反应性聚丙烯/三元乙丙橡胶共混物的流变性能研究

采用高压毛细管流变仪 ,研究了EPDM含量、交联剂、交联助剂等因素对反应性PP/EPDM共混物性能的影响。结果表明 ,EPDM分散相浓度为 2 0～ 2 5phr,反应共混工艺对体系的消缠降粘效果显著 ;交联剂A的含量越高 ,体系表观粘度越小 ,但粘度对剪切的响应不敏感 ;交联剂B和并用交联剂S可抑制PP降解 ,进一步优化材料力学性能 ,并仍保持体系加工流动性高于简单共混PP/EPDM。     

PP／PE复合基材及其增韧研究

研究了PP/PE共混复合基材的力学性能和形态结构与组成配比的关系.结果表明,PP/HDPE/EPDM和PP/LLDPE共混体系可以制成具有高抗冲击性能的复合基材,且其他力学性能均衡,加工性能良好。弹性体SRS对复合基材的力学性能及形态有较大影响.实验结果表明,LLDPE具有分割、插入、细化PP球晶的作用,并与PP有较好的相容性;EPDM对PP/HDPE共混体系具有良好的增容效果。     

CaSO_4晶须对EPDM/PP热塑性弹性体相态结构和力学性能的影响

研究了硫酸钙晶须的加入对以三元乙丙橡胶(EPDM)和聚丙烯(PP)为基体材料的动态硫化热塑性弹性体(TPV)相态结构及力学性能的影响。采用差示扫描量热仪(DSC)分析了EPDM/PP的结晶性能,通过扫描电子显微镜(SEM)分析研究了TPV的微观相态结构,利用万能实验机等对其力学性能进行测试,并研究了TPV的耐热老化性能以及耐油性能。结果表明,经硅烷偶联剂处理过的硫酸钙晶须能与基体材料形成较好的界面包覆结构,其添加量为11%时,TPV的结晶温度提高了3.2℃,EPDM交联颗粒粒径最小,EPDM/PP的耐老化性能和耐油性能最好;当硫酸钙晶须添加量为8%时,压缩永久变形最小。     

聚丙烯/硫酸钙晶须复合材料的研究

采用活性硫酸钙晶须、增韧剂(乙烯/辛烯)共聚物(POE)和其它助剂与共聚聚丙烯(PP)通过熔融挤出共混制得PP/硫酸钙晶须复合材料。讨论了硫酸钙晶须含量对PP/硫酸钙晶须复合材料力学性能和热性能的影响,并探讨了硫酸钙晶须增强PP的机理,观察了PP/硫酸钙晶须复合材料的微观结构。结果表明,硫酸钙晶须在PP中分布均匀,能起到明显的增强作用。     

动态硫化PP/EPDM热塑性弹性体的研究进展

阐述了动态硫化聚丙烯(PP)/三元乙丙橡胶(EPDM)共混型热塑性弹性体的发展历史和发展状况;概述了动态硫化PP/EPDM共混型热塑性弹性体的硫化体系及硫化原理;总结了共混体系的成份配置和工艺条件对PP/EPDM共混物性能和结构的影响;简述了动态硫化PP/EPDM热塑性弹性体的研究现状与应用;最后展望了动态硫化PP/EPDM热塑性弹性体的发展趋势。     

共混时间对动态硫化EPDM/PP体系结构与性能的影响

研究了共混时间对动态硫化EPDM/PP体系结构、静态以及动态力学性能的影响。试验结果表明,随着共混时间的延长,EPDM/PP体系中PP相的结晶度先减小后增大,当共混时间为15min时,PP相的结晶度最小,PP的晶格结构未变化;EPDM相的交联密度逐渐增大,直至趋于一定值;EPDM的Tg峰向高温区移动;PP的Tg峰变化不明显,其tanδ峰值在共混时间为15min时最大;共混时间为12min时EPDM/PP体系的力学性能最佳。     

过氧化二异丙苯（DCP）在mEPDM／PP复合材料体系中的影响

本文采用过氧化二异丙苯为硫化剂对三元乙丙橡胶(EPDM)/聚丙烯(PP)进行了共混改性研究。通过改变体系中硫化剂过氧化二异丙苯(DCP)的量,对体系的力学性能进行了研究。结果表明:EPDM橡胶的动态硫化,大幅度提高了EPDM与PP体系的力学、加工性能;使其具有高流动,高抗拉伸性能。DCP的用量对PP/EPDM共混体系力学性能的影响较复杂,除了断裂伸长率,其它力学性能都有下降。应依据产品的不同要求,采用相应的用量比例。     

