共查询到19条相似文献,搜索用时 149 毫秒
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三元乙丙橡胶共混改性聚丙烯 总被引:9,自引:0,他引:9
分别用茂金属催化聚合所得的三元乙丙橡胶(mEPDM)和传统Ziegler-Natta催化剂聚合所得的三元乙丙橡胶(EPDM)对PP进行共混改性。考察了增韧剂质量分数对共混物冲击强度、拉伸强度和热变形温度等力学性能的影响,以及共混物结构形态和结晶行为。结果表明,与PP/EPDM共混物相比,PP/mEPDM共混物的脆韧转变增韧剂临界质量分数小,扯断伸长率高。PP/mEPDM共混物的脆韧转变区间远小于PP/EPDM共混物。随增韧剂质量分数的增加,PP/mEPDM和PP/EPDM共混物的拉伸强度、弹性模量和维卡软化点均单调下降,但后者的下降幅度更大。电镜分析和结晶行为研究表明,PP与mEPDM的相容性优于PP与EPDM的。 相似文献
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纳米莫来石填充PP/EPDM共混物的脆韧转变 总被引:1,自引:0,他引:1
制备了含纳米莫来石的三元乙丙橡胶(EPDM)和马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)母料,研究了纳米莫来石对聚丙烯(PP)/EPDM和PP/EPDM-g-MAH共混物脆韧转变的影响。结果表明:纳米莫来石的加入使PP/EPDM和PP/EPDM-g-MAH共混物的脆韧转变提前,尤其在纳米莫来石用KH-550改性后,PP/EPDM共混物发生脆韧转变时EPDM的含量由15%降至10%;在橡胶相含量相同时,加入纳米莫来石后共混物的弹性模量和拉伸强度略有下降,而断裂伸长率显著下降。 相似文献
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对聚丙烯(PP)/三元乙丙橡胶(EPDM)共混合金的结构与性能进行了研究。结果表明:国产三元乙丙橡胶J3080P能够大幅度提高PP的常温和低温缺口冲击强度;PP基体的性质和EPDM的用量对增韧效果有明显影响。PP/EPDM共混合金发生脆韧转变所需的EPDM用量为20~30份。EPDM对PP增韧机理遵从银纹-剪切带机理。J3080P对PP的增韧效果优于日本产EPDM 501A。 相似文献
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PP/HDPE/SBS三元共混物的研究——基体韧性和弹性体分散相对PP三元共混物脆—韧转变的影响 总被引:1,自引:0,他引:1
研究了固定PP/HDPE/SBS三元共混物配比,采用不同共混工艺条件下的脆-韧转变规律。研究表明:PP三元共混物的冲击强度与SBS分散相粒径有密切关系。当SBS分散相粒间距T等于临界值T_c时,PP三元共混物将发生脆-韧转变。研究还表明基体韧性与T_c有密切关系,当基体韧性增高时,T_c值将增大。 相似文献
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动态硫化增韧聚丙烯/三元乙丙橡胶共混物的研究 总被引:1,自引:0,他引:1
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。 相似文献
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三元乙丙橡胶接枝马来酸酐及其在尼龙6中的应用 总被引:2,自引:0,他引:2
分析了在含有适量聚丙烯(PP)的三元乙丙橡胶(EPDM)熔融接枝马来酸酐(MAH)反应体系中,引发剂过氧化二异丙苯(DCP)、MAH用量对产物接枝率和流变性能的影响,考察了二甲基苯胺(DMBA)、二甲基甲酰胺(DMF)、硫代二丙酸二月桂酯(DLTDP)3种阻交联剂对接枝反应体系的影响,并研究了尼龙6(PA6)/(EPDM/PP)-g-MAH共混物的微观结构与性能。结果表明:当DCP的质量分数为0·08%、MAH的质量分数为1·2%时,产物的接枝率可达到1·0%左右;在相同条件下,3种阻交联剂对产物的接枝率都有不同程度的降低,而加入DMBA最大程度地降低了体系的交联度;接枝物(EPDM/PP)-g-MAH以较小的粒径均匀分布在连续相PA6中;当(EPDM/PP)-g-MAH质量分数为15%~20%时,共混物发生由脆到韧的转变;当(EPDM/PP)-g-MAH质量分数为25%时,共混物的综合力学性能达到最佳;同时,接枝物的加入增大了共混物中PA6的结晶难度。 相似文献
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茂金属聚乙烯弹性体和三元乙丙橡胶增韧聚丙烯的比较 总被引:9,自引:1,他引:8
用茂金属聚乙烯弹性体(mPE)代替三元乙丙橡胶(EPDM)对聚丙烯(PP)增韧改性并进行了比较。结果表明,mPE共聚物中的辛烯质量分数越高,其中对PP的增韧效果越好;随着共混物中弹性体质量分数的增加,共混物的拉伸强度和弹性模量降低,扯断伸长率增大。PP/mPE与PP/EPDM增韧体系相比,二者的拉伸强度差别不大,但PP/mPE的弹性模量和扯断伸长率稍低;与EPDM相比,mPE对PP具有较好的增韧效果,含有质量分数40% mPE的共混物试样在-30℃下的缺口冲击强度已超过纯PP的20倍,约是相同弹性体质量分数PP/EPDM的近9倍。另外,PP/mPE还具有较低的拉伸永久变形、压缩永久变形和蠕变变形。 相似文献
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徐科杰;王晓东;傅李丹;王旭;许向彬 《中国塑料》2009,23(6):45-49
采用熔融法分别制备了三元乙丙橡胶(EPDM) /纳米碳酸钙(CaCO3)二元预混料及其与聚丙烯(PP)共混的三元复合材料。利用动态力学分析仪研究了纳米CaCO3含量和共混时间对EPDM /纳米CaCO3二元预混料的动态力学性能的影响,利用扫描电子显微镜分析了分散相纳米CaCO3和EPDM在PP基体中的形态。结果表明,常温下,纳米CaCO3含量为70 %(质量分数,下同)、共混时间为15 min时,EPDM/纳米CaCO3二元预混料的储能模量、损耗模量和损耗角正切达到最高值;纳米CaCO3与EPDM组成的二元共混物分散于PP基体中,通过纳米CaCO3团聚体及EPDM协同变形、界面脱黏成纤及诱导剪切带的形成耗散外界作用能,显著提高了PP/EPDM/纳米CaCO3三元复合材料的冲击强度。 相似文献
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制备EPDM/聚烯烃简单共混型热塑性弹性体。研究了聚合物种类、橡塑比、二元和三元共混对共混物力学性能的影响。结果表明,部分结晶性EPDM共混物的力学性能比无定形EPDM共混物好,部分结晶性EPDM与LDPE(低密度聚乙烯)共混物的拉伸强度大于两者的加和值,而其它二元共混物的拉伸强度均低于两共混单元的加和值;用LDPE部分替代PP,或用氯磺化聚乙烯(CSM)部分替代结晶性EPDM进行三元共混,能改善部分结晶性EPDM/PP共混物的某些性能。 相似文献
