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。     

三螺杆动态混炼挤出机制备TPV的力学性能研究

在振动力场作用下的三螺杆动态混炼挤出机上,采用硫磺硫化体系对不同配比EPDM／PP共混物进行动态硫化实验。通过调节螺杆振动参数(频率和振幅)改变加工过程中振动力场的振动强度,探讨了振动力场对 EPDM／PP共混物力学性能的影响规律。结果表明:振动力场的引入可以使热塑性硫化体系(TPV)拉伸强度最大提高23％,100％定伸应力最大提高20％,断裂伸长率最大提高28．7％;而振动力场的施加使得TPV材料的永久变形增大,说明其弹性下降,另外对硬度影响不大。     

酚醛树脂动态硫化三元乙丙橡胶/聚丙烯热塑性弹性体的动力学研究

以二水合氯化亚锡为催化剂制备酚醛树脂动态硫化三元乙丙橡胶(EPDM)/聚丙烯(PP)热塑性弹性体(TPV),研究酚醛树脂和二水合氯化亚锡用量对EPDM/PP TPV硫化特性的影响以及助交联剂氧化锌和高乙烯基聚丁二烯(HVPBd)在硫化体系中的作用。结果表明：随着酚醛树脂用量的增大,EPDM/PP TPV的t₉₀略有延长;随着二水合氯化亚锡用量的增大和硫化温度的升高,EPDM/PP TPV的t₉₀明显缩短,硫化反应速率常数明显增大,硫化反应活化能先减小后增大;氧化锌和HVPBd可用于控制EPDM交联密度大小,提高EPDM/PP TPV的加工性能及抗压缩永久变形性能。     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

动态硫化对三元乙丙橡胶/聚丙烯共混体系等温结晶行为和形态结构的影响

研究了三元乙丙橡胶/聚丙烯(EPDM/PP)共混物和动态硫化EPDM/PP热塑性弹性体(TPV)的等温结晶行为及形态结构,并用Avrami方程对其进行等温结晶动力学分析。结果表明,EPDM/PP共混物和EPDM/PP TPV的等温结晶行为符合Avrami方程,在相同的结晶温度下,TPV比共混物的Avrami指数小,半结晶时间短,结晶速率常数大;EPDM/PP共混物为双连续相结构,而EPDM/PP TPV是以硫化的细小橡胶颗粒为分散相、PP为连续相的"海-岛"结构,橡胶颗粒尺寸约为0.5μm。     

PP/EPDM动态硫化热塑性弹性体的改性研究进展

简要介绍了动态硫化热塑性弹性体(TPV)的技术特点、结构与性能,从力学性能改良、阻燃改性、电性能改良和耐老化性能改良及其它改性方面,阐述了近年来聚丙烯(PP)/三元乙丙橡胶(EPDM) TPV的改性研究进展情况。最后展望了PP/EPDM TPV的应用前景,并指出实现传统TPV材料的高性能化和新功能化将是今后PP/EPDM TPV的研究重点。     

振动力场强化制备热塑性弹性体形态图像分析

基于Matlab图形图像处理技术,开发了聚合物共混材料微观结构形态图像处理与分析应用软件,对振动力场强化制备的动态硫化EPDM/PP热塑性弹性体SEM照片进行处理与分析,获得了EPDM在基体PP中的微观结构分布,进一步揭示振动参数对聚合物共混材料分散相细化与均布的强化作用。     

动态硫化三元乙丙橡胶/聚丙烯热塑性弹性体的研究进展

介绍动态硫化三元乙丙橡胶(EPDM)/聚丙烯(PP)热塑性弹性体(TPV)的发展历程、配合体系、动态硫化工艺、应用领域和发展前景。相较于传统橡胶,动态硫化TPV作为新一代橡胶产品的典型代表,无论在生产工艺还是性能上均具有较大优势,且TPV对环境的影响较小,符合绿色环保理念。未来EPDM/PP TPV的研究方向将主要集中在环保、低挥发性有机物、高性能化和多功能化等方面。     

