用ES共聚物对PE—PS共混物增容的研究

准无规乙烯－苯乙烯共聚物是由一种限定几何结构的催化剂制备,对聚乙烯－聚苯乙烯共混物的增容是非常有效的。     

ABS/SAN/中粘度PMMA三元共混物的性能研究

制备不同配比的丙烯腈－丁二烯－苯乙烯（ABS）／苯乙烯－丙烯腈（SAN）／中粘度聚甲基丙烯酸甲酯（PMMA）合金，分别测试其缺口冲击强度、拉伸强度、热变形温度、熔体流动指数等，结果表明：ABS／SAN可以引发中粘度PMMA产生大量的银纹，从而大幅度提高共混物的冲击强度；引入中粘度PMMA可以提高ABS／SAN的耐热性能；添加中粘度PMMA，合金的流动性能呈现下降的趋势。     

核—壳共聚物对光盘级聚碳酸酯的增韧研究

研究了甲基丙烯酸甲酯－丁二烯－苯乙烯共聚物（MBS）对光盘级聚碳酸酯的增韧作用，结果表明，MBS对PC增韧效果显著，且MBS分散性越好，达到晚一韧转变时所需的MBS含量越少，求得达到脆－韧转变时的临界粒间距为50nm，对共混物损伤机制的研究表明，MBS增韧PC共混物的增韧机理为MBS粒子的空洞化引发基体的剪切屈服。     

增容剂苯乙烯－乙烯／丁烯－苯乙烯三嵌段共聚物对LDPE／PS共混物形态的影响

以苯乙烯－乙烯／丁烯－苯乙烯三嵌段共聚物（ＳＥＢＳ）作增容剂，用２种方法制备ＬＤＰＥ／ＰＳ共混物，均对混合物分散相颗粒尺寸和形态有影响，主要是由于界面现象，而不是流变行为。同时还计算了ＳＥＢＳ／ＬＤＰＥ以及ＳＥＢＳ／ＰＳ共混物的相互作用能密度β。试验表明，随着ＳＥＢＳ中ＥＢ体积分数的增加，ＳＥＢＳ／ＬＤＰＥ共混物的β值减小，而ＳＥＢＳ／ＰＳ共混物的β值增加，并在ＥＢ体积分数约０．４５时两条曲线相交。还提出了含增容剂的二元共混物分布的３种模型，用２种方法制备的共混物的分布模型均属于结合型。     

苯乙烯—马来酸酐无规共聚物的合成方法及其增容作用

介绍了苯乙烯－马来酸酐无规共聚物的四种制备方法：本体聚合法、溶液聚合法、乳液聚合法以及本体－悬浮聚合法，讨论了苯乙烯－马来酸酐无规共聚物摩尔分子质量及其马来酸酐含量、苯乙烯－马来酸酐无规共聚物的用量以及共混顺序等因素对其增容作用的影响。     

环氧化三元乙丙胶与苯乙烯—马来酸酐共聚物的共混行为研究

利用反应共混技术实现了环氧化三元乙丙橡胶（e-EPDM）对苯乙烯－马来酸酐（SMA）共聚物的增韧改性。以EPDM／SMA共混体系为参比,考察了共混物结构、流变行为、冲击性能和断面形态。结果表明,e－EPDM与SMA反应共混可原位形成偶联接枝产物,改善共混体系的相容程度,提高SMA的韧性。     

PP／AS／DCP反应共混中SEBS的添加效应

研究了在聚丙烯（ＰＰ）／丙烯腈－苯乙烯共聚物（ＡＳ）／过氧化二异丙苯（ＤＣＰ）共混物反应挤出过程中添加热塑弹性体氢化（苯乙烯－丁二烯－苯乙烯共聚物）（ＳＥＢＳ）对ＰＰ／ＡＳ共混物降解的抑制效果对接枝反应的促进作用。对反应经物中ＰＰ相ＭＦＲ、红外测试及扫描电子显微镜与航向电子显微镜对共混物的观察结果表明,加入ＳＥＢＳ不但可以抑制反应共混中ＰＰ和ＡＳ的降解,而且可以大大促进反应共混中的接枝反应的进行,     

