复合调节体系对合成SBS微观结构及反应速率的影响

通过活性阴离子聚合手段,以正丁基锂为引发剂、环己烷为溶剂,合成苯乙烯-丁二烯-苯乙烯三元嵌段共聚物(SBS).分别研究了单一调节剂四氢呋喃(THF)、复合调节体系四甲基乙烯基二胺(TMEDA)与THF、二乙二醇二甲醚(2G)与THF对SBS微观结构的影响.结果表明,在聚合温度为60℃,苯乙烯(St)与丁二烯(Bd)质量...     

用偶联法合成极性官能化苯乙烯-丁二烯-苯乙烯嵌段共聚物

以环己烷为溶剂、正丁基锂为引发剂、环氧氯丙烷为偶联剂合成了极性官能化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS),研究了偶联剂用量、偶联反应的温度和时间及苯乙烯-丁二烯活性双嵌段聚合物(SB)的分子量对偶联反应的影响,以及偶联效率对极性官能化SBS力学性能的影响。结果表明,偶联效率随偶联剂用量增加和偶联温度升高而先升高后降低;随着SB数均分子量的增大,偶联效率逐渐降低。当偶联剂与正丁基锂的摩尔比为0. 6、偶联温度为80～90℃时偶联效率最大,可达80%以上,且偶联反应可在5 min内完成。极性官能化SBS的力学性能要优于市售线型SBS。     

苯乙烯-丁二烯-苯乙烯嵌段共聚物的加氢反应及产品性能

讨论了温度和压力在苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)加氢过程中对聚丁二烯链段中乙烯基及顺式-1,4-结构和反式-1,4-结构加氢速率的影响,比较了不同反应器对加氢反应的影响,考察了加氢前后SBS相对分子质量及其分布、动态力学性能、形态及力学性能的变化.结果表明,当反应温度为50～70 ℃和压力大于2.0 MPa...     

溶胀接枝法制备具有微-纳米表面结构的苯乙烯-丁二烯-苯乙烯接枝共聚物(英文)

中对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)与马来酸酐进行了溶胀接枝反应,当接枝率控制在11.5%时可以获得微-纳米表面粗糙结构的接枝聚合物,水在SBS接枝共聚物的表面接触角明显减小。关键词:苯乙烯-丁二烯-苯乙烯嵌段共聚物;溶胀接枝法;微-纳米表面结构;表面接触角     

~1H-NMR法测定苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物的加氢度和微观结构

采用核磁共振氢谱(1H-NMR)法测定苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)的加氢度和微观结构。结果表明,采用镍系催化剂对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行加氢反应制备SEBS时,在苯乙烯链段未参与加氢反应的前提下,通过对SBS和SEBS的谱峰进行归属,建立了用1H-NMR测定SEBS总加氢度的方法,且无需已知苯乙烯的摩尔分数,适用范围较宽;用该法还可直接得到SEBS中各微观结构含量和丁二烯1,2-结构和1,4-结构的加氢度。     

活化条件对二氯二茂钛/正丁基锂催化苯乙烯-丁二烯-苯乙烯嵌段共聚物加氢反应的影响

以二氯二茂钛(Cp2TiCl2,简称Ti)为催化剂、n-BuLi为引发剂,对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行加氢反应制备苯乙烯-乙烯/丁烯-苯乙烯三嵌段聚合物(SEBS),考察了活化过程中氢气压力、活化时间、n-BuLi用量等条件对SBS加氢反应的影响。结果表明,在溶有10 g SBS干胶的200 mL环己烷溶剂中,Ti催化剂的加入量为0.025 mmol、氢气压力为1.6 MPa、浓度为2.5 mol/L的n-BuLi用量为3 mL、活化时间为3 h以及活化温度为25℃的条件下,SEBS的加氢度可以达到67.0%以上。     

苯乙烯-丁二烯-苯乙烯嵌段共聚物的中试连续镍系加氢反应及反应器的放大模型

采用镍系催化剂对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行加氢,分析了SBS中不同微观结构的加氢反应动力学,研究了SBS中试连续加氢反应中各反应器的反应效率,提出了中试第1反应器的放大模型,并与实际值进行了比较.结果表明,乙烯基与反式-1,4-结构的反应活化能分别为20.3,24.7 kJ/mol;延长反应时间有利...     

