氢调法高MFR抗冲击共聚PP K9928H的结构与性能

采用偏光显微镜、旋转流变仪及毛细管流变仪等对用氢调法生产的高熔体流动速率(MFR)抗冲击共聚聚丙烯(PP)K9928H、进口同类PP及用可控流变法生产的PP K9928进行结构性能分析与评价。结果表明:K9928H的MFR接近或略低于进口同类PP,乙烯含量和乙丙橡胶含量高于进口同类PP,综合力学性能较好,外观、色泽正常,加工稳定性好;K9928H的重均分子量和相对分子质量分布(Mw/Mn)与进口同类PP接近,但其Mw/Mn大于K9928。     

高流动抗冲击共聚聚丙烯K9928的工业生产

通过分析高流动抗冲击共聚聚丙烯(PP)专用树脂的应用要求,确定PP K9928的乙烯质量分数需达到9.5%～11.5%,其橡胶相的乙烯质量分数需达到52.2%～56.3%。采用红外分析、升温淋洗分级、差示扫描量热法、凝胶渗透色谱法等分析了K9928的橡胶相含量、化学组成、熔融和结晶、长链立构规整性、相对分子质量及其分布等。结果表明:K9928的乙烯质量分数较高,达10.4%;丙烯高立构规整长序列含量较高,乙烯序列分布较为均匀;产品兼具良好的刚性和韧性。     

二元乙丙橡胶中乙烯含量对增韧聚丙烯的影响

采用小角激光散射仪和扫描电子显微镜等研究了两种不同乙烯含量的二元乙丙橡胶(EPR)增韧聚丙烯(PP)的相行为.不同乙烯含量的EPR与PP的共混体系遵循不同的低临界溶解温度特性,导致其在加工过程中处于不同的相形态,进而对增韧效果产生重大影响.当w(EPR)小于25％时,乙烯含量较低的EPR对PP的增韧效果更好,橡胶分散性...     

无规共聚聚丙烯的结构与性能

利用博里叶变换红外光谱仪与差示扫描量热仪分析了五种无规共聚聚丙烯(PP)的组成和结构,测试了五种PP产品的力学与光学性能.五种无规共聚PP都是由乙烯与丙烯无规共聚合而成,在高分子链中没有乙烯结晶.PP树脂的拉伸屈服应力随着共聚单体乙烯含量的升高而降低,Izod缺口冲击强度、光学性能随着乙烯含量的增加而提高.加入乙烯的质量分数控制在2％～3％为宜.     

HDPE增韧PP-R/石墨复合材料力学性能的研究

采用高密度聚乙烯(HDPE)为增韧剂、乙烯 丙烯 二烯三元共聚物(EPDM)、乙烯 辛烯共聚物(POE)为相容剂、石墨为功能性助剂制备了以无规共聚聚丙烯(PP R)或嵌段共聚聚丙烯(PP B)为基体的PP R或PP B／HDPE／石墨复合材料。详细研究了HDPE含量、弹性体种类及含量对PP R或PP B／HDPE／石墨复合材料力学性能的影响。结果表明HDPE用量在20%、EPDM含量为5%时,PP R或PP B复合材料力学性能优异;POE可以实现PP R或PP B／HDPE／石墨复合材料力学性能的平衡。     

异戊橡胶与三元乙丙橡胶并用胶料及其硫化胶的结构与性能

研究了三元乙丙橡胶的化学组成和物理结构对其性能的影响、不同品种三元乙丙橡胶与异戊橡胶并用胶及其共硫化胶结构与性能的关系。线型高乙烯含量的三元乙丙橡胶(乙烯／丙烯70：30)具有较好的物理性能。并用胶的性能与两胶的比例有关，也与三元乙丙胶的类型有关。异戊橡胶与三元乙丙胶(组成比为70：30)的并用胶具有良好的物理机械性能和耐热性。     

聚丙烯K6810的结构与性能

利用差示扫描量热仪、凝胶渗透色谱仪、扫描电子显微镜等分析了中流动、中抗冲、高硬度聚丙烯(PP)K6810及两种国外同类产品的结构与性能。结果表明:K6810是丙烯与乙烯的共聚物,乙丙橡胶的相对分子质量较大,且以直径为1~2μm的球形微粒均匀分布在PP基体中,保证了材料具有优良的抗冲击性能;K6810的相对分子质量分布适中,熔体流动速率为9.1 g/10 min,加工性能优良;K6810的熔融温度为167.7℃,耐热性较好。     

