Ni(naph)_2-i-Bu_3Al_2Cl_3催化丁二烯聚合的研究

Ｎｉ（ｎａｐｈ）_２－ｉ－Ｂｕ_３Ａｌ_２Ｃｌ_３催化丁二烯聚合的研究徐玲，李绍军，陈滇宝，仲崇淇，唐学明（高材系）０前言目前，我国镍系顺丁橡胶工业化生产采用以加氢汽油为溶剂，Ｎｉ－－Ａｌ陈化，稀Ｂ单加的聚合工艺［１］，但由于ＢＦ３·ＯＥｔ２在加氢汽油中...     

聚丁二烯聚氨酯-脲密封材料的性能研究

以端羟基聚丁二烯 (HTPB)、二异氰酸酯 (TDI或IPDI)为原料制备预聚体 ,利用多元胺或多元醇作固化剂 ,制成聚氨酯及聚氨酯 脲弹性体。测试了这些材料的力学性能、动态力学性能、粘接性能、耐介质、耐水解及透气性能。结果表明 :HTPB型聚氨酯 脲具有优良的力学性能 ,其耐介质及耐水解性明显优于聚醚型或聚酯型聚氨酯 ,具有很好的密封性能 ,可用作水下密封材料。     

TSS1126型脱水振动筛的设计与分析

针对原１万ｔ／ａ橡胶后处理装置中脱水振动筛存在的问题，在５万ｔ／ａ橡胶后处理装置中设计了ＴＳＳ１１２６型激振电机式振动筛，并对其进行了运动学参数的计算和自同步动力学分析，较好的解决了生产中的振动问题。     

The Role of Cloisite 30B as a Phase Transfer Catalyst (PTC) in Polybutadiene Epoxidation

This study aimed at improving the structure of polybutadiene through epoxidation at a constant temperature. This was accomplished using dimethyl dioxirane (DMD) as an in-situ generated oxidant in the presence of Cloisite 30B as a phase-transfer catalyst (PTC). Indeed, this experiment was an attempt to see how Cloisite 30B modifies the process of epoxidation. More specifically, we added different quantities of Cloisite 30B and, spectroscopy methods, checked the products after different periods. Cloisite 30B was found to be particularly selective: it caused more of the cis double bonds and less of the trans and vinyl bonds to be epoxidized.     

A Study of Rheological Behavior and Compatibility of NR/BR Blends

In this study, we research the Mooney viscosity, curing rates, and processibility of natural rubber (NR) and polybutadiene rubber (BR) blends at different blending ratios. The changing values are measured during vulcanization processing and were tested by Mooney viscometer, Monsanto viscometer, etc. The results of scanning electron microscope (SEM) and dynamic mechanical analysis (DMA) experiments are used to explore the surface morphologies and molecular mobility of NR/BR blends.

The experimental results indicate that Mooney viscosity tends to decrease with increasing NR content of NR/BR blends, and this results in superior processibility of NR/BR blends with increasing NR content. NR/BR blends' curing rate improved with increasing NR content. The DMA experimental results show that the temperature is suitable to produce a character peak (T_αn) in molecular motions of NR/BR blends. There tends to a lower temperature range with decreasing NR content of NR/BR blends. In addition, T_αb would move to a lower temperature with decreasing BR content of NR/BR blends.     

Inverse gas chromatography of liquid polybutadienes

Results of inverse gas chromatography study of liquid polybutadiene and dihydroxypolybutadiene are presented. The study was motivated by the application of polybutadiene polyols in polyurethane chemistry where miscibility problems are often encountered. The experimental results revealed marked differences in interaction behavior of polybutadiene and dihydroxypolybutadiene, particularly with relation to the polar molecules. Influence of temperature is discussed as well as relation to the previous miscibility study.     

热水用塑料管材的性能及应用

介绍了热水用塑料管材的基本性能以及根据使用级别和使用压力等最终选择热水用管材的种类。     

Studies on Mechanical,Thermal, and Flame Retarding Properties of Polybutadiene Rubber (PBR) Nanocomposites

An effect of nanosize CaCO₃ on physical, mechanical, thermal and flame retarding properties of PBR was compared with commercial CaCO₃ and fly ash filled PBR. CaCO₃ at the rate of 9, 15, and 21 nm were added in polybutadiene rubber (PBR) at 4, 8 and 12 wt.% separately. Properties such as swelling index, specific gravity, tensile strength, Young's modulus, elongation at break, modulus at 300% elongation, glass transition temperature, decomposition temperature, flame retardency, hardness, and abrasion resistances were determined. The swelling index decreased and specific gravity increased with reduction in particle size of fillers in PBR composites. There was significant improvement in physical, mechanical, thermal and flame-retarding properties of PBR composites due to a reduction in the particle size of fillers. Maximum improvement in mechanical and flame retarding properties was observed at 8 wt.% of filler loading. This increment in properties was more pronounced in 9 nm size CaCO₃. The results were not appreciable above 8 wt.% loading of nano fillers because of agglomeration of nanoparticles. In addition, an attempt was made to consider some thermodynamically aspects of resulting system. The cross-linkage density has been assessed by Flory-Rehner equation in which free energy was increased with increase in filler content.     

Highly active and stereospecific polymerizations of 1,3-butadiene by using bis(benzimidazolyl)amine ligands derived Co(II) complexes in combination with ethylaluminum sesquichloride

A family of cobalt(II) complexes supported on tridentate dibenzimidazolyl ligands having a general formula: [N(CH₃)(CH₂)₂(Bm-R)₂]CoCl₂ (where Bm = benzimidazolyl, R = H; -Me; -Bz), have been prepared by the condensation of o-phenylene diamine with methyliminodiacetic acid. The Co(II) complexes exhibited high activities for the polymerization of 1,3-butadiene, on activation with ethylaluminum sesquichloride (EASC), to yield predominantly cis-1,4 microstructure. The polymers are characterized by high molecular weight with polydispersity values between 2.35 and 3.37. The ligand modification shows remarkable influence on polymerization activity. The stereospecificity of the catalysts is consistent for a wide range of reaction conditions, except temperature. The electronic influence of ligand structure towards metal center is investigated by using cyclic voltammetric analysis and the generation of cationic active centers is identified via UV-vis spectroscopic analysis of the catalyst system.     

复合调节体系对聚丁二烯反应动力学及微观结构的影响

以正丁基锂为引发剂、环己烷为溶剂,采用阴离子聚合工艺进行了丁二烯的均聚.考察了不同复合结构调节体系(SDBS/THF,SDBS/TMEDA)对聚合反应动力学和聚合物微观结构(1,2结构含量)的影响.结果表明,采用复合结构调节体系可加快聚合反应,缩短聚合时间,同时可在较大范围内调节聚合物的1,2结构含量.