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。     

聚苯乙烯／聚乙烯共混体系的研究

讨论了不同第三组分和不同种聚乙烯对以聚苯乙烯为基质的ＰＳ／ＰＥ共混体系结构和性能的影响，发现苯乙烯－丁二烯－苯乙烯嵌段共聚物和苯乙烯－氢化丁二烯－苯乙烯嵌段共聚物作为第三组分对ＰＳ／ＰＥ共混体系均具有增容作用，用ＳＢＳ的效果比ＳＥＢＳ好，而ＳＢＳ的结构对增韧效果的影响不大。在ＳＢＳ存在下，ＬＬＤＰＥ对ＰＳ增韧效果最好，ＨＤＰＥ次之，ＬＤＰＥ最差。     

国外动态

新的增容剂ＳＢＭ嵌段共聚物和ＰＰＳ／ＰＳ共混物相反,ＰＰＥ／ＳＡＮ和ＰＰＥ／ＡＢＳ共混物中各组份是不相容的,从而需要增容剂和抗冲改性剂提高共混物性能,ＳＢＭ三嵌段共聚物对ＰＰＥ／ＳＡＮ既有相容剂的作用,又有抗冲改性剂的作用,该嵌段共聚物是苯乙烯、丁二...     

PE/PS合金的研究进展

综述ＰＥ／ＰＳ合金相容剂的合成方法，包括接枝共聚法、嵌段共聚法和反应性增容法。使用相容剂后，ＰＥ／ＰＳ合金的机械性能和相容性能大大提高。     

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。     

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…

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。     

聚苯硫醚—聚砜嵌段共聚物的合成及初步表征

用巯端基聚苯硫醚（ＰＰＳ）齐聚物和氯端基聚砜（ＰＳＦ）齐聚物，在极性溶剂中常压合成了ＰＰＳ－ＰＳＦ嵌段共聚物，用红外光谱表征了其链结构，Ｘ－射线衍射及热分析测试结果表明，由于无定形砜基的引入，导致了嵌段共聚物的结晶度和熔融温度的下降。在合成ＰＰＳ－ＰＳＦ嵌共聚物的基础，合成了ＰＳＦ－ＰＰＳ－ＰＳＦ三嵌段共聚物，用红外光谱及Ｘ－射线衍射等分析手段对其进行了初步表征。     

CHR/PVC共混增容研究

以聚2－乙烯基吡啶和聚环氧乙烷多嵌段共聚物（P2VP－b－PEO）为增容剂，研究了氯醚橡胶（CHR)和聚氯乙烯（PVC）之间的共混，考察了增容剂用量、PVC／CHR配比、增容剂组成、增容剂中P2VP链段长度对共混物机械性能的影响。发现2％－3％的多嵌段共聚物能够很好地增容CHR／PVC共混体系，多嵌段共聚物中PEO链段含量越高、P2VP链段越长，增容效果越好。     

BR／PVC／SBS动态硫经体系的增容技术

采用差示扫描量热分析、扫描电子显微镜和力学方法研究了在丙烯酸酰胺和引发剂过氧化二异丙苯（ＤＣＰ）存在下,顺丁二烯橡胶／聚氯乙烯－丁二烯－苯乙烯嵌段共聚物（ＢＲ／ＰＶＣ／ＳＢＳ）动态硫化挤出共混的结果。初步探讨了引入丙烯酸酰胺“就地”产生增容剂的机理。实验证明,采用该方法较以α－甲基苯乙烯为增容剂的相同体系具有更好的增容效果。     

共混MCS树脂的力学性能,形态与流变性

利用增容原理,以α－甲基苯乙烯为增容性性单与,与人烯酸甲酯、苯乙烯乳液共聚,所得共聚物与氯化聚乙烯共混得ＭＣＳ合金。研究了α－ＭＳ、ＣＰＥ用量对树脂力学性能和流变性的影响,同时考究了树脂的微观结构与形态。     

国内外PS/PE共混改性研究新进展

综述了国内外采用接枝共聚物,嵌段共聚物以及反应性共混提高PS／PE相容性的研究方法。并提出应继续开发PS／PO合金的途径,并将其转化为工业产品。     

少量PS对H-PVC/CPE/PE共混体系性能的影响

本文研究了在H-PVC/CPE/PE共混体系中添加少量刚性有机粒子PS对体系性能的影响。在PVC/CPE/未交联PE的配比为100/6/5时,添加少量(1～3份)PS粒子,能使体系的冲击强度成倍增加,拉伸强度基本不变。在PVC/CPE/动态微交联PE的配比为100/6/5时,添加少量PS粒子,出现与PS改性PVC/CPE/未交联PE体系类同的规律性,并且效果更好,冲击强度可高达86kJ/m~2,拉伸强度最高达48MPa。共混方式对PVC/CPE/PE/PS体系的性能影响较大,其中以四步法的效果最佳,不仅冲击强度提高幅度最大,拉伸强度也达到了最大值。     

Compatibilizing effect of poly(styrene)‐block‐poly(isoprene) copolymers in heterogeneous poly(styrene)/natural rubber blends