苯乙烯-丁二烯-苯乙烯嵌段共聚物极性化研究进展

综述了苯乙烯-丁二烯-苯乙烯嵌段共聚物极性化在大分子化学改性和负离子原位聚合改性这两种方法中的研究进展,详细阐述了两种方法的技术手段及优缺点,并对极性化后SBS的应用进行简单概述.     

在超临界:氧化碳中制备具有微/纳米表面结构的苯乙烯-丁二烯-苯乙烯嵌段共聚物接枝马来酸酐

在超临界CO2中进行了苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)与马来酸酐(MAH)的接枝反应,用扫描电子显微镜对接枝共聚物进行了表征.结果表明,控制适当的接枝率,可以分别得到具有皱折型和乳突型的微/纳米表面粗糙结构的接枝共聚物.     

丁二烯-苯乙烯共聚物改性沥青的研究进展

介绍了丁二烯-苯乙烯共聚物改性沥青的发展状况,分析了聚合物改性剂苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)、丁苯橡胶(SBR)与基质沥青的分散性、溶胀性和相容性问题,着重论述了丁二烯-苯乙烯共聚物化学改性沥青的可能性。指出SBS、SBR与沥青适当相容并达到均匀分散,是充分发挥改性效果的前提;化学改性以及复合改性技术是提高沥青性能的重要手段。     

Radiation-induced graft polymerization of 4-vinyl pyridine to styrene–butadiene–styrene triblock copolymer

The radiation-induced graft polymerization of 4-vinyl pyridine to styrene–butadiene–styrene triblock copolymer (SBS) was investigated. Relations between the rate of grafting and the dose rate when SBS was irradiated in 4-vinyl pyridine–methanol solution, and between the rate of grafting and 4-vinyl pyridine concentration of 4-vinyl pyridine–methanol solution have been investigated. An experiment that had been carried out on SBS immersed in various 4-vinyl pyridine concentration of 4-vinyl pyridine–methanol solutions showed that the extent of swelling of SBS by the various 4-vinyl pyridine–methanol solutions increased with increasing 4-vinyl pyridine concentration. The largest rate was found at 20 vol % 4-vinyl pyridine–methanol solution. The rate was smaller at the volume percent of 4-vinyl pyridine higher or lower than 20 vol %. On the assumption that the theory of homogeneous homopolymerization could be applied to this grafting reaction, the value of k_p²/k_t was obtained, where k_p and k_t are the propagation and termination constant, respectively. The value of k_p²/k_t greatly decreased with increasing adsorbed concentration of vinyl pyridine–methanol solution. This decrease of k_p²/k_t was explained by the fact that 4-vinyl pyridine and methanol absorbed in SBS acted as a plasticizer which increased the molecular motion of the polymer. The solvent effect on the graft polymerization was also investigated. The result was explained by solubility parameter. When the chosen solvent had better solubility with the polymer, the degree of grafting was smaller. That was connected with the extent of the polymer chain mobility.     

In-situ IR Monitoring the Synthesis of Amphiphilic Copolymery P(HEMA-co-tBMA) via ARGET ATRP

The amphiphilic copolymer poly(hydroxyethyl methacrylate-co-tert-butyl methacrylate) [P(HEMA-co-tBMA)] was synthesized by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), with the synthesis process monitored by in-situ infrared spectroscopy (IR). The molecular weight, chemical structure and characteristics of the copolymer were determined by 1H NMR, gas chromatography and gel permeation chromatography. The influences of various parameters on the living polymerization were explored. The molecularweight of the copolymer with narrowmolecularweight distribution (M_w/M_n b 1.50) increases approximately linearly with the monomer conversion, indicating a good control of polymerization. In the reaction temperature range from 50℃ to 90℃, the monomer conversion is higher at 60℃. The tBMA conversion rate decreases gradually with the increase of tBMA content, while the HEMA conversion is hardly affected by HEMA content. Weak polar solvent is more favorable to the polymerization compared to polar solvent. The molar ratio of reducing agent to catalyst has significant effect on the polymerization and increasing the amount of reducing agent will accelerate the reaction rate but causes wider molecular weight distribution. It is indicated that in-situ IR monitoring contributes to a more in-depth understanding of the mechanism of methacrylate monomer copolymerization.     

