双组分钛基催化剂合成反式-1,4-聚异戊二烯/3,4-聚异戊二烯复合胶

以钛酸正戊酯[Ti(C5H11O)4]-TiCl4/MgCl2(简称Ti)-Al(Et)3(简称Al)组成的双组分钛基催化剂引发异戊二烯(Ip)聚合,原位合成反式-1,4-聚异戊二烯(TPI)/3,4-聚异戊二烯(PIp)复合胶,考察了聚合活性和复合胶在汽油中可溶性的影响因素,表征了复合胶的微观结构,并研究了复合胶的特性黏数。结果表明,在Ti/Ip(摩尔比)为6×10-5、Ti(C5H11O)4/Ip(摩尔比)为1.2×10-3、Al/Ti(C5H11O)4(摩尔比)为10的条件下,聚合活性最优;复合胶的汽油可溶物部分含量变化的趋势遵循以下规律:随着Ti(C5H11O)4用量的增加而增大;随着Al/Ti(C5H11O)4的增大先升高后降低最后趋于平稳;随着Ti/Ip的增大而逐渐降低。TPI的相对分子质量大于3,4-PIp。     

溶液聚合法合成低分子反式-1,4-聚异戊二烯蜡

以加氢汽油为溶剂，采用负载型TiCl4／MgCly-Al(i-Bu)，体系催化异戊二烯聚合，高压氢气调节相对分子质量，溶液聚合法合成出了低相对分子质量反式-1，4-聚异戊二烯蜡(LMTPIW)，并分别探讨了氢气压力和聚合温度对LMTPIW的相对分子质量、聚合物组成以催化效率的影响。结果表明：氢气压力由0．8MPa增加至4．0MPa，LMTPIW的特性粘数由0．391dL／g下降至0．1951dL／g，相应数均相对分子质量从1500降至1000以下，常温下汽油可溶物的质量分数由49．3％逐渐上升至77．6％，相对分子质量分布变窄。随聚合温度的升高，LMTPIW的相对分子质量有所增大，分布加宽。氢气压力及聚合温度的上升均使体系催化效率下降，但仍可保持在2500g／gTi以上。     

3,4-聚异戊二烯橡胶的研究进展

介绍了3,4-聚异戊二烯橡胶的结构与性能及在高速轮胎胎面胶中的应用情况,综述了合成3,4-聚异戊二烯橡胶的引发剂体系、微观结构的调节和聚合动力学,并对3,4-聚异戊二烯橡胶的发展前景进行了展望。     

稀土催化合成反式,环化和顺反立构嵌段聚异戊二烯

采用新型稀土催化体系Ｌ３－ｎＬｎＸｎ－Ｒ３Ａｌ－ＲＸ，研究了催化体系各组分、室温下再陈沦时间、ＲＸ和Ｒ３Ａ种类及用量、溶剂种类等因素对异戊二烯聚合的影响。在此基础上，经经环化聚合合成出环化聚异戊二烯，并尝试了异戊二 立构癌段聚合，用Ｉ动态力学测试等方法表片了聚合物的结构，合成出含１，４－结构６８．１％含环化结构的２８．９％，顺－１，４和反－１，４链段的Ｔｇ分别为－２９℃和７０℃的顺反立嵌段聚异戊二     

用钕系催化剂合成具有拉伸结晶特点的聚异戊二烯(英文)

采用由Nd（vers）3（简称Nd）、Al（i—Bu）3（简称Al）和Al（i—Bu）2Cl组成的均相催化剂进行异戊二烯的聚合,考察了Nd和Al的用量对聚异戊二烯结构和性能的影响。结果表明,高相对分子质量（大于100×10^4）、窄相对分子质量分布（小于2．2）和高顺式-1,4-结构含量（大于96％）的聚异戊二烯具有拉伸结晶特点。     

