Study on characterization and properties of nanosilica‐filled thermoplastic vulcanizates

Thermoplastic vulcanizates (TPVs) are a special class of thermoplastic elastomer, produced by simultaneously mixing and cross‐linking a rubber with a thermoplastic at elevated temperature. Dicumyl peroxide‐cured TPVs based on blends of maleated ethylene propylene rubber (m‐EPM) and polypropylene (PP) thermoplastic using maleated‐PP as a compatibilizer have been developed. To reinforce the properties of these TPVs, nanosilica was added at different levels. With the increase of nanosilica concentrations, significant improvement in tensile strength, modulus, and impact strength of TPVs have been achieved. Morphology study shows that nanosilica is uniformly dispersed in the polymer matrices. Dynamic mechanical analysis shows that tan δ value at low temperature decreases with increasing nanosilica concentration indicating less damping characteristics. Thermogravimetric study revealed that thermal stability of TPVs is improved in presence of nanosilica. Equilibrium swelling study confirms that solvent resistance of TPVs could be improved by nanofiller incorporation. Rubber process analyzer found a very useful tool to understand the melt rheology of nanosilica filled TPVs in terms of dynamic functions over a wide range of strain amplitude and frequency. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Multifunctional peroxide as alternative crosslink agents for dynamically vulcanized epoxidized natural rubber/polypropylene blends

Commonly used dicumyl peroxide (DCP) in combination with coagent, triallyl cyanurate (TAC), as a crosslinking agent is well acceptable for dynamically vulcanized rubber phase of thermoplastic vulcanizates (TPVs). However, it generally produces volatile decomposition products, which cause a typical unpleasant smell and a blooming phenomenon. In this work, influence of two types of multifunctional peroxides: 2,4‐diallyloxy‐6‐tert‐butylperoxy‐1,3,5‐triazine (DTBT) and 1‐(2‐tert‐butylperoxyisopropyl)‐3‐isopropenyl benzene (TBIB), on properties of TPVs based on epoxidized natural rubber (ENR)/polypropylene (PP) blends were investigated. The conventional peroxide/coagent combinations, i.e., DCP/TAC and tert‐butyl cumyl peroxide (TBCP)/α‐methyl styrene (α‐MeS) were also used to prepare the TPVs for a comparison purpose. The TPVs with multifunctional peroxide, DTBT, provided good mechanical properties and phase morphology of small dispersed vulcanized rubber domains in the PP matrix which were comparable with the DCP/TAC cured TPVs. However, the TPVs with TBIB/α‐MeS and TBCP/α‐MeS showed comparatively low values of the tensile properties as well as rather large phase morphology. The results were interpreted by three main factors: the kinetic aspects of the various peroxides, solubility parameters of respective peroxide/coagent combinations in the ENR and PP phases, and the tendency to form unpleasantly smelling byproducts. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Systematic investigation on the effect of crosslinking agent type and dosage on the performance of TPU/MVQ based thermoplastic vulcanizates

Dynamic vulcanized thermoplastic polyurethane (TPU)/methyl vinyl silicone rubber (MVQ) thermoplastic vulcanizates (TPVs) were prepared in torque rheometer. The influence of the type and amount of peroxide crosslinking agent on the mechanical properties, thermal stability, micromorphology and melt flowability was systematically investigated. The results showed that the mechanical properties of the TPVs vulcanized by 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane (DBPH) first increased and then decreased with increasing the peroxide amount, while for dicumyl peroxide (DCP) vulcanizing system the mechanical properties slowly increased. Besides, the comprehensive mechanical properties vulcanized by DBPH were better than those of DCP group. The results of the thermogravimetric analysis showed that the TPVs vulcanized by DBPH had better heat stability, corresponding to the excellent thermo-oxidative aging performance and the 38% increase in tensile strength after aging. In addition, the MVQ rubber particles showed better dispersing performance for DBPH vulcanizing system. The melt flow rate of the TPVs showed a linear relationship with increasing DBPH dosage and became worse after the amount of crosslinking agent exceeded 1.5 phr. By comprehensive comparison, the TPVs have better performance when use peroxide DBPH as the crosslinking agent and the dosage is 1.5 phr.     

