PP/PS形态与性能的研究

主要研究了将苯乙烯-乙烯/丁二烯-苯乙烯共聚物(SEBS)、沙林(Surlyn)和聚丙烯与苯乙烯接枝共聚物(PP-g-PS)作为相容剂对聚丙烯/聚苯乙烯(PP/PS)流动性能、力学性能和微观形态的影响。结果发现:PP-g-PS使PP/PS合金分散相尺寸变小,分布变窄,相界面模糊消失,相容性得到有效改善;同时SEBS显著提高PP/PS合金的冲击强度,但其拉伸强度有所下降;Surlyn使PP/PS合金力学性能有所下降,不能起到增容效果。     

PP-g-PS对PP/SBS增容作用的研究

研究了聚丙烯(PP)固相接枝苯乙烯制备的PP-g-PS对PP/苯乙烯-丁二烯-苯乙烯三元嵌段共聚(SBS)相容性的影响,PP-g-PS明显改进了PP和SBS的相容性,改善了PP的低温韧性。     

聚丙烯固相接枝苯乙烯和丙烯酸乙酯的研究

用固相接枝共聚方法制备聚丙烯（PP）接枝聚苯乙烯（PP-g-PS)和聚丙烯接枝聚丙烯酸乙酯（PP-g-PEA)，考察了引发剂浓度、反应温度、反应时间与单体种类对接枝反应的影响，对接枝改性的PP进行结构和热分析表征，并用接枝功能化的聚丙烯做增容剂，研究了其对纳米SiO2/PP复合材料力学性能的影响。力学性能研究表明：低含量接枝聚丙烯的存在可使SiO2/PP复合材料的韧性大幅提高。     

马来酸酐及苯乙烯同时接枝聚丙烯的研究

用过氧化二异丙苯(DCP)作为引发剂，采用双螺杆反应挤出的苯乙烯、马来酸酐2种单体同时接枝聚丙烯．研究了单体总浓度、单体比例、引发剂浓度对PP的接枝率、接枝效率和熔体流动速率的影响。通过实验发现苯乙烯的加入使接枝率和接枝效率比单独的马来酸酐接枝都有很大的提高。     

PP接枝聚合物对PP/PS共混物相形态的影响

通过原子转移自由基反应合成了聚丙烯(PP)接枝聚苯乙烯(PS) (PP-g-PS),研究了PP-g-PS对PP/PS共混物相形态的影响.采用扫描电子显微镜、偏光显微镜观察了共混物的断面形貌和等温结晶形态.结果表明: 加入PP-g-PS对PP/PS共混物起到了良好的增容作用,表现在两相界面模糊,分散相尺寸减小.当PP-g-PS中x(PS)为5.10% 左右时即可起到增容改善相界面的作用.相容性的提高改善了PP/PS共混物的发泡性能.     

悬浮溶胀法合成接枝聚丙烯

用BPO作引发剂以水相悬浮胀法合成接枝聚丙烯，研究了反应条件、组分等因素对PP的接枝率（Gr)和接枝效率（Ge)的影响，发现溶胀剂、悬浮剂、引发剂、催化剂是该接枝物的主要影响因素。用此方法接枝的聚丙烯有工艺简单，接枝率高，聚丙烯降解程度小等优点，用它作PP／CaCO3、PP/PA6、PP／MBS体系的相容剂，测试结果表明，复合材料的力学性能有很大的提高。     

相容剂对PP／PS形态与力学性能的影响

研究了苯乙烯-乙烯／T-烯-苯乙烯共聚物（SEBS）、聚丙烯与苯乙烯接枝共聚物（PP—g-PS）、沙林（Surlyn）对聚丙烯／聚苯乙烯（PP／PS）形态和力学性能的影响。结果表明：SEBS对PP／PS的冲击强度有比较明显的提高，但拉伸强度有所下降；PP-g-PS使PP／PS相界面变得模糊，分散相微粒尺寸变小，分布变窄，PP／PS相容性得到改善；Surlyn使PP／PS力学性能略微下降，增容作用不显著。     