改性五氯化钼催化剂合成3,4-聚异戊二烯

利用正辛醇改性五氯化钼催化体系催化异戊二烯聚合得到了3,4-聚异戊二烯。研究了n(Mo)/n(Ip)、n(Al)/n(Mo)、间甲酚用量等聚合条件对聚合活性和聚合产物相对分子质量的影响。利用红外对聚合物进行了表征,并且通过红外谱图研究了聚合温度对聚合物3,4-结构含量的影响。结果表明,改性五氯化钼催化得到的聚合产物与铁系低分子聚合物具有相近的3,4-结构含量(质量分数为55%～61%),并且3,4-结构含量随着聚合温度升高先升高后降低。对聚合物进行特性粘数和GPC的表征表明,合成的3,4-聚异戊二烯特性粘数为1.2～2,多分散系数小于3。     

氯化稀土异辛醇配合物/烷基铝催化剂聚合异戊二烯

用可溶于己烷的氯化稀土异辛醇配合物(NdCl3·4EHOH)与烷基铝组成催化剂体系对异戊二烯进行聚合,并与不溶解于己烷的氯化稀土异丙醇配合物体系[NdCl3·3(i-PrOH)]进行了对比。结果表明,NdCl3·4EHOH催化体系可形成稳定的胶体状态;与NdCl3·3(i-PrOH)催化体系相比,具有较好的分散性和更高的催化活性。烷基铝影响催化活性从大到小的顺序为AlEt3,Al(i-Bu)2H,Al(i-Bu)3。通过调节Al/Nd(摩尔比)和聚合温度,可调节聚合物的相对分子质量(20×104~70×104)和相对分子质量分布(2.77~6.18),聚合物的顺-1,4-结构的摩尔分数可达到96%。     

天然橡胶/低相对分子质量3,4-聚异戊二烯复合材料的制备与性能

用阴离子溶液聚合法制备了3,4-结构摩尔分数为68.99%的低相对分子质量3,4-聚异戊二烯(3,4-LIR),将其应用到天然橡胶(NR)配方中,制备了NR/3,4-LIR复合材料。通过红外光谱和核磁共振氢谱测试,表征了3,4-LIR的微观结构。应用平衡溶胀法、动态力学分析以及物理机械性能测试等方法,研究了3,4-LIR对复合材料性能的影响。结果表明,随着3,4-LIR添加量的增加,硫化胶的交联密度、拉伸强度、撕裂强度呈现先增加后减小的趋势;动态力学性能0℃处的tan δ逐渐增大,表明3,4-LIR能够提升硫化胶的抗湿滑性能;综合耐热氧老化性能,当3,4-LIR的填充份数为5份时,硫化胶的综合性能较优。     

3,4-聚异戊二烯橡胶3,4-ПИ的性能

用独创的生态型纯可溶解的钠-镁有机化合物作催化剂,合成了不同乙烯基链段含量和不同分子量的3,4-聚异戊二烯橡胶（3,4-ПИ）。该橡胶的α＇-转变温度接近室温。3,4-ПИ橡胶的热稳定性、气密性及弹性阻尼性能良好。不同分子量及不同微观结构的3,4-ПИ有良好的互溶性,由此可调节T＇α。3,4-ПИ是颇有发展前途的新型阻尼材料、吸音材料和粘合材料,可用于航空、船舶和汽车制造业。     

均相Nd(vers)3/Al(i-Bu)2H/Al(i-Bu)2Cl催化聚合异戊二烯

采用A l(i-Bu)2C l(简称C l)、Nd(vers)3(简称Nd)和A l(i-Bu)2H(简称A l)在少量异戊二烯(Ip)存在下,Nd与A l在50℃下反应后,再与C l作用,可配制成均相高效催化剂体系。考察了Nd和A l二组分陈化时间、Nd和A l、C l三组分陈化时间、A l/Nd(摩尔比)、C l/Nd(摩尔比)、聚合温度及溶剂对催化剂相态和Ip聚合的影响。结果表明,上述反应因素对催化剂的相态和产物微观结构均无影响,聚异戊二烯(PI)的顺式-1,4-结构摩尔分数在95.0%以上;Nd和A l二组分陈化时间应控制在10 m in之内;Nd、A l和C l三组分陈化时间对PI收率无影响。当A l/Nd为15或C l/Nd为1.0时,均相Nd/A l/C l催化剂体系仍具有高的聚合活性。当聚合温度为30~70℃时,提高温度可提高PI收率;以环己烷替代或部分替代己烷可提高PI收率。     

