间规聚苯乙烯热性能研究

对间规聚苯乙烯（sPS）的热性能（包括熔点、晶型及热稳定性等）进行了差示扫描量热、热重分析和动态力学性能等的测量和分析，发现sPS中存在着不同的晶型，它理想晶体的热力学临界分子量熔点为270．13℃，sPS在静态和动态时间的使用温度可达250℃，说明sPS具有良好的热性能。研究结果有助于sPS的进一步加工和应用。     

间规聚苯乙烯的应用研究进展

介绍了间规聚苯乙烯（ｓＰＳ）的结构与性能,综述了其国内外发展情况和改性方向,展望了其应用前景。     

红外光谱法研究间规聚苯乙烯结晶行为进展

间规聚苯乙烯是一种具有高结晶能力的聚合物,它的复杂多晶现象非常有趣。该文概述了聚合物的结晶理论和间规聚苯乙烯的应用,并讨论了红外光谱在间规聚苯乙烯上的研究,最后展望了该方法在结晶研究上的可发展性。     

溶液聚合间规聚苯乙烯非等温结晶动力学

介绍了有关物质结晶行为的Ozawa方程和Liu方法的理论背景。用DSC方法研究了间规聚苯乙烯（s-PS）的非等温结晶动力学。结果表明,降温速率越大,s-PS的结晶峰越小,结晶度也越小。s-PS非等温结晶行为服从Ozawa方程和Liu方法。Ozawa指数为3,是以异相成核的三维生长或均相成核的二维生长方式结晶的;相对结晶度为0.20～0.80时,降温速率的对数与结晶时间的对数具有较好的线性关系。     

间规聚苯乙烯/等规聚丙烯共混物的热性能

用差示扫描量热法(DSC)、动态力学分析(DMA)和热重法(TGA)等研究了间规聚苯乙烯/等规聚丙烯(sPS/iPP)、sPS与聚-1-丁烯(B30)组成的嵌段共聚物和sPS/iPP/B30共混体系的热性能。结果表明sPS/iPP是不相容体系,B30与iPP可相容,B30可作为sPS/iPP共混物的相容剂。DSC和DMA分析结果表明,加入适量的B30时,sPS/iPP/B30共混物中iPP的玻璃化转变温度随B30加入量的增加而逐渐升高,而sPS的玻璃化转变温度则随B30加入量的增加而逐渐降低;TGA分析结果表明共混体系的热失重温度高于300℃,比iPP的高。     

酰化间规聚苯乙烯的合成与热性能

采用异相反应合成了乙酰化间规聚苯乙烯,用FTIR,NMR,DSC对乙酰化间规聚苯乙烯的结构与性能进行了研究.结果表明,乙酰化间规聚苯乙烯与间规聚苯乙烯相比,玻璃化转变温度升高,熔融温度和熔融热焓下降.     

间规聚苯乙烯的热分解行为分析

利用热重分析（TG—DTA）法研究了间规聚苯乙烯（sPS）在不同气氛（空气和氮气）下的热分解行为机理。研究表明,sPS在两种气氛下都是只有一个主要的热分解过程。结果表明,用Kissinger最大失重速率法求得空气气氛下的表观活化能为133．86kJ／mol,而在氮气气氛下的表观活化能为158．96kJ／mol;用Ozawa等失重百分率法求得空气气氛（10％～30％的失重率）下的表观活化能为92．05～105．88kJ／mol,而在氮气气氛下的表观活化能为149．00—175．38kJ／mol;sPS的热裂解和热氧分解过程均为一级反应。     

间规聚苯乙烯的多晶现象

概述了间规聚苯乙烯多晶的成因及分析方法。     

茂金属间规聚苯乙烯

论述了茂金属催化体系,影响聚合和聚合物性能的主要因素,聚合反应釜以及间规聚苯乙烯的性能,加工及应用。     

间规聚苯乙烯的特性及应用前景

用茂金属催化剂制得间规聚苯乙烯（ｓＰＳ）是一类新型结晶聚合物，具有优良的耐热性，耐化学性和电气性能。综合考虑价格／性能因素，ｓＰＳ在工程塑料的应用市场上具有很强的竞争力，本文对ｓＰＳ的物性及应用景景作一简要介绍。     

间规聚苯乙烯改性的研究进展

综述了近年来间规聚苯乙烯改性的研究进展，分别对其共混改性、化学共聚改性和纳米改性等方法进行了评述。     

间规聚苯乙烯共混改性研究进展

介绍了间规聚苯乙烯(SPS)的特点，论述了间规聚苯乙烯共混改性的研究进展。详细介绍了SPS和聚苯醚共混，SPS和弹性体共混以及SPS和聚酰胺、聚酯等高聚物的共混改性，并展望了SPS的应用前景。     

均相茂金属催化剂催化苯乙烯间规聚合中搅拌的作用

在不同搅拌型式的聚合反应器中使用均相茂金属催化剂（Cp^*Ti(OR)3/MAO/TIBA催化苯乙烯本体间规聚合。研究搅拌桨型式、反应器以及搅拌速度对聚合物形态以及聚合过程的影响,并分析了搅拌、结晶和聚合之间的关系。研究表明,良好的搅拌剪切对避免凝胶、促进粉状间规聚苯乙烯的生成至关重要。聚合动力学的研究表明,搅拌转速不仅能影响聚合物的颗粒形状,也能通过改变聚合物原生晶的结晶速率从而影响聚合速率。     

