Supported catalysts for the polymerization of 1,3-butadiene

Summary Highly dispersed supported catalysts were prepared by supporting various complexes of CoCl₂, CoBr₂and NiCl₂ on SiO₂, MgO, Al₂O₃ and MgCl₂ in n-heptane, followed by evacuating at room temperature. The catalysts combined with AlEt₂Cl or Al₂Et₃Cl₃ showed very high activities for cis-1,4-polymerization of 1,3-butadiene.     

醇改性负载钛系催化剂用于1,3-丁二烯的聚合

以不同种类不同用量的醇改性TiCl4／MgCl2催化丁二烯聚合。结果表明,与改性前催化剂合成的高结晶度硬塑料状反式聚丁二烯不同,改性催化剂制备的聚丁二烯为低结晶度的弹性体,其乙烯基质量分数已达到中乙烯基聚丁二烯的范畴,反式-1,4-结构质量分数仍高于50％,顺式-1,4-结构质量分数基本低于10％。随醇用量的增加,乙烯基质量分数可进一步提高。     

Modelling the polymerization of 1,3-butadiene in solution with a neodymium catalyst

The batch polymerization of butadiene in hexane with an in-situ-activated Ziegler-Catalyst containing neodymium versatate, ethylaluminium sesquichloride and triisobutylaluminium was studied at 45°C. The rate of polymerization was determined by online density measurements. A mathematical model has been developed which is able to describe the kinetics of polymerization at different catalyst ratios. At molar ratios of aluminium/neodymium above 40 a bimodal molar mass distribution can be observed by gel permeation chromatography which leads to the assumption of more than one active species being present in the polymerization system.     

ZnR2对镍催化体系合成高顺式聚丁二烯的影响

采用新的镍催化体系Ni(naph)2-Al(i-Bu)3-ZnR2-BF3OEt2合成高顺式聚丁二烯，系统地研究了ZnR2的加入对聚合反应及其产物的影响。考查了聚合反应动力学，并对聚合产物进行了测试和表征。实验结果表明：在Ni-Al-B催化体系中加入ZnR2后，丁二烯的聚合反应速率略有降低，分子量分布逐渐变窄，顺1，4式的质量分数保持在96％以上，凝胶含量显著降低。     

The polymerization of 3-methyl-N-(phenylsulfonyl)-1-aza-1,3-butadiene

Summary A study of the polymerizability of the first crystalline 1-azabutadiene carrying an electron-withdrawing group on nitrogen is described. A convenient one-step synthesis of 3-methyl-N-(phenylsulfonyl)-1-aza-1,3-butadiene (MPAB) from methacrolein and benzenesulfonamide using titanium tetrachloride and triethylamine led to a crystalline azabutadiene monomer in good yield. With anionic initiators the monomer readily oligomerized to materials in which MPAB has reacted in a 4,1-fashion. Under radical conditions the monomer did not homopolymerize, but did copolymerize with styrene monomers to polymers with molecular weights up to 10,000. These radical copolymerizations involved exlusive 4,3-propagation (vinyl) for the azadiene monomer.     

新癸酸钕体系对丁二烯聚合活性及产物结构的影响

综述了新癸酸钕(NdV3)/烷基铝/氯化合物三元催化体系催化丁二烯聚合的一般规律,分析了烷基铝结构及用量、氯化合物的品种及用量对催化活性和聚合物结构,包括活性中心的成因、单体插入方式、分子量分布及顺式-1,4-结构含量的影响。     

Microemulsion polymerization of styrene

Summary Heats of polymerization of three carbazolyl-containing epoxides 9-(2,3-epoxypropyl)carbazole, 1,2-epoxy-6-(9-carbazolyl)-4-oxahexane and 3,6-dibromo-9-(2,3-epoxypropyl) carbazole have been determined on the differential microcalorimeter DAK 1-1A (USSR). The influence of the structure of monomers upon the values of polymerization heat is discussed.     

