"胶乳法"氯化天然橡胶薄层干燥影响因素的研究

采用二次回归正交设计方法,对“胶乳法“氯化天然橡胶(CNR)进行薄层干燥试验.分析了热风温度、风速和物料的粒径等因素对干燥速率、干燥后物料性能的影响规律,确定了影响物料薄层干燥速率各因素的主次,提出了较佳的干燥工艺和合理的性能参数.     

酚醛泡沫夹芯板甲醛释放与检测初步探讨

对酚醛泡沫夹芯板中甲醛的来源、释放的影响因素以及控制方法进行了初步探讨。介绍了国内外关于人造板甲醛释放量的相关规定。根据材料的特点及甲醛释放情况,采用40L干燥器法进行了甲醛检测,并进行了讨论。结果表明:与仲裁检测法———1m3气候箱法相比较,该检测方法的结果偏差很小,当取置信水平为0.95时,检测结果的变异系数均小于10%,重现性好。     

Microcellular foaming of PE/PP blends

Three different polyethylene/polypropylene (PE/PP) blends were microcellular foamed and their crystallinities and melt strengths were investigated. The relationship between crystallinity, melt strength, and cellular structure was studied. Experimental results showed that the three blends had similar variation patterns in respect of crystallinity, melt strength, and cellular structure, and these variation patterns were correlative for each blend. For all blends, the melt strength and PP melting point initially heightened and then lowered, the PP crystallinity first decreased, and then increased as the PE content increased. At PE content of 30%, the melt strength and PP melting point were highest and the PP crystallinity was least. The blend with lower PP crystallinity and higher melt strength had better cellular structure and broader microcellular foaming temperature range. So, three blends had best cellular structure at PE content of 30%. Furthermore, when compared with PE/homopolymer (hPP) blend, the PE/copolymer PP (cPP) blend had higher melt strength, better cellular structure, and wider microcellular foaming temperature range, so it was more suited to be microcellular foamed. Whereas LDPE/cPP blend had the broadest microcellular foaming temperature range because of its highest melt strength within three blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4149–4159, 2007     

Synthesis and surface characterization of poly(methyl methacrylate)‐block‐polydimethylsiloxane copolymers from macroazoinitiator

Poly(methyl methyacrylate)‐block‐polydimethylsiloxane (PMMA‐b‐PDMS) copolymers with various compositions were synthesized with PDMS‐containing macroazoinitiator (MAI), which was first prepared by a facile one‐step method in our lab. Results from the characterizations of X‐ray photoelectron spectroscopy (XPS), contact angle measurements, and atomic force microscopy (AFM) showed that the copolymer films took on a gradient of composition and more PDMS segments enriched at the film surfaces, which then resulted in the low surface free energy and little microphase separation at the film surfaces. By contrast, transmission electron microscopy (TEM) analysis demonstrated that distinct microphase separation occurred in bulk. Slight crosslinking of the block copolymers led to much steady morphology and more distinct microphase separation, in particularly for copolymers with low content of PDMS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

无三苯CR/SBS/MMA/BA自交联鞋用胶粘剂的研制

采用复合引发剂 ,以N 羟甲基丙烯酰胺 (NAM )及丙烯酸 (AA)为功能单体 ,与CR、苯乙烯 丁二烯嵌段共聚物 (SBS)、甲基丙烯酸甲酯 (MMA)和丙烯酸丁酯 (BA)进行多元共混接枝共聚 ,再配以混合型增粘树脂 ,研制出不含苯、甲苯和二甲苯 (简称三苯 )自交联环保型鞋用胶粘剂。探讨了SBS用量、MMA/BA配比、功能单体NAM及AA用量对胶粘剂粘合性能的影响。结果表明 ,CR/SBS/MMA/BA/AA/NAM自交联型接枝胶粘剂对非极性鞋材的粘合性能明显优于CR/MMA/BA三元接枝胶和CR/SBS/MMA/BA四元接枝胶。     

多孔催化剂效率因子的多组分扩散模型(Ⅴ) 表面中毒并伴有平衡死区圆柱状催化剂效率因子的有限元求解

针对表面中毒并伴有平衡死区二维圆柱状催化剂的反应-扩散偏微分方程组的特殊性,引入有限元方法求解该类问题,建立了求解步骤。实际计算所得效率因子与实验值对照表明,本法结果准确,过程简单,容易推广应用于各种相类似的体系。     

A－6型甲胺催化剂的工业应用

Ａ－６型甲醇胺化制甲胺催化剂．液空速１１．７ｈ（－１）条件下考察５００ｈ，甲醇转化率９７．５２ｍｏｌ％，活性稳定，产物分布几乎不随时间变化．该催化剂已工业运转１５０天，转化率９８～９９ｍｏｌ％．Ｎ／Ｃ＝１．９５条件下产物粗肢中一、二、三甲胺分别为（ｗｔ％）：２９．２４、４０．７６和３０．００．     

TiCl4水解法制备纳米TiO2粉体

以TiCl4为原料,采用低温液相水解法制备了纳米TiO2粉体,着重研究了Ti4 的浓度和添加聚乙烯吡咯烷酮(Polyvinylpyrrolidone,PVP)对产物的晶相、颗粒大小和表面形貌的影响.使用XRD,TEM,SEM,激光粒度测试仪对样品进行了表征.结果表明,Ti4 浓度影响TiO2粉体的相转变温度,随着Ti4 浓度的升高金红石相的含量逐渐升高,但粉体分散性变差;添加PVP提高了所得TiO2粉体的分散性,粒径降低为40～50 nm左右,并改善了粉体的形貌.     

Preparation of narrowly distributed nanoparticles of poly(n‐butyl methacrylate‐co‐vinyl pyrrolidone) through microemulsion polymerization

Narrowly distributed nanoparticles of poly (n‐butyl methacrylate‐co‐vinyl pyrrolidone) were prepared through microemulsion polymerization with a nonionic surfactant of Tween‐80 as emulsifier (6 wt % of the latex) and n‐butanol as coemulsifier. The polymerizations were initiated with benzoylperoxide (BPO), potassium persulfate (KPS), KPS/ferric sulfate (FeSO₄), and BPO/FeSO₄, respectively, where the initiation in the case of BPO/FeSO₄ took place mainly at the interphase between the oil phase and the reaction media. Namely, this interfacial‐initiated microemulsion polymerization resulted in larger particles with relatively narrower particle size distribution as well as higher limiting monomer conversion but lower polymerization rate compared with the polymerization initiated with KPS/FeSO₄. In this article, the influences of initiation method, monomer ratio, and addition of water‐soluble components on microemulsion polymerization and latex particle size were studied to discuss the mechanism of interfacial‐initiated microemulsion polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2334–2340, 2004     

内构件存在时提升管内流动及颗粒混合行为研究

he hydrodynamics and solids mixing behavior in a riser with blunt internals are studied. A uniform radial distribution for solids fraction and particle velocity achieves near the internals. The turbulent velocity of particles near the wall increases with the addition of the internals, with the lateral solids mixing enhanced significantly. Probability density distribution of particle velocity is bimodal in the riser with internals, which is similar to that in the conventional riser, indicating that no significant difference in the micro flow structure exists between the riser with internals and the conventional riser. At the same time, the axial solids mixing behavior changes insignificantly with the addition of internals. These results indicate that the micro flow structure in the riser is very stable, which changes insignificantly with the change of the bed structure.