PF/PU低温固化体系的研究

将端羟基封端和端羧基封端的聚氨酯(PU)预聚物分别与酚醛树脂(PF)复合，加入对甲苯磺酸(PTSA)，在低温下固化，通过对固化体系的参数进行研究，选择的固化条件为：PTSA用量在3．5％，固化温度为80℃。通过扫描电镜对两个体系的复合物进行表征，对两种不同的增韧机理进行讨论。     

A Semi‐Batch Process for Nitroxide Mediated Radical Polymerization

Summary: A semi‐batch process using nitroxide mediated polymerization, was explored for the design of low molecular weight solvent‐borne coatings, typical of those used in the automotive industry. While living radical polymerization (LRP) offers many advantages in the control of polymer chain microstructure that may confer important physical and chemical property benefits to coatings, adapting LRP to a semi‐batch process poses significant challenges in the design and operation of the process. Using styrene monomer, various two‐component initiating systems (free radical initiator, 4‐hydroxy‐TEMPO) were studied to understand the effects of different initiators on the course of polymerization. In addition, an alkoxyamine was synthesized and used as the initiating source. The initiators Luperox 7M75 and Luperox 231 give higher polymerization rates and reasonable control over polymerization, while benzoyl peroxide (BPO), Vazo 67, and the alkoxyamine are less effective. The number of polymer chains in the final product is always less than the theoretical value, reflecting poor initiation efficiency, probably resulting from undesirable termination reactions that become important due to the nature of the semi‐batch process. Adding camphorsulfonic acid (CSA) or charging initiator concurrently with monomer during semi‐batch feed, can increase the polymerization rate while maintaining the living character of the polymerization. The copolymerization of styrene and butyl acrylate is also shown to exhibit living character.

Schematic representation of the exchange reaction to produce N‐TEMPO capped polymer chains.     

Adhesion Mechanisms of Polyurethanes to Glass Surfaces I. Structure-Property Relationships in Polyurethanes and Their Effects on Adhesion to Glass

Polyurethanes were prepared from toluene diisocyanate (TDI), 1-4-butane diol (BDO) and polycaprolactone-based triols with varying molecular weights. Among each molecular weight triol-based urethane, hard segment content was varied from 20% to 70%. Differential scanning calorimetry, tensile testing, and Iosipescu shear testing were done on all the various urethanes prepared. Thermal characterization data revealed the dependence of phase separation on hard segment content as well as on the triol molecular weight. Tensile data and Iosipescu shear data further confirmed the observations made from the DSC data. The data further indicated that phase separation can greatly improve the modulus of cross-linked segmented urethanes. Adhesion of these urethanes to glass surface was evaluated using soda-lime float glass plate. Urethane samples were cast on the air side of the glass plates and adhesion was measured in shear mode. Adhesion data indicated that in addition to hard segment content, modulus, cross-link density, and molecular weight of the triols, phase separation seems to be a major factor in controlling adhesion. Surfaces of the failed adhesion samples were also analyzed and the failure mode was found to be cohesive, in varying degree, with the different urethane systems.     

VTMS对丙烯酸酯乳液的改性研究

研究了交联剂乙烯基三甲氧基硅烷（VTMS）对丙烯酸酯乳液聚合及乳液性能的改性作用。通过正交实验。得出合成弹性乳液的最优化条件：有机硅用量3％，引发剂用量0．5％，乳化剂用量4．8％，反应温度78℃。用激光粒度分析仪、红外光谱仪和差热分析仪对聚合物的形态及结构进行了表征。     

异氰酸酯改性光敏水性环氧丙烯酸酯的合成

以双酚A型环氧树脂与丙烯酸反应合成了具有羟基侧基的环氧丙烯酸酯，再用甲苯二异氰酸酯与内烯酸-β-羟乙酯的半加成物对上述环氧丙烯酸酯树脂进行接枝改性，再用酸酐引入羧基，经胺中和后，水性化．可得较为稳定的自乳化光敏树脂水分散体系。通过化学测试和IR解析．确定了合成条件、合成终点及产物结构，并以此为基料配成紫外光固化涂料，所得涂层性能优异。     

聚氨酯-聚丙烯酸酯复合乳液的动态力学性能

采用种子乳液聚合法合成了聚氨酯一聚丙烯酸乙（丁）酯[PU／PE（B）A]复合乳液。并研究了不同组成对复合乳液性质、相客性、阻尼性能及拉伸性能的影响。耐水性及稳定性测试表明，随PE（B）A含量的增加，涂膜的耐水性变好，而乳液的稳定性变差。动态力学性能测试（DMS）表明，合成的PU／PE（B）A复合乳液为半相容体系，其相容性随PE（B）A含量的增加而增强。DMS和拉伸试验表明PU／PEA／P（B）A（质量比50／25／25）复合乳液具有优良的阻尼性能、抗拉强度和断裂伸长率，可用作宽温域阻尼涂料。     

Different effects of tri(acryloyloxyethyl) phosphate on the thermal degradation of photopolymerized epoxy acrylate and polyurethane acrylate films

Tri(acryloyloxyethyl) phosphate (TAEP) was blended in different ratios with epoxy acrylate EB600 and polyurethane acrylate EB270 to obtain a series of UV curable flame retardant resins. The thermal degradation mechanisms of their cured films in air were studied by thermogravimetric analysis, in situ Fourier‐transform infrared spectroscopy, and direct pyrolysis/mass spectrometry measurements. The results showed that the phosphate group in TAEP first degraded to form poly(phosphoric acid) before the degradation of EB600. Then, the formed poly(phosphoric acid) effectively promoted the conversion of EB600 to form char, which prevented the sample from further burning. However, urethane group in EB270 degraded simultaneously with phosphate group in TAEP, leading to not effectively increase the conversion of EB270 to char during the thermal degradation. It was thus found that the addition of TAEP more effectively improved the thermal stability, flame retardance, and the char yield during combustion of EB600 than those of EB270. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3130–3137, 2006     

聚氨酯/聚丙烯酸酯复合弹性体的力学性能研究

采用预聚体法合成了一系列聚氨酯／聚丙烯酸酯复合弹性体，研究了组成比例对PU／PA复合弹性体的力学性能的影响。结果表明：聚丙烯酸甲酯的比例在一定范围内时，可以较大程度地提高材料的力学强度和断裂伸长率，而将丙烯酸甲酯和甲基丙烯酸甲酯混合加入聚氨酯中，形成的复合弹性体的力学性能无明显改善。     

软段含离子基团的阴离子型水性聚氨酯胶粘剂的研究(Ⅱ)——硬段结构的影响

以含有不同离子基团的聚酯多元醇为软段,采用丙酮法合成了一系列水性聚氨酯乳液。研究了不同硬段结构和硬段含量和扩链剂对其干膜物理机械性能和吸水率的影响。     

有机硅氧烷改性水性聚氨酯的合成

采用有机硅氧烷单体与聚醚、二羟甲基丙酸（DMPA）和甲苯二异氰酸酯（TDI）反应制备水性聚氨酯涂料。研究结果表明采用后添加有机硅氧烷单体的合成工艺，可制备贮存稳定好的水性聚氨酯乳液；凝胶渗透色谱（GPC）分析表明有机硅氧烷改性水性聚氨酯提高了聚氨酯的相对分子质量；性能测试表明有机硅氧烷改性水性聚氨酯涂料具有明显的优点：涂膜硬度高，耐沾污性、耐水性好和耐溶剂性好。