汽车密封条用动态硫化EPDM/PP热塑性弹性体的研究进展

概述了动态硫化EPDM/PP热塑性弹性体的发展历史,重点阐述了应用于汽车密封条的动态硫化EPDM/PP热塑性弹性体的制备工艺（反应器法制备TPO、茂金属催化剂法合成TPO、动态全硫化法制备TPV）、加工技术（挤出成型、水发泡成型、注射成型等）、应用领域和研发方向。     

环烷油对PP/EPDM动态硫化热塑性弹性体的影响

运用动态硫化法制备聚丙烯(PP)/三元乙丙橡胶(EPDM)动态硫化热塑性弹性体(TPV),研究了EPDM含量对TPV性能的影响,发现PP/EPDM质量比为60/40时,TPV的拉伸性能达到最大,在此优化配比下研究了环烷油充油前后TPV拉伸性能、结晶性能、热稳定性能、动态力学性能及流变性能的变化规律。结果表明,环烷油的加入使得PP/EPDM拉伸强度下降,断裂伸长率增加;环烷油阻碍TPV中PP相的结晶,其结晶、熔融温度及相应焓值在充油过后都有所下降;环烷油降低了TPV的热降解速率,且使TPV中EPDM相和PP相分子链的玻璃化转变温度(T_g)降低,其中EPDM相的T_g降低更明显,同时熔融状态下TPV的复数黏度、储能模量和损耗模量下降,表明熔融状态TPV中聚合物分子链运动能力增加,分子链内摩擦减小,加工性能得到提高。     

EPDM/PP共混型热塑性弹性体的研制

以充油（乙烯/丙烯/二烯）共聚物（EPDM）、粉状聚丙烯（PP）、超细活性滑石粉为基本材料,采用动态硫化法在单螺杆挤出机组上制备了完全交联的EPDM/PP共混型热塑性弹性体（TPV）;探讨了TPV的配方组成、工艺条件与性能的关系;摸索了TPV的加工性;为TPV的投产与应用提供技术参数。     

The Effect of Vibration on Mechanical Properties of Blends of EPDM/PP in a Tri-screw Dynamic Mixing Extruder

The effects of vibration force field on mechanical properties of blends of EPDM/PP during process of plastics in tri-screw dynamic mixing extruders were investigated experimentally. It was found that vibration force field enhanced mechanical properties of blends of EPDM/PP, and the amplitude of enhancement varied as EPDM content varying. The yangs modulus, the impact strength and the tensile strength were improved the maximum 17, 28, and 17.3%, respectively under dynamic conditions than that under steady conditions. Mechanical properties of blends of EPDM/PP represented a tendency of a rising followed by a fall with the increase of vibration frequency and amplitude.     

动态硫化EPDM/PP TPV的配方设计

研究了4种型号EPDM和过氧化物一溴化酚醛树脂复合硫化体系对动态硫化三元乙丙橡胶(EPDM)／聚丙烯(PP)热塑性硫化橡胶(TPv)力学性能的影响。采用正交设计安排19次实验得出4种助剂各有4个不同用量时力学性能最佳的配方，而不必对4^5(1024)种可能配方都进行实验。结果表明EPDM型号和溴化酚醛树脂用量对力学性能影响最大。力学性能最佳的配方(质量份)为：门尼粘度适中、碘值为8的EPDM100；PP120；溴化酚醛树脂7；双叔丁过氧异丙基苯1．3；三烯丙基异氰脲酸酯0．8；钛白粉4。采用此配方制备TPV不腐蚀加工设备，产品无气味，外观为乳黄色，易染色；力学性能为郡尔硬度51D：拉伸强度37．23MPa、断裂伸长率728％；超过国外同类产品水平。     

EPDM/PP动态硫化热塑性弹性体的研制及应用

根据粘度相近共混原则，通过（乙烯／丙烯／二烯）共聚物（EPDM）充油、筛选高流动性的粉状聚丙烯（PP）、添加超细活性滑石粉等方法，使EPDM与PP充分均匀分散；采用动态硫化法在单螺杆挤出机组上制备了完全交联的EPDM／PP共混型热塑性弹性体（TPV）；用SEM、力学测试、布拉本流变仪等实验方法，探讨了TPV的配方组成、工艺条件与性能的关系；摸索了TPV的加工性；研究了TPV对PP的增韧效果，发现TPV能大大改善PP的综合性能。     

