极性调节剂对SSBR微观结构及性能的影响

以正丁基锂为引发剂,环己烷为溶剂,采用SDBS/THF为复合调节剂,制备了溶聚丁苯橡胶（SSBR）;研究了聚合物微观结构对聚合物性能的影响。结果表明：复合调节剂使聚合物链中乙烯基含量和苯乙烯含量均匀分布,得到的产品是完全无规化的SSBR,随着聚合物链中乙烯基含量和苯乙烯含量的增加,产品的玻璃化转变温度明显增加,产品的动态力学性能得到显著提高,分子质量分布大于1.6,合成的SSBR具有良好的物理机械性能。     

高性能SSBR的制备及性能研究

采用阴离子聚合方法,分别以环己烷和环戊烷为溶剂,以十二烷基苯磺酸钠(SDBS)及四氢呋喃(THF)为复合结构调节剂,以n-BuLi为引发剂,SnCl4为偶联剂,合成了性能优异的SSBR。考察了不同溶剂对聚合过程的影响、复合结构调节剂用量对SSBR结构及偶联效率的影响,采用T型关联度分析法对门尼粘度的影响因素进行了研究。并采用国标方法对SSBR的物理机械性能进行了测定。结果表明,环戊烷可用于合成SSBR,且对SSBR性能影响不大;当复合结构调节剂SDBS/THF与正丁基锂的摩尔比为4∶0.7∶1时,SSBR的无规化程度较好;当SDBS与THF的用量较小时,偶联效率可达51.3%;对SSBR门尼粘度影响较大的因素为丁苯共聚物的组成(共聚物单体配比)、聚合物分子量及聚合物分子量分布。     

溶聚丁苯橡胶的合成及动态力学性能研究

以正丁基锂为引发剂,环己烷为溶剂,四氢呋喃(THF)/十二烷基苯磺酸钠(SDBS)、SDBS/五甲基二乙烯基三胺(PMDETA)为复合调节剂,制备了溶聚丁苯橡胶(SSBR)。考察了玻璃化转变温度与苯乙烯含量以及1,2-结构含量的关系。测试了合成SSBR样品的力学性能和动态力学性能,结果表明,合成的SSBR产物具有突出的抗湿滑性能和较低的滚动阻力。     

高温溶液法制备SBR的结构和性能研究

以正丁基锂（n-BuLi）为引发剂、醚类化合物为调节剂、环己烷／正己烷为溶剂,采用阴离子高温聚合工艺合成了溶聚丁二烯／苯乙烯橡胶（SSBR）。通过GPC、NMR分别测试了SSBR的相对分子质量及其分布和微观结构;并对硫化胶性能和门尼粘度进行了测定。考察了调节剂、温度等因素对SSBR的相对分子质量及其分布、共聚物微观结构、序列分布以及动态力学性能和物理机械性能的影响。研究结果表明：所用调节剂是有效的SSBR高温聚合调节剂,可很好地调节SSBR中的乙烯基含量,获得微观结构适中的中高乙烯基丁苯共聚物;n（调节剂）／n（Li）对聚合速率及共聚物的1,2-结构含量有明显的影响,但对共聚物的相对分子质量分布无明显影响;温度对共聚物的转化率及微观结构均有一定的影响。     

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.     

中石油兰州研发中心制备出高性能SSBR

中国石油兰州研究开发中心研究人员采用阴离子聚合方法,分别以环己烷和环戊烷为溶剂,以十二烷基苯磺酸钠(SDBS)及四氢呋喃(THF)为复合结构调节剂,以n-BuLi为引发剂,SnC14为偶联剂,合成了性能优异的SSBR。     

新型结构调节剂制备溶聚丁苯橡胶及其性能研究

用自制的四氢糠基乙基醚（ETE）作为结构调节剂,正丁基锂作为引发剂,制备了高乙烯基含量的溶聚丁苯橡胶（SSBR）。在5L不锈钢反应釜内,详细研究了调节剂用量和引发温度对聚合反应的影响;用气相色谱（GC）、凝胶渗透色谱（GPC）和核磁共振仪（1H-NMR）分别测定了单体转化率、偶联反应效率和共聚物的微观结构。结果表明,改变调节剂的用量以及引发反应温度,可以控制SSBR分子链段中的乙烯基含量在10%～60%之间变化;50℃下,丁苯活性链与四氯化锡的偶联效率始终保持在60%以上。对所得SSBR的相关性能测试表明,聚合物具有良好的物理性能、加工性能及突出的抗湿滑性能。有望应用于雨胎和赛车胎用胶。     

调节剂对连续聚合溶聚丁苯橡胶乙烯基含量的调节

在连续聚合工艺条件下,采用调节剂四氢呋喃(THF)和复合调节剂对溶聚丁苯橡胶(SSBR)的乙烯基含量进行调节.结果表明,SSBR的乙烯基含量与THF/n-BuLi的相关性不强,而与THF的用量呈现较好的线性相关;与THF调节体系相比,复合调节体系对乙烯基结构的调节能力更强;连续聚合的SSBR相对分子质量分布宽,综合性能优于间歇聚合产品,其中高苯乙烯基和高乙烯基SSBR具有较高的抗湿滑性能.     

