The Effects of Dynamic Vulcanization by Dicumyl Peroxide (DCP) and N,N-m-Phenylene Bismaleimide (HVA-2) on the Properties of Polypropylene (PP)/Ethylene-Propylene Diene Terpolymer (EPDM)/Natural Rubber (NR) Blends

ABSTRACT

This paper discusses some properties of the polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) blends, such as tensile properties, heat resistance, gel content, and morphology. Dicumyl peroxide (DCP) and N,N-m-phenylene bismaleimide (HVA-2) and their combination were applied in PP/EPDM/NR blends as cross-link agents. In terms of tensile properties, the combination of DCP with HVA-2 shows the highest tensile strength and elongation at break in all PP/EPDM/NR blend ratios compared to similar blends, except with DCP or HVA-2 alone. The addition of HVA-2 produced blends with good heat resistance, while the combination of DCP with HVA-2 shows the highest gel content dealing with the cross-links formation. SEM micrographs from the surfaces extraction of the blends support that the cross-links have occurred during dynamic vulcanization process.     

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.     

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.     

EPDM/氟橡胶的动态硫化

研究了 Ｅ Ｐ Ｄ Ｍ 硫化体系、硫化剂叔丁基苯酚甲醛树脂（２４０２ 树脂） 用量以及动态硫化时间对 Ｅ Ｐ Ｄ Ｍ／氟橡胶共混物物理性能的影响。结果表明,当２４０２ 树脂用量超过３０ 份时, Ｅ Ｐ Ｄ Ｍ 的硫化程度和动态硫化共混物的力学性能不再变化;动态硫化时间对共混物物理性能的影响不明显。     

The Effect of Dynamic Vulcanization on the Mechanical Properties of EPDM/PP Thermoplastic Elastomers

ABSTRACT

EPDM/PP blends were prepared by melt mixing using Brabender Plasticorder at 200°C and 100 rpm. The curative concentration was progressively increased from 1 to 3.5 phr EPDM in order to study the influence of dynamic vulcanization on the mechanical properties of the blend. The effectiveness of dynamic vulcanization was ascertained by Brabender torque Rheometry, the increase in crosslink density, and the reduction in swelling index as well. The mechanical properties were found to increase with sulfur up to 1.4 phr after which reversion occurred. Scanning electron micrographs were inspected to differentiate between the cured EPDM/PP TPEs and the uncured counterpart. The micrographs showed that the blended system contains two incompatible phases. This is evident in both the case of the dynamically cured sample where the EPDM phase remains as dispersed particles in the PP matrix, and in the case of the uncured blend where the EPDM and PP formed two continuous phases.     

Flow Behavior of Polypropylene/Ethylene-Propylene Diene Terpolymer/Natural Rubber (PP/EPDM/NR) Blends by Torque Rheometer: The Effect of N,N-m-Phenylene Bismaleimide (HVA-2) Addition

Blends of polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) with different ratio were investigated using a Haake torque rheometer. The effect of N,N-m-phenylene bismaleimide (HVA-2) addition on the flow behavior of PP/EPDM/NR blends also was studied. The torque data was collected at different rotor speeds in the range of 30–60 rpm and different processing temperatures in the range of 170–190°C. The recorded data were interpreted in terms of apparent shear rate, apparent shear stress, and apparent viscosity. The shear stress–shear strain curve shows that all blends follow the power law where the pseudoplasticity behavior of melt viscosity increases with increasing NR content as well as addition of HVA-2. The apparent viscosity of the blends was found to increase with increasing NR content in the blend. The addition of HVA-2 increases the apparent viscosity due to the formation of cross-linking in rubber phase. However, blends with HVA-2 show lower flow activation energies than do similar blends without HVA-2. Scanning electron microscopy (SEM) shows good correlation with the flow properties of the blends.     

动态硫化增韧聚丙烯／三元乙丙橡胶共混物的研究

研究了动态硫化和简单共混增韧聚丙烯（PP）／三元乙丙橡胶（EPDM）共混物的力学性能、形态结构、流动性能和脆韧转变。结果表明：动态硫化的增韧效率要比简单共混的增韧效率高；随着EPDM用量的增加，共混物的力学性能均随之发生变化，流动性明显降低；简单共混物的橡胶颗粒尺寸随EPDM含量的增加呈增大趋势，而动态硫化可以降低橡胶颗粒的尺寸；动态硫化物的临界基体层厚度大约为0.3μm，简单共混物的临界基体层厚度大约为0．2μm，并且动态硫化和简单共混物均在各自的临界基体层厚度处发生脆韧转变，验证了wu氏增韧理论。     

