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991.
通过微发泡注射成型方法制备PP/EPDM(三元乙丙橡胶)/滑石粉复合材料制品,并研究滑石粉的含量对PP/EPDM/滑石粉微孔发泡复合材料的微观形态和力学性能的影响。结果表明:添加适量滑石粉的PP/EPDM/滑石粉复合材料的发泡效果优于仅添加单一的EPDM的PP/EPDM复合材料的发泡效果,而且当PP/EPDM/滑石粉的质量比为79/21/4时,微孔制品的微观形态最好;且此比例的PP/EPDM/滑石粉微孔发泡制品与未添加滑石粉的PP/EPDM微孔发泡复合材料制品相比,其拉伸强度、弯曲强度、冲击强度分别提高了2%、6%、4%。 相似文献
992.
993.
设计并合成了一种新型的含有大体积基团phenyl的α-二亚胺配体1a及其Ni(Ⅱ)配合物1b,采用NMR谱、XPS对其进行了表征。研究了聚合条件如Al/Ni摩尔比、聚合反应温度及配体结构等因素对催化剂活性的影响。在反应温度为5℃,Al/Ni摩尔比为800时,该催化体系催化乙烯聚合的活性最高,可达5.57×106g PE/(molNi·h·bar),所得聚乙烯具有较高的支化度,最高可达136 branches/1000C。采用1H NMR、DSC、GPC、TG分别对聚合物进行了表征。 相似文献
994.
实验室采用DTA-TG,SEM-EDS等手段对海外矿拜尔法赤泥合成聚合氯化铝铁进行了研究,重点试验了原料配比、助剂种类条件,工艺过程影响因素,确定PACF的最佳制备条件,最后对实验室合成的PACF进行了混凝对比,表明采用海外矿拜耳法赤泥合成的PACF浊度去除率高达92%,略优于市售PAC产品混凝效果,此技术的成功研发为赤泥综合利用开辟了一套新的途径。 相似文献
995.
采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯(TiO2/PMMA)纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷(HD)更能抑制甲基丙烯酸甲酯(MMA)液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵(DNS-86)占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。 相似文献
996.
997.
Preparation,properties, and applications of acrylic–polyurethane hybrid emulsions in extinction electrophoresis
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Aqueous acrylic–polyurethane hybrid emulsions (PUA) were fabricated by semibatch emulsion copolymerization using a mixture of acrylic (AC) monomers in the presence of an isocyanate terminated polyurethane (PU). The effects of PU content on the morphology of the hybrid emulsions and film properties were here investigated in detail using FT‐IR, UV, TEM, and SEM. TEM images clearly showed that hybrid emulsions exhibited a core‐shell structure before neutralization. However, after neutralization with N,N‐dimethylethanolamine, the typical particles exhibited phase inversion, producing particles with irregular hemispheres shapes and diameters about 0.5 μm. SEM images showed that the film surface became rougher as PU content increased, peaking at 10 wt %, the gloss of this film was 23.1 (60°). The UV transmittance spectra of the PUA hybrid emulsion within a wavelength range 700–200 nm decreased as PU content increased. This was consistent with the changes in the surface roughness of the film. Electrophoresis took place on an aluminum alloy surface and the product was dried at 120°C. The film exhibited excellent mechanical performance due to curing reaction between the N?C?O group on PU and hydroxyl group on the AC copolymer. The gloss of the film was found to be as low as 4.0 after electrophoresis testing. These films may be useful in practical extinction electrophoresis. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40078. 相似文献
998.
Preparation and properties of polyamide‐6‐based thermoplastic laminate composites by a novel in‐mold polymerization technique
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Nadya Dencheva Ana S. Sampaio Filipa M. Oliveira António S. Pouzada Antonio M. Brito Zlatan Denchev 《应用聚合物科学杂志》2014,131(8)
In this work, a method for preparation of polyamide‐6 (PA6) based laminates reinforced by glass fiber‐ (GFL) or polyamide‐66 (PA66) textile structures (PL) via reactive injection molding is disclosed. It is based on in‐mold anionic polymerization of ε‐caprolactam carried out at 165°C in the presence of the respective reinforcements performed in newly developed prototype equipment whose design concept and operation are described. Both composite types were produced for reaction times of 20 min, with conversion degrees of 97–99%. Initial mechanical tests in tension of GFL samples displayed almost twofold increase of the Young's modulus and stress at break values when compared with the neat anionic PA6. The improvement was proportional to the volume fraction Vf of glass fiber fabric that was varied in the 0.16–0.25 range. A 300% growth of the impact strength was registered in PL composites with Vf of PA66 textile of 0.1. Removing the surface finish of the latter was found to be a factor for improving the adhesion at the matrix–fiber interface. The mechanical behavior of GFL and PL composites was discussed in conjunction with the morphology of the samples studied by optical and electron microscopy and the matrix crystalline structure as revealed by synchrotron X‐ray diffraction. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40083. 相似文献
999.
This study reports a novel one‐step method to synthesize a new spherical support for Ziegler‐Natta catalyst under moderate condition. The support is obtained from a dispersion system where the particle stabilizer polyvinylpyrrolidone plays a main role to stabilize the spherical particles. The new chemical of the support is CH3CH2OMgOCH(CH2Cl)2, which is first reported here, has been approved by newly filed patents and also confirmed by solution NMR, solid state NMR, pyrolysis‐gas chromatography‐mass spectrometry (Py‐GC‐MS), and ICP‐MS. The support and catalyst particles have uniform distributions. The catalyst prepared from this support has been evaluated with high activity. The polypropylene obtained has high isotacticity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41014. 相似文献
1000.
Thermotropic systems with fixed domains exhibiting enhanced overheating protection performance
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Within this study, a time saving photo‐initiated miniemulsion polymerization process (duration of polymerization was 15 min) was established in order to encapsulate a paraffin wax with an acrylate polymer shell. The obtained freeze‐dried latex was an off‐white powder exhibiting spherical particles with mean diameters around 400 nm and a concentration of paraffin wax around 56%. Mixing the reaction product with a UV‐curable resin matrix resulted in thermotropic overheating protection glazings with high light‐shielding efficiency. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40417. 相似文献