Study on Blends of Ethylene Propylene Diene Rubber and Thermoplastic Polyurethanes

Blends of ethylene propylene diene rubber (EPDM) and thermoplastic polyurethane (TPU) have been studied to understand the compatibility and morphology. The study was initially done with unmodified EPDM and subsequently with modified EPDM through maleation process. Mechanical properties of unmodified EPDM blends are improved with the addition of TPU. However, the appearance of two T _gs even at lower concentrations of PU in the blends indicates that the blends are incompatible. Blends of maleated EPDM with TPU showed a single T _g and further improvement in mechanical properties which is attributed to the improvement in compatibility as also confirmed by SEM analysis.     

Modification of Ethylene Propylene Diene Terpolymer Rubber by Some Thermoplastic Polymers

Abstract

Blends of ethylene propylene diene terpolymer (EPDM) rubber with thermoplastic polyolefins such as low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), high molecular weight polypropylene (PP), and polypropylene random copolymer grade (PP‐R) were prepared by melt mixing. The physico‐mechanical properties, equilibrium swelling in benzene, and aging properties of the binary blends were investigated, analyzing the effect of the rubber/thermoplastics ratio and the type of the thermoplastic material on these properties. The data obtained indicate that EPDM/PP‐R blend in 20/80 w/w% shows the highest physico‐mechanical properties with improved retained tensile strength at 90°C for 7 days. This blend ratio also gives excellent retained equilibrium swelling in benzene at room temperature for 7 days, although EPDM/LDPE blend in 80/20 w/w% imparts the highest retained elongation at break at 90°C for 7 days.     

The Effect of Functionalized Ethylene Propylene Diene Rubber (EPDM) on the Kinetics of Sulfur Vulcanization of Normal Rubber/EPDM Blends

The effect of mercapto‐ and anhydride‐functionalized ethylene propylene diene rubber (EPDM) or ethylene–vinyl acetate (EVA) copolymers on the vulcanization kinetics of natural rubber/EPDM blends was investigated using the oscillatory disk rheometer. The mercapto groups in both EPDM and EVA copolymers resulted in a significant decrease of the curing time. The Coran's model was applied to set the kinetic constants within each distinct step of the vulcanization process. The highest curing velocity was perceived in a blend containing 2.5 phr of mercapto‐functionalized EVA. The functionalized EVA, especially that which was functionalized with anhydride groups, also displayed a lower solvent uptake on blending, which would imply an increase of the crosslink density as well a covulcanization phenomenon.

     

Polymer Blends of PBT and PP Compatibilized by Epoxidized Ethylene Propylene Diene Rubber

Summary In this paper, ethylene-propylene-diene-rubber (EPDM) was epoxidized with an in situ formed performic acid to prepare epoxided EPDM(eEPDM). The eEPDM were used to compatibilize poly(butylenes terephthalate)(PBT) and polypropylene(PP) blends in a haake mixer. FTIR results showed that the EPDM had been epoxidized. FTIR and torque test showed the epoxy functional groups in the eEPDM can react with the carboxylic acid or hydroxyl terminal groups in PBT at the interface to form PBT-g-EPDM copolymers. SEM observation showed that these in situ formed grafted copolymers tent to concentrate along the interface to reduce the interfacial tension at the melt and suppress coalescence by steric hindrance. higher quantity of eEPDM compatibilizer in the blend results in a better compatibilized blend in terms of finer phase domains. Notched Izod impact tests showed that both the adding of rubber and the formation of PBT-g-EPDM copolymer improved the toughness of PBT/PP blends.     

聚氨酯／顺丁橡胶共混物结构与性能的研究

采用物理共混的方法,制备了廉价的ＢＲ和贵的热塑性聚氨酯（ＴＰＵ）共混物。利用电子拉力机,液变仪,动态粘弹仪,偏光显微镜和电子显微镜对力学性能、流变性能,动态粘弹性和形态结构进行了研究和分析。结果表明,ＢＲ和ＴＰＵ有较好的相容性,ＴＰＵ／ＢＲ共混物能达到使用要求,一些性能好于纯ＴＰＵ《     

Optimization of Process Parameters of Immiscible Blends of Linear Low-Density Polyethylene and Poly Dimethyl Siloxane Rubber Using Taguchi Methodology

Blends of Linear low density polyethylene (LLDPE) and Poly dimethyl siloxane rubber (PDMS) are immiscible due to dissimilarity in their structures and wide difference in their surface energies. The processing parameters such as temperature, rotor speed and time in an internal mixer (Brabender Plasticorder) were optimized by using Design of Experiments (DOE) as per Taguchi Methodology, for a blend ratio of 50:50. Mechanical properties such as tensile strength and impact strength were chosen as the criteria for assessing the optimization phenomenon. The optimum processing parameters were found to be a temperature of 200°C, a rotor speed of 100 rpm and the time as 8 minutes.     

