End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerizatio...End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerization systems,it is highly challenging to achieve such end-functionalizations,because most of polydienyl chains are capped withη3-allyl-Nd moiety during the end of polymerization,which shows very poor reactivity with nucleophile compounds.We launched a new diene polymerization strategy calling coordinative chain transfer polymerization(CCTP)[1].In such a system,all the polydienyl chains are capped withη1-allyl-Al moieties,which reveal greater reactivity with cyclic esters and epoxide compounds,providing an effective manner to prepare polydiene-polyester amphiphilic block copolymers.Inspired by such findings,we now show herein how such types of chain-ends react with isot-hiocyanate to demonstrate an efficient in-situ manner to access end-functionalized polydienes by using CCTP.展开更多
Neodymium(Nd)-based catalyst in butadiene(Bd)polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal(Ti,Co,Ni,etc.)-based catalysts[1-2].Such outst...Neodymium(Nd)-based catalyst in butadiene(Bd)polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal(Ti,Co,Ni,etc.)-based catalysts[1-2].Such outstanding high cis-1,4-unit selecti-vity is hypothetically originated from the presence of 4 f orbitals,that can participate in monomer coordination and thereby govern subsequent enchainment manners.This unique characteristic also renders the active species highly susceptible to Lewis bases,and may impact the overall selectivity as well as polyme-rization behavior after coordination.Nevertheless,it is still a virgin area in such a field,and the influence of Lewis bases on Nd-based diene polymerizations is still a black box.Based on this consideration,how nitrogen-containing donors(D)impacts the overall behaviors of Nd-mediated Bd polymerizations is disclosed.展开更多
Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） a...Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） as a compatibilizer for enhancing the interfacial adhesion between the two components.The morphology,dynamical rheology response and mechanical properties of the blends were characterized by means of SEM,rheometer and tensile test,respectively.The results show that the ternary PP/UFBR blends compatibilized with PP-g-MA possess rheological behaviors like highly branched PP,while no obvious strain hardening is observed in its control binary PP/UFBR blends,a low level of PP-g-MA in PP/UFBR blends can even endow the material with rheological characteristics of high melt strength materials like highly branched PP.The enhancement interfacial interaction between the UFBR particles and PP matrix accounting for the rheological behavior of compatibilized blends and effectiveness of PP-g-MA were proposed and proved.展开更多
Coordinative chain transfer polymerization(CCTP)is a newly developed strategy that features similarly,but superiorly,to classical living polymerization,in other words,precise molecular weight controlling,narrow molecu...Coordinative chain transfer polymerization(CCTP)is a newly developed strategy that features similarly,but superiorly,to classical living polymerization,in other words,precise molecular weight controlling,narrow molecular weight distribution,atom economy and so on,and has been quickly grown as a powerful tool to prepare the target polymer materials[1].As an extension of this concept,the present study discloses our recent progresses on CCTP of butadiene(Bd)and isoprene(Ip)to prepare precisely controlled Bd/Ip copolymers.展开更多
Morphologies,crystallization behavior and mechanical properties of polypropylene（PP）/syndiotactic 1,2-polybutadiene（s-1,2 PB）blends were investigated.Morphology observation shows the well dispersed domains of s-1,...Morphologies,crystallization behavior and mechanical properties of polypropylene（PP）/syndiotactic 1,2-polybutadiene（s-1,2 PB）blends were investigated.Morphology observation shows the well dispersed domains of s-1,2 PB in PP matrix with the rather small domain sizes from 0.1 to 0.5μm when the s-1,2 PB content increases from 5%to 20%（mass fraction）in the blends,and the phase structure tends to become co-continuous as s-1,2 PB content further increases.Crystallization temperature（Tc）of PP component in the blends is fluctuated with the variation of s-1,2 PB content in the blends.Compatibilization,to some extent,between the two components is inferred from the examination of both morphology and crystallization behavior.Improvement of impact strength of PP toughened by s-1,2 PB becomes significant only in the case of s-1,2 PB content above 20%（mass fraction）.展开更多
基金Supported by PetroChina Company Limited(2020 B-2711)。
文摘End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerization systems,it is highly challenging to achieve such end-functionalizations,because most of polydienyl chains are capped withη3-allyl-Nd moiety during the end of polymerization,which shows very poor reactivity with nucleophile compounds.We launched a new diene polymerization strategy calling coordinative chain transfer polymerization(CCTP)[1].In such a system,all the polydienyl chains are capped withη1-allyl-Al moieties,which reveal greater reactivity with cyclic esters and epoxide compounds,providing an effective manner to prepare polydiene-polyester amphiphilic block copolymers.Inspired by such findings,we now show herein how such types of chain-ends react with isot-hiocyanate to demonstrate an efficient in-situ manner to access end-functionalized polydienes by using CCTP.