Synthesis and characterization of syndiotactic 3,4-polyisoprene prepared with diethylbis(2,2′-bipyridine)iron-MAO

The soluble system diethylbis(2,2′-bipyridine)Fe-MAO is very active for the polymerization of isoprene to predominantly 3,4 polymers (ca. 80%). The polymers obtained at 25 °C are amorphous by X-ray examination, while those obtained below 10 °C are crystalline. The identity period determined from the X-ray fiber spectrum, ca. 5.2 Å, and the NMR analysis show that the polymer contains stereoregular sequences of 3,4 syndiotactic structure. An interpretation is given of the effect of polymerization temperature on stereospecificity. Some differences between the 1,2 polymerization of butadiene and the 3,4 polymerization of isoprene are examined.     

异戊二烯—环己烷—乙醚体系负离子聚合产物的微观结构

研究了在１５－３０℃下,以正丁基锂为引发剂,环己烷为溶剂,乙醚为极性调节剂的异戊在负离子聚合产物的微观结构。结果表明：在同一乙醚／正丁基锂摩尔比值下,随聚合温度升高,试样的３,４－结构摩尔分数降低;在同一温度下,随乙醚用量的增加,３,４－结构摩尔分数增加;以乙醚为极性添加剂时,聚合物分子链上含有３,４－和１,４－结构,不含１,２－结构;以乙醚为溶剂时,聚合物分子 含有３,４－,１,４－及１,２－结     

Cationic polymerization of isoprene using zinc halides as co‐initiators: towards well‐defined oligo(isoprene)s under mild conditions

The activity of ZnX₂‐based initiating systems (X = Cl, Br, I) in the cationic polymerization of isoprene was studied. The highest activity was achieved when co‐initiator (ZnX₂) was solubilized in a minimal amount of strongly coordinating solvent such as diethyl ether or acetone and when trichloroacetic acid was used as an initiator. It is shown that the polymerization rate increased in the series ZnI₂ < ZnCl₂ < ZnBr₂. An increase of initiator concentration and temperature also led to an increase of the polymerization rate. The obtained polyisoprenes did not contain high‐molecular‐weight and insoluble fractions and were characterized by low number‐average molecular weight and relatively narrow molecular weight distribution. Unsaturation of polyisoprene decreased with an increase of monomer conversion and reaction temperature. The unsaturated part of the polyisoprene chain possessed predominantly 1,4‐trans microstructure with regular and inverse addition, whereas the 1,2‐ and 3,4‐isomers were present as minor components. It is shown that the synthesized low‐molecular‐weight polyisoprenes are effective plasticizers for rubber compounds in the manufacture of tyres. © 2012 Society of Chemical Industry     

甲基铝氧烷对稀土催化体系催化异戊二烯聚合的影响

考察了甲基铝氧烷(MAO)作为助催化剂对稀土催化体系催化异戊二烯聚合的影响,结果表明MAO可极大地提高体系的催化活性,获得顺-1,4结构含量95%(质量分数)以上的聚异戊二烯,并且调节n(MAO)/n(Nd)和n(Al)/n(Nd)的值可有效地提高聚合产物的相对分子质量.     

