Heterogeneous polymerization represents a widely employed method in the polyolefin industry.In recent years,various heterogenization strategies for late transition metal catalysts have been developed,enabling effectiv...Heterogeneous polymerization represents a widely employed method in the polyolefin industry.In recent years,various heterogenization strategies for late transition metal catalysts have been developed,enabling effective control of polymer morphology and optimization of catalytic performance.However,while most studies have focused on designing anchoring groups and advancing support approaches,systematic investigations into how the support influences the catalytic behavior of the late transition metal catalysts.In this work,we fabricated supported α-diimine nickel catalysts by functionalizing the ligand with alkyl alcohol chains of varying lengths and supporting them onto MgCl_(2)supports.The ethylene polymerization behavior of these catalysts was then investigated.By precisely adjusting the alkyl alcohol chain length,the distance between the catalytically active metal center and the support surface was modulated.This approach demonstrates that support-induced steric hindrance effect can be effectively regulated by controlling the separation distance between the metal center and the support surface.展开更多
Chirality is a fundamental geometric property prevalent in nature,spanning from biomolecules to macroscopic structures.This review explores the rapidly evolving field of chiral polymer micro/nano-objects,which are inc...Chirality is a fundamental geometric property prevalent in nature,spanning from biomolecules to macroscopic structures.This review explores the rapidly evolving field of chiral polymer micro/nano-objects,which are increasingly applied in chiral recognition,asymmetric catalysis,and circularly polarized luminescence.Conventional heterogeneous polymerization techniques—such as emulsion,precipitation,dispersion,and suspension polymerizations—have emerged as powerful methods for preparing these chiral micro/nano-objects.Additionally,the polymerization-induced chiral self-assembly strategy based on living heterogeneous polymerization has attracted attention for its efficiency and versatility in producing well-defined chiral polymer assemblies with tunable morphologies.This review summarizes recent advances in these preparation strategies,emphasizing the importance of heterogeneous polymerization in developing chiral polymer materials with enhanced optical and functional properties.展开更多
To better characterize the properties of surface-initiated polymers, simultaneous bulk-and surface-initiated polymerizations are usually carried out by assuming that the properties of the surface-initiated polymers re...To better characterize the properties of surface-initiated polymers, simultaneous bulk-and surface-initiated polymerizations are usually carried out by assuming that the properties of the surface-initiated polymers resemble those of the bulk-initiated polymers. Through a Monte Carlo simulation using a heterogeneous stochastic reaction model, it was discovered that the bulk-initiated polymers exhibit a higher molecular weight and a lower dispersity than the corresponding surface-initiated polymers, which indicates that the equivalent assumption is invalid. Furthermore, the molecular weight distributions of the two types of polymers are also different, suggesting different polymerization mechanisms. The results can be simply explained by the heterogeneous distributions of reactants in the system. This study is helpful to better understand surface-initiated polymerization.展开更多
Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the init...Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar n-hexane.Interestingly,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in n-hexane.The obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism analysis.Also,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative conversion.Together,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low reactivity.Besides,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.展开更多
Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers,owing to its sensitivity to the structure change of hetero-geneous systems.In t...Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers,owing to its sensitivity to the structure change of hetero-geneous systems.In this article,recent progress in the studies on the morphology/structure and rheological properties of heterogeneous systems is summarized,mainly reporting the findings of the authors and their collaborators,involving the correlation between the morphology and viscoelastic relaxation of LCST-type polymer blends,the microstructure and linear/nonlinear viscoelastic behavior of block copolymers,time scaling of shear-induced crystallization and rheological response of poly-olefins,and the relationship between the structure/properties and rheological behavior of filled polymer blends.It is suggested that a thorough understanding of the characteristic rheological response to the morphology/structure evolution of multiphase/multi-component polymers facilitates researchers’op-timizing the morphology/structure and ultimate mechanical properties of polymer materials.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52473338)the National Natural Science Foundation of China(Nos.52173004 and 51873055)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0540000)Advanced Materials-National Science and Technology Major Project(No.2025ZD0614000)Hebei Natural Science Foundation(No.E2022202015)Anhui Province Science and Technology Innovation Tackling Key Project(No.202423i08050025)。
文摘Heterogeneous polymerization represents a widely employed method in the polyolefin industry.In recent years,various heterogenization strategies for late transition metal catalysts have been developed,enabling effective control of polymer morphology and optimization of catalytic performance.However,while most studies have focused on designing anchoring groups and advancing support approaches,systematic investigations into how the support influences the catalytic behavior of the late transition metal catalysts.In this work,we fabricated supported α-diimine nickel catalysts by functionalizing the ligand with alkyl alcohol chains of varying lengths and supporting them onto MgCl_(2)supports.The ethylene polymerization behavior of these catalysts was then investigated.By precisely adjusting the alkyl alcohol chain length,the distance between the catalytically active metal center and the support surface was modulated.This approach demonstrates that support-induced steric hindrance effect can be effectively regulated by controlling the separation distance between the metal center and the support surface.