EPDM/CIIR Blends: Effect of EPDM Grade on Mechanical Properties

Blends of chlorobutyl rubber (CIIR) with two grades of ethylene-propylene diene monomer rubber (EPDM) were prepared and the effect of blend ratio on the cure characteristics, hot air ageing resistance, steam ageing resistance, and mechanical properties were evaluated. The blend of CIIR with EPDM grade 301 T showed additive behavior and the blend with the other grade of EPDM (NDR 4640) showed synergistic behavior.     

Thermoplastic Elastomer Composites of Palm Ash-Filled Ethylene Vinyl Acetate/Natural Rubber Blends: Effects of Palm Ash Loading and Size

Thermoplastic elastomer composites of ethylene vinyl acetate (EVA)/natural rubber (NR) blends filled with palm ash were prepared by melt-mixing using a Haake Rheomix Polydrive R600/610 at 120°C with rotor speed of 50 rpm for 10 minutes. Increase in palm ash loading in composites resulted in increase the value of stabilization toque, Young's modulus and swelling resistance of the composites, but decreased the tensile strength and elongation at break. Scanning electron microscope micrographs revealed that higher filler loading resulted in agglomeration of palm ash in the composites. When smaller particle size of palm ash was used, further improvement in tensile strength, elongation at break, swelling resistance and stabilization torque value were observed.     

Effects of Malienated Ethylene Propylene Diene Monomer (EPDM) Rubber on Dynamic-Mechanical and Rheological Properties of Polyamide 66 (PA 66) Composites

Reactive blends of ethylene propylene diene monomer (EPDM) and polyamide (PA) 66 were prepared in the single screw and twin screw extruder using maleic anhydride as coupling agent and dicumyl peroxide (DCP) as initiator. The optimum concentration of DCP for grafting maleic anhydride on EPDM was determined. The grafting efficiency was determined by Fourier transform infrared (FTIR) spectroscopy, and (DMTA) tests were conducted to determine the damping, loss, and storage modulus of PA 66 composites. A capillary rheometer and parallel plate rheometer were employed to characterize the rheological properties at high and low shear rates. It was seen that the glass fibers are not long and continuous, and they act as fillers, therefore reducing the damping in the composite. No significant change was observed in the glass transition temperature of the blend as compared with the individual components, especially PA 66. In malienated EPDM blends with increasing EPDM from 10 to 15%, the height of glass transition temperature peak increases. Capillary rheometer tests show that for all samples the apparent viscosity decreases with increasing shear rate, which is a characteristic of a non-Newtonian pseudo plastic fluid. The viscosity ration of malienated EPDM and PA 66 shows a considerable difference between them and only at higher shear rates do the viscosities get closer.     

高聚合度PVC／TPU共混物的制备与研究

本文研究了采用高聚合度聚氯乙烯(PVC)和热塑性聚氨酯(TPU)为主体材料制备高聚合度PVC/TPU共混物的过程,讨论了高聚合度PVC/TPU并用比、填料、增塑剂、共混工艺等因素对高聚合度PVC/TPU共混物性能的影响。     

Effect of Substrate on the Properties of Polymer Alloys and Blends

The thermodynamic aspects of the influence of the solid surface on the properties and adhesion of polymer blends and alloys are discussed. It is shown that under the influence of the surface the properties and composition of the interphase may be changed. The effects are explained by the influence of the surface on the phase equilibrium in compatible and incompatible blends.     

