聚丙烯交联改性的研究

以聚丙烯为基础树脂,采用不同的交联助剂对树脂在力学性能、凝胶率、热稳定性能方面的影响。结果表明,不同交联助剂均有提高凝胶含量和改善聚丙烯(PP)降解程度、提高力学性能的用途。     

改性聚丙烯板框专用料研究

从共混改性的角度探讨了用改性聚丙烯生产的板框专用料的耐热性及物理性能。考察了板框专用材料的抗老化性能,冲击强度,为形温度,弯曲强度,熔体流动速率,拉伸强度,等。开发的板框专用料的性能超过了进口料的性能,大幅度降低了原料,取产好的效果。     

一步法硅烷接枝交联改性聚丙烯的研究

采用反应挤出法一步实现聚丙烯（PP）的硅烷接枝和交联改性，制备出了具有部分交联结构的高熔体强度PP。通过改性前后红外光谱、熔体流动性能、凝胶含量、结晶行为、力学性能和发泡性能的变化考察了改性对材料性能的影响。结果表明，一步法改性后PP大分子中引入了硅烷接枝交联结构，使熔体强度、熔体黏度提高，熔体流动速率显著降低，并且体系中出现了高达48％的凝胶；交联结构的引入使PP的结晶速率减缓；改性后材料的力学性能有所提高，而发泡性能大大改善，可以获得高质量的泡沫塑料。     

聚丙烯塑料的改性研究

概述了目前广泛采用的聚丙烯塑料的改性方法研究,包括聚丙烯塑料的共聚、接枝、交联等化学改性以及共混、增强、填充等物理改性方法.     

硅烷交联聚丙烯的研究

通过大量实验、筛选到所接枝助剂能够有效地解决聚丙烯（ＰＰ）在接枝过程中的降解问题,同时根据共聚合原则,优选出接枝助剂与硅烷有机配合的反应体系,提高了接枝效率,优化了工艺配方,得到了高凝胶率和性能较好的硅交联Ｐ左示扫描量热法对所制得的硅无效联ＰＰ进行了表征;用扫描电子显微镜观察了ＰＰ、交联ＰＰ的冲击断口形态以及硅烷交联ＰＰ的凝胶相与非凝胶相,研究了凝胶率与硅烷交联ＰＰ的性能关系。     

马来酸酐改性聚丙烯的交联副反应

用加入助剂和不加助剂的马来酸酐(MAH)熔融接枝改性聚丙烯(PP)。研究了单体MAH、引发剂过氧化二异丙苯(DCP)和助剂亚磷酸三苯酯(TPP)用量对PP交联的影响。PP交联副反应是由DCP引发生成的PP大分子自由基和由MAH激态分子生成的PP大分子自由基而产生的。TPP含有给电子体,可减小PP分子中甲基产生的正电诱导效应倾向,阻止PP发生分子内自由基的转移反应和分子间的转移反应,减小PP的交联;TPP化合物中含有磷原子,它与MAH的激态分子产生电子转移作用,使MAH的激态分子浓度减小,从而减少PP的交联。     

改性本体聚丙烯汽车保险杠材料的研制

阐述了采用交联改性聚丙烯，制取汽车保险杠用材料的方法。     

Foaming polypropylene prepared by a novel one-step silane-grafting and crosslinking method

High-melt-strength polypropylene (HMSPP) used for foaming was prepared by a novel one-step of silane grafting and crosslinking of a normal isotactic polypropylene (IPP) in a twin-screw extruder. The HMSPP has been achieved using vinyl unsaturated silane with long chain as a grafting monomer, benzoyl peroxide (BPO) as an initiator, styrene as a coagent, trace amounts of water as a catalyst for crosslinking. The function of each agent in the formulation for the IPP modification was investigated. The results indicate that all of the agents are effective and necessary, and the proportions of the components, especially BPO, highly influenced the melt flow rate (MFR) of the HMSPP. Due to the presence of traced water in the system, the crosslinking of IPP is accompanied by the grafting of silane, which leads to a one-step production of crosslinked IPP. A high-qualified foam with uniform, closed and independent cells were fabricated from the HMSPP with appropriate MFR. With the decrement of the MFR of the HMSPP, the average size of the cells and the number of the unclosed cells decrease while the density of the cells increases.     