基金supported by the National Natural Science Foundation of China(92356305 and 22301208)the China Postdoctoral Science Foundation(2022M722312)+4 种基金the Jiangsu Natural Science Foundation(BK20230505)the Jiangsu Funding Program for Excellent Postdoctoral Talentthe Natural Science Foundation of Anhui Province(2308085J15 and 2408085QB044)the Natural Science Foundation of Anhui Provincial Higher Education Institutions(2023AH010012)the Scientific Research Start-up Fund Project of Anhui Polytechnic University for Introducing Talents(2022YQQ074)。
文摘Chirality is a fundamental geometric property prevalent in nature,spanning from biomolecules to macroscopic structures.This review explores the rapidly evolving field of chiral polymer micro/nano-objects,which are increasingly applied in chiral recognition,asymmetric catalysis,and circularly polarized luminescence.Conventional heterogeneous polymerization techniques—such as emulsion,precipitation,dispersion,and suspension polymerizations—have emerged as powerful methods for preparing these chiral micro/nano-objects.Additionally,the polymerization-induced chiral self-assembly strategy based on living heterogeneous polymerization has attracted attention for its efficiency and versatility in producing well-defined chiral polymer assemblies with tunable morphologies.This review summarizes recent advances in these preparation strategies,emphasizing the importance of heterogeneous polymerization in developing chiral polymer materials with enhanced optical and functional properties.
基金financially supported by the National Natural Science Foundation of China (No.22263002)the “Overseas 100 Talents Program” of Guangxi Higher Education。
文摘To better characterize the properties of surface-initiated polymers, simultaneous bulk-and surface-initiated polymerizations are usually carried out by assuming that the properties of the surface-initiated polymers resemble those of the bulk-initiated polymers. Through a Monte Carlo simulation using a heterogeneous stochastic reaction model, it was discovered that the bulk-initiated polymers exhibit a higher molecular weight and a lower dispersity than the corresponding surface-initiated polymers, which indicates that the equivalent assumption is invalid. Furthermore, the molecular weight distributions of the two types of polymers are also different, suggesting different polymerization mechanisms. The results can be simply explained by the heterogeneous distributions of reactants in the system. This study is helpful to better understand surface-initiated polymerization.
基金supported by the National Natural Science Foundation of China(22201197,21925107)the Collaborative Innovation Center of Suzhou Nano Science and Technology,National Key R&D Program of China(2022YFB3704900)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20220507)the Natural Science Foundation of Jiangsu Higher Education Institutions(21KJB150035)。
文摘Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar n-hexane.Interestingly,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in n-hexane.The obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism analysis.Also,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative conversion.Together,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low reactivity.Besides,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.
基金Supported by the National Basic Research Program of China(Grant No.2005CB623800)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20040335077)
文摘Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers,owing to its sensitivity to the structure change of hetero-geneous systems.In this article,recent progress in the studies on the morphology/structure and rheological properties of heterogeneous systems is summarized,mainly reporting the findings of the authors and their collaborators,involving the correlation between the morphology and viscoelastic relaxation of LCST-type polymer blends,the microstructure and linear/nonlinear viscoelastic behavior of block copolymers,time scaling of shear-induced crystallization and rheological response of poly-olefins,and the relationship between the structure/properties and rheological behavior of filled polymer blends.It is suggested that a thorough understanding of the characteristic rheological response to the morphology/structure evolution of multiphase/multi-component polymers facilitates researchers’op-timizing the morphology/structure and ultimate mechanical properties of polymer materials.
