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1.
以正丁基锂(简称Li)为主引发剂、二乙二醇单乙醚基钡(简称Ba)和三异丁基铝(简称Al)为助引发剂、环己烷为溶剂,对异戊二烯(Ip)聚合反应动力学及产物的微观结构进行了研究。结果表明,在Ba/Al/Li引发的聚合体系中,Ip的聚合反应速率与单体浓度呈动力学一级反应关系,假一级表观增长反应速率常数和表观增长反应活化能均与引发体系的三组分摩尔比相关;Al是引发体系中重要的活性组分,且随Ba/Al/Li引发体系中Al用量的增加,聚合反应速率先升高后下降,当Ba/Al/Li(摩尔比)为1/4/4时,聚合反应速率达到最大;Ba在调节聚异戊二烯反式-1,4-结构摩尔含量中的作用大于Al;聚合温度对聚合产物微观结构含量基本无影响。  相似文献   

2.
以二乙二醇单乙醚基钡(简称Ba)/三异丁基铝(简称Al)/正丁基锂(简称Li)为三元引发体系,采用负离子聚合法合成了高反式苯乙烯-异戊二烯(Ip)-丁二烯(Bd)三元共聚物(SIBR),考察了引发剂组分、单体配比和聚合温度对SIBR微观结构的影响,并研究了Al/Li(摩尔比)和Bd/Ip(质量比)对SIBR结晶行为的影...  相似文献   

3.
以环己烷为溶剂,正丁基锂(简称Li)为主引发剂,加入有麝香草酚钡(简称Ba)和三异丁基铝(简称Al)形成的复合引发剂体系,合成了中反-高反的嵌段聚丁二烯(PB)。通过改变Ba和Al的加入时间合成了不同结构的嵌段中反-高反PB,研究了不同引发剂添加量对嵌段中反-高反结构与玻璃化转变温度(Tg)的影响。结果表明,均聚物高反式PB只有1个Tg,为-86.9℃,而嵌段PB则有2个Tg,分别为-92.7℃和-32.7℃;随着高反式嵌段含量的减少,PB总的反式结构含量降低,但高反式嵌段的反式结构含量基本保持不变。  相似文献   

4.
对比研究了Nd(naph)3/Al(i-Bu)3/C60Cl20和传统的Nd(naph)3/Al(i-Bu)3/Al(i-Bu)2Cl催化合成的顺式-1,4-聚丁二烯的性能,前者所得聚丁二烯的数均分子量低,分子量分布窄,顺式-1,4-结构、凝胶含量高,具有较高的屈服强度及断裂强度,但其扯断伸长率有所减小,且耐老化性能更佳。  相似文献   

5.
以六亚甲基亚胺锂(LHMI)与二乙烯基苯(DVB)合成的氮官能化多锂(简称Li)为引发剂,N,N,N’,N’-四甲基乙二胺(TMEDA)为极性调节剂,环己烷为溶剂,制备了带有氮官能化基团的星形无规苯乙烯-异戊二烯-丁二烯共聚物(SIBR),用核磁共振法进行了表征,并分析了TMEDA用量、聚合温度、引发剂浓度及DVB/Li(摩尔比)对SIBR微观结构和玻璃化转变温度(Tg)的影响。结果表明,在DVB/LHMI(摩尔比)为0.8的条件下,SIBR中有C-N存在,并且为臂数不等的星形聚合物;随着TMEDA用量的增加和聚合温度的降低,SIBR中非l,4-结构含量增加,Tg提高;在实验范围内引发剂浓度和DVB/Li对SIBR中非1,4-结构含量和其,Tg影响不大。  相似文献   

6.
采用配位聚合引发体系环烷酸钴(简称Co)-三异丁基铝(简称Al)-二硫化碳(CS2)引发异戊二烯聚合制得3,4-聚异戊二烯(PIp),考察了聚合条件对单体聚合活性的影响,通过凝胶渗透色谱、核磁共振氢谱和差示扫描量热法表征了3,4-PIp的相对分子质量及其分布、微观结构及玻璃化转变温度(T g)。结果表明,在Co/Ip(摩尔比)为4.0×10-4、Al/Co(摩尔比)为55~65、CS2/Co(摩尔比)为15、聚合温度为40~50℃的条件下合成了3,4-结构(含1,2-结构)摩尔分数约为80%的非结晶材料PIp,其数均分子量为3.4×104,分子量分布指数为1.8,T g为-6.5℃。  相似文献   

7.
以六亚甲基亚胺锂(LHMI)与二乙烯基苯(DVB)合成的氮官能化多锂(简称Li)为引发剂,N,N,N′,N′-四甲基乙二胺(TMEDA)为极性调节剂,环己烷为溶剂,制备了带有氮官能化基团的星形无规苯乙烯-异戊二烯-丁二烯共聚物(SIBR),用核磁共振法进行了表征,并分析了TMEDA用量、聚合温度、引发剂浓度及DVB/Li(摩尔比)对SIBR微观结构和玻璃化转变温度(Tg)的影响。结果表明,在DVB/LHMI(摩尔比)为0.8的条件下,SIBR中有C—N存在,并且为臂数不等的星形聚合物;随着TMEDA用量的增加和聚合温度的降低,SIBR中非1,4-结构含量增加,Tg提高;在实验范围内引发剂浓度和DVB/Li对SIBR中非1,4-结构含量和其Tg影响不大。  相似文献   