Exploring a novel cyclic monofunctional peroxide for curing of silicone rubber at elevated temperature

The curing characteristics of silicone rubber (polydimethylsiloxane [PDMS]) in the presence of structurally different peroxides, namely dicumyl peroxide (DCP) and 3,3,5,7,7‐pentamethyl‐1,2,4‐trioxepane (PMTO), have been studied in details. At moderate temperature, DCP is more prominent for curing the silicone rubber but at high temperatures it suffers from low scorch safety. An inhibitor 2,2,6,6‐tetramethylpiperidinyloxyl (TEMPO) was added with DCP to stabilize the radicals in order to increase the scorch safety time. On the other hand, PMTO showed a prolonged scorch safety and better crosslinking efficiency rather than (DCP + TEMPO) mix at higher temperatures. PMTO‐crosslinked PDMS shows better crosslinking efficiency as indicated by a higher gel content and low swelling index value. Also the mechanical properties, thermal stability, and dynamic mechanical behavior of PMTO‐crosslinked PDMS are much superior than (DCP + TEMPO)‐crosslinked PDMS. Apart from thermoplastic vulcanizates (TPVs) made from PMTO‐crosslinked PDMS show better physicomechanical behavior compared to the TPVs made from (DCP + TEMPO)‐crosslinked PDMS. Moreover, DCP undergoes decomposition reactions at a higher temperature and forms acetophenone, which leads to an unpleasant smell in the final products whereas no such phenomenon is observed for PMTO. Therefore, PMTO turns out to be the suitable peroxide for crosslinking of PDMS at higher temperature. POLYM. ENG. SCI., 57:1073–1082, 2017. © 2016 Society of Plastics Engineers     

Dynamically vulcanized blends of polypropylene and ethylene octene copolymer: Influence of various coagents on thermal and rheological characteristics

The present study focuses on the influence of the three structurally different coagents, namely triallyl cyanurate (TAC), trimethylol propane triacrylate (TMPTA) and N,N′‐m‐phenylene dimaleimide (MPDM) on the thermal and rheological properties of thermoplastic vulcanizates (TPVs) based on the polypropylene (PP) and ethylene octene copolymer (EOC). Depending on the structure and reactivity, different coagents show different behaviors. All the TPV compositions were made by melt mixing method in a Haake Rheomix at 180°C. Rheological properties have also been evaluated at the same temperature. Viscoelastic properties of the TPVs were analyzed by a dynamic oscillatory rheometer in the melt state in a Rubber Process Analyzer (RPA 2000). Morphologically, TPVs consist of dense crosslinked rubber domains dispersed in a continuous thermoplastic matrix. The crosslinked rubber particles have a tendency to form agglomerates and build local clusters which undergo disintegration by shearing. A variety of rheological characteristics such as Payne effect, shear rate sensitivity, modulus recovery and dynamics of relaxation were studied by performing strain sweep, frequency sweep and stress relaxation tests. Among the various coagents taken for investigation, MPDM‐based TPVs show improved dynamic functions (complex modulus and complex viscosity) and lower rate of stress relaxation over TAC, TMPTA and the control sample without any coagent. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of dicumyl peroxide and phenolic resin as a mixed curing system on the mechanical properties and morphology of TPVs based on HDPE/ground tire rubber

Thermoplastic vulcanizates (TPVs) are a special group of thermoplastic elastomer with the characteristic that consists of rubber elasticity and the processability of thermoplastic polymers. TPVs based on high density polyethylene (HDPE)/ground tire rubber (GTR) with phenolic resin (HY‐2045) and dicumyl peroxide (DCP) as vulcanizing agents are prepared through dynamic vulcanization in this article. The blends consisting of 40/60 HDPE/GTR are melt‐mixed in an internal mixer and then pressed with a compression molding machine. The aim of this experiment is to study the influence of a compound curing agent system on the mechanical properties of the HDPE/GTR composites. The results indicate that the mechanical properties of the HDPE/GTR blends are improved significantly by adding 4 phr HY‐2045 and 0.3 phr DCP than those of TPVs without any vulcanizing agents after dynamic vulcanization. The X‐ray photoelectron spectroscopy study and the FTIR‐ATR analysis confirmed that the crosslinking phenomenon occurred in the preparation of TPVs; and the gel fraction analysis indicates that the GTR components and the HDPE components of the HDPE/GTR blends are all moderately crosslinked. In addition, the morphology of the HDPE/GTR blends has been investigated by scanning electron microscopy. POLYM. COMPOS., 36:1907–1916, 2015. © 2014 Society of Plastics Engineers     

