丙烯酰胺与蒙脱土的接枝反应

摘 要 研究了偶联剂对蒙脱土的偶联作用，得到偶联后的产物c－MMT。利用溶液聚合接枝的方法制得丙烯酰胺接枝蒙脱土产物AM－g－c－MMT。研究了反应条件对丙烯酰胺接枝蒙脱土的接枝率和接枝效率的影响，并用IR和DSC对接枝物加以表征。     

原位乳液聚合法制备改性蒙脱土及其表征

通过原位乳液聚合的方法制备改性蒙脱土,在聚合之前,可聚合的小分子先接枝到蒙脱土的表面或层间,然后加入苯乙烯单体引发聚合,使聚合物大分子接枝到蒙脱土的表面和层间。十六烷基三甲基溴化铵(CTAB)在乳液聚合改性蒙脱土的过程中既是插层剂又是乳化剂。X射线衍射分析表明,经过处理引入了CTA+和PS大分子使得层间距扩大;红外、热重法分析表明,小分子和大分子已接枝到蒙脱土上。蒙脱土的存在影响了聚合反应动力学,并就小分子的影响作了简单的讨论。     

原位接枝插层法制备聚丙烯/蒙脱土纳米复合材料

采用原位接枝插层法制备了聚丙烯/蒙脱土纳米复合材料.借助长链有机胺有机化的蒙脱土在溶液中与马来酸酐和少量辅助溶胀剂进行溶胀;溶胀后的有机蒙脱土再与聚丙烯、适量引发剂在Haake混炼机中进行熔融反应,得到一种聚丙烯/蒙脱土接枝插层共混物;再将接枝插层共混物按一定比例与聚丙烯在Haake混炼机中进行混炼得到聚丙烯/蒙脱土纳米复合材料.用X射线衍射仪(XRD)、透射电镜(TEM)和热失重分析仪(TGA)分别对各步骤的产物进行表征.产物的XRD和TEM分析结果表明蒙脱土完全剥离并均匀分散在聚丙烯基体中,形成了真正的聚丙烯/蒙脱土纳米复合材料.TGA分析结果显示出该纳米复合材料具有相当好的热稳定性.     

NR/有机蒙脱土/GMA纳米复合材料的制备与性能研究

采用胶乳接枝插层法制备NR／有机蒙脱土／甲基丙烯酸缩水甘油酯(GMA)纳米复合材料，并对其性能进行研究。结果表明，在NR胶乳与有机蒙脱土体系中加入GMA，并使之原位聚合，同时实现对NR的接枝和对有机蒙脱土的插层并与有机蒙脱土层间的基团产生化学结合，可以制备NR／有机蒙脱土／GMA纳米复合材料；采用胶乳接枝插层法制备的NR／有机蒙脱土／GMA纳米复合材料的物理性能和耐热氧老化性能优异，动态力学性能良好，热稳定性与NR胶料相差不大。     

蒙脱土的表面修饰

概括介绍了蒙脱土的结构和基本性质,蒙脱土表面修饰技术是其能否产业化的瓶颈,本文介绍了表面吸附、阳离子交换、阴离子交换、偶联剂和插层接枝等蒙脱土表面修饰方法,且对其特点、修饰机理进行了归纳和分析.最后指出蒙脱土表面修饰朝向与聚合物更好的相容性、分散性方向发展.     

光聚合和热聚合蒙脱土插层纳米复合材料的研究

利用光引发聚合和热引发聚合研究了单体(MMA)和蒙脱土(Mot)插层复合材料(PMMA/Mot)的制备问题。用小角X光衍射技术对两种产物内蒙脱土的结构进行了表征。结果表明,蒙脱土经改性后能很好的使聚合单体插入蒙脱土层内并在光或热的作用下“就地”发生聚合反应生成复合材料,利用DSC、SEM研究了产物的结构和形态,并对两种聚合方法制备蒙脱土纳米复合材料的特点进行了初步讨论。     

蒙脱土接枝插层改性胶乳与天然胶乳热降解动力学的研究

采用胶乳接枝插层法制备了蒙脱土接枝插层改性胶乳；采用热重分析法对天然胶乳（NRL）和蒙脱土接枝插层改性胶乳进行了等速升温热降解动力学研究。结果表明。NRL和蒙脱土接枝插层改性胶乳在氮气中的热降解过程相似。2者的热降解率（C）不受升温速率的影响；NRL和蒙脱土接枝插层改性胶乳的平衡起始降解温度相近，而后者的平衡最大降解率开始温度和终止温度均高于前者；NRL的反应级数为2．4，表观反应活化能为218kJ／mol,而蒙脱土接枝插层改性胶乳的反应级数为1．8，表观反应活化能为151．7kJ／mol。     