P2VP-b-PS-b-PI三嵌段共聚物的RAFT合成及表征

以S-十二烷基-S’-(α,α’-二甲基-α’’-乙酸)-三硫代碳酸酯(DDMAT)为链转移剂,通过可逆加成-断裂链转移自由基聚合(RAFT)方法制备了窄分布的聚2-乙烯基吡啶。再以该聚合物为大分子链转移剂,引发苯乙烯的RAFT聚合,得到聚2-乙烯基吡啶-b-聚苯乙烯(P2VP-b-PS)的两嵌段共聚物。以P2VP-b-PS为RAFT试剂,合成聚2-乙烯基吡啶-b-聚苯乙烯-b-聚异戊二烯(P2VP-b-PS-b-PI)的三嵌段共聚物。运用1H NMR、IR和凝胶渗透色谱(GPC)等技术对产物的结构和分子量及分子量分布进行表征,采用原子力显微镜(AFM)观察三嵌段共聚物薄膜的微相分离结构。结果表明,所得三嵌段共聚物P2VP72-b-PS136-b-PI300分子量分布较窄(PDI=1.69),合成过程具有活性/可控聚合特征,聚合物薄膜经溶剂退火处理后出现了明显的微观相分离结构。     

SBS/VP homograft membrane for oxygen enrichment

The grafting of 4-vinyl pyridine (VP) onto styrene-butadiene-styrene triblock copolymers (SBS) by homografting irradiation with dissolved oxygen was studied. Homograft membranes of various degree of grafting were prepared from a casting solution of grafted copolymer in benzene. The mechanical properties of membranes, gas permeability, and the effect of operating temperature on gas permeation were investigated. The degree of grafting of 8.4% was the largest at an irradiation time of about 15.5 h. It was smaller at both shorter and longer duration because of the interference of dissolved oxygen. It was found that the tensile strength and elongation of SBS-g-VP were similar to those of SBS. The stress relaxation of SBS-g-VP was slower than that of SBS, and this might be due to the formation of rigid microphase separation domain of poly(4-vinyl pyridine), which acted as permanent crosslinking points to reduce the stress relaxation. Using the properties of high flux of SBS and high O₂/N₂ selectivity of poly(4-vinyl pyridine), the performance of gas permeation of 4-vinyl pyridine homografted SBS membrane was studied. The selectivity of SBS-g-VP membrane increased with increasing degree of grafting. However, it was done at the expense of a decrease in the gas permeability. When the operating temperature of gas permeation increased, the permeability of oxygen and nitrogen increased, and the O₂/N₂ permeability ratio decreased. The activation energy (Ep) for gas permeation through different degree of grafting of SBS-g-VP membrane (obtained by the Arrhenius law) increased with increasing degree of grafting. For ungrafted SBS membrane, Ep was 5.5 kcal/mol for oxygen and 7.2 kcal/mol for nitrogen. For 8.4% grafting degree SBS-g-VP membrane, Ep for oxygen and nitrogen, were 6.5 and 8.1 kcal/mol, respectively.     

环氧化SDS型热熔压敏胶的制备及粘接性能研究

采用苯乙烯-丁二烯-苯乙烯(SBS)和苯乙烯-异戊二烯-苯乙烯(SIS)嵌段共聚物,并配合极性的环氧化SBS(ESBS)和环氧化SIS(ESIS)作为基体材料,制备了环氧化SDS(苯乙烯系热塑性弹性体)型热熔压敏胶。研究了ESBS和ESIS用量对压敏胶的初粘力、持粘力和在不同极性底材上剥离强度的影响。结果表明,随着ESBS和ESIS用量的增加,压敏胶的初粘力和持粘力下降,在聚乙烯(PE)上的剥离强度下降,但在聚氯乙烯(PVC)和不锈钢上的剥离强度先增加后下降。当ESBS和ESIS的质量份数均为20份时,压敏胶的初粘力和持粘力分别为23#和43.6 h,在PVC和不锈钢底材上的剥离强度分别达到0.82 N/mm和1.10 N/mm。     

