无机-有机纳米复合乳液的原位聚合及其应用

综述了原位乳液聚合法制备无机．有机纳米复合乳液的技术现状及其形成机理，并运用此技术合成了舍无机纳米粒子的压敏胶用无机-有机纳米复合乳液，分析了纳米粒子在制备过程中的分散性能，从纳米粒子引入方式、乳化剂用量、纳米粒子加入量3方面对压敏胶性能进行考查。     

用阳离子可聚合表面活性剂超声辐照乳液聚合制备聚合物纳米粒子

合成了一种阳离子可聚合表面活性剂甲基丙烯酰氧乙基十二烷基二甲基溴化铵(C12N+),应用于超声辐照苯乙烯乳液聚合中,采用红外光谱、表面张力测试、核磁共振氢谱、透射电镜对聚合产物的结构和形貌进行了表征。结果表明,可聚合表面活性剂与苯乙烯发生了共聚反应,且反应完全,制备了高纯聚合物纳米胶乳。实验证明,C12N+同时起到了乳化剂、引发剂和共聚单体三重作用,与用一般乳化剂十二烷基硫酸钠(SDS)相比,表现出引发效率高(诱导期<15 m in)、反应速率快(最大反应速率为SDS体系的3倍)、低声强下单体转化率高(反应60 m in单体转化达到90%以上)、无乳化剂残留的优点。     

pH控制下细乳液界面聚合制备有机-无机杂化纳米胶囊

通过调节体系pH值,在不加外加交联剂的条件下仅依靠甲基丙烯酸3-三甲氧基硅丙酯(MPS)单体中硅氧烷基团的水解-缩合反应,将齐聚物自由基锚定在乳胶粒子和水界面上,合成了有机-无机杂化纳米胶囊。考察了体系pH值、MPS单体用量以及油相中单体含量对胶囊形态的影响。结果表明,强化硅氧烷基团的水解-缩合反应能够提高齐聚物自由基的锚定效果,有利于纳米胶囊形成。通过外加交联剂验证了界面聚合中交联剂锚定齐聚物自由基的重要作用。     

无机纳米粒子改性复合乳液的研究进展

综述了近五年来用乳液聚合法制备无机纳米粒子改性乳液的研究现状,着重介绍了原位分散聚合、溶胶-原位聚合和乳液插层聚合等制备无机纳米粒子改性乳液的方法。     

纳米TiO2原位聚合硅丙复合乳液的制备

采用硅烷偶联剂对纳米二氧化钛进行表面处理,以改性纳米二氧化钛和有机硅中间体为种子乳液,以过硫酸钾为引发剂,甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(MBA)为主要共聚单体,通过原位聚合反应,合成纳米TiO2-硅丙复合乳液。采用红外光谱、透射电镜(TEM)、激光粒度分布等手段,对所制备的纳米TiO2-硅丙复合乳液进行了表征,证明所得产品是硅氧烷和丙烯酸酯的共聚物,具有核/壳结构,且乳液粒径分布较窄,平均粒径在63 nm左右。     

超声辐照制备聚醋酸乙烯酯/碳纳米管/炭黑导电复合材料

采用两步法制备了导电性聚醋酸乙烯酯/碳纳米管/炭黑复合材料。实验结果表明:超声辐照乳液聚合比常规搅拌能更有效地破坏CNTs的团聚和缠绕,实现其均匀分散。因而CNTs可作为"桥梁"连接导电炭黑,形成导电网络,增加复合材料中形成的导电通路数,增大载流子在导电粒子间的跃迁几率,提高聚醋酸乙烯酯/炭黑复合材料的导电率。当聚醋酸乙烯酯/炭黑复合材料中含有0.28%碳纳米管时,复合材料的电阻率从7.7×104Ω·cm降低到3.9×103Ω·cm,下降了19倍。     

