γ-辐射对PP/EPDM的流变学和形态学的影响

研究了一系列不同含量的三元乙丙橡胶与聚丙烯的共混物的辐射效应，经γ－辐射后，PP／EPDM表观粘度下降，共混界面改善。辐照一定剂量后，由于辐射交联和裂解的进行，使各种体系粘度趋同，都大幅度下降，从而改善了PP／EPDM的加工性能。     

动态硫化EPDM/PP热塑性弹性体应力松弛的研究

从相态结构角度讨论动态硫化EPDM／PP共混物的应力松弛行为,并与纯PP以及静态硫化EPDM的应力松弛相比较,研究了制备工艺对动态硫化EPDM／PP共混物应力松弛的影响,结果表明,动态硫化EPDM／PP应力松弛主要由PP连续相决定的,EPDM分散相对共混物应力松弛有一定的影响。随橡塑化和软化剂用量的增加,EPDM／PP应力松弛明显降低,增大硫化剂用量,EPDM／PP应力松弛相对较小。     

PP固相接枝物增容PP/PA6共混物的界面相互作用和力学性能

研究了PP固相接枝混合三单体（gPP)增容PP／PA6共混物的界面相互作用和力学性能，结果表明，该gPP是PP／PA6共混物的有效增容剂，在PP／PA6共混物的所有组成范围内，加入少量的gPP均可达到良好的增容效果，能显著提高共混物的力学性能，固相接枝物对PP／PA6共混体系的增容效果与固相接枝物用量及制备固相接枝物时第三单体的用量相关，通过Molau实验，傅里叶红外谱换光谱测试，抽提实验等证实；gPP的加入使得PP／PA6共混物在共混过程中就地形成了两相之间的增容剂PP－gPA6，增强了两相界面间的相互作用，gPP用量越大，PP－g-PA6的生成量越大，两相间的界面相互作用越强     

剪切和拉伸流场对动态硫化EPDM/PP的力学性能与结晶结构的影响

利用以拉伸流场为主的叶片挤出机(VE)和以剪切流场为主的双螺杆挤出机(TSE)分别制备了不同组分比的动态硫化三元乙丙橡胶/聚丙烯(EPDM/PP)热塑性弹性体。通过对2种流场作用下共混物的力学性能、结晶熔融行为以及晶体形貌和晶体结构的对比分析,研究了拉伸流场对动态硫化EPDM/PP结构与性能的影响。结果表明,与双螺杆挤出机相比,由于拉伸流场更好的分散混合效果,EPDM/PP热塑性弹性体中的PP相能在较低温度结晶,共混物中PP相的晶体尺寸更小,分布更均匀,EPDM相与PP相界面结合更好,共混物的力学性能得到了显著提高;拉伸流场对EPDM/PP热塑性弹性体中PP相的晶格结构无影响,但对PP的结晶度影响较大。     

DCP用量对PP／EPDM共混物力学性能及形态的影响

过氧化二异丙苯（DCP）能有效降解PP;当DCP用量为2‰（质量分数）时,PP／EPDM共混物的冲击强度较高。共混物的相形态结构表明,EPDM橡胶粒子均匀地分散在基体中。     

聚乳酸/聚丙烯两相体系的光辐照原位反应性增容

改善聚合物共混物体系的界面相容性一般都采用添加增容剂的方式实现。文中提出在熔融挤出聚乳酸/聚丙烯共混物(PLA/PP)的过程中,通过光引发聚合物两相基体之间原位反应的方式来达到提高相容性的目的。在紫外光辐照作用下,加入的多官能团单体三羟甲基丙烷三甲基丙烯酸酯(TMPTA)与聚丙烯和聚乳酸共同反应,在两相界面间生成链接两相结构的接枝或嵌段共聚物作为相间增容剂。通过差示扫描量热仪、扫描电子显微镜、偏光显微镜和旋转流变仪对共混物的结晶性能、微观形貌和动态粘弹性进行了研究。结果表明,原位光辐照反应后的PLA/PP共混物相容性明显提高,分散相PP的粒子尺寸大大降低,PLA相最大结晶成核速率比纯PLA增加超过4倍,且PLA的晶粒细化。PLA与PP相界面发生反应后,产生了支化结构和链缠结,使得储能模量和复数黏度大大增加。     