ABS熔融接枝丙烯酸及在无卤阻燃ABS中的应用

以过氧化二异丙苯(DCP)为引发剂，在转矩流变仪中进行了丙烯酸(AA)熔融接枝ABS树脂的研究。纯化后样品的红外光谱分析表明，从接枝ABS产物在1720cm^-1处出现了C=O基吸收峰，证实从接枝到了ABS树脂上。研究了单体用量、引发剂用量、螺杆转速和反应温度对接枝率的影响。研究结果表明：控制适当的反应条件可使AA接枝到ABS上的量达1．8％-2．43％。将ABS—g-AA从接枝物应用于ABs／膨胀型阻燃剂(IFR)／蒙脱土(MMT)无卤阻燃体系中时发现，复合材料的力学性能得到了有效改善。     

界面改性剂对聚丙烯/蒙脱土纳米复合材料结构与性能的影响

通过多固相接枝技术合成了接枝率相当而极性有较大差异的多单体接枝聚丙烯(TMPP),以其为界面改性剂制备了PP/有机蒙脱土复合材料.通过XRD和扫描电镜表征了其结构,实验表明接枝物的极性对蒙脱土在聚丙烯中有一定影响,极性合适的接枝物TMPP2有助于蒙脱土的纳米分散,接枝物极性过高或者过低不利于蒙脱土的分散.力学性能结果也证实采用TMPP2为界面改性剂的纳米复合材料力学性能最佳,与纯PP相比,其弯曲模量提高60%,弯曲强度提高25%,缺口冲击强度提高1倍.     

聚合方法对硅胶表面接枝聚合物过程的影响研究

分别用溶液聚合与分散聚合两种方法,在硅胶载体表面实施了苯乙烯的接枝聚合,重点考察了聚合方法对接枝聚合过程的影响。结果表明,在基本相同的反应条件下,分散聚合体系的接枝率明显高于溶液聚合体系的接枝率,最高可达47%(即47g/100g);除聚合方法之外,影响聚合物在硅胶表面接枝率的因素还有硅胶表面的双键含量、单体浓度、引发剂浓度、温度等。     

Structure and properties of cellulose graft copolymers. I. Radiation-induced rayon–styrene graft copolymer

Rayon–styrene graft copolymers were prepared by the direct radiation method, with the use of the preswelling technique, by irradiation with γ-rays from ⁶⁰Co. The grafting was carried out in bulk styrene and in styrene–solvent mixtures, such as styrene–methanol and styrene–acetone, to study their effect on the graft copolymerization reaction and the structure of the resulting graft copolymer. The effects of carbon tetrachloride, a chain-transfer agent, was also investigated. Three different types of rayon yarn were used; Fortisan, a modifier-type high wet-modulus rayon, and a high-tenacity tire yarn, in order to study the effect of rayon microstructure on the grafting reaction. The molecular structure of the rayon–styrene graft copolymers was studied by hydrolyzing away the cellulose backbone and measuring the molecular weights of the grafted polystyrene branches. For grafting in bulk styrene, the molecular weights of the grafted polystyrene ranged from 400,000 to 1,000,000, while those of the polystyrene homopolymer formed in the outside solution were of the order of 30,000–50,000. The molecular weights of the grafted polystyrene branches tended to increase with per cent grafting in the graft copolymer. For grafting in styrene–methanol and styrene–acetone mixtures, the molecular weights of the polystyrene branches decreased with increasing solvent content. The addition of carbon tetrachloride to bulk styrene resulted in a sharp decrease in the molecular weights of the grafted branches. The grafting frequency or number of polystyrene branches per cellulose chain was calculated from the per cent grafting and the molecular weights of the polystyrene branches. The morphology of the rayon–styrene graft copolymers and some of their physical properties are discussed.     

聚丙烯（PP）／黏土复合材料熔融剂的研究

以马来酸酐（MAH）等为单体接枝聚丙烯作为聚丙烯（PP）／黏土复合材料熔融剂,考察了马来酸酐用量、引发剂过氧化苯甲酰（BPO）用量、反应时间、温度等因素对产物接枝率的影响,并通过红外光谱图对PP-g-MAH进行表征。结果表明,当m（PP）：m（复配单体）：m（BPO）=10．0：2．0：0．6、反应温度控制在120℃左右、复配单体为马来酸酐／苯乙烯时,熔融剂PP-g-MAH的接枝率可获得较大值3．9％。实验同时表明,反应时间对接枝率的影响不大;苯乙烯的加入对接枝率有较大的影响,与普通单体单一马来酸酐相比,加入苯乙烯的接枝率明显提高。     

银纳米微粒接枝木纤维的制备及抗菌性能研究

以聚乙烯吡咯烷酮(PVP)为稳定剂和分散剂,硼氢化钠为还原剂制备了聚乙烯吡咯烷酮-银纳米微粒(PVP-Ag NPs),并将其通过硅烷偶联剂接枝到木纤维上,得到了具有抗菌活性的木纤维。利用扫描电子显微镜(SEM)和傅里叶-红外光谱(FT-IR)对PVP-Ag NPs接枝的木纤维进行了结构形貌的表征,并且通过热重分析仪(TG)分析其热稳定性能。结果表明,PVP-Ag NPs接枝木纤维的最佳反应条件是硅烷偶联剂用量4%、偶合时间5 h及接枝时间10 h,此条件下得到PVP-Ag NPs接枝木纤维的接枝率为5.8%;PVP-Ag NPs接枝的木纤维对革兰氏阳性菌金黄色葡萄球菌、蜡状芽疱杆菌、革兰氏阴性菌大肠埃希氏菌以及耐药性细菌耐甲氧西林金黄色葡萄球菌这4种菌种的抑菌率均大于95%,此外,PVP-Ag NPs接枝到木纤维板上的抗菌效果也较好。     