SiO_2/PAE杂化乳液及建筑涂料的制备

采用共混法制备无机-有机杂化乳液及无机建筑涂料,研究有机聚合物乳液添加量对涂膜性能的影响规律。研究发现,添加适量有机聚合物乳液可以很好地改善硅溶胶的成膜性能;FT-IR测试发现硅溶胶与聚合物乳液发生了氢键缔合,杂化涂膜中的硅溶胶发生了凝胶化反应,生成Si—O—Si空间网络结构,但仍残留硅羟基;SEM图表明当聚合物乳液含量为60%时,无机相在涂膜的表面富集并以团聚体的形式镶嵌于聚合物涂膜中,而当聚合物含量为40%时,无机相已经全部穿插在有机相中,相界面几乎消失;通过配方优化得到综合性能优异的建筑涂料。     

复合絮凝剂制备研究进展

在介绍复合絮凝剂的分类和优势的基础上,综述了无机复合型絮凝剂、有机复合型絮凝剂和无机-有机复合型絮凝剂的制备方法,简要介绍了3类复合絮凝剂在水处理中的应用,并对今后复合絮凝剂的发展趋势以及研究方向作了展望。     

复合絮凝剂制备研究进展

在介绍复合絮凝剂的分类和优势的基础上,综述了无机复合型絮凝剂、有机复合型絮凝剂和无机-有机复合型絮凝剂的制备方法,简要介绍了3类复合絮凝剂在水处理中的应用,并对今后复合絮凝剂的发展趋势以及研究方向作了展望。     

无皂纳米苯丙复合乳液的制备

向乳液中添加纳米粒子则可使最终的乳液产品同时兼具无皂乳液和纳米复合乳液两者的优点,使复合乳液的综合性能有大幅提高.本文通过实验,确定了无皂条件下制备纳米苯丙复合乳液的最佳条件及最优配方.     

超声辐射丙烯腈的无皂乳液聚合

以过硫酸铵为引发剂,用超声波引发丙烯腈单体进行无皂乳液聚合,研究了单体浓度、引发剂浓度、反应时间对单体转化率的影响情况,并对聚合物进行了IR、TEM表征,结果显示聚丙烯腈乳胶粒尺寸均匀,约为50nm。     

Preparation and properties of polydimethylsiloxane/polyacrylate composite latex initiated by 60Co γ‐ray irradiation

In this study, polydimethylsiloxane (PDMS)/polyacrylate composite polymer latex was synthesized via polymerization of the acrylate monomer in the presence of vinyl‐containing PDMS seeded latex. The polymerization was initiated by ⁶⁰Co γ‐ray irradiation. The morphology of the PDMS/polyacrylate composite polymer latex was a core–shell structure with PDMS as the core and polyacrylate as the shell. There was an interpenetration layer between the PDMS core and the polyacrylate shell. The composition of the vinyl‐containing PDMS and the PDMS/polyacrylate composite latex were investigated with NMR and Fourier transform infrared spectroscopy, respectively. The effect of irradiation dose on the seeded emulsion polymerization conversion is discussed. Finally, the mechanical properties of latex film, such as water‐absorption ratio, tensile strength, pendulum hardness, and heat‐decomposed temperature, were tested. The results showed that the mechanical properties of the PDMS/polyacrylate film were remarkably improved when compared to the polyacrylate film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2732–2736, 2003     

Preparation of polymer/inorganic nanoparticles composites through ultrasonic irradiation

In this paper, ultrasonic induced encapsulating emulsion polymerization was first used to prepare the novel polymer/inorganic nanoparticles composites. The behaviors of several inorganic nanoparticles (SiO₂, Al₂O₃, TiO₂) under ultrasonic irradiation, such as dispersion, crushing, and activation, were studied. The dispersion stability, morphology, and structure of the ultrasonic irradiated nanoparticles were characterized by means of transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and spectrophotometry, respectively. The results show that the inorganic nanoparticles in the aqueous solution can redisperse more effectively by ultrasonic irradiation than by conventional stirring. This is the basis for preparation of polymer/inorganic nanoparticles composites. By this technique, the long‐term stable latex, which mainly consists of polymer/inorganic nanoparticles composite latex particles, were successfully prepared. TEM, FTIR, thermogravimetric analysis, X‐ray photoelectron spectroscopy, spectrophotometry, and element analysis confirmed that well‐dispersed nanoparticles were encapsulated by the formed polymer, and the thickness of encapsulating polymer layer was in the range of 5–65 nm. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1478–1488, 2001     