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In order to further understand the brittle-ductile (B-D) transition in PP/EPDM blends, a shear stress field achieved via dynamic packing injection molding was used to control the rubber particles as elongated and orientated in the PP matrix. The impact strength of the blends was measured in three fracture directions, namely, along the shear flow direction, perpendicular to and oblique (45°) with the flow direction. A definite B-D transition of impact strength was found at 20 wt% of EPDM content along the shear flow direction. About 10 times increase of impact strength was observed at the B-D transition. However, a B-D transition and then a decrease of impact strength brittle-ductile-brittle (B-D-B) was found as increasing of EPDM content in the impact direction perpendicular to and oblique with the flow direction. One observes a big increase of impact strength at 20-30 wt% of EPDM content (B-D transition) from 10-20 to 70-80 kJ/m2, then a sharp decrease of impact strength is seen when EPDM content reaches to 30-45 wt% (D-B transition) from 70-80 to 40-50 kJ/m2. Correspondingly, there exists a change of rubber particles from roughly spherical shape to highly elongated and oriented shape at D-B transition. SEM shows a very smooth fractured surface when fracture propagation is along or oblique with the shear flow direction, but a lay-by-layer fracture behavior when fracture propagation is perpendicular to the shear flow direction. Our results suggest that the impact fracture direction with respect to the orientation direction play an important role to determine the impact strength. Wu's theory holds true as long as the rubber particles are roughly spherical when viewed in the same direction with fracture propagation direction, but no longer valid when dispersed rubber particles are elongated and oriented when viewed in the direction perpendicular to or oblique with the fracture propagation direction. 相似文献
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The dependences of phase structure and notch impact strength on conditions of mixing have been compared for the binary blend PP/EPDM and for two ternary blends PP/EPDM/PE possessing different viscosities of polyethylene. At low rates and short times of mixing a phase structure with pronounced inhomogeneities (particles of the dispersed phase having diameters of tens μm) is formed in all blends. Conditions of mixing needed for the formation of a homogeneous phase structure (with particles having diameters of several μm) depend on the average viscosity of the components forming the inclusions (EPDM elastomer or EPDM elastomer/polyethylene). Depending on the conditions of mixing and on the rheological properties of components, substitution of one part of the EPDM elastomer with PE may lead to an increase or decrease in the impact strength of the final blend. 相似文献
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Polypropylene (PP)/nylon 11/maleated ethylene‐propylene‐diene rubber (EPDM‐g‐MAH) ternary polymer blends were prepared via melt blending in a corotating twin‐screw extruder. The effect of nylon 11 and EPDM‐g‐MAH on the phase morphology and mechanical properties was investigated. Scanning electron microscopy observation revealed that there was apparent phase separation for PP/EPDM‐g‐MAH binary blends at the level of 10 wt % maleated elastomer. For the PP/nylon 11/EPDM‐g‐MAH ternary blends, the dispersed phase morphology of the maleated elastomer was hardly affected by the addition of nylon 11, whereas the reduced dispersed phase domains of nylon 11 were observed with the increasing maleated elastomer loading. Furthermore, a core‐shell structure, in which nylon 11 as a rigid core was surrounded by a soft EPDM‐g‐MAH shell, was formed in the case of 10 wt % nylon 11 and higher EPDM‐g‐MAH concentration. In general, the results of mechanical property measurement showed that the ternary blends exhibited inferior tensile strength in comparison with the PP matrix, but superior toughness. Especially low‐temperature impact strength was obtained. The toughening mechanism was discussed with reference to the phase morphology. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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Tensile and impact properties of the ternary system polypropylene (PP)/ethylene propylene diene elastomer (EPDM)/glass fiber (GF) and the corresponding binary systems PP/EPDM blend and PP/GF composite are studied. Results are presented and analyzed as functions of compositional variables, viz., (i) matrix PP/EPDM blending ratio at constant GF loadings and (ii) GF loading at constant matrix blending ratios for the ternary system and (iii) EPDM content for PP/EPDM binary system and (iv) GF content for the binary system PP/GF, respectively. The role of individual components EPDM and GF in these mechanical properties is discussed and their combined effects are inspected at certain composition ranges. Theoretical analysis of tensile data is presented which reveals the effect of EPDM on the reinforcing effect of GF. Unlike the conventional role of an elastomer, increase of EPDM content in the presence of GF increases the modulus of the ternary system. Impact strength of the ternary system increases with increasing GF content both in the presence and absence of EPDM, showing a distinct minimum at matrix blending ratio PP/EPDM 90/10. Scanning electron micrographs of impact-fractured surfaces are presented to illustrate the dispersion of the two phases of the polyblend matrix, fiber alignment, and the fiber interface. 相似文献
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PP/HDPE/SBS三元共混物的研究——形态结构与性能 总被引:2,自引:0,他引:2
研究了PP/HDPE/SBS三元共混物的性能及形态结构特征。研究结果表明,PP三元共混物的冲击韧性除与SBS的含量密切相关外,还与HDPE的含量有关,HDPE起到了与SBS相似的增韧作用。由于HDPE的掺入,减少了SBS的含量,制成了一种力学性能均衡的超高韧性PP三元共混材料。形态结构的研究表明,共混物中,SBS呈颗粒状分布,另外SBS还与HDPE组成了具有包藏结构的复合粒子。 相似文献
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In this paper, EPDM rubber and nano-SiO2 particles were employed to modify PP simultaneously. Our goal was to control the distribution and dispersion of EPDM and nano-SiO2 particles in PP matrix by using an appropriate processing method and adjusting the wettability of nano-SiO2 particles toward PP and EPDM, so as to achieve a simultaneous enhancement of toughness and modulus of PP. With regard to this, two kinds of nano-SiO2 particles (with hydrophilic or hydrophobic) as well as two processing methods (one-step or two-step) were employed to prepare PP/EPDM/SiO2 ternary composites. A unique structure with the majority of EPDM particles surrounded by SiO2 particles was first observed by using hydrophilic SiO2 and two-step processing method, resulting in a dramatically increase of Izod impact strength as the rubber content in the range of brittle-ductile transition (15-20 wt%). The observation that poor adhesion and poor compatibility between particles and PP matrix could result in a significant increase in Izod impact strength was unusual and needed further investigation. This could be tentatively understood as a consequence of the overlap of the ‘stress volume’ between EPDM and SiO2 particles due to the formation of the unique structure. Our work provided a deep understanding of the toughening mechanism and a new way for the preparation of high performance polymer composites. 相似文献