Heat Shrinkable Polymer Blends Based on Grafted Low Density Polyethylene and Chlorosulfonated Polyethylene (Part-II)

Abstract

Heat shrinkability of the polymer which depends on elastic memory can be introduced into the system in the form of an elastomeric phase. The present study deals with the measurement of heat shrinkability of the blend of grafted polyethylene and CSM. Interchain crosslinking between grafted polyethylene and elastomer improved the shrinkability. Maleic anhydride and glycidyl acrylate is used as grafting materials. Glycin and 4 4prime; diamino diphenyl sulphone is used as coupling agents. Maximum amount of crosslinking is obtained when glycidyl acrylate is used as grafting agent Minimum amount of interchain crosslinking is observed when 4 4prime; diamino diphenyl sulphone is used as coupling agent. Probable interactions of rubber and plastic phase are confirmed by IR spectroscopy. Extraction of the elastomeric phase is restricted due to interchain crosslinking as confirmed by SEM study which is more prominent in the case of glycidyl acrylate grafted LDPE.     

高温本体聚合合成ACS树脂的接枝率研究

研究了聚合条件、配方组成及氯化聚乙烯(CPE)的氯化度对高温本体聚合合成丙烯腈(AN) CPE苯乙烯(St)接枝共聚物（ACS）树脂接枝率的影响。结果表明,本体聚合合成ACS树脂过程中接枝反应主要发生在聚合转化率低于50 %的低转化率阶段;反应温度、引发剂及链转移剂用量是影响本体聚合合成ACS接枝率的主要因素;提高聚合反应温度、增加引发剂和链转移剂浓度均会导致接枝率显著下降;St/AN的质量比、CPE橡胶的含量及氯化度对接枝率的影响较小。     

马来酸单十八酯接枝气相白炭黑对弹性体SBS性能增强效应

利用偶联剂KH570,马来酸单十八酯和苯乙烯对气相白炭黑进行接枝改性,用傅立叶红外光谱（FT—IR）,热重分析法（TGA）等手段对改性后白炭黑进行表征。探讨了不同配方改性的白炭黑对SBS机械性能的影响,寻求增强SBS的最优配方。红外光谱分析和热重分析结果表明混合单体成功接枝在白炭黑表面;在白炭黑接枝改性过程中,滴加方式投料比一次投料更有效,马来酸单十八酯和苯乙烯的最佳单体摩尔比例为5：8;不同总单体浓度改性的白炭黑,对SBS性能增强不同,总单体浓度达15％时,增强效果最好。改性白炭黑的用量对增强效果有很大影响,在白炭黑添加量为SBS质量分数的15％时,材料达到最佳性能。     

Synthesis of phenoxymethyl ethylene carbonate using quaternary ammonium salt catalysts grafted onto styrene-vinylbenzylchloride-montmorillonite support

The synthesis of phenoxymethyl ethylene carbonate (PMEC) from carbon dioxide and phenyl glycidyl ether (PGE) was investigated using styrene-vinylbenzylchloride-montmorillonite supported quaternary ammonium salt catalysts. The catalysts were prepared by grafting the copolymer of styrene (ST) and vinylbenzyl chloride (VBC) onto montmorillonite (MMT) interlayers, followed by the quaternization using trialkylamines. The influence of VBC concentration, the structure of trialkylamine, and the type of support on the catalytic activity was discussed. Quaternary ammonium salt grafted onto organophilic ST-VBC-MMT intercalates showed higher conversion of PGE than that grafted onto montmorillonite interlayers since the former exhibits greater affinity for organic solvents than the latter does.     

山梨醇类成核剂对改性聚丙烯发泡性能的影响

以过氧化苯甲酰（BPO）为引发剂,经熔融挤出过程将苯乙烯（St）接枝到等规聚丙烯（iPP）上,同时加入山梨醇类成核剂［1,3:2,4二（对甲基卞叉）山梨醇,MDBS］,制备可发泡的iPP,并考查MDBS在其发泡过程中所起的作用。结果发现,St接枝到iPP上,降低了iPP的熔体流动速率,即提高了其熔体强度;在发泡过程中,MDBS起固定泡孔和泡孔成核的作用,使iPP泡沫具有规则完整的泡孔结构,且泡孔密度从纯iPP的1.1×10^7个/cm3增加到1.2×10^8个/cm3,适宜发泡温度范围拓宽至150~160 ℃。