聚乳酸/聚丙烯两相体系的光辐照原位反应性增容EI北大核心CSCD

改善聚合物共混物体系的界面相容性一般都采用添加增容剂的方式实现。文中提出在熔融挤出聚乳酸/聚丙烯共混物(PLA/PP)的过程中,通过光引发聚合物两相基体之间原位反应的方式来达到提高相容性的目的。在紫外光辐照作用下,加入的多官能团单体三羟甲基丙烷三甲基丙烯酸酯(TMPTA)与聚丙烯和聚乳酸共同反应,在两相界面间生成链接两相结构的接枝或嵌段共聚物作为相间增容剂。通过差示扫描量热仪、扫描电子显微镜、偏光显微镜和旋转流变仪对共混物的结晶性能、微观形貌和动态粘弹性进行了研究。结果表明,原位光辐照反应后的PLA/PP共混物相容性明显提高,分散相PP的粒子尺寸大大降低,PLA相最大结晶成核速率比纯PLA增加超过4倍,且PLA的晶粒细化。PLA与PP相界面发生反应后,产生了支化结构和链缠结,使得储能模量和复数黏度大大增加。     

聚丙烯/三元乙丙胶/凹凸棒土三元复合体系的力学性能与亚微相态

通过两步法共混工艺制备了含核-壳结构特征相包容粒子的聚丙烯／三元乙丙胶／凹凸棒土三元复合材料,研究了复合材料的力学性能和亚微现相态结构,并对核-壳结构特征相包容粒子对PP的增韧机理进行了初步探讨．结果表明,AT在EPDM中疏松堆砌,形成以AT堆砌体为核、EPDM为壳的分散岛相。核-壳结构特征相包容粒子对基体具有良好的增韧和增强效果的平衡,对于m(PP)／m(EPDM)／m(AT)=100／20／5的体系,其缺口冲击强度较纯PP提高约5倍,而屈服强度和扬氏模量分别较m(PP)／m(EPDM)=100／20体系提高25％和110％。     

DCP用量对PP／EPDM共混物性能和形态的影响

用动态硫化法制备的PP／EPDM共混型热塑性弹性体的性能明显优于直接共混型PP／EPDM热塑性弹性体,这是由于模量低的EPDM柔性长链经化学交联后,强化对PP的增韧效果,而交联后又被扯断细化的EPDM的颗粒,改变了因EPDM相互缠结所导致的熔融粘度大,加工性能差的缺陷。制备PP／EPDM热塑性弹性体的关键是动态硫化,由于PP／EPDM共混物的动态硫化是一个融物理共混、化学引发交联和剪切细化分散为一体的复杂过程,材料的性能除决定于组成、组分性能和化学交联体系外,还强烈依赖于所采用的共混工艺方式及其条件。本章采用过氧化二异丙苯（DCP）作为硫化剂,研究了过氧化物用量对动态硫化PP（K8303）／EPDM共混物性能和形态的影响。     

动态保压注射成型中POE-g-MAH 对PA1010-PP 共混物的增容作用

以马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)作为增容剂, 采用熔体共混的方法制备了PA1010-PP共混物, 通过扫描电镜(SEM)、 力学性能和差示扫描量热(DSC)测试, 研究了动态保压注射成型中POE-g-MAH对PA1010-PP共混物的增容作用。力学性能测试结果表明, 在注射成型过程中施加剪切应力, 明显提高了共混物的拉伸和冲击性能。SEM结果表明, 剪切诱导制品产生多层次结构, 而且分散相相区尺寸显著减小, 分散更趋均匀, 相界面更加模糊。DSC结果表明, 剪切应力作用下, 当POE-g-MAH的质量分数达到15%时, PP出现2个结晶峰, 即出现异相成核结晶和均相成核结晶, PP均相成核结晶的出现从另一个方面表明动态试样中分散相PP尺寸小于静态试样。剪切应力作用下增容作用的提高归因于剪切应力作用下独特相形态的形成。      