Compatibility of poly(styrene) (PS)/natural rubber (NR) blend is improved by the addition of diblock copolymer of poly(styrene) and cis‐poly(isoprene) (PS‐b‐PI). The compatibilizing effect has been investigated as a function of block copolymer molecular weight, composition and concentration. The effect of homopolymer molecular weight, processing conditions and mode of addition on the morphology of the dispersed phase have also been investigated by means of optical microscopy and scanning electron microscopy. A sharp decrease in phase dimensions is observed with the addition of a few percent of block copolymers. The effect levels off at higher concentrations. The leveling off could be an indication of interfacial saturation. For concentrations below the critical value, the particle size reduction is linear with copolymer volume fraction and agrees well with the prediction of Noolandi and Hong. The addition of the block copolymer improves the mechanical properties of the blend. An attempt is made to correlate the mechanical properties with the morphology of the blends. © 2001 Society of Chemical Industry     

Polyethylene-polystyrene grafting reaction: effects of polyethylene molecular weight

Blending of different thermoplastic polymers usually results in segregated and low value materials for almost any mixing condition. Nevertheless, a synergetic combination of properties can be obtained by an adequate compatibilization via reactive blending. In this work a Friedel-Crafts alkylation reaction is used to graft polyethylene chains onto polystyrene. The relation between the initial PE molecular weight (MW) and the structure of the compatibilizer copolymer is studied by a combination of size exclusion chromatography and Fourier transform infrared spectroscopy. The amount of copolymer formed is estimated from the amount of polystyrene reacted. The relative lengths of the grafted polyethylene chains are assessed. It is found that lower MW PE produces, upon reaction, a greater amount of short chain length grafted PE onto PS than higher MW PE. The results are in agreement with theories relating the component MW to the reaction localization at the interface.The low cost Friedel-Crafts alkylation results in a convenient reaction for the in situ compatibilization of PE/PS blends. It produces enough graft copolymer to compatibilize the phases without causing PS crosslinking and PE chain scission.     

PP／PS合金技术进展

PP和PS是不相容的聚合物 ,直接机械共混的产物性能较差 ,通过添加相容剂 ,如嵌段共聚物或接枝共聚物能提高共混物性能。在线增容技术已用于PP、PS反应性增容 ,生产高性能的合金。     

茂金属聚合物进展

综述了茂金属聚合物的新进展 ,重点介绍了五种茂金属聚合物的性能、应用现状和发展趋势。     

Reactive compatibilization of PE/PS blends. Effect of copolymer chain length on interfacial adhesion and mechanical behavior

This paper deals with in situ compatibilization of PE/PS blends via Friedel-Crafts reaction, performed at the interphase. Two polyethylenes having different molecular weights, and the same PS, were used along a wide range of catalyst concentration. The influence of the graft copolymer architecture and content on the efficiency of blend compatibilization was studied. The emulsifying effect, morphological aspects and mechanical behavior were also assessed for these blends. The amount of copolymer formed increases with catalyst concentration and the short chain length fraction of the homopolymers. The high molecular weight (MW) copolymers behaved as better compatibilizers as they showed, at the cmc, greater graft copolymer concentration than the low MW ones. A substantial increase in interfacial adhesion and particle size reduction was observed, even at catalyst concentrations as low as 0.3 wt%. In correspondence, mechanical properties, like ductility and yield strength, were enhanced by the effect of this Friedel-Crafts reaction's compatibilization.     

ABS,PS,PP／PE共混物的声发射研究

报道了ＡＢＳ,ＰＳ,ＰＰ／ＰＥ共混物的声发射研究。探讨了热处理和温度骤变对ＡＢＳ和ＰＳ声发射的影响,考察了ＰＰ／ＰＥ不同共混比的声发射和断裂行为,并且用电镜分析了共混物的取向结构和断面形态。结果表明,声发射与材料内应力的大小关系密切,提出了可以用声发射技术来评价塑料的成型条件的观点,揭示了ＰＰ／ＰＥ共混材料单轴拉伸断裂主要是由分子链高度取向所形成的纤维断裂和滑移造成的。     

DSC and TGA study of the transitions involved in the thermal treatment of binary mixtures of PE and EVA copolymer with a crosslinking agent

The crosslinking process of PE and EVA with different concentrations of a crosslinking agent (CA) has been studied. The extent of the crosslinking has been evaluated by gel fraction and density measurements. The different transitions involved in the thermal processing and decomposition have been studied by DSC and TGA and compared for all the mixtures prepared. Mechanistic pseudo-kinetic models have been suggested and applied involving all the fractions susceptible of undergoing transitions or reactions. The models applied can be of great interest in understanding the phenomena involved, as well as in modeling the heat effects in the whole processing or pyrolysis of this type of products.     

Optical transparency,thermal resistance,intermolecular interaction,and mechanical properties of poly(styrene‐butadiene‐styrene) copolymer‐based thermoplastic elastomers

The optical transparency, thermal resistance, intermolecular interaction, and mechanical properties of poly(styrene‐block‐butadiene‐block‐styrene) (SBS), which were modified by blending with crystalline polypropylene (PP) or amorphous polystyrene (PS), were analyzed. The dynamic mechanical test indicated that the PP exhibited an intermolecular interaction with SBS and PS was compatible with SBS. The optical properties indicated that the direction of the light was changed due to the difference between the refractive indices of SBS and the added modifiers. Additionally, refraction and reflection occurred at the interface, reducing the transparency of SBS. The thermal resistance of SBS clearly improved upon modification by the addition of crystalline PP polymer. The thermal treatment increased the tensile strength and the elongation at breakage of modified SBS by reducing the internal stress, which was generated during the blending process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010