Influences of blend proportions and curing systems on dynamic,mechanical, and morphological properties of dynamically cured epoxidized natural rubber/high‐density polyethylene blends

Thermoplastic elastomers (TPEs) based on dynamically cured epoxidized natural rubber/high‐density polyethylene (ENR/HDPE) blends were prepared. Influence of the process oil, blend proportion, and curing systems were investigated. It was found that the oil‐extended thermoplastic vulcanizates (TPVs) exhibited better elastomeric properties and improved ease of the injection process. Increasing the proportion of ENR caused increasing elastic response of elongation at break, tension set properties, and tan δ. It was also found that the TPV treated with phenolic resin exhibited superior mechanical properties and the smallest vulcanized rubber domains. The TPV treated with the conventional peroxide co‐agent curing system showed superior strength properties but had poor elastomeric properties. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Influence of a crosslinked system on the morphology and properties of TPVs based on PA/NBR

The mechanical properties of thermoplastic vulcanizates (TPVs), depend strongly on their morphologies, which themselves depend on the properties of the primary polymers, the composition of the TPV, and the crosslink system and crosslink process. The morphology is defined during the dynamic vulcanization. This work deals with the study of the influence of crosslink systems on TPVs based on PA/NBR (copolyamide PA6/6‐6 and nitrile rubber) in a 40/60 composition. Dicumyl peroxide, bismaleimide, phenolic resin, a sulfur‐accelerated system, and dicumyl peroxide with two coagents were used as crosslinkers. TPVs were characterized by taking into account their mechanical strength, solvent resistance, compression set, and morphology. The curing system constituted by dicumyl peroxide and sulfur/bismaleimide as coagents resulted in a more defined morphology, and therefore the TPV exhibited the best properties. For these TPVs, a morphology consisting of spherical domains of rubber distributed homogeneously on the polyamide matrix could be observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Development of novel polar thermoplastic vulcanizates based on ethylene acrylic elastomer and polyamide 12 with special reference to heat and oil aging

Thermoplastic vulcanizates (TPVs) based on ethylene acrylic elastomer (AEM) and polyamide 12 (PA12) have been developed by the dynamic vulcanization process, in which selective cross‐linking of the elastomer phase (AEM) during melt mixing with the thermoplastic phase (PA12) has been carried out simultaneously. TPVs at varied blend ratios (50 : 50, 60 : 40, 70 : 30) of AEM/PA12 were prepared at 185°C at a rotor speed of 80 rpm up to 5 min of mixing. Di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) was chosen as the suitable cross‐linking peroxide to carry out the dynamic vulcanization. Morphology study reveals the development of continuous agglomerate of rubber network in case of all the TPVs took place and the average dimension of the rubber particles are in the range of 30–40 nm. TPV based on 50 : 50 AEM/PA12 shows better physicomechanical properties, thermal stability, and dynamic mechanical behavior among all the TPVs. For aging test, TPVs were exposed to air, ASTM oil 2 and 3. Air aging tests were carried out in hot air oven for 72 h at 125°C, while the oil aging tests were carried out after immersion of the samples into the oils in an aging oven. After aging, there are only slight deterioration of physicomechanical properties of the TPVs. Particularly in case of 50 : 50 blend of AEM/PA12, the retention of the properties even after aging was found excellent. The recyclability of these new TPVs is also found to be excellent leading to find potential application in automotives. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42655.     

Automotive applications of thermoplastic vulcanizates

Thermoplastic vulcanizates (TPVs) are special classes of thermoplastic elastomers, in which dynamic vulcanization of the rubber phase takes place during melt mixing with a semicrystalline thermoplastic matrix phase at elevated temperature. This review article focus on the different types of thermoplastic vulcanizates (TPVs) from various elastomer and thermoplastic blends that are suitable for the automotive applications purpose. A detailed study of the various TPVs based on polypropylene-ethylene propylene diene rubber (PP-EPDM) and polypropylene-ethylene α-olefin has been focused and their application in the automobile sector has been summarized. Most of the commercially available TPVs are PP-EPDM based. Limited applications of that TPVs in high heat and oil resistant application purposes requires new generation of TPVs. High performance TPVs or super TPVs are new generation TPVs that exhibit high heat resistance as well as excellent oil resistance property suitable for automotive under-the-hood applications. Therefore TPVs based on XNBR-PA12, HNBR-PA12 and FKM-PA6 system has also been explored in details in this study and the possibility of the use of those TPV system has been focused for the high temperature application purpose in the automobile sector where high and oil resistant application properties is the prime concern.     