Effect of dynamic crosslinking on crystallization and thermal degradation of polypropylene in polypropylene (PP)/ethylene-propylene DIENE (EPDM) rubber blends

Blends of isotactic polypropylene and ethylene propylene diene (EPDM) rubber were dynamically vulcanized using the dimethylol phenolic resin/stannous chloride crosslinking system. The EPDM blends are thermally more stable than polypropylene (PP). Dynamic curing rendered the vulcanizate thermally more stable than unvulcanized blends. The variations in degree of crosslinking and degree of crystallinity are the main factors for observed increase in thermal stability of vulcanized blends. Degree of crosslinking increases the interfacial adhesion between the PP and EPDM phases. Dimethylol phenolic resin used as a compatibilizer also enhanced the thermal stability of the PP/EPDM blends. Crystallization of PP in the blends of PP/EPDM was also studied through modulated differential scanning calorimetry. Other detailed analyses 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. Kinetic parameters were also determined.     

Effect of crosslinking on morphology and phase inversion of EPDM/PP blends

This study investigates the effect of cross-linking on morphology and phase inversion of EPDM/PP blends. Several EPDM/PP blends without and with cross-linking agent were prepared in a Haake batch mixer under constant conditions. The morphology was studied by electronic microscopy (SEM and TEM), and cross-linking was followed by EPDM gel content and swelling. The results showed that the position of the phase inversion region is essentially governed by composition, being independent of the viscosity ratio of the EPDM/PP blend. The TPVs’ morphology of the EPDM/PP blend, with 70 and 50 wt% of PP, consists of EPDM cross-linked particles dispersed in the PP matrix. For EPDM-rich composition (30 wt% of PP), the TPVs’ morphology appears to be co-continuous. Even though dynamic vulcanisation of the rubber phase always improves the dispersion of the EPDM phase, complete phase inversion (from fully dispersed PP in the EPDM matrix to EPDM fully dispersed in the PP matrix) was achieved only with low viscosity EPDM.     

Highly toughened polypropylene/ethylene–propylene-diene monomer/zinc dimethacrylate ternary blends prepared via peroxide-induced dynamic vulcanization

Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends.     

Effect of liquid additives on morphology and properties of thermoplastic elastomers prepared from phase-modified EPDM elastomer and isotactic polypropylene blends

Thermoplastic elastomers (TPEs) were prepared from ternary blends of ethylene propylene diene poly methylene rubber (EPDM), isotactic polypropylene (PP), and low loadings (5–10 phr) of different types of interfacial phase modifiers (like maleated EPDM, styrene-ethylene-co-butylene-styrene block copolymer, and maleated PP). These showed much improved physico-mechanical properties compared to the binary blend of EPDM-PP. The effects of non-polar paraffin oil and polar di-octyl phthalate liquid additives (5–20 phr) were investigated in these phase-modified ternary and binary EPDM-PP blends. Only 5 phr of liquid additives provided synergistic improvement in physical properties (maximum stress, modulus, and elongation at break) and generated improved finer morphology of the ternary blends as revealed from scanning electron and atomic force microscopy studies. Enhanced physical properties and dynamic mechanical properties of these blends were explained with the help of better phase morphology and enhanced crystallinity of the blends.     

采用β成核动态硫化PP/EPDM共混物增韧聚丙烯

采用β成核的动态硫化iPP/EPDM共混物即热塑性硫化胶(TPV)改性聚丙烯,并与通用增韧剂聚烯烃弹性体(POE)、三元乙丙橡胶(EPDM)增韧聚丙烯进行比较,考察了增韧体系的力学性能、热性能和相形态.结果表明,随增韧剂含量的增加,增韧体系的拉伸屈服强度和弯曲模量均有所下降,而冲击强度提高.TPV改性体系的强度、模量和...     

