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
A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and...A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.展开更多
Polyurethanes(PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications...Polyurethanes(PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications. In this work, surface modifications of PU were achieved first by incorporating polyhedral oligomeric silsesquioxane(POSS), followed by alteration of the surface topography via the breath figures method. Subsequently, surface chemistry was also modified by immobilization of gelatin molecules through grafting, for the enhancement of the surface cytocompatibility. Scanning electron microscopy(SEM) was used to verify the formation of highly ordered microstructures while static contact angle, FTIR and XPS confirmed the successful grafting of gelatin molecules onto the surfaces. In vitro culture of human umbilical vein endothelial cells(HUVECs) revealed that endothelial cell adhesion and proliferation were significantly enhanced on the gelatin-modified surfaces, as shown by live/dead staining and WST-1 proliferation assay. The results indicated that the combination of the strategies yielded an interface that improves cell attachment and subsequent growth. This enhancement is important for the development of higher quality biomedical implants such as vascular grafts.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Key Foundation of Shannxi Province,China (No.04JK181)China Textile Industry Association(No.2007049)
文摘A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.
基金supported by the National Natural Science Foundation of China(21376054)the Educational Commission of Zhejiang Province of China(Y201223742)the AcRF Tier 1 Grant RG 36/12,Ministry of Education,Singapore
文摘Polyurethanes(PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications. In this work, surface modifications of PU were achieved first by incorporating polyhedral oligomeric silsesquioxane(POSS), followed by alteration of the surface topography via the breath figures method. Subsequently, surface chemistry was also modified by immobilization of gelatin molecules through grafting, for the enhancement of the surface cytocompatibility. Scanning electron microscopy(SEM) was used to verify the formation of highly ordered microstructures while static contact angle, FTIR and XPS confirmed the successful grafting of gelatin molecules onto the surfaces. In vitro culture of human umbilical vein endothelial cells(HUVECs) revealed that endothelial cell adhesion and proliferation were significantly enhanced on the gelatin-modified surfaces, as shown by live/dead staining and WST-1 proliferation assay. The results indicated that the combination of the strategies yielded an interface that improves cell attachment and subsequent growth. This enhancement is important for the development of higher quality biomedical implants such as vascular grafts.