Thermoplastic elastomers based on high‐density polyethylene,ethylene–propylene–diene terpolymer,and ground tire rubber dynamically vulcanized with dicumyl peroxide

Thermoplastic vulcanizates (TPVs) based on high‐density polyethylene (HDPE), ethylene–propylene–diene terpolymer (EPDM), and ground tire rubber (GTR) were dynamically vulcanized with dicumyl peroxide (DCP). The polymer blend was composed of 40% HDPE, 30% EPDM, and 30% GTR, and the concentration of DCP was varied from 0.3 to 3.6 parts per hundred rubber (phr). The properties of the TPVs were determined by evaluation of the gel fraction content and the mechanical properties. In addition, IR spectroscopy and differential scanning calorimetry analysis were performed as a function of the DCP content. Decreases in the Young's modulus of the blends and the crystallinity of HDPE were observed when the content of DCP was greater than 1.8 phr. The results regarding the gel content indicate that the presence of DCP promoted the crosslinking of the thermoplastic matrix, and optimal properties were obtained with 1.5% DCP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39901.     

Organoclay‐reinforced dynamically vulcanized thermoplastic elastomers of polyamide‐6/polyepichlorohydrin‐co‐ethylene oxide

Dynamically vulcanized thermoplastic elastomers (TPVs) based on polyamide‐6 (PA‐6) and poly(epichlorohydrin‐co‐ethylene oxide) (ECO) and their nanocomposites were prepared via melt‐blending process. The unfilled and organoclay (OC)‐filled TPVs were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry, thermal gravimetric analysis (TGA), and mechanical tests. XRD and TEM results showed that the OC particles were well exfoliated into the samples with high rubber content while both intercalated and exfoliated structures were found in the samples with low rubber content. The mechanical properties showed that ECO improved the elongation at break and the presence of OC increased the Young's modulus. Also, wide angle XRD analysis showed an increase in α‐crystals of PA‐6 with addition of ECO rubber. Moreover, it was found that by increasing OC content, crystallization temperature increased but the degree of crystallinity decreased. TGA showed that increasing ECO content decreased thermal stability of the samples, while the presence of OC did not have any considerable effect on the thermal stability. POLYM. COMPOS., 38:1948–1956, 2017. © 2015 Society of Plastics Engineers     

Influence of phenolic curative on crosslink density and other related properties of dynamically cured NR/HDPE blends

Dynamically cured 60/40 NR/HDPE blends with various amounts of phenolic curative were prepared in an internal mixer at 160°C. A simple blend (i.e., the blend without curative) was also prepared using the same materials and blend proportion for comparison purposes. Mechanical, dynamic, and morphological properties; swelling resistance and crosslink density of the blends were investigated. It was found that the thermoplastic vulcanizates (TPVs) gave superior mechanical and dynamic properties than the simple blend. Furthermore, the mechanical properties in terms of elongation at break, modulus and tensile strength and elastic response in dynamic test in terms of storage modulus increased with increased loading amount of the curative. The complex viscosity also increased but the tan δ and tension set decreased with increased loading level of the curative. The crosslink density of the TPVs was estimated based on the elastic shear modulus. It was found that the crosslink density of the blends increased with increased loading levels of the curative while the degree of swelling decreased. This correlated well with the trend of mechanical and dynamic properties. SEM micrographs were used to confirm the level of mechanical and dynamic properties. It was found that the simple blend at a given blend ratio exhibited co‐continuous phase morphology. However, the TPVs showed micron scale of vulcanized rubber domains dispersed in a continuous HDPE matrix. The size of vulcanized rubber domains decreased with increasing amounts of the curative. This led to greater interfacial adhesion between the phase and hence superior mechanical and dynamic properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dynamically vulcanized blends of polypropylene and ethylene‐octene copolymer: Comparison of different peroxides on mechanical,thermal, and morphological characteristics