聚丙烯（PP）／黏土复合材料熔融剂的研究

以马来酸酐（MAH）等为单体接枝聚丙烯作为聚丙烯（PP）／黏土复合材料熔融剂,考察了马来酸酐用量、引发剂过氧化苯甲酰（BPO）用量、反应时间、温度等因素对产物接枝率的影响,并通过红外光谱图对PP-g-MAH进行表征。结果表明,当m（PP）：m（复配单体）：m（BPO）=10．0：2．0：0．6、反应温度控制在120℃左右、复配单体为马来酸酐／苯乙烯时,熔融剂PP-g-MAH的接枝率可获得较大值3．9％。实验同时表明,反应时间对接枝率的影响不大;苯乙烯的加入对接枝率有较大的影响,与普通单体单一马来酸酐相比,加入苯乙烯的接枝率明显提高。     

PP-g-GMA的制备及其改性PP/PA6合金性能

采用双螺杆熔融接枝的方法,在引发剂过氧化二异丙苯(DCP)作用下,将甲基丙烯酸缩水甘油酯(GMA)和共单体苯乙烯(St)接枝到聚丙烯(PP)上。通过傅立叶变换红外光谱仪确定了接枝物的生成,采用酸碱滴定法测定了接枝率。探讨了GMA,St,DCP不同用量对PP接枝物的接枝率和熔体流动速率的影响,并将接枝产物PP–g–(St–co–GMA)加入PP/尼龙6(PA6)的合金中,通过注塑成型样条,测定其力学性能,并观察微观结构。结果表明,St的加入能够提高接枝率,抑制副反应的发生。在PP/PA6合金中加入接枝物PP–g–(St–co–GMA),其拉伸强度可提高46.45%,弯曲强度可提高32.47%,但对冲击强度影响不大。     

亚临界二甲醚协助双单体固相接枝改性聚丙烯

以亚临界二甲醚为溶胀剂,偶氮二异丁腈(AIBN)为引发剂,在聚丙烯(PP)上接枝甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St),制备了接枝产物PP-g-(GMA-co-St).考察了溶胀时间、溶胀温度、反应时间、反应温度、St用量和引发剂用量对接枝产物相对接枝率和水接触角的影响.采用傅里叶变换红外光谱对接枝产物进行定量...     

Gel formed during the solid‐state graft copolymerization of styrene and spherical polypropylene granules. I. Influence of reaction conditions on the gelation and its mechanism

Graft copolymers of polystyrene (PSt) with spherical polypropylene (PP) granules were synthesized by solid‐state reaction. In the copolymerization as a by‐product some gel was formed. The effects of the amount of free radical initiator, feed ratio of St monomer, species of free radical initiator, and composition of the spherical polyolefin granules on the grafting degree of PSt and the gelation were studied. It is found that larger amount of initiator used, and higher feed ratio of St monomer lead to a higher grafting degree and higher content of gel. During the cross‐link reaction process, both styrene and free‐radical participate in the reaction that discloses the reason of the increment of gel with the increment of styrene consumption or initiator consumption. Using PPR, which is a random copolymer of 95.1 mol % propylene units and 4.9 mol % ethylene units, as grafting matrix, higher grafting degree and higher content of gel can be reached than that using isotactic PP as grafting matrix. Using tert‐butyl peroxy benzoate (TBPB) as initiator, under the same conditions there were more PSt grafted to the spherical PP granules and more gel formed than that using benzoyl peroxide (BPO) as initiator. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3682–3687, 2007     

焦磷酸锰络阴离子引发淀粉与苯乙烯及其二元单体接枝共聚的研究

采用廉价无毒的焦磷酸锰（Ｍｎ＾３＋）络离子作为引发剂，以十二烷基硫酸钠为乳化剂，对淀粉与苯乙烯及二元单体接枝共聚进行了初步探索，研究了单体浓度，引发剂浓度，反应温度及反应时间对接枝反应的影响趋势，发现Ｍｎ＾３＋具有良好的引发效果，接枝效率在６５％～９０％，接枝率可达２００％，对淀粉与Ｓｔ／ＡＮ，Ｓｔ／ＥＡ二元单体接枝共聚的研究表明接枝效率不高。     

聚碳酸酯-g-聚苯乙烯共聚物的合成与表征

研究了聚碳酸酯（ＰＣ）与苯乙烯（ＳＴ）的悬浮接枝共聚合,考察了ＰＣ／ＳＴ质量比、引发剂质量分数、反应时间对共聚合的影响,获得了接枝率为３５％,接枝效率为６５％的接枝共聚物,并对接枝共聚物进行ＩＲ、ＤＳＣ、ＤＭＡ等表征,测定了支链ＰＳ的分子量及支链数。     

