Properties of dynamically vulcanized EPDM and LLDPE blends

The tensile, rheological, and thermal properties of dynamically vulcanized ethylene–propylene–diene terpolymer (EPDM) and linear low-density polyethylene (LLDPE) blends were reported along with their crystalline structure and morphology. The EPDM/LLDPE blends were prepared in a laboratory internal mixer by simultaneous blending and vulcanization. Vulcanization was performed with dicumyl peroxide. For comparison, linear LLDPE/EPDM blends were also prepared. In comparison to the linear blends, dynamically vulcanized blends showed higher tensile strength and modulus and exhibited improved compatibility. It was found, however, that the crystal structure of LLDPE was not changed by the inclusion of EPDM and the dynamic vulcanization process. © 1996 John Wiley & Sons, Inc.     

氟橡胶/EPDM动态硫化共混物的研究

研究了动态硫化工艺条件和共混比对氟橡胶（ＦＫＭ）／ＥＰＤＭ共混物拉伸性能拉、热油老化性能和应力松弛性能的影响。结果表明：与直接静态硫化相比,动态硫化可避免两种硫化体系的相互影响;静态硫化共混物拉伸强度只有２ＭＰａ,而动态硫化共混物可达１０ＭＰａ以上;工艺条件对动态硫化共混物性能的影响不大;随共混物中ＥＰＤＭ用量的增大,共混物的热空气老化和热油老化性能均有所下降     

EPDM熔融接枝甲基丙烯酸缩水甘油酯及其与NR动态硫化共混物的性能

研究了三元乙丙橡胶熔融接枝甲基丙烯酸缩水甘油酯（ＧＭＡ）的接枝反应温度、过氧化二异丙苯（ＤＣＰ）及ＧＩＭ用量对ＥＰＤＭ－ｇ－ＧＭＡ／ＮＲ动态硫化共混物力学性能的影响。结果表明：与直接静硫化胶相比,动态硫化胶的拉伸强度提高了４８．２％;接枝反应温度８为１６０℃、ＤＣＰ用量为０．３份、ＧＭＡ用量为３￣５份时,动态硫化共混物的力学性能较好。另外红外光谱测试结果表明,在ＥＰＤＭ上已成功接枝了ＧＭＡ。     

On the compatibilization and dynamic vulcanization of polyacetal/ethylene propylene diene terpolymer blends

This study describes an attempt to improve the impact resistance of polyacetal (POM)/ethylene propylene diene terpolymer (EPDM) blends by means of compatibilization and dynamic vulcanization. A commerical copolymer, poly(acrylic acid)-grafted polypropylene (PGP), has been used as a compatibilizer to control the phase morphology of the blend system. Dicumyl peroxide is used to dynamically vulcanize the EPDM elastomer in the blend. At temperatures higher than 185°C, the compatibilizer decreases the viscosity of compatibilized and dynamically vulcanized (cdv) POM/EPDM blends. Impact strength of the cdv blend system increases considerably with a marginal decrease in tensile yield stress and heat deflection temperature as the PGP content increases. The significant increase in impact strength seems to be due to the role of PGP as a linking agent for the binary blends rather than as a third component. Though dynamic mechanical studies do not indicate any compatibility in cdv-POM/EPDM blends, scanning electron microscopy reveals the strong interpenetrating interphase in the compatibilized blend system. Dynamic vulcanization raises elastic recovery and tensile modulus of the blends. Hysteresis energies of the blends increase consistently with the addition of PGP. The crystalline structure of POM is not affected by compatibilization and vulcanization. © 1994 John Wiley & Sons, Inc.     

The Effect of Dynamic Vulcanization on the Properties of Polypropylene/Ethylene-Propylene Diene Terpolymer/Natural Rubber (PP/EPDM/NR) Ternary Blend

The effects of dynamic vulcanization on the process development and some properties, such as tensile properties, swelling index, gel content, crystallinity, and morphology, of the polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) blends were investigated. Dynamically vulcanized blends show higher stabilization torque than unvulcanized blends. In terms of tensile properties, the tensile strength and tensile modulus (stress at 100% elongation, M₁₀₀) of the vulcanized blends have been found to increase as compared with the unvulcanized blends, whereas the elongation at break is higher in the blend with richer EPDM content. These results can be attributed to the formation of cross-linking in the rubber phase. The formation of cross-links in the rubber phase has also been proved by swelling index and gel content. The percentage of crystallinity of the blends is decreased by dynamic vulcanization. Scanning electron microscopy (SEM) micrographs from the surface extraction of the blends support that the cross-links occurred during dynamic vulcanization.     