Thermoplastic vulcanizates (TPVs) are prepared by the dynamic vulcanization process, where crosslinking of an elastomer takes place during its melt mixing with a thermoplastic polymer under high shear. TPVs based on polypropylene (PP) with different grades of ethylene‐octene copolymers (EOC) were prepared with a coagent assisted peroxide crosslinking system. The effect of dynamic vulcanization and influence of various types and concentrations of peroxide were mainly studied on the basis of the mechanical, thermal, and morphological characteristics. Three structurally different peroxides, namely dicumyl peroxide (DCP), tert‐butyl cumyl peroxide (TBCP), and di‐tert‐butyl peroxy isopropyl benzene (DTBPIB) were investigated. The mechanical properties of the TPVs are primarily determined by the extent of crosslinking in the EOC and the degree of degradation in the PP phase. Among all peroxides used DCP gives best overall properties with low‐molecular‐weight EOC, whereas TBCP shows best property level with high‐molecular‐weight EOC‐based TPVs. These can be explained on the basis of the molecular characteristics of EOC and the nature of the peroxide used. Differential scanning calorimetery (DSC) and morphological analysis reveal that PP and EOC are a thermodynamically immiscible system. The melting endotherm was studied to determine the influence of various peroxides on crystallinity of the PP phase. Tensile fracture patterns were also analyzed to study the failure mechanism of the samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dependence of microstructure and properties of polypropylene/bromo-isobutylene-isoprene rubber thermoplastic vulcanizates on the molding process

To explore the dependence of the microstructure and properties of thermoplastic vulcanizates (TPVs) on the molding process. The polypropylene/bromo-isobutylene-isoprene rubber thermoplastic vulcanizates (PP/BIIR-TPVs) are molded by high rate shear injection and compression molding, and the phase morphology and physical-mechanical properties of PP/BIIR-TPVs specimens are investigated. Detailed small-angle X-ray scattering, scanning electron microscopy and atomic force microscopy investigations demonstrate that the high rate shear of injection molding not only decreases the size of BIIR particles but also induces the orientation of the PP matrix and further increases its crystallinity. Subsequently, the PP/BIIR-TPVs molded by injection molding have higher tensile strength and Young's modulus, while the compression molding benefits to higher elongation at break. The mechanism regarding the effects of high rate shear during injection molding on phase morphology development of PP/BIIR-TPVs is discussed. This study guides the preparation of TPVs products with desired properties.     

Selectively located aluminum hydroxide in rubber phase in a TPV: Towards to a halogen‐free flame retardant thermoplastic elastomer with ultrahigh flexibility

Novel thermoplastic vulcanizate (TPV) based on two EVAs with different VA contents, ethylene vinyl acetate rubber (VA content =50 wt%; EVM) and ethylene VA copolymer (VA content =28 wt%; EVA₂₈), has been successfully prepared by dynamic vulcanization in our previous work. In this study, we have incorporated aluminum hydroxide (ATH) into the TPV based on EVM/EVA₂₈ for the purpose to fabricate halogen‐free flame retardant TPVs with high flexibility. The morphology and the properties of the ATH filled TPVs have been investigated. It was found that the ATH particles were finely dispersed into the crosslinked EVM phase, while few ATH particles were observed in the EVA₂₈ matrix. The fabricated TPVs with 45% ATH exhibit LOI of 30.2%, significantly prolonged ignition time, and drastically reduced heat release rate. At the same time, the TPVs show excellent stretchability (>300% elongation at break), nice elasticity (only about 30% remnant strain at 100% stretching), high strength, and good flexibility as well. We have attributed the multifunctional performance of the ATH filled TPVs to both the fine phase structure of the base TPVs and the selective dispersion of ATH fillers in the rubber phase. POLYM. COMPOS., 36:1258–1265, 2015. © 2014 Society of Plastics Engineers     

Influence of various crosslinking systems on the mechanical properties of gas phase EPDM/PP thermoplastic vulcanizates

Dynamically cured thermoplastic elastomers or thermoplastic vulcanizates (TPVs) are widely used nowadays for their unique characteristics. In this paper, gas phase ethylene–propylene–diene terpolymer (GEPDM)/Polypropylene (PP) TPVs with various crosslinking systems have been extensively studied to optimize the curative level in each crosslinking system with special reference to their mechanical properties. Optimized systems were compared for heat aging, recyclability, crosslink density, morphology studies, and dynamic mechanical analysis. Crosslinking by peroxide in the presence of triallyl cyanurate as a coagent gives best overall performance with reference to excellent heat aging behavior, tension set, and compatibility between GEPDM and PP. Conventional EPDM/PP system was also compared with GEPDM/PP system. GEPDM/PP system was found to exhibit better behavior in all respects. Significant correlations were obtained between delta torque values obtained from Moving Die Rheometer and modulus or cross link density of TPVs irrespective of the nature of crosslinking agent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5463–5471, 2006     