The Effect of Epoxidized Natural Rubber (ENR-50) or Polyethylene Acrylic Acid (PEA) as Compatibilizer on Properties of Ethylene Vinyl Acetate (EVA)/Natural Rubber (SMR L) Blends

The effect of epoxidized natural rubber (ENR) or polyethylene acrylic acid (PEA) as a compatibilizer on properties of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends was studied. 5 wt.% of compatibilizer was employed in EVA/SMR L blend and the effect of compatibilizer on tensile properties, thermal properties, swelling resistance, and morphological properties were investigated. Blends were prepared by using a laboratory scale of internal mixer at 120°C with 50 rpm of rotor speed. Tensile properties, thermal properties, thermo-oxidative aging resistance, and oil swell resistance were determined according to related ASTM standards. The compatibility of EVA/SMR L blends with 5 wt.% of compatibilizer addition or without compatibilizing agent was compared. The EVA/SMR L blend with compatibilizer shows substantially improvement in tensile properties compared to the EVA/SMR L blend without compatibilizer. Compatibilization had reduced interfacial tension and domain size of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends.     

Effect of Rubber Content of ABS on Properties of PC/ABS Blends. I. Rheological,Mechanical, and Thermal Properties

ABSTRACT

The effect of rubber content of poly (acrylonitrile butadiene styrene) (ABS) on compatibility and properties of polycarbonate (PC)/ABS blend systems has been investigated. The rheological, mechanical, physical, and thermal properties of PC/ABS blend systems containing ABS of different rubber content were studied. The reduced torque data on Torque Rheocord indicated improved processability of PC by addition of ABS, however, in ABS-rich compositions, higher rubber content reduces the extent of improvement. The tensile strength of PC decreased with addition of ABS to it but PC-rich compositions have a nearly additive response. The deviation form additivity for blends having higher rubber ABS was more pronounced. However, the impact strength of blends having higher rubber ABS were higher than other types and showed a positive deviation from additivity with variation in compositions. The blends containing ABS with lower rubber content showed a single glass-transition temperature (Tg) in differential scanning calorimetry studies (DSC) in the whole composition range indicating miscibility. Although two Tgs, one associated with PC phase and one with ABS phase, were observed for blends containing high rubber ABS, the shift in Tgs with respect to pure component values indicates partial miscibility. The decrease in the extent of shift with increase of ABS in these blends indicates undesirable phase separation due to poor adhesion of higher level of rubber content.     

Influence of Maleic Anhydride Grafted Ethylene-Vinyl Acetate Copolymer as a Compatibilizer on Combustion and Thermal Stability Properties of Magnesium Hydroxide Flame-Retardant Ethylene Propylene Diene Terpolymer Composites

New halogen-free, flame-retardant ethylene propylene diene terpolymer (EPDM)/organically modified magnesium hydroxide (MH) composites have been prepared via melt compounding method, using maleic anhydride grafted ethylene-vinyl acetate copolymer (MAH-g-EVA) as a compatibilizer. Influence of MAH-g-EVA on the fire and thermal properties of the composites are investigated by means of LOI, UL94 vertical burning, cone calorimeter tests, thermogravimetric analysis (TGA), real time fourier-transform infrared spectroscopy (RTFTIR) and environmental scanning electron microscopy (ESEM). The results show that MAH-g-EVA plays a positive role in improving the flame retardancy and thermal stability of the composites.     

乙烯-丙烯嵌段共聚物与高密度聚乙烯熔体相容性的探讨

利用MiniLab微型混合流变仪测定高聚物熔体平衡转矩-转速关系曲线,探讨乙烯-丙烯嵌段共聚物(E-b-P)和高密度聚乙烯(HDPE)的熔体相容性.结果表明:Eb-P/HDPE共混物熔体是完全互容的,HDPE对E-B-P中的PE链段有更大的亲和力,可形成不同的核壳结构,使共混物的平衡转矩偏离原有的加和性,表现出协同效应.     

Use of Monomethyl Itaconate Grafted Poly(propylene) (PP) and Ethylene Propylene Rubber (EPR) as Compatibilizers for PP/EPR Blends

The use of grafted poly(propylene) (PP) and a random copolymer of ethylene and propylene (EPR) with an itaconic acid derivative, monomethyl itaconate (MMI), as compatibilizer for PP/EPR blends was analyzed. The grafting reaction was performed at 190 °C in a Brabender Plasticorder. 2,5‐Dimethyl‐2,5‐bis(tert‐butylperoxy) hexane was the radical initiator for the functionalization of PP; dicumyl peroxide was used as the radical initiator for the modification of EPR. The obtained degree of grafting was 1.5% by weight for PP and 1.2% by weight for EPR. The compatibilizing effect of modified polymers on the processability, morphology, and mechanical and thermal properties of the blends was of interest. Compatibilization substantially improved the toughness and deformation with little effect on the tensile modulus and strength. Moreover, this effect was particularly evident when both polymeric phases were grafted. Regarding compatibilization, the viscosity of the blends increased due to the high interfacial adhesion. Morphological studies showed that the particle size of the rubbery phase was reduced and the dispersion in the matrix improved by compatibilization. The grafted polymers behaved as nucleating agents, accelerating the PP crystallization.

