Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst ...Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...展开更多
Ethylene/norbornene(NBE)copolymers are the most representative and widely-used cyclic olefin copolymers(COCs).Higher NBE content in COCs leads to higher transparency,glass transition temperature and mechanical strengt...Ethylene/norbornene(NBE)copolymers are the most representative and widely-used cyclic olefin copolymers(COCs).Higher NBE content in COCs leads to higher transparency,glass transition temperature and mechanical strength,but also makes the COC more brittle and therefore hampers its end uses.In this study,to improve the brittleness of COCs while maintaining their high strength,heat-resistant and transparency,bimodal distributed COCs have been prepared via two selective catalysts reactive blending in one pot.The shape of the molecular weight distribution curves of the obtained COCs could be easily controlled by adjusting the proportion of the two catalysts.These COCs maintained high glass transition temperature,balanced tensile performance,high transparency.展开更多
Studies on transition-metal catalyzed olefin-polar monomer coordination copolymerization and their resulting polar-functionalized polyolefin materials have attracted attention from both academia and industry.After dec...Studies on transition-metal catalyzed olefin-polar monomer coordination copolymerization and their resulting polar-functionalized polyolefin materials have attracted attention from both academia and industry.After decades of research,recent developments in a variety of high-performance catalytic systems have shown that this field is on the brink of industrialization.This review summarizes representative olefin-polar monomer coordination copolymerization catalyst systems that may be suitable for industrial polyolefin production via homogeneous solution-phase processes or heterogeneous gas-phase/slurry-phase processes.展开更多
Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on th...Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on the acetoacetate-functionalized polyolefin copolymers, which were produced through the direct copolymerization of ethylene with polar comonomers using a phosphinesulfonate palladium catalyst. The pendant acetoacetate group could mediate several characteristic reactions, such as the Michael addition reaction, ketone-amine condensation and metal coordination reaction. As such, structurally adjustable polyolefin vitrimers can be accessed by introducing various dynamic crosslinking bonds, including disulfide exchange, transamination of vinylogous urethane and labile metal coordination bond. The utilization of different crosslinking reactions and the mole ratio of crosslinkers significantly impact the material properties of the resultant polymers. Specifically, the generated polyolefin vitrimers demonstrated excellent reprocessability and closed-loop recycling properties. The study in this work provides an efficient strategy to access various polyolefin vitrimers.展开更多
基金Grant-in-Aid for Scientific Research(B)from the Japan Society for the Promotion of Science(JSPS,No.18350055).
文摘Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...
基金subsidy provided by the National Natural Science Foundation of China(No.U1510124).
文摘Ethylene/norbornene(NBE)copolymers are the most representative and widely-used cyclic olefin copolymers(COCs).Higher NBE content in COCs leads to higher transparency,glass transition temperature and mechanical strength,but also makes the COC more brittle and therefore hampers its end uses.In this study,to improve the brittleness of COCs while maintaining their high strength,heat-resistant and transparency,bimodal distributed COCs have been prepared via two selective catalysts reactive blending in one pot.The shape of the molecular weight distribution curves of the obtained COCs could be easily controlled by adjusting the proportion of the two catalysts.These COCs maintained high glass transition temperature,balanced tensile performance,high transparency.
基金supported by the National Key R&D Program of China(grant no.2021YFA1501700)the National Natural Science Foundation of China(grant nos.52025031,22001004,52373002,U1904212,and 52203016).
文摘Studies on transition-metal catalyzed olefin-polar monomer coordination copolymerization and their resulting polar-functionalized polyolefin materials have attracted attention from both academia and industry.After decades of research,recent developments in a variety of high-performance catalytic systems have shown that this field is on the brink of industrialization.This review summarizes representative olefin-polar monomer coordination copolymerization catalyst systems that may be suitable for industrial polyolefin production via homogeneous solution-phase processes or heterogeneous gas-phase/slurry-phase processes.
基金supported by the National Natural Science Foundation of China (21971230, U19B6001)the Natural Science Foundation of Anhui Province (2308085Y35, 2023AH030002)+1 种基金the Hefei Natural Science Foundation (202304)the strong support from Professor Changle Chen (University of Science and Technology of China)。
文摘Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on the acetoacetate-functionalized polyolefin copolymers, which were produced through the direct copolymerization of ethylene with polar comonomers using a phosphinesulfonate palladium catalyst. The pendant acetoacetate group could mediate several characteristic reactions, such as the Michael addition reaction, ketone-amine condensation and metal coordination reaction. As such, structurally adjustable polyolefin vitrimers can be accessed by introducing various dynamic crosslinking bonds, including disulfide exchange, transamination of vinylogous urethane and labile metal coordination bond. The utilization of different crosslinking reactions and the mole ratio of crosslinkers significantly impact the material properties of the resultant polymers. Specifically, the generated polyolefin vitrimers demonstrated excellent reprocessability and closed-loop recycling properties. The study in this work provides an efficient strategy to access various polyolefin vitrimers.
