Synthesis and characterization of polystyrene initiated using polymeric peroxide

Polymer peroxides were synthesized by copolymerizing tert‐butyl‐3‐isopropenylcumylperoxide (D‐120) with styrene (St). Exothermic peak at 192.7°C in DSC thermogram indicated that peroxy bonds in D‐120 remained intact during the copolymerizing process. The polymeric peroxide was used to initiate polymerization of St. GPC results showed that polystyrene (PS) initiated by the polymeric peroxides was composed of both linear and branched molecules. In addition, the rheology test showed that PS samples initiated by polymeric peroxide contained branched structure and had lower shear viscosities. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 197–202, 2006     

Use of natural rubber‐g‐polystyrene as a compatibilizer in casting natural rubber/polystyrene blend films

Natural rubber/polystyrene (NR/PS) blend films with weight ratios of 70/30, 60/40, and 50/50 were prepared using polystyrene grafted natural rubber copolymers (NR‐g‐PS) as the compatibilizer. Copolymers with molar ratios of 90/10, 80/20, and 70/30 were synthesized via emulsion copolymerization using tert‐butyl hydroperoxide/tetraethylene pentamine as an initiator. The copolymers were subsequently added into the blends at 0, 5, 10, 15, 20, 25, and 30 phr. The mixtures were cast into films by the solution‐casting method using toluene as the casting solvent. Mechanical and morphological properties of the prepared films were investigated. The film prepared from 80/20 NR‐g‐PS showed higher tensile and tear strength, as well as finer domain size of the dispersed phase, than those prepared from 90/10 and 70/30 NR‐g‐PS. However, the mechanical properties of the films were decreased at high loading of the copolymers. In addition, themogravimetric analysis revealed that weight loss was decreased upon introduction of the compatibilizer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 826–831, 2005     

废聚苯乙烯泡沫塑料接枝丙烯酸丁酯改性白乳胶的研制

通过对聚苯乙烯泡沫塑料进行乳化研究，获得了稳定的聚苯乙烯乳液。再采用丙烯酸丁酯（BA）和功能单体对聚苯乙烯进行接枝改性，制成水乳型胶粘剂。研究了溶剂比、乳化剂与稳定剂用量、改性单体及功能单体的用量、引发剂及交联剂用量等因素对粘接性能的影响。     

聚苯乙烯-铂络合物催化硅氢加成反应机理的研究

将巯甲基化交联聚苯乙烯－铂络合物微球用于催化苯乙烯与甲基二氯硅烷的加成反应，考察了用硅氢加成试剂处理催化剂的时间对其催化行为的影响。发现催化活性中心主要是Pt（Ⅱ），催化剂的后处理时间明显影响硅氢加成反应的诱导期和活性，并根据实验结果提出了可能的催化机理。     

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.     

催化干气的利用

炼厂气含C_1～C_4组份,未被回收利用。催化裂化干气中含乙烯10％～20％,氢50％～70％。采用膜分离技术从重油催化裂化干气中回收氢气,制氢成本低,能源利用合理;介绍了从催化裂化干气中回收乙烯的方法及乙苯的利用。指出炼油厂采用膜分离技术回收氢及用催化裂化干气中的乙烯生产苯乙烯,是合理利用石油副产物的有效途径。     

低烟阻燃高抗冲聚苯乙烯的研究

用氢氧化镁（MH）和硼酸锌（ZB）与十溴二苯醚（DBDPO）－氧化锑或包覆红磷共同使用以阻燃高抗冲聚苯乙烯（HIPS）可使燃烧过程中的发烟量降低40％左右。与十溴二苯醚－氧化锑和包覆红磷体系相比，聚苯醚（PPO）和一种磷酸酯阻燃剂配合作用时HIPS的阻燃、抑烟作用以及对力学性能有较大改善作用。     

对塑料“白色污染”的认识及治理对策

塑料“白色污染”的治理对策应当是在所谓的“白色污染”持正确看法的前提下,以发展回收和再利用技术为主,辅之以社会行为和其他技术,针对不同种类的废弃塑料,提出相应的解决办法。最后还就聚苯乙烯（PS）泡沫塑料消泡回收及再利用的新技术做了介绍。     

Transitions from solid to liquid in isotactic polystyrene studied by thermal analysis and X-ray scattering

A three-phase model, comprising mobile amorphous fraction (MAF), rigid amorphous fraction (RAF) and crystalline fraction (C), has been applied to interpret the thermal transitions and structure of cold-crystallized isotactic polystyrene (iPS) from below the glass transition temperature, T_g, to above the melting point. Quenched amorphous iPS films were isothermally crystallized at different temperatures for 12 h. The fraction of crystalline phase, ?_c, was measured by differential scanning calorimetry (DSC), wide angle X-ray scattering and Fourier Transform infrared spectroscopy. The fraction of the mobile amorphous phase, ?_MAF, was obtained from the heat capacity increment at the glass transition temperature. In the three-phase model, the fraction of the rigid amorphous phase, ?_RAF, was found from 1−?_MAF−?_c. Specific heat capacity measurements by standard DSC confirm that the experimental baseline heat capacity conforms to a three-phase model for temperatures ranging from below T_g, up to the relaxation of RAF. The relaxation of RAF appears as a sigmoidal change in heat capacity accompanied by excess enthalpy, in which solid-like RAF is converted to an identical amount of liquid-like MAF.At temperatures above the relaxation of RAF, either one or two major crystal melting endotherms are observed in standard DSC, dependent upon crystallization temperature. However, using quasi-isothermal temperature modulated DSC, we always observed two reversing melting endotherms. The effects of annealing on iPS structure during the quasi-isothermal measurement were assessed using small angle X-ray scattering (SAXS). Combining the DSC and SAXS results, a model for the melting of iPS lamellae at low heating rates is presented.     

嵌段共聚物增容剂对LDPE／PS分散相粒径的影响

研究了增容剂苯乙烯－丁二烯二嵌段共聚物，苯乙烯－乙烯／丙烯二嵌段共聚物和苯乙烯－乙烯／丁烯－苯乙烯三嵌段共聚物对ＬＤＰＥ／ＰＳ共混物分散相粒径尺寸的影响，结果表明，在增容剂用量约３％时，分散相的粒径尺寸接近最小值，进一步增加增容剂的用量，粒径尺寸没明显的变化；增容剂中苯乙烯嵌段和橡胶嵌段之间的溶度参数差越大，分子间排斥作用越大，分散相的粒径越小。