Change in complex viscosity with angular frequency at 180 °C for unmodified and MMI‐functionalized PP/EPR (70/30) blends.     

Thermal Characterization of Polyhydroxyalkanoates and Poly(lactic acid) Blends Obtained by Injection Molding

In this work we present the thermal characterization of the full scope of polyhydroxyalcanoate and poly(lactic acid) blends obtain by injection molding. Blends of polyhydroxyalcanoate and poly(lactic acid) (PHA/PLA) were prepared in different compositions ranging from 0–100% in steps of 10%. The blends were injection molded and then characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD). The increment of PHA fraction increased the degree of crystallinity of the blend and the miscibility of the base polymers as verified by the Fox model. The WAXD analysis indicates that the presence of PHA hindered the PLA crystallization. The crystallization evolution trough PHA weight fraction (wf) shows a phase inversion around 50-60%. SEM analyses confirmed that the miscibility of PHA/PLA blends increased with the incorporation of PHA and became total for values of PHA higher that 50%.     

Effect of Silica on Uncompatibilized and Compatibilized Styrene Butadiene Rubber and Nitrile Rubber Blends

The present paper investigates the interaction of silica filler in uncompatibilized and compatibilized styrene butadiene rubber/nitrile rubber (SBR/NBR) blends of varying compositions. The use of a dynamic mechanical analyzer as a tool for confirming the compatibility by the addition of dichlorocarbene modified styrene butadiene rubber (DCSBR) in these blends has been described. The addition of silica in uncompatibilized as well as compatibilized blends has been found to be increasing the rheometric-processing characteristics such as maximum viscosity and rate of cure. The magnitude of these values has been found to be higher for compatibilized blends and for 50/50 composition. The optimum cure time has been found to be decreasing with silica loading regardless of the presence of the compatibilizer. The magnitude of optimum cure time has been found to be higher for uncompatibilized system and for the composition with higher SBR content. Enhancement in mechanical properties with the addition of silica has been observed for compatibilized blends, more intensely than uncompatibilized samples. A good correlation between mechanical properties and solvent sorption behavior has also been observed.     

增塑剂对聚乳酸/热塑性淀粉共混物结构与性能的影响

采用柠檬酸三丁酯(TBC)、聚乙二醇(PEG)增塑聚乳酸(PLA)/热塑性淀粉(TPS)共混体系,调节PLA的流变性能,改善PLA与TPS相容性、熔融共混特性和共混物的微观结构和力学性能.结果表明:TBC的改性效果比PEG更佳;TBC能增加TPS分散均匀性,相分散尺寸明显变小;TBC改性PLA/TPS的拉伸强度和断裂伸长率明显提高.吸水率较小.     

Properties of Polypropylene (PP)/Ethylene-Propylene Diene Terpolymer (EPDM)/Natural Rubber (NR) Vulcanized Blends: The Effect of N,N-m-Phenylenebismaleimide (HVA-2) Addition

This paper discusses process development, tensile properties, morphology, oil resistance, gel content, and thermal properties of polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) vulcanized blends with the addition of N,N-m-phenylenebismaleimide (HVA-2) as a compatibilizer. Blends were prepared in several blend ratios in a Haake Polydrive with temperature and rotor speed of 180°C and 50 rpm, respectively. Results indicated that the combination of dicumyl peroxide (Dicup) with HVA-2 shows high torque development and stabilization torque as compared to the blend with Dicup vulcanization alone. In terms of tensile properties, the combination of Dicup with HVA-2 shows higher tensile strength, tensile modulus (M₁₀₀), elongation at break, oil resistance, and gel content in all blend ratios compared to similar vulcanized blends with Dicup without HVA-2 addition. Scanning electron microscope (SEM) micrographs of the blends support that the cross-linking and compatibilization occur during the process of the vulcanized blend containing HVA-2. In the case of crystallinity of the blends, the addition of HVA-2 in Dicup vulcanized blend revealed a tendency for the percentage of crystallinity (Xc) to decrease. The addition of HVA-2 in Dicup vulcanization also produced blends with good thermal stability dealing with the so-called coagent bridge formation.