基金Supported by PetroChina Company Limited Project (2020 B-2711)。
文摘Neodymium(Nd)-based catalyst in butadiene(Bd)polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal(Ti,Co,Ni,etc.)-based catalysts[1-2].Such outstanding high cis-1,4-unit selecti-vity is hypothetically originated from the presence of 4 f orbitals,that can participate in monomer coordination and thereby govern subsequent enchainment manners.This unique characteristic also renders the active species highly susceptible to Lewis bases,and may impact the overall selectivity as well as polyme-rization behavior after coordination.Nevertheless,it is still a virgin area in such a field,and the influence of Lewis bases on Nd-based diene polymerizations is still a black box.Based on this consideration,how nitrogen-containing donors(D)impacts the overall behaviors of Nd-mediated Bd polymerizations is disclosed.
基金Supported by the National High Technology Research and Development Program of China(No.2002AA333040)the Special Funds of Science and Technology Bureau of Harbin for Hi-Tech Research,China(No.2007AA4BG140)
文摘Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） as a compatibilizer for enhancing the interfacial adhesion between the two components.The morphology,dynamical rheology response and mechanical properties of the blends were characterized by means of SEM,rheometer and tensile test,respectively.The results show that the ternary PP/UFBR blends compatibilized with PP-g-MA possess rheological behaviors like highly branched PP,while no obvious strain hardening is observed in its control binary PP/UFBR blends,a low level of PP-g-MA in PP/UFBR blends can even endow the material with rheological characteristics of high melt strength materials like highly branched PP.The enhancement interfacial interaction between the UFBR particles and PP matrix accounting for the rheological behavior of compatibilized blends and effectiveness of PP-g-MA were proposed and proved.
基金Supported by Jilin Provincial Science and Technology Development Program(20190103122JH).
文摘Coordinative chain transfer polymerization(CCTP)is a newly developed strategy that features similarly,but superiorly,to classical living polymerization,in other words,precise molecular weight controlling,narrow molecular weight distribution,atom economy and so on,and has been quickly grown as a powerful tool to prepare the target polymer materials[1].As an extension of this concept,the present study discloses our recent progresses on CCTP of butadiene(Bd)and isoprene(Ip)to prepare precisely controlled Bd/Ip copolymers.
基金the Natural Science Foundation of Heilongjiang Province,China(No.B2005-09).
文摘Morphologies,crystallization behavior and mechanical properties of polypropylene（PP）/syndiotactic 1,2-polybutadiene（s-1,2 PB）blends were investigated.Morphology observation shows the well dispersed domains of s-1,2 PB in PP matrix with the rather small domain sizes from 0.1 to 0.5μm when the s-1,2 PB content increases from 5%to 20%（mass fraction）in the blends,and the phase structure tends to become co-continuous as s-1,2 PB content further increases.Crystallization temperature（Tc）of PP component in the blends is fluctuated with the variation of s-1,2 PB content in the blends.Compatibilization,to some extent,between the two components is inferred from the examination of both morphology and crystallization behavior.Improvement of impact strength of PP toughened by s-1,2 PB becomes significant only in the case of s-1,2 PB content above 20%（mass fraction）.
