单茂钪催化剂(C_5H_5)Sc(CH_2C_6H_4NMe_2-o)_2合成高顺式窄分布聚丁二烯  

Synthesis of High cis-1,4 Polybutadiene with Narrow Molecular Weight Distribution Catalyzed by a Half-sandwich Scandium Catalyst(C_5H_5)Sc(CH_2C_6H_4NMe_2-o)_2

作　　者：史正海[1] 孟蕊[1] 郭方[1] 许蔷[1] 李婷婷[1] 李杨[1] 王玉荣[1] 

机构地区：[1]大连理工大学化工学院高分子材料系精细化工国家重点实验室,大连116024

出　　处：《高分子学报》2014年第10期1420-1427,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金重点项目(基金号21034001);中央高校基本科研业务费专项资金(项目号DUT12RC(3)94)资助

摘　　要：合成了6种单茂稀土催化剂Cp’LnR2（THF）n（其中,Cp’=C5H5,C5Me4SiMe3;R=CH2C6H4NMe2-o,CH2SiMe3;Ln=Sc,Y,Lu;n=0或1）,并以[Ph3C][B（C6F5）4]为助催化剂,甲苯为溶剂,考察催化剂结构对丁二烯聚合活性,立体选择性,催化剂利用率以及聚合物分子量和分子量分布的影响.通过1H-NMR,13C-NMR,FTIR,GPC以及DSC对聚丁二烯进行表征,结果表明,当Cp’=C5H5,R=CH2C6H4NMe2-o,Ln=Sc,n=0时,催化剂（C5H5）Sc（CH2C6H4NMe2-o）2对丁二烯聚合活性最高,可达9600 kg-polymer/mol-Sc·h,催化剂利用率为45%,聚丁二烯顺-1,4结构含量在96%~98%之间,分子量分布窄,指数在1.3左右;以甲苯或氯苯作为聚合溶剂时,聚合活性最高,聚丁二烯分子量保持窄分布,在所有溶剂中聚丁二烯顺-1,4结构含量均达到96%以上;催化剂聚合活性随温度下降而降低,而聚合物分子量分布有变窄的趋势,温度对聚丁二烯立体选择性无明显影响;当[Bd]/[Sc]摩尔比从500增加到3000时,聚合反应1 min转化率均达到100%,聚丁二烯分子量呈可控线性增大,最高达44.6×104,且均保持聚合物窄分布.DSC谱图表明聚丁二烯Tg为-107℃,当升降温速率为10 K/min时,在-63℃和-8℃附近呈现出明显的冷结晶峰和熔融峰.Six half-sandwich rare earth catalysts Cp’ LnR2（THF）n（Cp’ = C5H5,C5Me4SiMe3; R =CH2C6H4NMe2-o,CH2SiMe3; Ln = Sc,Y,Lu; n = 0 or 1） have been synthesized for polymerization of butadiene activated with [Ph3C][B（C6F5）4]in toluene. The polymerization activity,stereoselectivity,catalyst efficiency,molecular weight and molecular weight distribution have been studied with these catalysts. The obtained polybutadiene was characterized by1H-NMR,13C-NMR,FTIR,GPC and DSC. The results revealed that catalyst（C5H5）Sc（CH2C6H4NMe2-o）2shown the highest activity（ up to 9600 kg-polymer /mol-Sc·h）,better catalyst efficiency（45%）,high cis-1,4 selectivity（ cis-1,4 content 〉 96%） and narrow molecular weight distribution（PDI ca. 1. 3）. The polymerization activity was high when the polymerization was carried out in toluene or chlorobenzene and decreased with the polymerization temperature reduction. Solvents and polymerization temperature have no obviously effects on the structure of polybutadiene. When the [Bd]/[Sc]molar ratio ranged from 500 to 3000,the molecular weight of polybutadiene has increased linearly（up to 44. 6× 104） with the constant low molecular weight distribution. The results indicated that the molecular weight and molecular weight distribution of polybutadiene could be well controlled. The glass transition temperature of polybutadiene was- 107 ℃,and there are also two distinct peaks at- 63 ℃ and- 8 ℃ shown in DSC curves at a heating /cooling rate of 10 K /min,corresponding to the cold crystallization and melting behavior of polybutadiene.

关 键 词：稀土催化剂 钪 高顺-1 4聚丁二烯 丁二烯 

分 类 号：O632.14[理学—高分子化学]