顺酐化苯乙烯-丁二烯-苯乙烯嵌段共聚物离聚体的制备及其结构和性能

在甲苯/环己烷混合溶剂体系中考察了顺酐化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)的制备条件,得到马来酸酐/SBS/过氧化苯甲酰质量比为30/100/1、SBS质量浓度为0.10 g/mL、过氧化苯甲酰/甲苯引发液的滴加时间为10 min及75 ℃下反应4 h的较为理想的反应条件.在此条件下既可以避免凝胶的生成,又可获得较高的接枝率(6.87%).所得顺酐化SBS经氢氧化钠溶液中和后生成钠离聚体,傅里叶变换红外光谱分析证实接枝反应和离聚体的合成均得到预期的产物.差示扫描量热分析结果表明离子化微区的存在使得离聚体在高温段有1个玻璃化转变温度.离聚体的拉伸强度、搭接剪切强度和乳化性能均随顺酐化程度的提高而改善.     

淀粉基湿法磷酸防沉降剂的合成及性能研究

采用水溶液聚合法,以淀粉为基体,以丙烯酸丁酯和腐植酸为单体,合成具有一定相对分子质量的聚合物。考查反应温度、单体质量比以及引发剂用量对聚合物相对分子质量的影响;同时研究聚合物加入量对湿法磷酸沉淀生成的影响。结果表明:在反应温度60℃、单体质量比0.65∶1.00、引发剂用量8%的反应条件下,聚合所得到的防沉降剂对湿法磷酸防沉降效果最佳。其中加入质量分数6‰的聚合物时其防沉降效果最好。     

聚丙烯酸铵水溶液聚合研究

采用水溶液聚合法合成聚丙烯酸铵,考察了温度、EDTA、引发剂、NaCl、聚合时间、链转移剂以及单体浓度对聚丙烯酸铵相对分子量的影响。结果表明,最佳聚合条件为:反应温度30℃,EDTA用量0.03%,引发剂用量0.03%,NaCl用量0.6%,反应时间3 h,单体浓度50%,链转移剂用量0.7%。在此条件下,合成的聚丙烯酸铵相对分子量为1 905万,且具有良好的溶解性能。     

AA-AMPS共聚物陶瓷分散剂的制备及分散性能

以丙烯酸和2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)为单体,过硫酸铵(NH4)2S2O8作为引发剂,次亚磷酸氢钠作为链转移剂,通过自由基聚合反应合成共聚物PAA-AMPS。探讨了不同反应条件对共聚物分散性能的影响,共聚物分散剂PAA-AMPS的最佳合成条件为:丙烯酸(AA)与2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)的摩尔比为8∶1;引发剂(NH4)2S2O8用量为单体总质量的1%;链转移剂次亚磷酸氢钠的用量为单体总质量的10%;单体质量分数为24%;反应温度85℃。通过FTIR、GPC及1HNMR等手段对共聚物的结构及相对分子质量及其分布进行了表征,并对添加不同量分散剂的料浆的黏度进行研究。结果表明,聚合物质量分数为0.3%,料浆的黏度最低,与进口产品PC-67(PAA-Na)相比,共聚物PAA-AMPS的分散效果更好。     

丙烯酰胺-丙烯酸钠反相微乳液体系制备聚合物纳米粒子

采用工业煤油/丙烯酰胺-丙烯酸钠/Span80(山梨糖醇酐油酸脂)-Tween60(聚氧乙烯失水山梨醇硬脂酸酯)反相微乳液体系制备聚合物纳米粒子。通过红外光谱、13C核磁共振、凝胶渗透色谱、透射电镜对其进行表征,着重研究共聚物结构、形态、黏均分子量大小和分布情况。结果表明：在40 ℃下,乳液稳定的最佳HLB值为9时,单体占水相总质量的40%,(NH)4S2O8-NaHSO3引发剂占单体总质量的0.7‰,得均一稳定透明的微乳液。产物为丙烯酰胺-丙烯酸钠共聚物,黏均分子量为5.0×105 g/mol,粒子分布均匀,呈规则球形,达到纳米级别。