振动共混对聚丙烯/聚碳酸酯流变性能的影响

在传统转矩流变仪上叠加机械振动制成了振动共混流变仪。实验证明，振动共混降低了70／30聚碳酸酯／聚丙烯共混物的粘度和储存模量，随着制备时的振动振幅和频率的提高，这种效果更加突出。但过大振幅振动中，低剪切与高剪切间的频繁更换，特别是明显的低剪切下相翻转转慢，导致形成了部分不稳定“双连续”相态，这时共混物粘度和模量反而比小振幅振动下制备的共混物的高。一个描述该体系表面张力／液滴半径之比与剪切速率关系的经验表达式较好地分析了流变参数与微观相形态之间的关系，说明了振动促使分散相粒子的破碎和两相的分散，确实影响共混物的相形态。振动共混对聚丙烯／聚碳酸酯流变性能的影响上海交通大学化学化工学院高分子材料研究所，上海　200240振动共混　聚丙烯　聚碳酸酯　流变性能　影响　转矩共混流变仪　相形态在传统转矩流变仪上叠加机械振动制成了振动共混流变仪。实验证明，振动共混降低了70／30聚碳酸酯／聚丙烯共混物的粘度和储存模量，随着制备时的振动振幅和频率的提高，这种效果更加突出。但过大振幅振动中，低剪切与高剪切间的频繁更换，特别是明显的低剪切下相翻转转慢，导致形成了部分不稳定“双连续”相态，这时共混物粘度和模量反而比小振幅振动下制备的共混物的高。一个描述该体系表面张力／液滴半径之比与剪切速率关系的经验表达式较好地分析了流变参数与微观相形态之间的关系，说明了振动促使分散相粒子的破碎和两相的分散，确实影响共混物的相形态。     

Effect of high density polyethylene addition and testing temperature on the mechanical and morphological properties of polypropylene/ethylene-propylene diene terpolymer binary blends

High density polyethylene (HDPE) was added to the polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM) binary blend, and the effect of testing temperatures on the modulus of elasticity, impact behavior and corresponding fracture morphology was analyzed. Modulus of elasticity generally decreased as the EPDM content increased regardless of the testing temperatures. However, it was found that the modulus of elasticity of PP/EPDM/HDPE ternary blend increased compared to PP/EPDM binary blend when tested at –30 and –60 °C. Notched Izod impact strength changed depending on the testing temperatures, however, there was not much difference between binary and ternary blends up to 20 wt% EPDM. However, at more than 30 wt% EPDM content, ternary blends showed higher impact strength compared to binary blends. Especially, at –30 °C, brittle-ductile transition was observed between 20 and 30 wt% EPDM. Subsurface morphology was also analyzed, and the relationship between the impact strength and the stress whitening zone was investigated. Scanning electron microscopy observation of impact fractured surfaces was conducted, and overall morphology was analyzed with respect to HDPE addition and testing temperature change.     

FI—IR研究PP／EPDM共混物表面与本体的结晶形态

用ＦＴ－ＩＲ方法研究了ＰＰ／ＥＰＤＭ共混物表面与本体的结晶形态,结果表明,随着ＥＰＤＭ含的增加,９９７ｃｍ＾－１吸收峰的位置不变,但峰宽变小,测算ＰＰ的结晶度的Ａ９９８／Ａ９７２比值随着变化,从表面与本体比较来看,一是表面ＰＰ结晶状态吸收峰是在９９７．０ｃｍ＾－１,而本体系在９９７．８ｃｍ＾－１即向低波数方向移动;二是表面非结晶状态吸收峰９７２ｃｍ＾－１增加较多,这都都共混物表面与本体ＰＰ结晶度及     

EPDM动态硫化增韧PP的性能和形态研究

采用羟甲基叔丁基酚醛树脂及２,５－二甲基－２,５－二叔丁基过氧基己烷／硫黄作交联剂,研究了三元乙丙橡胶动态硫化对增韧聚丙烯性能的影响。实验证实,随酚醛树脂用量增加共混物的抗冲韧性显著提高,但流动性明显下降。过氧化物既能有效硫化橡胶,又能使聚丙和解,从而得到高韧性和高流动性的共混物。扫描电镜分析表明,交联剂用量增加,共混物中橡胶相粒径显著减小,这归因于橡胶相的交联和在橡界面形成接枝或嵌段共聚物。