PSt乳胶纳米粒子的制备

采用乳液原子转移自由基聚合法,成功制备出了聚合物乳胶纳米粒子。用光子相关光谱(PCS)和透射电子显微镜(TEM)对聚合物乳胶粒子的形貌、粒径和粒径分布进行了表征,结果表明:聚合物乳胶粒子的粒径小于100nm。研究了乳化剂的用量对乳胶粒子粒径大小的影响,研究发现:聚合物乳胶粒子的粒径随乳化剂用量的增大而减小。     

超声波对乳液聚合丁腈胶的影响研究

研究了超声波作用时间对乳液聚合丁腈胶固含量、转化率的影响,对丁腈胶的微观结构进行了红外测试分析。结果表明,随着超声波作用时间的延长,聚合物的固含量和转化率增加,超声波作用的反应体系所得聚合物的微观结构与传统乳液聚合所得聚合物的微观结构一致。     

细乳液聚合法制备PY-17/PE蜡/PS复合乳胶粒子

通过细乳液聚合法制备彩色墨粉用多组分复合乳胶粒子,即通过细乳液聚合法制备聚苯乙烯包覆有机颜料PY-17和聚乙烯蜡的三元复合乳胶粒子。通过透射电子显微镜、激光粒度仪、紫外可见分光光度计和热失重分析仪对制备的复合乳胶粒子形貌、粒度、热学和光学特性进行表征,着重研究了乳化剂种类及用量、颜料用量和聚乙烯蜡用量对复合乳胶粒子粒径和形貌的影响,并对复合乳胶粒子的热学及光学特性进行了表征。结果表明,使用复合乳化剂,颜料PY-17用量不大于单体量8%、聚乙烯蜡用量占单体量不大于10%时,制备的复合乳胶粒子粒径较小,分布窄,包覆较为完整;并且复合乳胶粒子的热学及光学特性发生了一定的改变。     

Polyaniline/FE3O4 magnetic nanocomposite prepared by ultrasonic irradiation

Ultrasonic irradiation is employed to assist the chemical oxidative polymerization of aniline in the presence of Fe₃O₄ nanoparticles in order to prepare a polyaniline (PANI)/Fe₃O₄ magnetic nanocomposite. In the chemical oxidative polymerization of aniline in the initially neutral medium, the optimum molar ratio of the oxidant ammonium persulfate to the monomer aniline is 2 : 1. The prepared PANI is in the emeraldine form and is doped by sulfate anions. Fe₃O₄ particles are encapsulated by PANI and dispersed well in PANI. Fe₃O₄ increases the doping level and decreases the crystallinity of PANI. The PANI/Fe₃O₄ nanocomposite possesses conductivity and magnetic properties. Increasing the Fe₃O₄ content increases the magnetization of the PANI/Fe₃O₄ composite but decreases its conductivity. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2107–2111, 2006     

纳米氧化锌改性PA6复合材料的制备及性能研究

利用熔融共混法制得了纳米氧化锌改性PA6复合材料,并研究了其有关性质。结果表明:纳米氧化锌能有效改善PA6的力学性能,其添加量在3%时材料力学性能最佳。结晶及热分析研究表明纳米粒子能有效限制PA6分子链段运动,使其结晶度下降。     

Study on bulk polymerization of methyl methacrylate initiated by low intensity ultrasonic irradiation

Methyl methacrylate (MMA) was polymerized in bulk solutions using low intensity ultrasonic radiation of 0.25 W/cm². The polymerization occurred after 1 h of irradiation time was applied. The polymerization rate was greatly accelerated either by increasing the amount of poly (methyl methacrylate) (PMMA) granular added into the system or by elongating the irradiation time. However, it was found that the reaction rate increased with the decreasing of the ultrasonic frequencies when the exposure time of the polymerization under the irradiation was less than 3 h. Experimental results verified that the polymerization was initiated by free radicals, which were mainly generated from the degradation of PMMA macromolecular chains, the friction between the polymer macromolecular chains and the solvent monomer. These findings were obviously different from those obtained when high intensity ultrasonic irradiation was used. The polymers fabricated in this study by using ultrasound irradiation have a narrower molecular weight distribution compared to those obtained from the polymerizations induced by the conventional initiators. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010