Statistical studies of branched ester latex and paint properties

Vinyl versatate, butyl acrylate and 2-ethylhexyl acrylate were compared as comonomer, for colloid-stabilized vinyl acetate latex polymers to assess their impact on latex coating properties. Vinyl versatate afforded advantages in scrub resistance, gloss, hydrophobicity and higher glass transition temperatures. Butyl acrylate developed better wet adhesion efficiency, gel content and hiding efficiency. 2-Ethylhexyl acrylate offered performance comparable to butyl acrylate in hiding efficiency, lowering copolymer glass transition temperatures, and gloss development. Combinations of these monomers, in many instances, afforded a better balance of performance properties than individual monomers alone. In the subject study, a simplex-centroid design was utilized to statistically map polymer compositions for determining the effect of comonomer composition on latex and paint film properties. In addition to developing contour maps of polymer and paint properties as a function of composition, a technique for studying structure-property relationships is presented.     

Emission Of Volatile And Semivolatile Organic Compounds From Waterborne Paints – The Effect Of The Film Thickness

A waterborne paint was applied to tin plated steel sheets with three different film thicknesses. The emission of volatile and semivolaile organic compounds ((S) VOCs) from the samples was measured in small climatic chambers under standard conditions over a two-week period. The purpose of the study was to evaluate the effect of the film thickness on the emission rate decay. First order decay models, including sink effects for the high boiling (S) VOCs, were fitted to the concentration versus time data. The results showed that the first order rate constants decrease with increasing film thickness. In uddition, the results indicated that the emissions of the (S)VOCs in the waterborne paint film seemed to be controlled by evaporation. The thicknesses of paint films used in climatic chamber tests to estimate emission rates for product compurison or emission prediction must be known in order to prevent erroneous conclusions     

PVC薄膜—尼龙织物复合用胶粘剂的研制

介绍 PVC 薄膜—尼龙织物复合用胶粘剂试制的情况。主要包含胶粘剂主体聚合物、增粘组分、增塑剂、反应促进剂及其它助剂的选择。并阐述了胶粘剂的放大试验情况及应用工艺条件。     

多用户MIMO系统低复杂度收发联合波束成形方案

基于多用户多输入多输出(MIMO)有限反馈系统提出了一种收发联合波束成形方法。该方法在发送端采用每个用户酉速率控制(PU2RC)波束成形技术,在接收端采用基于信干噪比(SINR)最大化的天线合并算法。天线合并算法利用用户SINR的广义Rayleigh熵特性寻找最佳的天线合并矢量。仿真结果表明,该方法能充分利用信道信息,不仅改善了传统PU2RC系统的和速率性能,相对于已有的迫零(ZF)联合波束成形方法,对信道状态信息的量化误差的敏感性更低,用户选择算法的复杂度更低,且低速率反馈条件下和速率性能更优。     

冰箱用聚氨酯泡沫塑料的密度分布机理及配方优化

对冰箱用聚氨酯泡沫塑料的密度分布机理进行了探讨,为配方和工艺优化提供了有价值的参考,并通过对密度分布的研究来解决冰箱泡沫的其他性能缺陷。     

高性能透明PU复印机刮板的研制

探讨异氰酸酯、扩链剂、交联剂和聚合工艺对高性能透明PU复印机刮板物理性能、工艺性能和透明性的影响。试验确定 ,以聚四亚甲基醚二元醇 (PTMEG)为主体材料 ,异氰酸酯选用 4,4′ 二苯基甲烷二异氰酸酯 (MDI) ,扩链剂选用 1,4 丁二醇 (1,4 BDO) ,交联剂选用三羟基丙烷 (TMP) ,按PTMEG/MDI/(BDO TMP) (其中BDO/TMP摩尔比为 6 5∶1)摩尔比为 1∶2∶1、预聚反应条件为 (70～ 80 )℃× 0 5h、扩链反应条件为 (12 5～ 13 0 )℃× 1h聚合PU浇注料 ,利用离心浇注成型法制备出透明PU弹性体 ,经机加工可以制得透明性和物理性能好的复印机刮板     

用FTIR研究聚氨酯／不饱和聚酯IPN体系的反应动力学

利用傅里叶变换红外光谱研究聚氨酯不饱和聚酯互穿聚合物网络体系的反应动力学，求出了ＰＵ的反应速度常数ｋ。实验结果表明，ＰＵ在半－ＩＰＮ体系中的反应为二级反应，ＩＰＮ体系中ＰＵ组分与ＵＰ组分的反应相互影响：ＵＰ组分使ＰＵ组分的前期反应速度变慢，后期反应速度相对增加；ＰＵ组分使ＵＰ组分聚合的诱导期明显缩短。ＰＵ和ＵＰ的配比对反应转化率的影响是反应前期ＰＵ组分含量越高，ＰＵ组分反应转化率也越高；反应后期，     

CB-g-WPU/WPU复合材料的制备与气敏响应性能

通过对导电填料炭黑（CB）进行官能化，在CB表面引入羧基官能团，利用CB表面的羧基等活性官能团与端异氰酸酯基聚氨酯预聚物反应得炭黑接枝水性聚氨酯（CB-g-WPU），采用乳液共混法制备得CB—g-WPU／WPU气敏导电复合材料，并对CB—g-WPU／WPU复合材料的气敏响应行为进行了研究。X射线光电能谱（XPS）、傅立叶变换红外光谱（FTIR）、热重分析（TGA）等分析结果表明聚氨酯接枝到了炭黑表面；SEM分析表明，炭黑经过接枝改性后均匀分散在基体WPU中。该法制备的CB—g-WPU／WPU复合材料逾渗值低、气敏响应度大、响应范围广，是一种综合性能优异的气敏导电复合材料。     

聚氨酯涂料中游离甲苯二异氰酸酯(TDI)单体的测定方法

研究了在GB/T18446-2001方法基础上改变内标物(使用无毒性记录的十二烷代替毒性大的1,2,4-三氯代苯)测定样品中游离TDI的方法。该方法简捷、快速、准确度高、精确度高、更环保。本方法的适用范围同GB/T18446-2001。     

HCFC-141b的生产现状与市场前景

介绍了聚氨酯发泡剂CFC-11的主要替代品HCFC-141b的生产工艺和生产现状,并分析了该产品的市场前景。