动态三螺杆挤出机制备热塑性硫化胶的研究

对比分析了动态热塑性硫化胶(TPV)的加工设备,着重介绍了附加振动力场的三螺杆反应挤出机的结构特点以及利用该机进行三元乙丙橡胶/聚丙烯(EPDM/PP)的动态全硫化,对制品的物理力学性能和微观结构分别进行了测试分析和电镜扫描。结果表明,振动力场作用下EPDM/PP共混体系反应挤出动态硫化加工可有效地实现动态硫化反应、硫化橡胶的粉碎和分散以及相态反转,振动力场的作用明显提高了TPV性能。     

EPDM/iPB共混型热塑弹性体的制备与性能

通过对比不同共混比的EPDM/iPB共混体系动态硫化与未硫化的力学性能研究发现,动态硫化后的EPDM/iPB体系的性能明显优于未硫化的,当EPDM/iPB的配比为60/40、动态硫化的时间为6min时,综合性能较好;同时,研究了硫化剂和硫化时间等因素对EPDM/iPB力学性能的影响,结果表明:采用DCP/S作为硫化剂、...     

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.     

The Effect of Dicumyl Peroxide Vulcanization on the Properties & Morphology of Polypropylene/Ethylene-Propylene Diene Terpolymer/Natural Rubber Blends

ABSTRACT

This article discusses some properties such as tensile properties, chemical and oil resistance, gel content, crystallinity, and morphology of polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) blends. Dicumyl peroxide (DCP) was applied as a crosslinking agent. In terms of tensile properties, peroxide vulcanized blend shows higher tensile strength and tensile modulus (stress at 100% elongation, M₁₀₀) as compared with the unvulcanized blend. The elongation at break of the peroxide vulcanized blend is higher for the blend with NR rich content compared with the EPDM rich content. The improvements in chemical and oil resistance as well as gel content of peroxide vulcanized blends have also proved the formation of crosslinks in the rubber phase. Scanning electron microscopy (SEM) micrographs from the surface extraction of the blends support that the crosslinks have occurred during dynamic vulcanization. Dynamical vulcanization with DCP has decreased the percent crystallinity of blends that can be attributed to the formation of crosslinks in the rubber.     

The control of miscibility of PP/EPDM blends by adding lonomers and applying dynamic vulcanization

The control of miscibility for isotactic polypropylene (PP) and ethylene-propylene-diene terpolymer (EPDM) has been attempted by adding poly(ethylene-comethacrylic acid) (EMA) ionomers and by applying dynamic vulcanization. The rheological properties, crystallization behavior, and morphology of the dynamically vulcanized EPDM/PP/ionomer ternary blends were investigated with a Rheometrics dynamic spectrometer (RDS), a differential scanning calorimeter (DSC), and a scanning electron microscope (SEM). Two kinds of EMA ionomers neutralized with different metal ions (Na⁺ and ZN⁺⁺) were investigated. Blends were prepared on a laboratory internal mixer at 190°C. Blending and curing were performed simultaneously, i.e., EPDM was vulcanized with dicumyl peroxide (DCP) in the presence of PP/ionomer. The composition of PP and EPDM was fixed at 50/50 by wt% and the contents of EMA ionomer were vaired from 5 to 20 parts based on the total amount of PP and EPDM. It was found that the addition of ionomers and the application of the dynamic vulcanization were effective in enhancing the miscibility of PP and EPDM. The structure of the blends was controlled by the following three component phases, i.e., the phase of the dynamially valcanized EPDM, PP, and Zn-neutralized ionomer. The ternary blends showed more miscibility than the PP/EPDM binary blend. This is due to the thermoplastic interpenetrating polymer network (IPN) of the ternary blends. The structure and properties of the ternary blends differed, depending on the types and contents of ionomer, i.e., the ternary blend containing Na-neutralized ionomer did not show a thermoplastic IPN structure clearly, even though the blend was prepared by dynamic vulcanization. The ternary blend containing Zn-neutralized ionomer clearly showed the behavior of a thermoplastic IPN when the contents of ionomer and DCP were 15 parts and 1.0 part, respectively.     