工艺因素对PP／EPDM动态硫化作用的研究

通过冲击试验、熔体指数、共混平衡扭矩（ＴＱ）和交联程度测试以及扫描电镜观察等手段,研究了引发剂用量和动态硫化时间两大工艺因素对ＰＰ／ＥＰＤＭ动态硫化过程以及动态硫化物性能的影响。结果显示,引发剂ＤＣＰ用量以能引发全部ＥＰＤＭ交联并稍过量为宜;硫化时间应控制在引发剂半衰期的６～７倍较为理想     

工艺因素对动态硫化EPDM/PP热塑性弹性体性能影响

本文综合地介绍了投料顺序、共混时间、共混温度、剪切速率以及制备设备等工艺因素对动态硫化EPDM/PP热塑性弹性体性能的影响。     

动态硫化EPDM/高聚合度PVC热塑性弹性体力学性能的研究

采用动态硫化的方法制备了三元乙丙橡胶（EPDM）/高聚合度聚氯乙烯（HPVC）热塑性弹性体。考察了PVC聚合度、橡塑比、增塑剂添加量、硫化剂用量（质量分数）及不同促进剂配比对体系性能影响,研究了动态硫化工艺条件（硫化时间和硫化温度）对体系性能的影响。实验结果表明：采用动态硫化方法,选用HPVC-2500、橡塑比为30/70、DOP用量为35份、硫化用量为0.4份及合适促进体系,可以制得性能优良的EPDM/HPVC热塑性弹性体,拉伸强度能达到15.18 MPa,断裂伸长率能达到544%。     

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.

     

DSC法对动态硫化PP／EPDM中PP—EPDM共交联结构的研究

根据共交联ＰＰ分子与正常ＰＰ分子在结晶与熔融特征及其对外因素响应上的差异,采用ＤＳＣ分析方法,研究了动态硫化ＰＰ／ＥＰＤＭ中ＰＰ－ＥＰＤＭ共交联结构。结果显示在动态硫化ＰＰ－ＥＰＤＭ的熔融ＤＳＣ曲线上的１５０℃曲线上约１５０℃处出现一新的熔融峰,改变结晶速率或ＤＳＣ测试程序,可发现形成这一新峰的化学结构具有强烈的结晶滞后性,而简单共混ＰＰ／ＥＰＤＭ的ＤＳＣ曲线上始终未出现类似新峰。结合化学反应理论     

动态硫化PP／EPDM性能对共混工艺的依赖及其机理研究

本文通过对一步法和母料法两种共混工艺制备的动态硫化ＰＰ／ＥＰＤＭ力学性能、拉伸形变特性,熔体流动行为,交联程度和微观结构等的表征和分析,研究了动态硫化ＰＰ／ＥＰＤＭ性能对共混工艺的依赖及其作用机理。结果显示,在保证有效地提高材料加工流动性的前提下,母料法能有效地抑制动态硫化中ＰＰ的降解,提高ＥＰＤＭ的交联程度,粒度均匀性和分散均匀性,从而强化材料的增韧效果以及其它力学性能,并提高材料性能的均匀性。     

Properties of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites: The Effect of Silane-Based Coupling Agent

Paper sludge was used as a filler in PP/EPDM composites and 3-aminopropyl triethoxysilane (3-APE) was used in this study as a coupling agent. The effects of filler loading and 3-APE on the mechanical properties, water absorption, morphology, and thermal properties of the composites were investigated. It was found that incorporation of a silane coupling agent (3-APE) increased the stabilization (equilibrium) torque, tensile strength, and Young's modulus but decreased the elongation at break and water absorption. Scanning electron microscopy (SEM) study of the tensile fracture surface of the composites indicated that the presence of 3-APE increased the interfacial interaction between paper sludge and PP/EPDM matrix. The addition of a silane coupling agent also increased the crystallinity of PP and thermal stability of PP/EPDM/PS composites.     

MOS阻燃动态硫化PP/EPDM性能研究

结合碱式硫酸镁晶须（MOS）的补强和阻燃功能，以微胶囊红磷（MRP）为协效剂，制备了无卤阻燃型PP（聚丙烯）／EPDM（三元乙丙橡胶）／MOS／MRP共混物，并与PP／EPDM／Mg（OH）2／MRP共混物进行比较。氧指数（LOI）及垂直燃烧（UL-94）测试表明MOS的阻燃效果优于Mg（OH）2。力学性能测试表明，MOS对PP／EPDM热塑性雌性体具有一定的增强作用，PP／EPDM／MOS／MRP阻燃体系的力学性能明显优于PP／EPDM／／MRP阻燃体系。而PP／EPDM热塑性弹性体的动态硫化进一步提高了PP／EPDM／MOS／MRP阻燃体系的力学与阻燃性能。     