聚氨酯和苯乙烯—马来酸酐无规共聚物反应性共混研究：Ⅰ合成与表征

以过氧化二异丙苯为引发剂，采用溶液聚合法合成了苯乙烯－马来酸酐无规共聚物，并使其在溶液中与聚氨酯进行反应性共混。用ＩＲ、ＤＳＣ、ＴＧ等对反应性共混物给予表征。     

聚氨酯/苯乙烯-马来酸酐无规共聚物反应性共混

采用反应性共混法合成聚氨酯／苯乙烯－马来酸酐无规共聚物共混物,用红外光谱,扫描电子显微镜研究了共混物的形态结构,并对共混物的性能进行了研究。     

用原子转移自由基聚合法制备SBS/聚(苯乙烯-甲基丙烯酸丁酯)互穿聚合物网络

将线型热塑性弹性体SBS溶胀于苯乙烯和甲基丙烯酸丁酯混合液中，以BPO为引发剂，在CuCl/2,2′－联吡啶酯位化合物催化下进行原子转移自由基聚合，制备了SBS／聚（苯乙烯－甲基丙烯酸丁酯）互穿聚合物网络。结果表明，实现了苯乙烯－甲基丙烯酸丁酯共聚物的可控聚合，聚合物数均相对分子质量随单体转化率的提高呈线性增长，且分布较窄，从而得到了组成和性能不同的互穿聚合物网络。     

负离子溶液聚合法高苯乙烯橡胶的合成及其性能

以环己烷为溶剂、苯乙烯和丁二烯为单体、n-BuLi为引发剂、二乙二醇二甲醚(2 G)为结构调节剂,通过活性负离子溶液聚合合成了高苯乙烯橡胶,研究了引发剂种类、聚合温度、2 G/n-BuLi(摩尔比)、苯乙烯/丁二烯(质量比)、相对分子质量及其分布对共聚橡胶力学性能的影响。结果表明,当苯乙烯/丁二烯为60/40、2 G/n-BuLi为1.0时,在(65±2)℃下可聚合得到力学性能较好的高苯乙烯橡胶,其数均分子量为15×104~20×104、分子量分布为1.40左右。     

Cationic polymerization of α-methyl styrene from polydienes. II. Tensile properties of poly(butadiene-g-α-methyl styrene) and poly(styrene-b-butadiene-g-α-methyl styrene) copolymers

Tensile properties of poly(butadiene-g-α-methyl styrene) copolymers have been investigated on molded samples. These graft copolymers show thermoplastic elastomer behavior because of their graft copolymer structure. Both modulus and strength increase with increasing α-methyl styrene content and tensile strength is highest at the 45–50% by weight α-methyl styrene level. Tensile strength at elevated test temperatures is considerably higher for these poly(butadiene-g-α-methyl styrene) copolymers than for styrene-butadiene-styrene triblock polymers. This is attributed to the higher glass transition temperature for poly(α-methyl styrene) segments compared to polystyrene segments. The oil acceptance of these graft copolymers appears to depend on the number of loose polybutadiene chain ends. Thus, the tensile strength of oil-extended poly(butadiene-g-α-methyl styrene) copolymers was considerably lower than oil-extended poly(styrene-b-butadiene-g-α-methyl styrene) copolymers even though both copolymers contained equal hard segment contents.     

橡胶增韧苯乙烯与马来酸酐共聚物的方法

对增韧无规苯乙烯/马来酸酐共聚物(SMA)的方法作了分类,并对国内外SMA研究方面的进展作了分析。可以认为,橡胶增韧无规SMA,无论从耐热、冲击性能,还是从价格/性能比而言,是一类值得开发的高分子材料。以不同品种橡胶(如乙丙橡胶、苯乙烯-丁二烯-苯乙烯和丁基橡胶等)作增韧剂,通过不同的增韧方法,可以达到不同的增韧效果,满足不同的需求。     

Improving glass transition temperature of unsaturated polyester thermosets: Conventional unsaturated polyester resins

Highly crosslinkable unsaturated polyester resins (UPR) have attracted many interests in the application as reinforced matrix materials. Here, we present a systematical study of the influence of different curing conditions and styrene concentrations on resin viscosity and dynamic-mechanical properties of the thermoset. The pure maleic Palapreg® P18-03 was selected as model UPR because of its broad industrial use. By applying newly developed thermal curing profiles (without thermal initiators) and by raising the styrene content, the T_g of the network could be increased up to 206/215°C (1/10 Hz). For the first time, a fast curable UPR based on propylene glycol and neopentyl glycol with a T_g of up to 215°C is described. A partial substitution of problematic styrene with methylmethacrylate, tert-butylacrylate, and maleic anhydride (MA) was studied as well. MA leads to significantly improved resin reactivity. A resin containing 42 wt% styrene and 8 wt% MA yields thermosets with remarkably improved mechanical properties and with a narrower glass transition range compared to the original P18-03.     