高乙烯基SSBR的制备及性能研究

采用自制环醚调节剂(调节剂T),以正丁基锂为引发剂,以环己烷-己烷为溶剂,采用阴离子聚合法合成高乙烯基溶聚丁苯橡胶(SSBR),并对其性能进行研究.结果表明,调节剂T具有较好的乙烯基含量调节能力,在用量较小的情况下即可合成高乙烯基SSBR;与中低乙烯基SSBR相比,高乙烯基SSBR具有良好的物理性能、优异的抗湿滑性能和较低的滚动阻力及生热.     

以2G－（i—Bu）_3Al为复合调节剂合成中乙烯基聚丁二烯

本文是以３－ＢｕＬｉ为引发剂，以２Ｇ和（ｉ－Ｂｕ）３Ａｌ为调节剂，环己烷为溶剂的丁二烯阴离子聚合．以合成中乙烯基型聚丁二烯。研究了Ａｌ／Ｌｉ与聚合反应速率及聚合物微观结构的关系。结果表明：随Ａｌ／Ｌｉ的增加，聚合速率下降，而对聚合物的微观结构影响较小。求得了聚合假一级表观增长速率常数ｋｐ及表观增长活化能Ｅｐ     

结构调节剂对锂系溶聚丁戊橡胶微观结构的影响

以正丁基锂为引发剂,环己烷/己烷混合溶剂为溶剂,四氯化硅为偶联剂,THF(四氢呋喃)、ESM(乙二醇二基叔丁基醚)为极性调节剂,分别进行了均聚和丁二烯、异戊二烯共聚实验,研究了调节剂种类及用量对聚合物微观结构的影响。研究结果表明:改变调节剂的种类及用量,可改变聚合物中乙烯基结构含量;调节能力为ESM>>THF,反应得到无规共聚物。     

High vinyl high styrene solution SBR

Objective: the objective of this study is to prepare high vinyl copolymers containing various levels of styrene and butadiene, and also to prepare random butadiene in high styrene content styrene-butadiene copolymers (SBR) while controlling the styrene block length. These materials could be used in race tread applications. Summary: This reports presents the synthesis and characterization of random, high vinyl copolymers containing styrene and butadiene (SBR's). The styrene content of these SBR's ranged from 10 to 80%. These SBR's were synthesized via anionic polymerization initiated by a catalyst system with a ratio of 1/0.4/5 of n-butyllithium (n-BuLi) to sodium dodecylbenzene sulfonate (SDBS) to N,N,N′,N′-tetramethylethylenediamine (TMEDA). Kinetic data as well as NMR and ozonolysis techniques confirm that random SBR copolymers are being produced for low styrene content polymers. The glass transition temperature (T_g), increased dramatically as the styrene content was increased. The amount of vinyl based upon the polymer's total composition within the copolymer was found to decrease linearly as you increase the amount of styrene in the polymer. TGA results show that high styrene content polymers degrade at lower temperatures. The RPA confirms that as the styrene content increases, the elastic modulus decreases. As the frequency increased, the tan delta decreased for each polymer. Tan delta does not appear to be a function of styrene content. TEM results helped to describe polymer microstructure.     

Preparation of copoly(vinyl alcohol–styrenesulfonic acid) resin and its catalytic activity on hydrolysis of carbohydrates. II. Two-step polymerization using tetraethylthiuram disulfide as an initiator

Copoly(vinyl alcohol–styrenesulfonic acid) resin was prepared by a two-step polymerization, consisting of a suspension polymerization of styrene containing divinylbenzene using tetraethylthiuram disulfide as an initiator and a subsequent block copolymerization of vinyl acetate to the crosslinked polystyrene obtained, followed by sulfonation and saponification. Some reaction conditions in the polymerization of styrene were investigated to obtain copolymer containing more vinyl alcohol units. The catalytic activity of the copolymer on the hydrolysis of dextrin was investigated and found to be increased with increasing amount of vinyl alcohol units and with a lowering degree of crosslinking of the copolymer. The maximum acceleration of rate obtained in the presence of the copolymer was about six times that in the presence of Amberlite 120B. Catalytic activity of the copolymer on hydrolysis of sucrose and methyl acetate were also investigated and found to be comparable each other and lower than that for dextrin. The difference between the activities for dextrin and for sucrose and methyl acetate increased with an increasing amount of vinyl alcohol units in the copolymer.     