EPDM/PA硫化共混物力学行为的模拟

采用Rivlin模型对EPDM／聚酰胺（PA）硫化共混物的单轴拉伸力学行为进行模拟。结果表明，2个参数的Ri。lin模型可以较好地描述PA用量不超过30份时EPDM／PA静态硫化共混物的应力-应变行为；3和5个参数的Rivlin模型在PA试验用量范围内对静态硫化共混物的拟合效果很好。3个参数的Rivlin模型可以很好地描述EP-DM／PA动态硫化共混物的应力-应变行为，但PA用量过大时，EPDM／PA动态硫化共混物显示出明显的塑料特征，拟合曲线与试验数据有所偏离。     

Dynamic properties of rubber vibration isolators and antivibration performance of ethylene–propylene–diene monomer/nylon 6 blend systems

This article examines thermoplastic elastomers (TPEs) and thermoplastic vulcanizates (TPVs) as two types of elastomers from melt-blended and dynamically vulcanized ethylene–propylene–diene monomer (EPDM) rubber materials and nylon 6 plastic materials. A series of investigations were conducted on the mechanical properties, morphology, dynamic mechanical properties, hysteresis behavior, and dynamic antivibration properties with different nylon 6 contents. The experimental results showed that the incompatibility between EPDM and nylon 6 led to the easy destruction of the TPV materials in two interfacial polymers upon the application of an external force. Thus, after a dynamic vulcanization process, the mechanical properties of the EPDM/nylon 6 blends were not as good as those of the TPE materials. In terms of morphology, nylon 6 plastics were uniformly distributed in the EPDM/nylon 6 blends during the EPDM rubber phase before vulcanization was performed. After the dynamic vulcanization, phase inversion was produced in which rubber microparticles were formed and dispersed in the nylon 6 plastic phase. The results of dynamic mechanical analysis, compression vibration hysteresis behavior, and dynamic property antivibration experiments showed that the blends provided better vibration isolation and antivibration performance after the amount of nylon 6 was increased and EPDM and nylon 6 were blended through dynamic vulcanization. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

振动力场强化动态全硫化EPDM/PP热塑性硫化胶的研究

介绍了动态三螺杆反应挤出机的结构特征,采用动态三螺杆反应挤出机对EPDM/PP共混物进行动态全硫化挤出,并对其制品的物理力学性能进行了测试分析以及微观结构的电镜扫描分析,结果表明,由于在动态全硫化挤出的全过程中引入了振动力场,经动态三螺杆反应挤出机动态全硫化挤出的热塑性硫化胶(TPV)具有优化的微观结构,力学性能优异。     

环氧树脂对EPDM性能影响的研究

研究了环氧树脂用量对三元乙丙橡胶工艺性能和力学性能的影响,研究结果发现,环氧树脂对三元乙丙橡胶有增塑和增粘作用,影响了其硫化特性,并降低了三元乙丙橡胶硫化胶的力学强度.     

加工方法对动态硫化的聚丙烯/三元乙丙橡胶/甲基丙烯酸锌复合材料的力学性能影响

通过三种不同的加工手段,制备了动态硫化的聚丙烯(PP)/三元乙丙橡胶(EPDM)/甲基丙烯酸锌(ZDMA)复合材料。结果表明,Haake密炼机制备的复合材料综合性能较佳,并且较低的加工温度能够获得综合性能较好的PP/EPDM/ZDMA复合材料。力学性能的数据表明,EPDM的加入,在降低了PP拉伸强度的同时,增加了PP的韧性,而加入ZDMA则进一步提高了复合材料的冲击强度。     

共混橡胶的共硫化研究

探讨了多种共混橡胶的共硫化体系及其对共混橡胶性能的影响。其中采用共硫化剂硫化CO/ECO、CSM/NBR、IIR/EPDM、IIR/CIIR共混胶,采用复合硫化剂硫化PUR/CR、ACM/ECO、ACM/NBR、CR/CIIR、CR/SBR共混胶,研究了硫化体系品种和用量对几种共混胶的硫化特性和力学性能的影响,为共混橡胶的硫化提供研究方案和理论指导。     

Comparison of Rheological and Mechanical Behavior of Dynamically and Statically Vulcanized PP/SBS Blends