Design and properties of a series of high‐temperature thermoplastic elastomeric blends from polyamides and functionalized rubbers

A series of high‐temperature thermoplastic elastomers (TPEs) and thermoplastic vulcanisates (TPVs) were successfully developed based on two different types of heat resistant polyamide (PA) (25 parts by weight)—PA‐12 and PA‐6, in combination with three different functionalized rubbers (75 parts by weight) of varying polarity, e.g., maleic anhydride grafted ethylene propylene diene terpolymer (MA‐g‐EPDM), sulphonated ethylene propylene diene terpolymer, and carboxylated acrylonitrile butadiene rubber, by melt mixing method. These rubbers have low level of unsaturation in its backbone, and the plastics showed high melting range. Thus, the developed TPEs and TPVs were expected to be high temperature resistant. Resol type resin was used for dynamic vulcanization to further increase the high temperature properties of these blends. Interestingly, initial degradation temperature of the prepared blends was much higher (421 °C for MA‐g‐EPDM/PA‐12) than the other reported conventional TPEs and TPVs. Fourier transform infrared analysis described the interactive nature of the TPEs and TPVs, which is responsible for their superior properties. The maximum tensile strength with lowest tension set was observed for the carboxylated acrylonitrile butadiene rubber/PA‐12 TPV. Mild increase in mechanical properties without any degradation was observed after recycling. Dynamic mechanical analysis results showed two distinct glass transition temperatures and indicated the biphasic morphology of the blends, as evident from the scanning electron microscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45353.     

Thermoplastic vulcanizates based on maleated natural rubber/polypropylene blends: Effect of blend ratios on rheological,mechanical, and morphological properties

Maleated natural rubber (MNR) was prepared and used to formulate thermoplastic vulcanizates (TPVs) based on various MNR/PP blends. The influence of mixing methods on the TPVs properties was first studied. We found that mixing all ingredients in an internal mixer provided the TPVs with better mechanical properties. The final mixing torque, shear stress, and shear viscosity of the TPVs prepared with various blend ratios of MNR/PP increased with increasing levels of MNR in the blends. This may be attributed to higher shear viscosity of the pure MNR than that of the pure PP. Furthermore, as evidenced in SEM micrographs, the TPVs are two phase morphologies with dispersed small vulcanized rubber domains in the PP matrix. Therefore, the higher content of PP caused the more molten continuous phase of the flow during mixing and rheological characterization. Tensile strength and hardness of the TPVs increased with increasing levels of PP, while the elongation at break decreased. Furthermore, the elastomeric properties, in terms of tension set, increased with increasing levels of MNR in the blends. This may be attributed to decreasing trends in the size of vulcanized rubber particles dispersed in the PP matrix with an increasing concentration of MNR. POLYM. ENG. SCI. 46:594–600, 2006. © 2006 Society of Plastics Engineers.     

Effect of the compatibilizer,on the engineering properties of TPV based on Hypalon® and PP prepared by dynamic vulcanization

Elastomeric Chlorosulfonated polyethylene (Hypalon^®) and thermoplastic Polypropylene (PP) based thermoplastic vulcanizates (TPVs) were prepared in presence of different doses of compatibilizer, maleic anhydride grafted PP (PP‐g‐MA) by employing dynamic vulcanization technique. The effect of incorporation in different proportions of compatibilizer on mechanical, spectral, morphological, thermal, and rheological properties of such TPVs was studied and the same were compared to that of virgin PP and amongst themselves. The mechanical analysis of the prepared TPVs exhibited significant improvements in stress at 25% modulus, ultimate tensile strength (UTS), and hardness values. FTIR studies revealed that a chemical interaction had taken place between Hypalon^® and functionalized compatibilizer during the process of dynamic vulcanization which led to an enhancement of interfacial adhesion between them. The two‐phase morphologies were clearly observed by scanning electron microscopic studies. The T_g values of Hypalon^® was modified in the TPVs as exhibited by differential scanning calorimetric studies. TGA studies indicated the increase in thermal stability of all TPVs with respect to the elastomeric Hypalon^®. Rheological properties showed that the compatibilizer reduces the melt viscosity of TPVs and thus facilitates the processibility of such TPVs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40312.