摘要
三(二苯甲酰甲烷)苯氧基钛酸酯[(dbm)3Ti(OPh)]在MAO作用下,催化p-甲基苯乙烯间规聚合。讨论了催化剂浓度、铝钛比和聚合温度对反应的影响;在催化剂浓度为350μmol/L、铝钛比为500时,聚合活性最大为7.5×105g/molTi.h。聚合物有两个熔点183℃、203℃,分别对应晶型和晶型,玻璃化转变温度为108℃左右。同时考察了在此催化体系下p-甲基苯乙烯与苯乙烯间规共聚的情况,苯乙烯和p-甲基苯乙烯的竞聚率分别为0.287、1.806。
The syndiotactic polymerization of p-methylstyrene was carried out with Ti(dibenzoylmethanato)_3(OPh) [(dbm)_3Ti(OPh)]/methylaluminoxane (MAO) catalytic system. The copolymerization of p-methylstyrene and styrene was also investigated using this catalyst system. The ()^(13)C-NMR spectra of these homopolymers and copolymers indicates that the polymers are highly syndiotactic. The changes of homopolymerization activity depend on the polymerization conditions. When the C(Ti) is 350 μmol/L, and the Al/Ti molar ratio is 500, polymerization activity is up to (7.5)×10~5 gPPMS/molTi·h, reaching the maximum value. The polymerization activity is increased with the enhancement of temperature from 20 ℃ to 100 ℃. But the syndiotacticity and the melting temperature is decreased in the certain range. In copolymerization of p-methylstyrene and styrene, the monomer reactivity ratios are estimated by using the Fineman-Ross method r__1=(0.287), r__2=(1.806), r__1×r__2=(0.518).
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2005年第3期103-105,109,共4页
Polymer Materials Science & Engineering
基金
国家自然科学基金资助项目(50273009)
关键词
间规聚合反应
共聚合
户-甲基苯乙烯
苯乙烯
β-二酮钛配合物
竞聚率
Syndiotactic polymerization
copolymerization
p-methylstyrene
styrene
β-diketonate titanium complex
reactivity ratio