2,3-二甲氧基-1,3-丁二烯的合成研究

选用新型催化剂及溶剂体系,通过相转移催化法在低温下合成了2,3-二甲氧基-1,3-丁二烯,采用减压蒸馏和柱层析的分离方法提高了产品纯度,通过在反应前引入吩噻嗪阻聚剂有效防止了产物聚合。实验表明:反应以十六烷基三甲基溴化铵作催化剂,v(2,3-丁二酮)∶v(原甲酸甲酯)=1∶3.5,并且在溶剂CH2Cl2中回流10h时,总收率达到77%。与文献相比,反应条件更温和,收率更高。     

D4的微乳液聚合

以八甲基环四硅氧烷(D4)为原料,在十二烷基苯磺酸(DBSA)催化下进行微乳液聚合反应,制得有机硅乳液.讨论了催化剂用量、乳化剂用量、加料方式、单体滴加速度对微乳液粒径及粒径分布的影响.结果表明:在一定范围内,随着催化剂、乳化剂用量的加大,乳胶粒粒径变小,粒径分布变宽;当催化剂DBSA用量为微乳液质量的3%、乳化剂OP用量为微乳液质量的2%、DBSA与乳化剂的质量比为3∶2、单体滴加时间为0.5 h时,聚二甲基硅氧烷的摩尔质量最大;与一次加料法相比,采用单体滴加法时乳胶粒的粒径更小,粒径分布更窄;单体滴加时间越长,乳胶粒的粒径越小,粒径分布越宽.     

丙烯酸酯三元共聚物的微乳液聚合

采用种子乳液聚合法合成了固含量达到40%,平均粒径40 nm左右的丙烯酸酯三元共聚物微乳液。利用动态光散射和TEM对微乳液的粒径进行了测试,结果表明,微乳液乳胶粒粒径分布均匀,均相成核、胶束成核等成核机理在聚合中同时存在,提高氧化还原引发剂的用量会加速微乳液形成水凝胶。DSC和TG测得所合成的丙烯酸酯三元共聚物具有较高的Tg,但热稳定性不高。     

Microemulsion polymerization kinetics and mechanisms

The mechanisms of microemulsion polymerizations stabilized by sodium dodecyl sulfate in combination with pentanol were investigated with a water‐insoluble dye as the probe. The major parameters chosen for study were the types of initiators [water‐soluble sodium persulfate (SPS) vs oil‐soluble 2,2′‐azobisisobutyronitrile (AIBN)] and the polarity of the monomers [relatively hydrophobic styrene (ST) vs relatively hydrophilic methyl methacrylate (MMA)]. Both continuous particle nucleation and limited particle flocculation had a significant influence on the polymerization kinetics. For the polymerizations investigated in this work, the relatively low initiation efficiency of AIBN resulted in a reaction system showing a quite different particle nucleation mechanism than that of the ST polymerization with SPS. The formation of particle nuclei in water was suppressed to some extent, and microemulsion droplet nucleation predominated in the ST polymerization initiated by AIBN. Homogeneous nucleation played an important role, and a mixed mode of particle nucleation (microemulsion droplet nucleation and homogeneous nucleation) was operative in the MMA polymerization. The MMA polymerization experienced stronger particle flocculation than its ST counterpart. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2005–2013, 2005     

甘胺酰马来酰亚胺与苯乙烯微乳液共聚合的研究

以苯乙烯-十二烷基硫酸钠-正戊醇-水微乳液(O／W)为体系。研究了甘胺酰马来酰亚胺(GMI)与苯乙烯在微乳液中的共聚合反应。通过实验确定了引发剂的用量，并对乳化剂的用量对单体配比的影响进行了优选。讨论了引发剂浓度对分子量及其分布的影响情况，单体配比对聚合物热性能的影响。用红外光谱(FT-IR)、凝胶色谱(GPC)、热失重(TG)对聚合物的结构与性能进行了表征。     

丙烯酰胺微乳液聚合条件的研究

采用微乳液聚合方法合成了相对分子质量大于1000万的速溶聚丙烯酰胺(PAM).研究了聚合条件对产物分子质量的影响,诸如单体浓度、引发剂、温度、pH值、氨、脲及乳化剂的用量对PAM分子质量的影响,并用傅里叶变换红外光谱和扫描电镜对聚合物进行了表征,分析了产品速溶原因.     

MCPVT测定1,3-丁二烯氧化动力学

用小型密闭压力容器实验(MCPVT)分别跟踪测定了1,3-丁二烯在氮气和氧气氛围下温度随时间的变化(T-t)和压力随时间的变化(p-t)。利用p-t曲线构建了1,3-丁二烯初期氧化反应动力学。结果表明,在氮气条件下,即使温度达到388.15 K也未检测到1,3-丁二烯发生化学反应。1,3-丁二烯与氧气在343.15～363.15 K范围内发生了氧化反应,反应器内的压力减小。1,3-丁二烯与氧气的初期氧化反应动力学是二级反应。另外,还考察了氧气过量和1,3-丁二烯过量时两种特殊情况下的假一级氧化反应动力学。探讨了过渡态的热力学参数,计算结果表明,1,3-丁二烯的热氧化是一个有序的分子数减少过程。用气相色谱-质谱联用仪和碘量法分析了氧化反应产物,其产物有呋喃和过氧化物。     

