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介绍了一些主要的可控/活性自由基聚合法,包括氮氧调解自由基聚合法(NMRP)、原子转移自由基聚合法(ATRP)、可逆加成断裂链转移聚合法(RAFT)在粒子表面接枝聚合形成无机纳米粒子/聚合物的壳核结构,达到了对粒子改性的目的。并提出了一些目前研究中存在的问题,对可控/活性聚合应用的发展进行了展望。 相似文献
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界面聚合通常指限定在液-液或液-固界面上进行的聚合反应,散见于少数高活性的缩聚反应体系。20世纪90年代,以RAFT聚合、ATRP等为代表的可逆失活自由基聚合(reversible deactivation radical polymerization,RDRP)因其兼具传统自由基聚合和活性阴离子聚合的优点,广泛用于聚合物链结构的可控制备。另一方面,RDRP已被用于构建更为普适的界面聚合反应,基于RDRP的界面聚合已发展成为一种可控制备具有精准纳米结构的功能性聚合物产品的新方法。本文以RAFT液-液界面聚合为主,阐述了RAFT法和ATRP法在液-液界面、液-固界面进行“活性”聚合的反应机理,总结了该领域的研究进展。在此基础上,重点介绍“活性”界面聚合在构建纳米(中空)胶囊、纳米界面工程与纳米分散以及纳米聚合物刷表面等方面的潜在应用前景。 相似文献
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以甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸为原料,纳米SiO2为改性剂,通过原位聚合法和共混法制备了水性丙烯酸树脂纳米复合材料。研究了纳米粒子的加入量对树脂硬度、拉伸强度、断裂伸长率、耐候性、热稳定性的影响,利用IR、TEM、TG等测试技术对纳米SiO2/水性丙烯酸树脂进行了表征。试验结果表明:纳米SiO2的加入使聚丙烯酸酯分子链之间增加了交联度,其力学性能有所提高;随着纳米SiO2含量的上升,硬度和拉伸强度都有较大的增加,而吸水率和断裂伸长率相应减小。同时由原位聚合法制备的水性丙烯酸树脂纳米复合材料的热分解温度也要高于共混法制备的水性丙烯酸树脂纳米复合材料。 相似文献
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SSA-PANI/ATP导电纳米复合材料的制备和表征 总被引:1,自引:0,他引:1
用原位聚合法在凹凸棒土(ATP)的表面包覆上5-磺基水杨酸(SSA)掺杂的聚苯胺(PANI),合成了SSA-PANI/ATP纳米复合材料,研究了SSA掺杂量、聚合温度、苯胺包覆率、聚合时间和过硫酸铵(APS)用量对复合材料体积电阻率的影响。结果表明:在m(An)∶m(APS)∶m(ATP)∶m(SSA)=1∶2.45∶3.33∶2.08,聚合温度为20℃,聚合时间为4 h时,复合材料体积电阻率可达到3.5Ω.cm。并通过TG-DTA、XRD、FTIR和TEM对该条件下制备的纳米复合材料进行了表征。 相似文献
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对PVC冲击改性剂——MBS、CPE和ACR的分子组成和分子结构进行了分析,研究了其抗冲改性机理及对PVC制品低温冲击强度、耐候性、维卡软化点、韧性的影响。从高分子热力学的角度分析了CPE和ACR在PVC中分散所形成的制品结构。指明了传统ACR和CPE在PVC改性中所存在的优缺点。在此基础上分析了理想冲击改性剂ACR应具有的结构特点,并设计和开发了新型冲击改性剂ACRHL-56和HL-58,通过试验对其性能与传统冲击改性剂ACR和CPE进行了比较,发现其性能远优于后者。 相似文献
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我国微生物法水处理技术的研究进展 总被引:1,自引:0,他引:1
介绍了微生物絮凝剂的基本研究方法,综述了4种絮凝机理,对其絮凝效果的因素进行了探讨,阐述了微生物絮凝剂在众多领域的应用情况,指出了微生物絮凝剂在生产过程中的现存问题和解决措施,微生物絮凝剂具有高效、无毒,无二次污染、成本低等优点,为水处理技术的研究和发展提供了一个新的方向. 相似文献
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溶液共混法制备聚氨酯/碳纳米管复合材料及其性能 总被引:3,自引:1,他引:2
通过强酸处理方法对碳纳米管进行改性处理并对其结构和分散稳定性进行分析。采用溶液共混法制备了聚氨
酯/碳纳米管复合材料,利用FTIR对其结构进行了分析,探讨了碳纳米管对复合材料力学性能、热稳定性能以及弹
性回复率的影响。结果表明,碳纳米管经酸处理后添加了羧酸活性基团,提高了其在溶剂中的分散性|在复合材料
中,碳纳米管以较强氢键与大分子连接,复合材料的力学性能和热稳定性能都有所提高,而弹性回复率没有受到很
大影响。 相似文献
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聚氨酯/碳纳米管复合材料的制备及其性能研究 总被引:2,自引:0,他引:2
通过强碱球磨方法对多壁碳纳米管(MWCNTs)进行了改性处理,并对其化学结构和微观形态进行了分析.采用溶液共混法制备了聚氨酯(PUR)/MWCNTs复合材料.利用扫描电子显微镜、傅立叶变换红外光谱仪对其进行了表征.探讨了MWCNTs对PUR/MWCNTs复合材料力学性能、热稳定性以及电导率的影响.结果表明,MWCNTs... 相似文献
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Performance of Dowel-Welded L-joints for Wood Furniture 总被引:1,自引:0,他引:1
《Journal of Adhesion Science and Technology》2013,27(15):1829-1837
Rotationally welded wood dowels were used to hold together step butt and mortise and tenon L-joints and these joints were tested against European Norms for these types of joints. A factorial experiment was carried out in which (1) these two types of joints were tested, (2) 4 or 6 dowels per joint were used, (3) dowels were inserted at either 45° or 90° to the surface of the wood, (4) two types of wood were used, beech and European ash, and (5) two types of tests were carried out, namely compression and tension tests. The strength results were used to find out which of these were the most important individual parameters and their interactions, namely type of joint, number of dowels, and type of test. The strength results were well in excess of the relevant L-joints standard specifications for wooden windows. 相似文献
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Polyimides were synthesized from one‐step polycondensation of BPADA and various diamines and were characterized with GPC, FTIR, NMR, DSC, and TGA. Polyimide membranes were prepared, and their hydrophilicity was estimated by contact angles and the free energies of interfacial interactions. Pervaporation properties were investigated for the dehydration of isopropanol, and comparisons were made between BPADA‐based membranes and 6FDA‐based membranes. The concentration coefficients of BPADA‐based membranes were calculated from the linear moiety contribution method based on the results from 6FDA‐based membranes, and they were compared to understand the effects of the feed concentration on pervaporation properties. The effects of temperature on permeation flux were studied with permeation activation energies for total flux and water flux in permeates. Moiety contribution factors for activation energies were used to correlate permeation flux and monomer moieties in the polymers, and reasonable results were obtained for BPADA. It is revealed that steric effects of monomers may change the diffusion properties, while functional groups are favorable to the changes in sorption properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献