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水滑石(LDH)是一类典型的阴离子型层状材料,具有优异的阻燃性和热稳定性,且低烟、低毒、环境友好。将其与聚合物复合制备复合材料,可以显著提升聚合物的耐火能力,因而受到研究者的广泛关注。本文介绍了LDH的结构特点及其有机改性方法,包括离子交换法、煅烧还原法、一步法和溶剂剥离法。总结了常用于制备聚合物/LDH复合材料的方法,并简述了它们各自的优缺点。重点综述了影响聚合物/LDH复合材料阻燃性的因素,主要包括LDH板层二价和三价阳离子、多金属阳离子的引入和改性剂等方面的影响;简述了其他阻燃材料配合LDH协同阻燃的进展。最后,笔者分析了阻燃型聚合物/LDH复合材料的研究现状,就该材料在产业化推广、进一步提升高效阻燃性能、明确阻燃机理等方面,提出了自己的观点。 相似文献
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王兴涌 《煤炭加工与综合利用》1995,(6):33-35
介绍了以乡乙烯多胺、环氧氯丙烷为主要原料合成的一种性能较好的阳离子聚合物;研究了水溶性聚合物以及阴、阳离子聚合物配合使用的双元聚合物体系对细粒煤泥水的絮凝沉降效果及其有关影响因素。 相似文献
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本文着重介绍阳离子聚合单体的结构、溶剂及引发体系对活性阳离子聚合技术的影响以及近几年来采用活性阳离子聚合技术制备侧基官能性乙烯基醚聚合物的方法,尤其是应用较广泛的羟基、羧基、氨基等侧基官能化聚合物的合成。研究乙烯基醚阳离子活性聚合,将对乙烯基醚阳离子光固化体系的应用研究具有重要的指导意义。 相似文献
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介绍了阳离子淀粉在洗涤用品领域的应用,综述了几种阳离子淀粉制备工艺的研究进展。简要探讨了阳离子淀粉今后的主要发展方向。 相似文献
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一剂多效的有机阳离子聚合物的研究 总被引:2,自引:0,他引:2
合成了六种阳离子聚合物,并测定了这些阳离子聚合物和XPI系列破乳剂复配后的破乳性能及其单独的破乳性能,同时也研究了阳离子聚合物对长庆油田污水的絮凝性能。表明阳离子聚合物具有一定的絮凝性能和较好的破乳性能,尤以MCE效果最佳。 相似文献
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The pigment retention efficiency, in a model papermaking system, of anionically and cationically modified polyacrylamides was compared to that of the unmodified homopolymer. The anionic polyacrylamide is a much less efficient retention aid, especially at high pH's; the nonionic and cationic polymers perform similarly and without any marked pH dependence. However, it is the nonionic and anionic polyacrylamides which are similarly poor at fiber flocculation, at pH's between 4.5 and 7.5, whereas the cationic polymer is a good fiber flocculant. All three polymers stabilize pigment suspensions. The anionic polymer is not effective in heteroflocculation of mixed dispersions of fibers and pigment, whereas both the nonionic and cationic are good flocculants, the latter being less susceptible to overdosing. Equilibrium adsorption isotherms were determined; the cationic polymers is, unlike the other modified polyacrylamide, very well adsorbed by cellulose fibers. Onto titanium dioxide, polymers adsorbed in the order anionic < nonionic < cationic. A further differentiation of the cationic polymer is that it gives high pigment retention in sheet formation without markedly increasing the resistance to fluid flow through the forming sheet. Although a process of heteroflocculation is postulated for both nonionic and cationic polymers, in the former case it is thought that the primary adsorption is onto titanium dioxide, whereas with the latter it is onto cellulose. 相似文献
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炭黑表面接枝聚合改性进展 总被引:3,自引:0,他引:3
从炭黑粒子表面性质及表面化学基团出发 ,并结合聚合反应理论 ,介绍了将单体接枝聚合或将聚合物直接接枝到炭黑表面的自由基接枝、正离子接枝、负离子接枝及其他功能化接枝改性方法。论述了实现这些过程的溶液法、熔融法及辐射法接枝等工艺方法及影响炭黑接枝改性的因素。炭黑表面接枝聚合改性能大大扩大炭黑的应用范围。 相似文献
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本文介绍了含二甲基二烯丙基氯化铵(DMDAAC)阳离子单元的聚合物及合成方法的研究进展。首先从二甲基二烯丙基氯化铵的单体分子结构出发,给出了其物理化学性质;进而以单体分子所含双键可参与的加成聚合反应为主线,分别归纳了其作为聚合反应中间体可参加的均聚反应和共聚反应,较为详细地介绍了以DMDAAC为结构单元的二元、多元结构聚丙烯酰胺、与特殊功能单体的共聚物和以其为基改性的天然产物及合成方法,指出了已有研究工作的特色与不足。最后,针对含DMDAAC单元聚合物的研究工作现状,提出可通过分子结构设计、改性来合成新型含DMDAAC单元聚合物以满足多个领域中的应用需要,加强这类聚合物的应用研究也是推动该类聚合物合成研究工作快速发展的重要动力。 相似文献
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Mechanistic transformations involving living and controlled/living polymerization methods 总被引:1,自引:0,他引:1
This review is prepared on the occasion of the 50th anniversary of the historic discovery of living anionic polymerization by Michael Szwarc. This process enabled preparation, with good control of polymer architecture, of well-defined polymers such as block and graft copolymers, star polymers, macrocycles, and functional polymers. Transformation reactions provide a facile route to synthesis of block copolymers that cannot be made by a single polymerization mode. A variety of transformation reactions involving step-growth, conventional and controlled free radical, cationic, anionic, group transfer, activated monomer Ziegler–Natta and metathesis reactions are known. In this article, transformation reactions involving living and controlled/living polymerization methods are reviewed. Other possibilities of combining different polymerization methods namely, macromonomer technique, coupling reactions, dual polymerizations and click chemistry are described. Preparation of star and miktoarm-star block copolymers by using mechanistic transformations is also presented. 相似文献