碳笼烯钕系催化异戊二烯聚合的动力学行为

测定了Ｎｄ（ｎａｐｈ）３－碳笼烯衍生物（Ｃ６０Ｘｎ）－Ａｌ（ｉ－Ｂｕ）３催化体系引发异戊二烯溶液聚合的动力学行为。在低转化率条件下,体系呈现稳态聚合特征,测量聚合反应速率方程为Ｒｐ＝Ｋｐ［Ｎｄ］＾１．８［Ｍ］０,表观活化能为２７．７ｋＪ／ｍｏｌ。体系具有聚合活性的高温稳定性和准活性聚合的特征。     

Effects of amines on the polymerization of isoprene with sec-butyllithium catalyst

Polymerization of isoprene (IP) with alkyllithium (RLi) catalysts in the presence of amines such as triethylamine (TEA), 1,2-dipiperidinoethane (DPPE) and N,N,N′,N′-tetramethyldiaminoalkanes [(CH₃)₂N(CH₂)_nN(CH₃)₂ where n=1, 2, 3, 4 and 6 (TMDAA)] has been studied. By adding the amines, the polymerization rate of IP was accelerated, and the contents of 3,4- and 1,2-units in the resulting polymers increased. The effects of methylene chain length of the TMDAA on the polymerization were examined. It was found that both the polymerization rates and the microstructure of the polymers depend on the methylene length of the TMDAA. The amines having 2 and 3 methylenes in (CH₃)₂N(CH₂)_nN(CH₃)₂ favoured production of the polymer consisting of predominantly 1,2- and 3,4-units. It was proposed that two types of active sites for the polymerization of IP were produced depending on the number n of the TMDAA. Two types of active species were confirmed to be produced with sec-BuLi in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) depending on the TMEDA/sec-BuLi mole ratios. © 1998 SCI.     

Polymerization of 1,3‐butadiene with VO(P204)2 activated by methylaluminoxane,purified methylaluminoxane,and trimethylaluminum

The effect of different aluminum‐based cocatalysts (MAO, pMAO, and TMA) on butadiene (Bd) polymerization catalyzed by VO(P204)2 was investigated. The bimodal dependence of the polymer yield on the [MAO]/[V] molar ratio was revealed, and an highest polymer yield was achieved at a rather low [MAO]/[V] molar ratio ([MAO]/[V] = 13). The microstructures of the resulting poly(Bd)s were also significantly influenced by the ratio. In the TMA or pMAO system, the polymer yields were also very sensitive to the [Al]/[V] molar ratio. However, the microstructures of the resulting poly(Bd)s were almost independent of the ratio. In relation to the microstructures of poly(Bd)s obtained by the MAO and TMA systems at various temperatures, the 1,2‐unit contents were found to be the most abundant microstructure for both systems. In the pMAO system, the trans‐1,4‐units were the most abundant. The results of the additions of Lewis bases (THF and TPP) into Bd polyerization system comfirmed the existing of the two types of the reactions of VO(P₂₀₄)₂‐MAO catalyst and had the polymerization process controlled to some extent. The different thermal behaviors of these catalytic systems also show that multiple types of active centers were formed during the reaction between VO(P₂₀₄)₂ and MAO. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Syndiospecific polymerization of styrene based on dichlorobis(1,3‐diketonato)titanium/methylaluminoxane catalyst system: effects of substituents on catalyst activity

Dichlorobis(substituted‐1,3‐diketonato)titanium complexes 4a–e have been synthesized and were combined with methylaluminoxane as cocatalyst to be employed in the polymerization of styrene. The polystyrenes produced have high syndiotacticities of 94.0–98.2%. The substituents at either 2‐ or 1,3‐positions of 1,3‐diketones can noticeably influence catalyst activities. The catalytic activities of 4a–c bearing 2‐substituents and 4e bearing 1,3‐diphenyl groups are tenfold higher than that of 4d bearing 1,3‐dimethyl groups. The effects of polymerization conditions on the catalyst activities and the syndiotacticities of the polystyrene produced have been examined. © 2000 Society of Chemical Industry