8.
研究了六亚甲基亚胺基锂、氮锂和正丁基锂引发剂引发苯乙烯的聚合速率,合成了端基官能化苯乙烯-丁二烯-苯乙烯三嵌段聚合物(SBS)。结果表明,在设计相对分子质量相同的情况下。随着四氢呋喃加入量的增加,端基官能化SBS的1,2-结构质量分数增加,顺式-1,4-结构和反式-1,4-结构质量分数下降,但两者比值基本不变。相同条件下,用氮锂引发剂制备的端基官能化SBS的1,2-结构质量分数要略高于用正丁基锂引发剂制备的SBS。  相似文献   

9.
以三异丁基铝(简称Al)/磷酸(H3PO4)/1,8-重氮-双环[5.4.0]-7-十一碳烯(DBU)为催化体系、甲苯为溶剂,对环氧氯丙烷(ECH)/环氧乙烷(EO)/烯丙基缩水甘油醚(AGE)进行三元共聚合,考察了催化剂组分及其加料顺序、陈化温度和时间对三元共聚合反应的影响,并对合成的三元氯醚橡胶进行表征。结果表明,在H3PO4中H2O含量为0、H3PO4/Al(摩尔比)为0.35、DBU/Al(摩尔比)为0.5的条件下,采用Al+H3PO4+DBU的加料方式、陈化温度为60℃、陈化时间为2.0 h时,单体转化率可超过97%,所制得的三元氯醚橡胶是由EO、ECH和AGE这3种结构单元组成,当EO/ECH/AGE(摩尔比)为56/40/4时,玻璃化转变温度为-47.2℃。  相似文献   

10.
研究了以乙二醇二乙氨基乙基丁基醚(GABE)为调节剂,正丁基锂为引发剂的丁二烯负离子聚合的聚合动力学及聚合物的微观结构。结果表明,随着GABE用量的增加,丁二烯的聚合速率增加,聚丁二烯中1,2-结构质量分数增加,聚合温度升高,聚合速率增加,但聚丁二烯中1,2-结构质量分数有所降低。  相似文献   

11.
A series of high trans-1,4-low-cis-1,4-high trans-1,4-stereotriblock polybutadienes (HTPB-b-LCPB-b-HTPBs) were synthesized through a sequential anionic polymerization of butadiene (Bd) initiated by barium salt of di(ethylene glycol) ethylether/triisobutylaluminium/dilithium (BaDEGEE/TIBA/DLi). The polymers consisted of elastic low-cis-1,4-polybutadiene (LCPB) chemically bonded with crystallizable high trans-1,4-polybutadiene (HTPB). The block ratios (HTPB:LCPB:HTPB) were designed at 25:50:25 (molar ratio) and finally determined by SEC. The microstructures and sequences of the specimens were investigated by FTIR and NMR. The resultant HTPB-b-LCPB-b-HTPBs consisted of LCPB block with 52.5% trans-1,4 content and HTPB block with 55.9–85.8% trans-1,4 content. According to differential scanning calorimetry (DSC), HTPB-b-LCPB-b-HTPB showed a significant cold crystallization which was discussed in terms of entanglement concept. The cold crystallization temperature (Tcc) decreased whereas the melting temperature (Tm) increased with the increasing trans-1,4 content of HTPB block.  相似文献   

12.
以EDTA二钠盐、硝酸钠混合处理钯炭,钠盐处理后的钯炭对4-(4-丙基环己基)苯酚(3PCO)加氢制备4-(4-丙基环己基)环己酮(3 HHK)有很高的选择性,用质量比5%的EDTA二钠盐、2%硝酸钠混合处理钯炭,在高温高压下加氢,3 HHK的选择性达到60%以上。用GC检测加氢产品。  相似文献   

13.
3,6‐bi(4‐fluorobenzoyl)‐N‐methylcarbazole and 3,6‐bi(4‐fluorobenzoyl)‐N‐ethylcarbazole were synthesized and used to prepare poly(arylene ether ketone)s (PAEKs) with high glass transition temperatures (Tg) and good solubility. High molecular weight amorphous PAEKs were prepared from these two difluoroketones with hydroquinone, phenolphthalein, 9,9‐bis(4‐hydroxyphenyl)fluorene and 4‐(4‐hydroxylphenyl)‐2,3‐phthalazin‐1‐one, respectively. All these polymers presented high thermal stability with glass transition temperatures being in the range 239–303 °C and a 5% thermal weight loss temperature above 460 °C. Compared with the Tg of phenolphthalein‐based PAEK (PEK‐C), fluorene‐based PAEK (BFEK) and phthalazinone‐based PAEK (DPEK) not containing a carbazole unit, these polymers presented a 30–50 °C increase in Tg. Meanwhile, PAEKs prepared from N‐ethylcarbazole difluoroketone showed good solubility in ordinary organic solvents, and all polymers exhibited excellent resistance to hydrochloric acid (36.5 wt%) and sodium hydroxide (50 wt%) solutions. In particular, phthalazinone‐based PAEK bearing N‐ethylcarbazole afforded simultaneously a Tg of 301 °C with good solubility. Tensile tests of films showed that these polymers have desirable mechanical properties. The carbazole‐based difluoroketones play an important role in preparing soluble PAEKs with high Tg by coordinating the relationship between chain rigidity resulting from the carbazole unit and chain distance from the side alkyl. © 2014 Society of Chemical Industry  相似文献   

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