动态力学分析仪在抗冲共聚聚丙烯中的应用

在双悬臂弯曲模式下对四种抗冲共聚聚丙烯样品进行动态力学分析(DMA)。DMA曲线显示四种样品都存在两个Tg转变峰,表明样品中同时存在乙丙橡胶非晶相和聚丙烯基质相(PP)。分析了样品的基本物理性能、乙烯和乙丙橡胶含量及SEM相态形貌,由分析结果可知:1#样品的乙丙橡胶非晶相和PP相的相容性较好,表现出较好的高温和低温韧性。实验结果表明DMA可快捷、直观地评价样品的微观结构对力学性能的影响。     

高乙烯含量乙丙橡胶的基本性能研究

研究了几种进口高乙烯含量三元乙丙橡胶(EPDM)的微观结构和宏观性能间的关系,并进行了对比。结果表明,高乙烯含量乙丙橡胶的微观结构中含有一些典型的乙烯结晶;针对高强度工程用试验配方,3种生胶所制备的混炼胶填充量大,硫化速度较快,拉伸强度和回弹性较高,耐热空气老化性能较好。     

高乙烯含量和低门尼粘度三元乙丙橡胶在密封制品和绝缘材料中的应用

研究高乙烯含量和低门尼粘度三元乙丙橡胶（EPDM）Keltan^? 2470C（以下简称K2470C）在高硬度汽车密封条和电线电缆护套绝缘层中的应用,并与其他牌号的EPDM进行对比。结果表明：K2470C的乙烯含量高,相对分子质量分布较窄,门尼粘度低,其高硬度胶料老化前后的邵尔A型硬度、100%定伸应力、拉伸强度和撕裂强度较高,K2470C特别适合在高硬度汽车密封条中应用;同时,K2470C具有良好的加工性和电性能,适合于在低压和中压电线电缆护套绝缘层中应用。     

中流动抗冲聚丙烯结构与性能研究

选取3种市售中流动抗冲聚丙烯产品,分析了产品的乙烯含量、橡胶相含量、橡胶相的相对分子质量和橡胶相形貌;同时对3种产品的热性能和力学性能进行了测试。结果表明,乙烯含量决定了橡胶相含量,橡胶相含量和橡胶相的相对分子质量对产品的刚韧平衡性能起到重要作用;乙烯在橡胶相中的含量达到50 %以上才能起到良好的增韧作用;根据此结论可优化抗冲聚丙烯产品的结构和共聚物含量,达到最佳的刚韧平衡。     

汽车用高流动性共聚聚丙烯的结构与性能

采用溶剂萃取分离的方法将汽车用高流动性共聚聚丙烯分成以乙丙橡胶为主要成分的可溶物和以等规聚丙烯为主的不溶物2个级分。用红外光谱,核磁共振碳谱、凝胶渗透色谱、偏光显微镜、原子力显微镜等测试手段,分析研究了各级分的链结构、聚集态结构,相态结构等,并与国外试样进行比较。结果表明：开发的汽乍用高流动性共聚聚丙烯中乙烯含量,橡胶含量以及橡胶中乙烯含量均较高,且乙烯在分子链上的分布均匀、合理,有效地提高了产品的抗冲击性能;不溶物立构规整性好、结晶度高．保持了材料的良好刚性。     

Quantitative characterization of dispersed particle size,size distribution,and matrix ligament thickness in polypropylene blended with metallocene ethylene–octene copolymers

The average rubber particle size, size distribution, and matrix ligament thickness between particles in polypropylene blends containing metallocene catalyzed ethylene–octene copolymers have been quantitatively analyzed, as functions of blend composition and phase viscosity ratio. Comparison has been made between experimental data and those predicted from a number of theoretical models. All blends showed two‐phase morphology, with interestingly a bimodal distribution of the rubber particle size. The ranges and averages of rubber particle size were mainly determined by blend composition and viscosity ratio between the phases, irrespective of comonomer content along the rubber chains. The logarithmic relationship between the matrix ligament thickness and rubber concentration was observed. The values of ligament thickness obtained from the experiments and theoretical models were not in agreement. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2140–2149, 2001     

高抗冲聚苯乙烯的研制 Ⅲ.橡胶粒径分布及其对HIPS性能的影响

采用本体-悬浮法研究了高抗冲聚苯乙烯(HIPS)所用橡胶的结构及工艺条件对产品性能的影响。研究发现,随橡胶中乙烯结构含量的增加,HIPS橡胶接枝率增加;低顺胶HIPS橡胶相与PS相的相容性较差,高顺胶HIPS橡胶相与PS相的相容性好;从力学性能看,各种胶的HIPS拉伸性能相似,高顺胶的HIPS冲击性能最好,低顺线型胶次之,低顺星型胶较差。聚合过程中搅拌速度、橡胶用量及引发剂种类对HIPS的结构及性能也有一定影响。     

