensile strength and Young's modulus of the blends were increased by EB whereas the elongation at break decreased. The tensile frac-ture surface also support the reduction of elongation at break by EB irradiation. Further analysis on the irradiated blends using Fourier transform infrared spectra indicated an increase of oxygenated product after undergoing EB irradiation. The differential scanning calorimetry result indicated that the melting temperature of the blends decreased after EB irradiation whereas the crystallinity increased. EB irradiation also enhanced the thermal stability of the blends as indicated by thermogravimetric analysis. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: 5220-5228, 2012
Modification of PVC/ENR blend by electron beam irradiation: effect of crosslinking agents
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1999
The eect of irradiation on ENR50 was studied with particular attention to irradiation-induced crosslinking. ENR50 was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. The in¯uence of several additives such as TMPTA, Irganox1010 and tribasic lead sulfate on irrradiation-induced crosslinking of ENR50 was investigated. The gel fraction, Ts, M100, Eb, hardness and Tg were used to follow the irradiation-induced crosslinking of the rubber. Results revealed that the increase in gel fraction upon irradiation of pure ENR50 could be associated with both irradiation-induced crosslinking as well as ring opening side chain reaction of oxirane group. The observation on the trend shown in the properties studied con®rmed that TMPTA is ecient in enhancing the irradiation-induced crosslinking of ENR50. The addition of Irganox1010 and tribasic lead sulfate found to inhibit irradiation-induced crosslinking of ENR50 to considerable extent. This in¯uence of stabilizing additives in particular, antioxidant, was observed to be more prominent at lower doses. The importance of TMPTA in preventing ring opening side chain reactions as well as the role of the stabilizing additives in introducing free chain ends are also discussed. However studies did not reveal the exact nature of irradiation-induced reactions involved in ENR. Ó
Electron beam irradiation of epoxidized natural rubber
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2000
The eect of irradiation on ENR50 was studied with particular attention to irradiation-induced crosslinking. ENR50 was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. The in¯uence of several additives such as TMPTA, Irganox1010 and tribasic lead sulfate on irrradiation-induced crosslinking of ENR50 was investigated. The gel fraction, Ts, M100, Eb, hardness and Tg were used to follow the irradiation-induced crosslinking of the rubber. Results revealed that the increase in gel fraction upon irradiation of pure ENR50 could be associated with both irradiation-induced crosslinking as well as ring opening side chain reaction of oxirane group. The observation on the trend shown in the properties studied con®rmed that TMPTA is ecient in enhancing the irradiation-induced crosslinking of ENR50. The addition of Irganox1010 and tribasic lead sulfate found to inhibit irradiation-induced crosslinking of ENR50 to considerable extent. This in¯uence of stabilizing additives in particular, antioxidant, was observed to be more prominent at lower doses. The importance of TMPTA in preventing ring opening side chain reactions as well as the role of the stabilizing additives in introducing free chain ends are also discussed. However studies did not reveal the exact nature of irradiation-induced reactions involved in ENR. Ó
Electron beam irradiation of epoxidized natural rubber: FTIR studies
Polymer International, 2000
The eect of irradiation on ENR50 was studied with particular attention to irradiation-induced crosslinking. ENR50 was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. The in¯uence of several additives such as TMPTA, Irganox1010 and tribasic lead sulfate on irrradiation-induced crosslinking of ENR50 was investigated. The gel fraction, Ts, M100, Eb, hardness and Tg were used to follow the irradiation-induced crosslinking of the rubber. Results revealed that the increase in gel fraction upon irradiation of pure ENR50 could be associated with both irradiation-induced crosslinking as well as ring opening side chain reaction of oxirane group. The observation on the trend shown in the properties studied con®rmed that TMPTA is ecient in enhancing the irradiation-induced crosslinking of ENR50. The addition of Irganox1010 and tribasic lead sulfate found to inhibit irradiation-induced crosslinking of ENR50 to considerable extent. This in¯uence of stabilizing additives in particular, antioxidant, was observed to be more prominent at lower doses. The importance of TMPTA in preventing ring opening side chain reactions as well as the role of the stabilizing additives in introducing free chain ends are also discussed. However studies did not reveal the exact nature of irradiation-induced reactions involved in ENR. Ó
Journal of Applied Polymer Science, 2001
Electron-beam initiated crosslinking of poly(vinyl chloride)/epoxidized natural rubber blends, which contained trimethylolpropane triacrylate (TMPTA), was carried out over a range of irradiation doses (20 -200 kGy) and concentrations of TMPTA (1-5 phr). The gel content increased with the irradiation dose and the TMPTA level, although the increase was marginal at higher doses and higher TMPTA levels. Blends containing 3-4 phr TMPTA achieved optimum crosslinking, which in effect caused the maximum tensile strength (TS) at a dose of 70 kGy. A further addition of TMPTA caused a decline in the TS above 40 kGy that was due to embrittlement, which is a consequence of excessive crosslinking and the breakdown of the network structure. The possible formation of a more open network as a result of the breakdown of the network structure was further confirmed by the modulus results. Dynamic mechanical analysis (tan ␦ curve) and scanning electron microscopy studies on samples irradiated at 0 and 200 kGy were undertaken in order to gain further evidence on the irradiationinduced crosslinking. The plasticizing effect of TMPTA prior to irradiation and the formation of microgels upon irradiation were also discussed.
Journal of Vinyl & Additive Technology, 2009
Effect of electron beam (EB) irradiation on the properties of ethylene vinyl acetate (EVA)/ethylene-propylene-diene monomer (EPDM) (50/50) blends was studied. The blends were firstly meltcompounded at 130 C followed with being irradiated using 4.0 MeV EB energy at doses ranging from 0 kGy to 200 kGy. It is found that the dosage of irradiation plays a key role in the properties of the blends. With the increasing dosage of irradiation, tensile strength and thermal stability were enhanced. The irradiation exerts a cross-linking effect on the blends, and the increase in density is responsible for the enhanced properties. Dynamic mechanical and thermal analyses and morphology indicate that irradiation does not play any negative role in the compatibility between EVA and EPDM. Hot set test reveals that irradiation could improve the heat deformation property of blends. Thus, it is reasonable and interesting to modify EVA/EPDM blends using EB irradiation to further increase its properties.
Radiation Physics and Chemistry, 2017
Gel content, mechanical properties and morphology of immiscible PE/EVA blends irradiated by high energy electron beam were studied. The results of gel content measurements showed that the capability of cross-linking of the blend samples increased with an increase of the EVA composition. Also, the gel content for most compositions of the blends displayed a positive deviation from the additive rule. The results of mechanical properties showed that the tensile strength and elongation at break of the samples increased and decreased, respectively, with irradiation dose. On the other hand, the mechanical properties of the irradiated blends also depicted a positive deviation from additive rule contrary to the un-irradiated blends. A synergistic effect observed for the mechanical properties improvement of the irradiated blends and it was attributed to the probable formation of the PE-graft-EVA copolymers at the interface of the blends during the irradiation process. A theoretical analysis revealed that irradiation induced synergistic effect was more significant for EVA-rich blends with weaker interfacial interaction as compared to PE-rich blends. The morphological analysis indicated that the blend morphology was not affected obviously, whereas it was stabilized by irradiation.
Polymer Degradation and Stability, 1999
The eects of 3 dierent types of antioxidants; a hindered phenol, a phosphite and a hindered amine light stabilizer (HALS) on the radiation-induced crosslinking and oxidative degradation of 70a30 polyvinyl chloride (PVC)/epoxidised natural rubber (ENR) blend with a crosslinking agent were studied. The gel fraction, tensile strength, elongation at break, modulus and hardness were used to follow the irradiation-induced crosslinking and oxidative degradation of the blend. Results on mechanical properties implied that the hindered phenol is an eective antioxidant for the investigated PVC/ENR blend system. The modulus and hardness results revealed that addition of antioxidant to the blend favours the formation of free ends in the crosslinked network upon irradiation. The Fourier transform infrared spectroscopy analysis indicated that the radiolysis products of hindered phenol at 60 kGy induce post irradiation reaction in PVC/ENR blends. However, studies did not reveal the exact nature of the radiolysis product responsible. # 1999 Elsevier Science Ltd. All rights reserved. 0141-3910/99/$ -see front matter # 1999 Elsevier Science Ltd. All rights reserved. P I I : S 0 1 4 1 -3 9 1 0 ( 9 9 ) 0 0 0 3 9 -7 Polymer Degradation and Stability 65 (1999) 481±490