Crosslink densities and phase morphologies in thermoplastic vulcanizates

The degree of EPDM crosslinking during dynamic vulcanization of a PP/ EPDM thermoplastic vulcanizate (TPV) was modified by varying its phenolic curative content. The rise in TPV viscosity, the drop in its swelling, the change in its NMR MAS lineshape, and the increase in its EPDM domain AFM force modulation hardness verified the increase in EPDM crosslink density with increasing curative content. Further, the EPDM crosslink extent in TPV was measured by either the bound phenolic or the residual diene content both determined by solid state NMR. SEM morphologies of cryo-faced and ruthenium-stained TPVs with varying curative contents were analyzed to determine the effects of cure on EPDM domain sizes and PP ligament thickness. A narrowing of the EPDM domain size distribution, with a decrease in the third moment of the distribution, was observed with increasing EPDM crosslink density. Correspondingly, the PP ligament number-average thickness was raised slightly.     

Effects of blend composition and dynamic vulcanization on the morphology and dynamic viscoelastic properties of PP/EPDM blends

The morphology and dynamic viscoelastic properties of isotactic polypropylene (PP) blended with oil-free/oil-extended ethylene–propylene–diene (EPDM) rubbers were studied. Unvulcanized and dynamically vulcanized blends with the compositions PP/EPDM = 50/50 and = 30/70 were investigated. The morphology was observed by phase contrasted atomic force microscopy. The dynamic viscoelastic properties were determined with a rheometer of plate–plate configuration. It was shown that the rheological behavior was strongly affected by both the composition and the morphology of the blends. Significant improvement in the flowability of the dynamically vulcanized blends was observed when oil-extended EPDM was used instead of the oil-free version. It was demonstrated that the rheological properties are mostly controlled by the elastomer phase at low frequencies, while in the high-frequency range the influence of PP becomes dominant. The peculiarities in the rheological behavior of the thermoplastic elastomers (uncured blends, TPE) and thermoplastic dynamic vulcanizates (TPV, dynamically cured blends) containing oil-extended EPDMs were traced to a limited compatibility between the PP and EPDM components in the melt. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation of crystallization behavior in dynamically vulcanized EPDM–nylon copolymer blends

A thermoplastic vulcanizate (TPV) of a ethylene–propylene–diene terpolymer (EPDM) and nylon copolymer (PA) was prepared by dynamic vulcanization. Maleic anhydride (MAH)–grafted EPDM (EPDM–g–MAH), MAH‐grafted EPR (EPR–g–MAH), and chlorinated polyethylene (CPE) were used as compatibilizers. The effect of dynamic vulcanization and compatibilizer on the crystallization behavior of PA was investigated. Differential scanning calorimeter measurement results showed no pronounced shift in the crystallization temperature for PA in EPDM–PA TPV compared to that for PA in the neat state, whereas the crystallization temperature increased after adding compatibilizer. The decrease in the crystallinity of TPVs was a result of the crystallization occurring in confined spaces between rubber particles. The equilibrium melting temperature (Tm⁰) of the PA copolymer was measured and was determined to be 157°C. The isothermal crystallization kinetics of PA in the neat and TPV states also was investigated. The crystallization rate was highest in the compatibilized TPV and lowest in the neat PA, whereas it was intermediate in the uncompatibilized TPV unvulcanized blends. Compared with unvulcanized EPDM–PA blends, the dynamic vulcanization process seemed to cause an obvious increase in the crystallization rate of the PA copolymer, especially when a suitable compatibilizer was used. This occurred because the dynamic vulcanization introduced fine crosslinked rubber particles that could act as heterogeneous nucleating centers. In addition, the use of a suitable compatibilizer permitted the formation of finely dispersed vulcanized rubber particles and therefore increased the density of the nucleating centers. The complex morphology of the blends was investigated by atomic force microscopy to evaluate the effect of compatibilizer on the size of the dispersed rubber particles. Compared with the morphology of TPVs with the same dosage of EPDM–g–MAH compatibilizer, the morphology of TPVs using EPR–g–MAH as compatibilizer showed much smaller dispersed rubber particles, which may have contributed to the higher crystallization rate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 824–829, 2003