Polymerization of 1,3-butadiene using aluminoxane-based Nd-carboxylate catalysts

The ternary neodymium-based catalyst for the polymerization of 1,3-butadiene, Nd(versatate)₃/AliBu₂H/tert-butyl chloride, has been examined with respect to the effects of replacing the alkylaluminium hydride with aluminoxane, namely methylaluminoxane (MAO) and tetraisobutyldialuminoxane (TIBAO). Catalysts based on MAO were found to be active even in the absence of a halogen source, whereas TIBAO catalysts were active only when a halogen was present (catalyst activity TIBAO > MAO). Using catalysts prepared both preformed and in situ, the effects of polymerization temperature, solvent and MAO level on catalyst activity and the characteristics of the final polymer are discussed. Polybutadiene cis contents and molecular weights were higher with MAO-based catalysts than with AliBu₂H-based catalysts. Cis contents were also higher when MAO catalysts containing tert-butyl chloride were used, compared to their non-chloride counterparts.     

Polymerization of 1,3-butadiene over cobalt exchanged Y-zeolite

Summary It was found that polymerization of 1,3-butadiene took place over cobalt(II) ion exchanged Y-zeolite without any additives.     

1-Chloro-1,3-butadiene copolymers. I. Synthesis of copolymer with 1,3-butadiene and physical properties of its vulcanizate

Emulsion copolymerization of 1-chloro-1,3-butadiene and 1,3-butadiene was carried out using potassium persulfate at 50°C. The thus synthesized 1-chloro-1,3-butadiene copolymer was possible to be cured with 2-mercaptoimidazoline (MI) as well as with sulfur. The tensile strength of the MI vulcanizate of the copolymer compounded with 30 phr HAF black reached 100 kg/cm² and was higher than that of the sulfur vulcanizate. Moreover, these two vulcanizates showed higher tensile strengths than the sulfur vulcanizate of emulsion butadiene rubber. The addition of the copolymer to the blend of chloroprene rubber (Neoprene GRT) and butadiene rubber extremely improved the elongation and the tensile strength. Dynamic measurements of the vulcanizates showed that the glass transition temperature of the copolymer was situated at the region between that of butadiene rubber and that of chloroprene rubber.     

Syndiotactically enriched 1,2-selective polymerization of 1,3-butadiene initiated by iron catalysts based on a new class of donors

A series of phosphoryl (PO) contained compounds: triethylphosphate (a), diethylphenylphosphate (b), ethyldiphenylphosphate (c) triarylphosphates (d and h-m), triphenylphosphine oxide (e), phenyl diphenylphosphinate (f) and diphenyl phenylphosphonate (g) have been prepared. Iron catalysts, which are generated in situ by mixing the compounds with Fe(2-EHA)₃ and AlⁱBu₃ in hexane, are tested for butadiene polymerization at 50 °C. Phosphates donated catalysts have been, unprecedently, found to conduct extremely high syndiotactically (pentad, rrrr = 46.1-94.5%) enriched 1,2-selective (1,2-structure content = 56.2-94.3%) polymerization of butadiene. Introduction of electron withdrawing substituents on phenyl rings oftriphenylphosphate (k-m) remarkably promotes catalytic activity, while bulky substituent isopropyl at 2-position (h) has beneficial influence on regioselectivity. Employment of e, f or g as donor, results in a suppressed monomer conversion, accompanied by deteriorated 1,2-regioselectivity. The effects of polymerization conditions such as reaction temperature, types of cocatalysts and polymerization medium are also investigated by using catalyst system with tri(2,4-difluorophenyl)phosphate (m) as donor. Highly tolerance to polymerization temperature up to 80 °C is observed for the first time in the iron-based catalyst.     

Inversion of stereoselectivity in 1,3-butadiene polymerization with a niobium catalyst induced by a change in the solvent system

Summary Catalytic 1,3-butadiene polymerization systems can be obtained with the new complex [NbO(C₁₆H₁₁O₆ ⁻)(C₂O₄ ²⁻)] as a catalyst. When the catalysis occurs in a homogeneous medium (toluene as a solvent) in conjunction with AlEt₂Cl, cis-1,4-polybutadiene is obtained. A remarkable inversion of stereoselectivity has been observed when the catalysis is carried out in a two phase system with the molten salt AlCl₃.1-methyl-3-n-butyl-imidazolium chloride (MBIC) as a solvent and AlEt₂Cl as a cocatalyst, giving the trans 1,4-polybutadiene. Received: 30 March 1998/Revised version: 25 May 1998/Accepted: 10 June 1998