Reactive compatibilization of PE/PS blends. Effect of copolymer chain length on interfacial adhesion and mechanical behavior

This paper deals with in situ compatibilization of PE/PS blends via Friedel-Crafts reaction, performed at the interphase. Two polyethylenes having different molecular weights, and the same PS, were used along a wide range of catalyst concentration. The influence of the graft copolymer architecture and content on the efficiency of blend compatibilization was studied. The emulsifying effect, morphological aspects and mechanical behavior were also assessed for these blends. The amount of copolymer formed increases with catalyst concentration and the short chain length fraction of the homopolymers. The high molecular weight (MW) copolymers behaved as better compatibilizers as they showed, at the cmc, greater graft copolymer concentration than the low MW ones. A substantial increase in interfacial adhesion and particle size reduction was observed, even at catalyst concentrations as low as 0.3 wt%. In correspondence, mechanical properties, like ductility and yield strength, were enhanced by the effect of this Friedel-Crafts reaction's compatibilization.     

抗氧剂3114合成反应热力学和动力学的研究

研究了常温溶剂法合成抗氧剂3114反应热力学和动力学过程。控制温度在117±2℃,研究结果表明,反应是零级反应,反应速率常数k=1.91×10-3/min,反应的平衡常数K=138.4(mol/L)-6,反应活化能Ea=1366.2J/mol。     

聚合转化率对硫调型氯丁胶结构与性能的影响

研究了硫调型氯丁橡胶乳液聚合中转化率对产晶结构与性能的影响.结果表明,随单体转化率的提高,聚合物的凝胶量及其交联密度增大,致使断链速度减慢,所得断链胶的门尼粘度上升,残存凝胶量增加,分子支化程度增大,分子量分布变宽,焦烧时间缩短。而相应硫化胶的拉伸强度、撕裂强度、冲击弹性和硬度等提高,扯断伸长率和永久变形下降。这些变化一般在转化率为80——85％时有明显转折.综合考虑产量与质量,聚合转化率控制在82±2％较为适宜。     

Correlation of reactivity and electrical resistivity of coke

A correlation between the reactivity and electrical resistivity of a series of cokes was determined using cokes prepared from blends of medium- and high-volatile coals. After correcting for the ash yield of the coke and the density of the resistivity specimen, a statistically significant relation between reactivity and resistivity was established. As the resistivity test requires much less time to perform than the reactivity test, it can be considered as an alternative approach to reactivity testing currently performed for quality control purposes.     

Nanocrystalline CeO2 in SBA-15: Performance of Pt/CeO2/SBA-15 Catalyst for Water-gas-shift Reaction

CeO₂ particles confined within the pores of an SBA-15 mesoporous silica host were prepared by incipient wetness impregnation (IMP) and deposition precipitation (DP) methods. The materials were characterized by XRD, N₂-adsorption and temperature programmed reduction (TPR) to evaluate the structure, texture, and redox properties. The preparation procedure had significant impact on the assembling mode of CeO₂ inside the SBA-15 mesopores. A high dispersion of CeO₂ particles was achieved via DP, whereas the dispersion of CeO₂ prepared by IMP was found to be inhomogeneous and CeO₂ partially blocked the pores. The CO conversion in the water-gas-shift reaction was enhanced over 1 wt% Pt supported on CeO₂-modified SBA-15 obtained by DP.     

Combustion of single char particles in a turbulent fluidized bed

The combustion of single bituminous char particles (4-12 mm diameter) was studied in a turbulent fluidized bed operated at 1098 K using air as the fluidising medium. Results indicated that particles burn with constant density following a shrinking sphere model. Burning rates are much higher than those observed in a bubbling fluidized bed. The rate of transfer of oxygen to the particle surface is also higher than that observed in bubbling beds. A model is proposed to calculate the Sherwood numbers of the burning carbon particles. Experimental values of the Sherwood numbers agree well with those predicted from the model.     

水合肼生产中氧化反应的研究和应用

分析了尿素法生产水合肼的氧化反应历程及影响因素，改进了反应器，并找到了最佳的工艺控制条件：①控制n(尿素)：n(次氯酸钠)=(1．05～1．10)：1，各原料的消耗较低，总经济效益佳；②采用-5℃冷冻盐水移走尿素、次氯酸钠混合段内氯化反应放出的热量，控制物料混合终点温度在15～30℃；③采用列管式加热器，将氯化反应与水解反应在不同的设备中进行，水合肼的收率提高到83％～85％；④采用列管式加热器代替双夹套反应器，提高了加热强度，生产能力大，1套合成反应器可生产1万t／a80％的水合肼。     

环氧SBS开环制备顺酐化离聚体及其物化性能的研究

利用环氧化苯乙烯-丁二烯-苯乙烯嵌段共聚物（ESBS）的环氧基与顺丁烯二酸氢钾（HKM）在相转移催化剂和开环催化剂存在的条件下开环反应制得钾离聚体。研究了其反应条件，由于添加了助剂BM，环氧基开环率达到了95．2％，并用FTIR确定了离聚体的生成；通过对不同环氧值ESBS开环反应，研究了不同离子基团质量摩尔浓度对离聚体物化性能的影响。     

对叔丁基苄胺的合成研究

摘要选择Delepine反应法的路线合成对叔丁基苄胺，并对反应投料比、反应温度及酸化后的反应时间进行了优化试验，得到了较好的反应条件：反应温度为40℃，对叔丁基苄氯与乌洛托品投料比为1：1；加入酸和醇后的保温时间为2h，从而使反应收率稳定在90％以上，含量达到95％。     

Conditional probability Markov chain simulation based reliability analysis method for nonnormal variables

Based on fast Markov chain simulation for generating the samples distributed in failure region and saddlepoint approximation(SA) technique,an efficient reliability analysis method is presented to evaluate the small failure probability of non-linear limit state function(LSF) with non-normal variables.In the presented method,the failure probability of the non-linear LSF is transformed into a product of the failure probability of the introduced linear LSF and a feature ratio factor.The introduced linear LSF wh...