Structure and properties of high melt strength polypropylene prepared by combined method of blending and crosslinking

High melt strength polypropylene (HMSPP) was prepared by in situ heat induction reaction, in which pure polypropylene (PP) powders without any additives was used as basic resin, and low density polyethylene (LDPE) and trimethylolpropane triacrylate (TMPTA) were added as blending resin and as crosslinking agent, respectively. Microstructure of the obtained HMSPP (PP/LDPE/TMPTA blends) was characterized by FTIR, Wide‐angle X‐ray diffraction (WAXD), and testing of gel content. The effect of LDPE content on melt strength and melt flow rate of HMSPP were investigated. When the content of LDPE was 40 wt %, the melt strength of the HMSPP was above 16 CN, which was much higher than those of pure PP powder (2.6 CN) and PP/LDPE blends without TMPTA (6.1 CN). Moreover, thermal behavior and mechanical properties of the HMSPP were also investigated. The results showed that the thermal stability and impact strength of HMSPP were greatly improved. In addition, HMSPP possessed good processing performance and good foaming properties. The foams produced by HMSPP showed uniform, closed, and independent cells. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

PP管材料改性及其应用

综述了国内外改性聚丙烯(PP)管材料的研究,包括纳米技术改性、复合技术改性、口晶型促进剂改性、聚乙烯改性、助剂改性;采用国家标准规范PP管市场,加强PP管材料特别是改性PP管材料的研究,提高产品质量,使之具有新的功能,缩短同国外产品的差距．以满足日益增长的PP管发展的需要。     

我国高熔体强度聚丙烯生产技术进展

综述了国内高熔体强度聚丙烯(HMSPP)的生产技术。射线辐照法所制HMSPP可在常温条件下进行,纯度较高,但无法精确控制HMSPP的结构,生产成本较高;直接聚合法可通过改变外给电子体种类及加入量、聚合工艺条件等得到具有支化结构的HMSPP,其具有良好的拉伸性能和耐热性能,但催化剂及聚合工艺条件的研发周期长;化学交联改性法可减少凝胶含量,降低单体用量,但反应温度较高时,聚丙烯易发生降解;共混改性法制备的共混物中各树脂间的协同效应和化学反应性好,但会影响HMSPP的力学性能;反应挤出法工艺稳定,操作简单,适合工业化连续化生产,但各树脂在掺混时会降低HMSPP的力学性能,且各相间的相容性差。     

有机磷酸盐类成核剂改性聚丙烯

具有蝶形结构的有机磷酸盐类成核剂HBP能显著改善PP的结晶行为和综合性能。当添加成核剂HBP的质量分数为0．2％时,PP的结晶度从46．4％提高到52．2％,弯曲强度和弯曲模量分别提高了23％和21％,热变形温度和结晶温度分别提高23．9℃和22．7℃,而制品的雾度则降低60％。     

Electron-induced crosslinking of polypropylene with the addition of hydrogen-donating hydrocarbons

Electron-induced crosslinking of polypropylene with the addition of hydrogen-donating hydrocarbons produced from petroleum (HHAP) together with A-TMPT (trimethylpropanetriacrylate) was studied, and the following results were obtained: (1) Effective cross-linking was achieved at lower doses under 10 kGy. (2) HHAP functions as an effective radical scavenger to suppress scissions. (3) Distinguished improvements in properties such as elongation and heat distortion temperature were achieved by the irradiation. (4) Distinct diminution in melt flow rate and evident increase in average molecular weight with the irradiation at lower doses were observed. (5) It was confirmed that the oxidative degradation during mixing and molding was noticeably inhibited by the addition of HHAP. This effect as an antioxidant during these procedures along with the irradiation seems to be a cause to promote cross-links. These effects are attributable to the high radical scavenging effects of HHAP and its pure hydrocarbon constitution without functional groups containing heteroatoms. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 311–319, 1997.     

Crosslinking of atactic polypropylene by the system peroxide-pentaerythritol tetraallyl ether

The influence of the concentration of peroxide (mainly dicumyl peroxide) and pentaerythritol tetraallyl ether as coagent and the effect of temperature on the crosslinking of atactic polypropylene (a-PP) with molar mass 12 000g/mol were investigated. Using this system, crosslinking of 40mass% of a-PP at 160°C was obtained. The problems associated with the mechanism for crosslinking of a-PP are discussed.     

纳米SiO2对天然橡胶/聚丙烯共混型热塑性弹性体的改性

在双辊电热式塑炼机上采用动态硫化法制备了天然橡胶/聚丙烯共混型热塑性弹性体(NR/PP TPV)。考察了纳米S iO2的加入顺序及其用量对NR/PP TPV力学性能的影响,研究了纳米S iO2填充改性TPV的耐溶剂性能和耐热变形性能,并用扫描电镜(SEM)观察了其两相结构和断面形貌。结果表明,纳米S iO2先与NR混炼均匀,再加入小料和硫黄所得的NR母炼胶与PP制备的TPV力学性能较好,且最佳的纳米S iO2加入量为3份;纳米S iO2改性的NR/PP TPV具有良好的耐溶剂性能和耐热变形性能;纳米S iO2提高了NR与PP相间结合强度。     

助剂改性聚丙烯耐候性研究进展

近年来,聚丙烯老化改性的研究引起了广泛的关注,其中包括有机助剂改性和无机助剂改性。综述了聚丙烯老化改性的几种常用方法、国内外发展情况以及老化改性的机理等内容。