高模量弹性体对PP结晶行为及力学性能的影响

应用DSC和力学性能测试研究了PP/OTE、PP/EPDM共混物的结晶行为和它们的增韧作用。结果表明 ,烯烃类热塑性弹性体 (以下简称OTE)对PP的结晶性能无明显影响 ,EPDM对PP成核速率有促进作用。PP/OTE在赋予PP较好低温韧性的同时 ,使共混物的刚性得以适度兼顾 ,且易于加工。PP/OTE共混体系的综合性能优于PP/EPDM共混物     

动态硫化PP／EPDM／莫来石性能的研究

采用双螺杆挤出机制备了一系列聚丙烯(PP)/三元乙丙橡胶(EPDM)共混型热塑性弹性体(TPE).研究了莫来石对用不同动态硫化剂硫化的EPDM/PP TPE的力学性能、耐热性能,加工性能的影响,并与碳酸钙填充的效果进行了比较.结果表明,动态硫化制备的EPDM/PP TPE性能远高于非硫化的EPDM/PP共混物的性能.其冲击强度提高2倍,维卡软化点提高20℃;过氧化物、酚醛和环氧树脂中,环氧树脂硫化的TPE综合性能最佳,过氧化物适合于制备高流动性TPE;莫来石在TPE基体中分散良好,其填充体系的增韧效果、加工性能均优于碳酸钙的,但补强效果不明显.     

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。     

硫酸钙晶须／PP／EPDM复合材料力学性能研究

采用对硫酸钙晶须进行表面处理和提高ＰＰ／ＥＰＤＭ基体树脂极性的方法制得具有良好界面层的硫酸钙晶须／ＰＰ／ＥＰＤＭ复合材料。力学性能测试结果表明，硫酸钙晶须可提高ＰＰ／ＥＰＤＭ基体的拉伸强度和弯曲强度，通过控制各组分配比可制得韧性和刚度均衡的复合材料。     

CaSO4晶须与EPDM／PP共混型热塑性弹性体复合材料的研究

研究了ＣａＳＯ４晶须与三元乙丙橡胶／聚丙烯共混型热塑性弹性体复合材料的物理机械性能、耐热性能、热老化性能、材料的和各向异性、流变性能,考察了复合材料物理机械性能与晶须用量、界面特性、弹性模量等之间的依赖关系。应用ＳＥＭ观察和ＤＳＣ热分析以及ＴＧ热重分析研究复合材料结构－性能间关系中存在的一些制约机理。     

PPS/GF/晶须复合材料流变性能

利用熔融共混法制备了玻璃纤维(GF)增强聚苯硫醚(PPS)复合材料.采用毛细管流变仪对PPS/GF以及PPS/GF/CaSO4晶须复合材料的流变行为进行了表征.结果表明,PPS/GF复合材料的黏度随着剪切速率的增大而逐渐降低,呈现出明显的"剪切变稀"行为.随着GF用量的增加,PPS/GF复合材料的黏度逐渐升高,非牛顿指数n值逐渐降低.晶须用量为5份时,PPS/GF/CaSO4晶须复合材料的黏度最低,结构黏度指数较低,纺丝加工性能较好.复合材料的黏度随晶须用量的继续增加而增加.在310~315℃时复合材料的结构黏度指数下降幅度最小,表明该温度范围熔体流动最稳定.     

EPDM/PP共混物老化性能的研究

研究了三元乙丙橡胶改性聚丙炮共混物的性能,探讨了不同含量的ＥＰＤＭ对共混物的力学性能,热性能、流变性能的影响,还探讨了不同品种,不同含量的抗氧剂对共混物耐老性影响。     

EPDM分布形态对动态硫化PP/EPDM共混物增韧效果的影响及其机理的研究

采用扫描电子显微镜（ＳＥＭ）技术研究了乙烯质量分数分别为０５３,０４５和０７５的３种ＥＰＤＭ与ＰＰ组成的动态硫化共混物的形态结构特征及其增韧效果。结果表明,当ＥＰＤＭ中乙烯质量分数在０４５～０５５之间时,ＥＰＤＭ的结构规整性差、熔融粘度高、与ＰＰ相容性小,动态硫化的实质是使ＥＰＤＭ分散颗粒由大变小、粒度均化、分布均匀,增大共混剪切强度有利于提高这种ＥＰＤＭ的增韧效果。当ＥＰＤＭ中乙烯质量分数达到０７５时,ＥＰＤＭ中因出现均聚ＰＥ序列结构而呈现部分结晶性,熔融粘度低,与ＰＰ相容性增大,动态硫化后ＥＰＤＭ分散颗粒由小变大,并同时形成“亚网结构”,强化化学交联反应可提高网络密度及网络连续性,从而提高增韧效果,而提高共混剪切强度,反而会使增韧效果下降     

Glass-fiber-reinforced polypropylene/EPDM blend. I. Melt rheological properties

Melt rheological properties of the blend of isotactic polypropylene (PP) and ethylene propylene diene rubber (EPDM) at varying ratios and of the glass fiber (GF) filled PP and PP/EPDM blend by varying both GF loading and blending ratio of the polyblend matrix are studied. Rheological measurements at 220°C in shear rate range 10¹?10⁴s^?1 were made on a capillary rheometer. Scanning electron micrographs of the extrudates are presented to show the morphology and the alignment of the glass fibers with respect to the flow direction. Variations of pseudoplasticity index, melt viscosity, and melt elasticity with EPDM content in PP/EPDM blend, and with varying GF content at any given composition of the matrix in PP/EPDM/GF ternary system, in the studied range are presented and discussed. Resultes on melt viscosity and melt elasticity show (i) reduced effect of GF at high shear rates on these properties and (ii) upward deviation of melt viscosity versus shear rate curve at low shear rates. A change in flow behavior in presence of GF is observed around a critical shear rate 2 × 10³ s^?1 and is attributed to the difference of interaction of GF and the dispersed rubber droplets at high and low shear rates. Elastic recovery showed nonequilibrium behavior at low shear rates.     

Structure and properties of dynamically cured EPDM/PP blends

The structure and properties of polyolefin blends of ethylene–propylene–diene terpolymer (EPDM) and polypropylene were studied. Blends were prepared in a laboratory internal mixer where EPDM was cured with PP under shear with dicumyl peroxide (DCP) at different shear conditions (blend–cure). Blends were also prepared for comparison from EPDM which were dynamically cured in the absence of PP and blended later (cure–blend). The effect of DCP concentration, intensity of the shear mixing, and rubber/plastic composition were studied. In blend–cure, the melt viscosity increased with increasing DCP concentration in blends of 75% EPDM and 25% PP, but it decreased with increasing DCP concentration in blends of 75% PP and 25% EPDM. In cure–blend, however, the melt viscosity increased with increasing DCP concentration for all compositions. The melt viscosity decreased with increasing intensity of the shear mixing presumably due to the formation of the smaller segregated microdomain of the crosslinked EPDM gels in both blend–cure and cure–blend materials. The crystallization rate was higher in EPDM/PP blends than in PP homopolymer. The crystallization rates for various blending conditions were also compared.     

酚醛交联PP/EPDM/SEBS的动态硫化性能

系统研究了酚醛树脂交联剂对聚丙烯/三元乙丙橡胶/苯乙烯一乙烯一丁二烯一苯乙烯共聚物(PP/EPDM/SEBS）动态硫化弹性体性能的影响:随着交联剂用量增加,材料的硬度和拉伸强度先增加然后趋于稳定,断裂伸长率、撕裂强度和熔体流动速率随之降低,压缩永久形变呈现先减小然后增大的趋势。在交联剂用量为10份(质量份,下同)时,制备出了高温下弹性优异的TPV材料,70 0C,125℃条件下的压缩永久形变分别为23. 9%和28. 30%,比未添加SEBS时分别降低了9. 8%和20. 7%,加人SEBS有效改善了材料的回弹性。随着剪切速率增加,材料的表观黏度降低,呈现剪切变稀现象。随着交联剂用量的增加,表观薪度呈现先增加后减小的规律,用量为10份时黏度最大。     

Effect of the viscosity and processing parameters on the surface resistivity of polypropylene/multiwalled carbon nanotube and ethylene–propylene–diene/multiwalled carbon nanotube nanocomposites

In this study, relatively large amounts of polypropylene (PP) and ethylene–propylene–diene (EPDM) were melt‐mixed with multiwalled carbon nanotubes (MWCNTs). Although the melt‐compounding method has many advantages, the uniform dispersion of carbon nanotubes in the polymer matrix is still the most challenging task. Because the electrical conductivity of composites is strongly influenced by the filler's state of dispersion and the extent of filler breakage during processing, the effects of the viscosity and processing conditions, such as the mixing time, rotor speed, and cooling rate, on the surface resistivity were studied. The PP/MWCNT nanocomposites displayed a high dependence of surface resistivity on the cooling rate, and the EPDM/MWCNT nanocomposites displayed a higher surface resistivity at the same content of MWCNTs and less dependence of surface resistivity on the cooling rate compared with PP/MWCNT nanocomposites. The increased surface resistivity of the EPDM/MWCNT nanocomposites was observed when EPDM with higher viscosity was used to prepare the EPDM/MWCNT nanocomposites. By increasing the rotor speed, lower surface resistivity was obtained in the PP/MWCNT nanocomposites. However, by increasing the rotor speed, a higher surface resistivity was obtained in the EPDM/MWCNT nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011