New Nanocomposites Based on Syndiotactic Polystyrene and Organo-Modified ZnAl Layered Double Hydroxide

New nanocomposites were prepared by mixing syndiotactic polystyrene (sPS) with organo-modified ZnAl layered double hydroxide (O-ZnAl-LDH) in toluene solution. Both wide-angle X-ray diffraction (WXRD) and transmission electron microscopy (TEM) examinations confirmed the nanocomposite formation with exfoliated or intercalated O-ZnAl-LDH distributed in the sPS matrix. Meanwhile, the nonisothermal crystallization behavior of the resulting nanocomposites was studied using differential scanning calorimetry (DSC) technique at various cooling rates. The results indicated that the O-ZnAl-LDH particles in nanometer size might act as nucleating agents and accelerate the overall nonisothermal crystallization process.     

Lamellar Thickness of a Syndiotactic Polystyrene Determined from Small-angle X-ray Scattering and Transmission Electron Microscopy

Extensive morphological studies on a syndiotactic polystyrene (sPS) sample prepared from compression molding were carried out using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). SAXS was conducted at 25C as well as at 150C to enhance the scattering contrast in order to obtain more reliable morphological parameters. The compression-molded sample was crystallized into a orthorhombic crystal lattice characterized by wide-angle X-ray diffraction (WAXD). A similar weight fraction of crystallinity, ca. 0.37, was obtained from both WAXD and differential scanning calorimetry measurements.In addition to the scattering peak at a scattering vector of ca. 0.36 nm^–1 attributable to the presence of lamellar/amorphous layers, anomalous scattering at the zero angle was found from the SAXS intensity profiles. Based on the Debye–Bueche theory, the scattering profile of this peculiar zero-angle scattering was deduced and was subtracted from the raw intensity profile to obtain the intensity profile exclusively associated with the lamellar/amorphous structure. A consistent long period was obtained for SAXS measured either at 25 or 150C, provided that the appropriate subtraction of intensities due to the zero-angle scattering was conducted. Moreover, the lamellar thickness deduced from the one-dimensional correlation function was in good agreement with TEM results. A difference scattering pattern derived from SAXS measured at 150 and 25C was obtained and a comparison of the morphological parameters was provided as well.     

Syndiotactic Polystyrene/Organoclay Nanocomposites: Synthesis via In Situ Coordination‐Insertion Polymerization and Preliminary Characterization

Summary: Syndiotactic polystyrene (sPS)/organophilic clay nanocomposites were obtained by in situ coordination‐insertion polymerization of styrene. Two cationic surfactants (alkylammonium and alkylphosphonium) were used for the intercalation of montmorillonite (MMT). For each organically modified clay, three protocols were performed using an MAO‐activated hemi‐metallocene catalyst, in order to compare the influence of experimental conditions on the composite microstructure and on its thermal stability. The microstructures of nanocomposites were investigated by wide angle X‐ray scattering and DSC. Partially exfoliated or intercalated materials were obtained in all cases and a decrease of crystallinity is observed. Thermal properties were also studied by DSC and thermogravimetric analysis. The presence of clay does not have a strong influence on the sPS thermal transitions but the thermal decomposition process of the material was slowed down in the presence of few organoclay percents, particularly in the degradation beginning. The influence of these two organically modified clays on the thermal stability of the material is discussed.

Gel and suspension formed from the combination of cloisite with toluene (left) and styrene (right), respectively.     

Microstructural Development of Uniaxial Stretched Anneal-Oriented Syndiotactic Polystyrene and its Blend with Poly (2,6-dimethyl-1,4-phenylene oxide): DSC,WAXD, SAXS and FTIR Studies

Studies have been done on strain-induced microstructure development in syndiotactic polystyrene (s-PS) and its blends with poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) in 70/30 and 50/50 compositions of stretched annealed samples. Wide-angle X-ray showed that crystal orientation is less in annealed blend samples compared to annealed pure s-PS for a higher draw ratio. It increases with annealing, and relaxation occurs after a certain annealing temperature at above 180° for both s-PS and s-PS/PPO 70/30 blends. No crystal orientation was observed in the blend of s-PS/PPO 50/50 stretched samples. Small angle X-ray scattering (SAXS) shows the inclusion of amorphous PPO chains in between s-PS crystals lamella. Fourier transform infrared (FTIR) spectroscopy shows that the s-PS molecular chain packing band at 905 cm^?1 is enhanced due to annealing in oriented samples and saturates to around 0.63. The crystal chain relaxation is lower than amorphous chains of s-PS. The molecular chains of amorphous PPO are less oriented into the blend matrix, whereas its relaxation is enhanced during heat treatment and reaches an optimum value after full relaxation. The different behaviors of orientation and relaxation of s-PS and PPO chains into the blend matrix produce superstructures.     

间规聚苯乙烯的合成与工业化研究

本文评述了间规聚苯乙烯（ｓＰＳ）的联合机理与工业化研究,介绍了茂金属催化剂和聚合反应器。强调要实现ｓＰＳ的工业化,尚需加强以聚合反应工艺和反应器开发为目标的聚合反应工程研究。