论文成果
Neodymium-Mediated Coordinative Chain Transfer Polymerization of Isoprene in the Presence of External Donors
点击次数:
关键字:RING-OPENING POLYMERIZATION; RARE-EARTH BOROHYDRIDES; STRAIGHTFORWARD ACCESS; COPOLYMERIZATION; CATALYST; 1,3-BUTADIENE; STYRENE; CIS; POLYBUTADIENE; POLYISOPRENE
摘要:Nd-based polydiene elastomers, including NdIR and NdBR, are regarded as indispensable key raw materials in preparing green tires with excellent performance capabilities, but their wide application is still limited by the relative higher cost of Nd precatalysts. Nd-mediated coordinative chain transfer polymerization (CCTP) of diene provides an effective strategy to reduce the precatalyst cost, because this method involves very high atom economy, i.e., each Nd molecule can generate multiple polymer chains. Nevertheless, all possible factors that could influence such CCTP behaviors are still mostly unexplored to date. In this report, the basic chemistry on the influence of external donors on the overall CCTP behaviors of isoprene was established for the first time. It was found that increasing the amount of external donors had a negative influence on the chain transfer efficiencies, resulting in gradually decreasing atom economies. Catalyst addition order studies revealed that the coordination of donors with cationic Nd active species, rather than alkylaluminium CTAs, contributed mostly to such decreased efficiencies. Moreover, it was found that when the ratio of donors and Nd compounds was higher than 1.0, the CCTP behaviors were corrupted, resulting in polymers with broad distributions, as well as resulting in low atom economies; nevertheless, when the ratio was lower than 0.5, the system still displayed CCTP characteristics, implying that the critical ratio for maintaining the CCTP was 0.5. Additionally, when such a ratio was 0.01, the high atom economy was almost the same as donor-free CCTP systems. Detailed kinetic studies at such a ratio demonstrated that the donor-contained system proceeded in a well-controlled manner, as concluded from the good linear relationship between the Mn of the PIps against the polymer yields, as well as the good linearity between the Mn against the (IP)/(Nd) ratios. Such maintained CCTP properties also allowed for seeding two-step polymerizations to prepare diblock copolymers with precisely controlled molecular weights. Expanding the types of donors to more phosphine, oxygen, and nitrogen containing compounds showed that they also affected the CCTP behaviors depending on their steric and electronic properties.
卷号:28
期号:21
是否译文:

张春雨

教授 博士生导师 硕士生导师

教师拼音名称:zhangchunyu

出生日期:1978-11-30

电子邮箱:

入职时间:2019-11-28

所在单位:先进橡胶材料教育部重点实验室

学历:博士研究生

办公地点:国家大学科技园北楼702 CCF大楼1517室

性别:男

联系方式:13844852208

学位:理学博士

毕业院校:吉林大学

所属院系:先进橡胶材料教育部重点实验室

学科:材料科学与工程其他专业
高分子化学与物理

崂山校区 - 山东省青岛市松岭路99号   
四方校区 - 山东省青岛市郑州路53号   
中德国际合作区(中德校区) - 山东省青岛市西海岸新区团结路3698号
高密校区 - 山东省高密市杏坛西街1号   
济南校区 - 山东省济南市文化东路80号©2015 青岛科技大学    
管理员邮箱:master@qust.edu.cn
访问量: 手机版 English 青岛科技大学

最后更新时间: ..