Summary Rheological behavior of dynamically and statically vulcanized blends of isotatic Polypropylene (PP) and 20% wt Styrene-Butadiene-Styrene block copolymer (SBS) was studied with reference to the effect of extrusion conditions, curing agents (sulphur, peroxide) and curing times. All blends showed pseudoplastic behavior. When using sulphur, a slight increase on melt viscosity was observed, showing no differences with vulcanization method or with pre-vulcanization time. With peroxide, melt viscosity changed drastically. Dynamically vulcanized blends with sulphur showed a noticeable rise on elongation at break as well as on toughness while those statically vulcanized showed very low values on these properties.     

Blends of polyacetal and ethylene-octene elastomer: Mechanical,dynamic mechanical and morphological properties

Polyacetal (POM) and ethylene octene copolymer(EOC) elastomers form immiscible blends with extremely low compatibility. In order to improve the dispersion, stability and properties of these blends, dynamic vulcanization was carried out in a twin screw extruder using dicumyl peroxide. The tensile strength decreased with increase in % elongation at break for both blend systems. There was a drastic decrease in impact strength for unvulcanized blends as the elastomer content increased and this was attributed to the coalescence of the elastomer particles as their content increased. In the case of dynamically vulcanized blends there was a significant increase in impact strength as the levels of elastomer increased. Dynamic mechanical analysis has been carried out to investigate the effect of blend composition and dynamic vulcanization on dynamic mechanical parameters such as storage modulus, loss modulus and loss factor. The results indicate gross incompatibility of POM and EOC blends. However, dynamically vulcanized blends show better adhesion between component polymers. The morphological studies reveal that the particle size and coalescence of elastomer was significantly reduced in comparison to unvulcanized bends. The phase adhesion was improved by dynamic vulcanization. Hence, it was observed that dynamic vulcanization effectively improves the morphology of the blend system and enhances the properties of polyacetal.     

Mechanical,thermal, and morphological characteristics of compatibilized and dynamically vulcanized polyoxymethylene/ethylene propylene diene terpolymer blends

Dynamically vulcanized blends of polyoxymethylene (POM) and ethylene propylene diene terpolymer (EPDM) with and without compatibilizer were prepared by melt mixing in a twin screw extruder. Maleic anhydride (MAH) grafted EPDM (EPDM‐g‐MAH) has been used as a compatibilizer. Dicumyl peroxide was used for vulcanizing the elastomer phase in the blends. Mechanical, dynamical mechanical, thermal, and morphological properties of the blend systems have been investigated as a function of blend composition and compatibilizer content. The impact strength of both dynamically vulcanized blends and compatibilized/dynamically vulcanized blends increases with increase in elastomer content with decrease in tensile strength. Dynamic mechanical analysis shows decrease in tanδ values as the elastomer and compatibilizer content increased. Thermograms obtained from differential scanning calorimetric studies reveal that compatibilized blends have lower T_m values compared to dynamically vulcanized blends, which confirms strong interaction between the plastic and elastomer phase. Scanning electron microscopic observations on impact fractured surface indicate reduction in particle size of elastomer phase and its high level of dispersion in the POM matrix. In the case of compatibilized blends high degree of interaction between the component polymers has been observed. POLYM. ENG. SCI., 47:934–942, 2007. © 2007 Society of Plastics Engineers     

PA6／POE-g-MAH体系的结构与性能研究

以动态硫化及非动态硫化方法制备了马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)增韧的聚酰胺6(PA6) 共混物,研究了PA6／POE-g-MAH体系的力学性能以及POE-g-MAH在PA6中的分散状况。结果表明动态硫化 PA6／POE-g-MAH共混物的屈服强度、冲击强度、断裂伸长率及弯曲模量均高于非动态硫化方法制备的PA6／POE-g- MAH共混物,动态硫化的PA6／POE-g-MAH共混物可以在材料的刚性与韧性之间达到良好的平衡。扫描电子显微镜图像的统计分析表明,非动态硫化PA6／POE-g-MAH共混物中分散的橡胶相数均颗粒尺寸随组成中POE-g-MAH 的含量增大而不断增大,动态硫化的PA6／POE-g-MAH共混物中分散的橡胶相数均颗粒尺寸随POE-g-MAH含量的增大变化不大。