ABS树脂市场分析

综述了国内外丙烯腈-丁二烯-苯乙烯（ABGS）树脂的生产能力,供需状况和消费结构。预测了市场走势,对发展我国ABS树脂产业提出了几点建议。     

PREPARATION OF MICROSPHERES WITH LIQUID CRYSTAL RESPONSES

We synthesized a ferroelectric liquid crystal monomer possessing both carboxyl p-benzolxy-benzoate and carboxyl (s)-(-)-2-methylbutyl ester in its side chain. The liquid crystal and styrene monomers were utilized to form matrices of microspheres prepared by the dispersion or suspension polymerization. In this study, we characterized in detail physicochemical properties, thermo-responses, or electro-optical responses in the microspheres. We demonstrated the following results: (1) the volume-averaged diameters of microspheres prepared by the dispersion or suspension polymerization were of 1.5 or 45 μm, respectively, (2) the microspheres prepared showed liquid crystal abilities at the prescribed temperature, (3) the phase transition temperatures toward the liquid crystal phase of the microspheres prepared by copolymerizing the liquid crystal and styrene monomers could be decreased with increasing styrene monomer concentrations, and (4) the microspheres obtained remarkably exhibited electro-optical responses at the appointed voltage.     

Partial replacement of carbon black with graphene in natural rubber/butadiene rubber based tire compound: Investigation of critical properties

Journal of Polymer Research - In this study, we prepared graphene oxide-based styrene/acrylic elastomeric disks (GSAE) from sugarcane bagasse/ferrocene (GO) and styrene/acrylic emulsion (SAE) to...     

Copolymerization of styrene with acrylamide derivatives in an emulsifier-free aqueous medium

Acrylamide derivatives were copolymerized with styrene in an emulsifier-free aqueous medium, and the copolymerization mode and the characteristics of the resulting latices were compared with those of a styrene–acrylamide copolymerization system. In their copolymerization mode, N-(hydroxymethyl)acrylamide and N,N-dimethylacrylamide resembled acrylamide, and their heterogeneous copolymerization course was divided into three stages on the basis of the main reaction locus. Copolymerization of styrene–methacrylamide did not resemble that of the others. The interfacial property and reactivity of acrylamides affected not only the polymerization mechanism but also the latex properties, e.g., particle size, distribution of acrylamides units in the latex, etc. The narrowest distribution of particle size was obtained in styrene–N-(hydroxymethyl)acrylamide copolymerization at a monomer ratio of 10:1. Delayed addition of styrene into the aqueous solution of N-(hydroxymethyl)acrylamide prepolymerized to some extent was found to be effective in preparing a latex with nearly monodisperse and large particles.     

苯乙烯可逆加成-断裂链转移聚合动力学

为了实现可逆加成-断裂链转移(RAFT)聚合过程中,苯乙烯均聚、高分子量聚苯乙烯的合成及苯乙烯与其他单体共聚时,对苯乙烯转化率、共聚时组成和分子量大小的控制,进行了二硫代苯乙酸-1-苯基乙酯(PEPDTA)调控苯乙烯本体和细乳液聚合动力学分析。在本体聚合中,反应速率慢,链增长自由基与"中间态"自由基的终止反应对聚合速率影响较小,很难合成窄分布、高转化率、高分子量的聚苯乙烯;在细乳液聚合中,反应速率快、转化率高,随着PEPDTA含量增加,乳胶粒数量减少、粒径分布变宽,诱导期和缓聚现象明显;聚合物的数均分子量随转化率线性增长,RAFT试剂浓度越高,分子量分布越窄,反应时间越长,分布越宽。以Smith-Ewart方程为基础,建立了苯乙烯RAFT细乳液聚合动力学模型,模型动力学曲线与实验数据相符合,能较好地预测实验过程。     

Polymerization of styrene in γ-cyclodextrin channels: Lightly rotaxanated polystyrenes with altered stereosequences

Modeling of polystyrene (PS) with various stereosequences in γ-cyclodextrin (γ-CD) channels has been conducted and it was found that only isotactic PS stereoisomers can fit into the γ-CD cavity. Thus, based on the modeling of stereoisomeric polystyrenes in narrow γ-CD channels, it was suggested that PSs with unusual microstructures might be produced via constrained polymerization of styrene monomer in its γ-CD-IC crystals. The in situ polymerization of styrene inside the narrow channels of its γ-CD-IC crystals suspended in aqueous media was performed. Alternatively, the solid-state polymerization of styrene/γ-CD-IC has also been conducted by exposure to γ-radiation. It was found that most host γ-CD molecules slip off during polymerization and the channel structure was not preserved. Consequently, much of the guest styrene monomer polymerizes outside of the host γ-CD channels, where the constrained environment is absent. Yet, a lightly rotaxanated structure has been obtained, where some threaded γ-CD molecules ∼15 wt% (∼1 γ-CD per 70 PS repeat units) are permanently entrapped along the PS chains after polymerization. ¹³C NMR spectra of PSs synthesized from styrene/γ-CD-IC and homogeneously in toluene show some differences, which are presumably due to variations in the stereosequences of PSs obtained from the partially constrained polymerization of styrene/γ-CD-IC.