Solid‐state modification of isotactic polypropylene (iPP) via grafting of styrene. I. Polymerization experiments

Grafting of vinyl monomers onto isotactic polypropylene (iPP) in the solid state, that is, below the melting point, displays several advantages over melt or solution grafting processes, such as negligible degradation of the iPP and absence of any solvent. The final properties of such iPP modifications or actually compatibilized PP blends are dependent on the dispersion of the new polymer into the iPP matrix, which is controlled to a large extent by the degree of grafting versus the amount of free homopolymer formed. In the present work, the solid‐state modification of iPP by styrene has been investigated from the point of view of the monomer polymerization behavior. In order to determine the styrene conversion and the distribution of the newly formed PS phase along the radius of the iPP powder particles, the reaction products were characterized by infrared (FTIR) and Raman spectroscopy. Fractionation of the reaction products via selective solvent extraction allowed the determination of the grafting efficiency (Φ). It was shown that besides the grafted PS two additional types of PS are formed, that is, free PS homopolymer in the pores of the PP powder and free PS in the amorphous PP phase. Phi shows an optimum as a function of the feed peroxide composition and the feeding rate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3279–3291, 2003     

Influence of an annealing treatment on the solid‐state grafting of styrene onto spherical isotactic polypropylene granules

The main place of solid‐state graft polymerization in polypropylene (PP) granules has been believed to be the amorphous region of PP. In this work, the solid‐phase morphology of nascent spherical PP (N‐PP) granules was found to be markedly changed by an annealing treatment. The crystallinity of PP granules was almost doubled after annealing at 150°C for 12 h, whereas the porosity of the granules was unchanged. Solid‐state grafting polymerizations of styrene initiated by tert‐butyl perbenzoate in both N‐PP and annealed polypropylene (A‐PP) granules were compared under different reaction conditions. The formation of gel in the product could be completely depressed at a low concentration of the initiator when A‐PP granules were used as the matrix and graft‐polymerized at 120°C. Both the introduction of styrene and the annealing treatment of the PP granules led to a depression of polymer degradation in the process of the grafting reaction. However, using A‐PP as the matrix caused an increase in the grafting degree at a relatively high concentration of the initiator. A reduction in the amorphous phase in the PP granules was thought to be the main reason for the effects of the annealing treatment on the structure of the graft polymerization products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

丙烯酸丁酯、马来酸酐、苯乙烯三单体固相接枝改性聚丙烯的研究

以丙烯酸丁酯（BA）、马来酸酐（MAH）和苯乙烯（St）为接枝单体,偶氮二异丁腈（AIBN）为引发剂,加入少量有机溶剂作分散剂,对聚丙烯进行固相接枝改性制备接枝共聚物。考察了反应时间、反应温度、引发剂用量等因素对接枝反应的影响,用红外光谱对接枝产物进行了表征。结果表明,当引发剂用量（以PP质量为基准）为0．3％,单体（n（BA）：n（St）：n（MAH）=2：1：1）总投料量为4％时,得到了接枝率为3．26％的接枝产品。单体利用率达到70％。     

Influence of grafting formulations and extrusion conditions on properties of silane‐grafted polypropylenes

The melt grafting of unsaturated silanes onto powdered polypropylene (PP) in a Haake TW100 twin‐screw extruder and curing in hot water were studied. The influence of grafting formulations and extrusion conditions on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. The gel percentages of methacryloylpropyltrimethoxysilane (VMMS)‐grafted PP were markedly higher than those of vinyltriethoxysilane (VTES)‐ and vinyltrimethoxysilane (VTMS)‐grafted PP, while significantly less degradation of PP during grafting was observed for VMMS‐grafted PP. When benzoyl peroxide (BPO) was used as an initiator, no degradation of PP during grafting was observed, and the melt flow rates of grafted PP decreased with increasing BPO concentration. In contrast, use of dicumyl peroxide (DCP) as an initiator resulted in severe degradation of PP, and the melt flow rates of grafted PP increased gradually with increasing DCP concentration. BPO resulted in higher gel percentages than those of DCP at a fixed initiator concentration. Introduction of styrene into the grafting system greatly improved the gel percentage of crosslinked PP and reduced the degradation of PP during grafting. The optimum molar ratio of styrene to monomer is at about 1.5:1. Relatively low processing temperatures and high screw speeds are favorable. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1233–1238, 2000