溶剂对低1,2—结构无规溶聚丁苯橡胶合成的影响

研究了不同溶剂对低１ ,２－ 结构含量无规溶聚丁苯橡胶合成的影响, 比较了在不同溶剂中溶聚丁苯橡胶的单体分布、微观结构、相对分子质量分布、共聚合速度和产物的物理机械性能。结果表明,在环己烷或环己烷／ 正己烷混合溶剂中制得的溶聚丁苯橡胶较在抽余油中制得的溶聚丁苯橡胶具有更好的物理机械性能     

表面活性剂对疏水改性丙烯酰胺共聚物增粘性能的影响

采用自由基胶束聚合法合成丙烯酰胺/丁基苯乙烯疏水缔合水溶性共聚物(PSAM),所用的十二烷基硫酸钠(SDS)、辛基酚聚氧乙烯醚(OP-10)和十六烷基三甲基溴化铵(CTAB)能显著影响疏水单体在聚合产物中的含量,从而影响聚合物的溶液粘度,其中以SDS合成得到的产物的溶解性及增粘性能最好。另外,少量表面活性剂的加入能显著地提高聚合物亚浓溶液的粘度,在十二烷基苯磺酸钠(SDBS)、SDS和CTAB中,SDBS对聚合物亚浓溶液粘度的影响最大,其浓度为0.7 mmol/L时,0.3 g/dL PSAM溶液的表观粘度从237 mPa.s上升到981 mPa.s。     

Effect of composition on the solution rheology of stearyl methacrylate‐co‐styrene‐co‐vinyl pyrrolidinone in paraffinic base oil

The rheological behavior of dilute and semi‐dilute solutions of stearyl methacrylate‐co‐styrene‐co‐vinyl pyrrolidinone copolymers (SMA‐S‐VP) was investigated over a wide range of temperatures (20–140°C) under steady shear (0.1–5000 s^?1) and dynamic conditions (0.01–500 rad/s). The solvent used was polyalpha olefin, PAO4 (C20‐C40 fraction), a fully synthetic paraffinic oil normally used as base oil for lubricant oil formulations. The investigation focuses on the effect of the polar comonomer segment content, of the copolymer, on the viscosity‐temperature relationship of the solution. This information provides insight into the effect of polymer microstructure on the viscosity index (VI) behavior of the lubricant. Copolymers with different ratios of stearyl methacrylate, styrene and vinyl pyrrolidinone were synthesized by solution radical polymerization. The microstructure and molecular weight of the copolymers were evaluated by nuclear magnetic resonance spectroscopy (NMR). The molecular weight and polydispersity of the polymers were determined using GPC. The polymer solutions exhibit non‐Newtonian behavior, which is more evident at lower temperatures and higher concentrations. The temperature‐concentration superposition principle developed by Ferry (1) was applied to steady shear data and the resulting master curve was fitted to the Carreau model. A modified Fedors equation for intrinsic viscosity calculation, at low and moderate polymer solution concentrations, was used. The results confirm that the viscosity index improver properties (VII) of the copolymer are superior when the VP content is low. The polymer‐solvent interactions and solvency power of PAO4 were analyzed using an Arrhenius expression. The results show that at low VP content, PAO4 is a better solvent for the copolymer. Polym. Eng. Sci. 44:736–748, 2004. © 2004 Society of Plastics Engineers.     

Using heavy ethers as structure modifiers in the synthesis of SBS block copolymers in cyclohexane

Heavy ethers—diethoxyethane (DIOXO) and triethylorthoacetate (TEOA)—were evaluated and compared with monoethers such as tetrahydrofuran (THF) and diethylether (DEE) as structure modifiers during the synthesis of linear styrene-butadiene block copolymers of polyA-block-polyB-block-polyA type (SBS). A smaller amount of a heavy ether than a monoether was needed to achieve the same targeted content of the 1,2-polybutadiene (vinyl) microstructure. The vinyl content increased from 10 to 71% with increase in the amount of TEOA from 10 ppm to 1 wt %, while the trans-1,4 and cis-1,4 units decreased. Similarly, increasing the amount of DIOXO from 10 ppm to 1 wt % increased the vinyl content from 17 to 89%. TEOA, 300 ppm, or DIOXO, 50 ppm, were suggested for making an SBS copolymer with a targeted 40% vinyl content. The addition of heavy ethers as structure modifiers also increased the rates of polymerization for both styrene and butadiene. Among all ethers, DIOXO enhanced the rate of butadiene polymerization the most, whereas TEOA caused the highest rate of styrene polymerization. Heavy ethers accelerated the rates of polymerization more than did monoethers. Furthermore, for an SBS polymer synthesized via a sequential method, the addition of heavy ethers enhanced the crossover efficiency, resulting in a narrower molecular weight distribution with a lower polydispersity. For an SBS polymer made via a coupling method, the coupling efficiency decreased and varied with the type of the coupling agent used. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2543–2560, 1997