动态硫化PP／HDPE／EPDM三元共混物的流变性能

本文采用不同的硫化剂，不同的硫化时间，对动态硫化的ＰＰ／ＨＤＰＥ／ＥＰＤＭ三元共混物的流变性能进行了研究。结果表明：１共混体系为假塑体，表现出切力变稀现象；２在低剪切应力下，以Ｍ为硫化剂的粘度与纯机械共混体系的粘度有很大差值，此差值随剪切应力的提高迅速减少；３以ＤＣＰ为硫化剂，体系的粘度低于纯机械共混体系的粘度。     

Effects of Natural Weathering on Properties of Recycled Newspaper-filled Polypropylene (PP)/Natural Rubber (NR) Composites

Natural weathering has been applied to investigate the properties of recycled newspaper (RNP)-filled polypropylene (PP)/natural rubber (NR) composites. Three sizes of RNP (11 mm, 23 mm, and 53 mm) were used in this study. These composites were subjected to natural weathering conditions; i.e, tropical climate in Penang, Malaysia, for 3 and 6 months. Different techniques including mechanical tests, Fourier transform infrared spectrometry (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used in order to obtain a comprehensive view of degradation occurring during the natural weathering of the composites. Results of mechanical tests show that an increasing content of RNP in composites decreased the tensile strength and elongation at break (EB), while increasing the Young's modulus after exposure of 3 and 6 months. Scanning electron microscopy on surfaces after weathering shows that the filler was poorly wetted by the matrix. This explains the reduction in tensile strength and elongation at break after weathering. The Fourier transform infrared spectrometry results on the composites after exposure to natural weathering indicate the presence of carbonyl, vinyl, and hydroxyl groups, which formed from various chemical reactions taking place during weathering.     

交联硫化体系对PP／POE／EPDM热塑性弹性体性能的影响

采用动态硫化法制备聚丙烯／聚烯烃弹性体／三元乙丙橡胶（PP/POE／EPDM）共混型热塑性弹性体,研究了交联前后不同POE／EPDM并用对比体系力学性能的影响。采用交联剂过氧化二异丙苯（DCP）及DCP／S硫化体系对PP／POE／EPDM体系进行硫化,研究了力学性能的变化。结果表明,EPDM可有效降低材料的硬度和断裂永久变形。助交联剂硫黄（S）对PP／POE／EPDM体系有较好的硫化作用,固定DCP用量为3份,S用量为0．4份时,体系力学性能最佳,交联对体系硬度影响很小。     

Effects of Dynamic Vulcanization and Acrylic Acid on Properties of Recycled Poly(vinyl chloride)/Acrylonitrile Butadiene Rubber (PVCr/NBR) Blends

Effects of dynamic vulcanization and acrylic acid (AAc) on processability, mechanical properties, swelling behavior, morphology, and thermal stability of recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were investigated. Blends were prepared in a Haake Rheomix at a temperature of 150°C and a rotor speed of 50 rpm. Recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were also prepared as comparison. It was found that the dynamic vulcanization and the addition of acrylic acid improved the stabilization torque, mechanical energy, stress at peak, stress at 100% elongation (M₁₀₀), swelling resistance, and thermal stability but decreased the elongation at break of the blends. The introduction of a cross-link into the elastomer phase and better compatibility between PVCr and NBR are responsible for the enhancement of thermal stability and mechanical properties of dynamically vulcanized PVCr/NBR + AAc as evidence from the scanning electron microscopy (SEM) of the tensile fracture surfaces and infrared spectroscopy study of the dynamically vulcanized of PVCr/NBR + AAc shows.     

Thermal Stability and Crystallization Behavior of TER Blends of Isotactic Polypropylene (iPP)/Ethylene-Propylene Diene Rubber (EPDM)/Nitrile Rubber (NBR)

The blends of isotatic polypropylene (iPP), ethylene-propylene diene rubber (EPDM), and nitrite rubber (NBR) were prepared using dimethylol phenolic resin as a crosslinking system. The dynamically crosslinked blends of iPP/EPDM/NBR showed superior thermal stability to that of virgin isotactic polypropylene (iPP). Dynamic crosslinking rendered the vulcanizate thermally more stable as compared to uncrosslinked blends, which can be attributed due to the variations in degree of crosslinking and degree of crystallinity.

Crystallization of iPP in the blends of iPP/EPDM/NBR was also studied through Temperature Modulated Differential Scanning Calorimetry (TMDSC). Other detailed analysis of endotherm peaks obtained after first and second melts in terms of heat of enthalpy, degree of undercooling, and degree of crystallinity were also evaluated. Various kinetic parameters were also determined. Degree of crosslinking increases the interfacial adhesion between the iPP and EPDM/NBR phases. Dimethylol phenolic resin used as a compatibilizer also enhanced the thermal stability of the iPP/EPDM/NBR blends.