Thermoplastic elastomeric composition based on maleic anhydride–grafted ground rubber tire

Ground rubber tire (GRT) powder was maleated in an internal mixer using maleic anhydride and dicumyl peroxide at 160°C. Maleated GRT was characterized by using X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, wettability, and differential scanning calorimetry. The physical properties of the dynamically vulcanized 60 : 40, rubber : plastic composition based on acrylated high‐density polyethylene as the plastic phase and ethylene propylene diene rubber containing maleated GRT as the rubber phase were found to be greater than the corresponding composition containing nonmaleated GRT. The blend was found to be reprocessable, like themoplastic elastomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 370–378, 2002; DOI 10.1002/app.10348     

高低温循环作用下三元乙丙橡胶胶料的压缩永久变形及回弹值研究

研究高低温循环作用下三元乙丙橡胶(EPDM)胶料的压缩永久变形及回弹值,考察了EPDM乙烯含量、胶料含胶率和交联程度的影响,并与常温、高温和低温条件下结果进行对比。结果表明:高低温循环作用对EPDM胶料压缩永久变形及回弹值的影响比单纯高温老化的影响大;EPDM乙烯含量、胶料含胶率及交联程度对EPDM胶料在高低温循环作用下压缩永久变形及回弹值的影响很大,其中胶料含胶率的影响最大,其次是EPDM乙烯含量,最后是胶料交联程度。     

乙丙嵌段共聚物相对分子质量及链结构对PP/EPR共混体系结构与性能的影响

设计合成了一系列不同相对分子质量和乙烯平均序列长度的乙丙嵌段共聚物（EP）,并将其作为聚丙烯（PP）/二元乙丙橡胶（EPR）共混体系的增容剂,考察了EP用量、相对分子质量及乙烯平均序列长度对共混体系性能及分散相形态演变的影响。结果表明,EP增容PP/EPR体系时存在最佳添加量,少量EP的加入可有效提高PP/EPR共混体系的抗冲击性能,并对分散相尺寸及形态起到良好的调控作用;同时,EP的相对分子质量越大对共混体系的冲击性能提高越明显,EP的组成与EPR越接近,对共混体系的增容效果越明显。     

Resistance to ozone cracking in elastomer blends

The phenomenon of ozone cracking has been investigated for elastomer blends containing an ozone-reactive phase (natural rubber) and an ozone-inert phase (ethylene–propylene rubber). Electron microscopical studies reveal phase separation in the blend and the locus of ozone attack. Ozone cracks traverse the reactive phase and occasionally jump across inert particles without severing them. This mechanism provides the basis of a theory which correctly predicts the dependence of both the critical stored energy for ozone cracking and the crack density upon the blend composition.     

Studies on blends of ethylene vinyl acetate and polyacrylic rubber with reference to their shrinkability

Preferential crosslinking was introduced in the rubber phase of a blend of ethylene vinyl acetate (EVA) and polyacrylic rubber (AR‐801). The heat shrinkability of the polymer blends was measured at room temperature (RT) and at a high temperature (HT) of 150°C. Various parameters were tried for a correlation with shrinkability. Shrinkability goes up with the increase in rubber content and is increased with increasing cure time in blends of a fixed ratio. The crystallinity of an HT (at 150°C) stretched sample was higher than that of a RT stretched sample, which was higher than that of the shrunk and original sample. The continuous cure characteristics, showed that the torque was increased with the rubber content. High temperature DSC demonstrated that the increase in AR‐801 content decreased the stability and further HT processing increased the stability. SEM showed that the rubber phase was more elongated in the HT stretched sample compared to the RT stretched sample. In the shrunk sample the rubber phase was more globular. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2088–2095, 2000     

Toughening and Compatibilization of Acrylonitrile–Butadiene–Styrene/Poly (Ethylene Terephthalate) Blends Using an Oxazoline-Functionalized Impact Modifier

An oxazoline-functionalized core–shell impact modifier was synthesized between aminoethanol and acrylonitrile/butadiene/styrene high rubber powder. According to the Fourier transform infrared spectroscopy test, the nitrile groups were partially converted into oxazoline groups successfully. The oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder was used as an impact modifier for acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends. The differential scanning calorimeter and rheological tests demonstrated that poly(ethylene terephthalate) was partially miscible with acrylonitrile–butadiene–styrene, because the oxazoline groups of oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder reacted with the end groups of poly(ethylene terephthalate). The results of scanning electron microscopy indicated that the morphology of acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends with proper oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder content was improved significantly. The best mechanical properties were achieved, When 6 wt% oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder was added into acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends.