The reaction kinetics of bisphenol-S epoxy resin with methyl-acrylic acid in the presence of quaternary ammonium salt catalyst was studied. The reaction rate constants at different temperatures were determined. The re...The reaction kinetics of bisphenol-S epoxy resin with methyl-acrylic acid in the presence of quaternary ammonium salt catalyst was studied. The reaction rate constants at different temperatures were determined. The reaction is first order with respect to epoxy group, zero order with respect to methylacrylic acid and 0.71 order with respect to quaternary ammonium salt catalyst, respectively. The mechanism of this reaction was discussed.展开更多
An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by graf...An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications展开更多
The heterogeneous free-radical polymerization of methyl methylacrylate (MMA) and divinylbenzene (DVB) as cross-linker within supercritical carbon dioxide-swollen silicon rubber (SR) has been studied as an approach to ...The heterogeneous free-radical polymerization of methyl methylacrylate (MMA) and divinylbenzene (DVB) as cross-linker within supercritical carbon dioxide-swollen silicon rubber (SR) has been studied as an approach to preparing semi-interpenetrating polymer network (semi-IPN) of SR and poly(methyl methylacrylate) (PMMA). The SR/PMMA semi-IPNs were characterized by scanning electron microscopy (SEM) and dynamic mechanical analyzer (DMA).展开更多
Hydrogels have emerged as appealing prospects for wound healing due to their superior biocompatible qualities.However,the integration of antibacterial active substances into hydrogels for effective wound repair remain...Hydrogels have emerged as appealing prospects for wound healing due to their superior biocompatible qualities.However,the integration of antibacterial active substances into hydrogels for effective wound repair remains challenging.Here,we present a novel double-network hydrogel for nasal mucosal injury repair with antibacterial and self-healing capabilities.This hydrogel is the result of mixing aldehyde polyethylene glycol(PEG)and a carboxymethyl chitosan(CMCS)-based hydrogel with a photocured methylacrylate gelatin(GelMA)hydrogel to envelop mesenchymal stem cell exosomes(MSC-Exos).CMCS is rich in amino groups and facilitates antibacterial repair.Given the dynamically reversible Schiff base connections between the amino group of chitosan and the aldehyde group of modified PEG,the hydrogel can be easily injected into the lesion site because of its excellent injection and shear thinning properties.GelMA introduces an additional network layer for the hydrogel,which enhances its strength and extends the duration of stem cell exosomes on the wound surface.On the basis of these characteristics,we provide evidence that this compound hydrogel can substantially increase cell proliferation and regeneration,inhibit scar hyperplasia,and stimulate angiogenesis in rabbit nasal septum mucosa trauma models.These results suggest that MSC exosome-loaded hydrogels(ME-Gel)have substantial clinical potential for the repair and regeneration of nasal mucosa after surgery or trauma.展开更多
文摘The reaction kinetics of bisphenol-S epoxy resin with methyl-acrylic acid in the presence of quaternary ammonium salt catalyst was studied. The reaction rate constants at different temperatures were determined. The reaction is first order with respect to epoxy group, zero order with respect to methylacrylic acid and 0.71 order with respect to quaternary ammonium salt catalyst, respectively. The mechanism of this reaction was discussed.
文摘An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications
基金This work was supported by the National Natural Science Foundation of China (50173030).
文摘The heterogeneous free-radical polymerization of methyl methylacrylate (MMA) and divinylbenzene (DVB) as cross-linker within supercritical carbon dioxide-swollen silicon rubber (SR) has been studied as an approach to preparing semi-interpenetrating polymer network (semi-IPN) of SR and poly(methyl methylacrylate) (PMMA). The SR/PMMA semi-IPNs were characterized by scanning electron microscopy (SEM) and dynamic mechanical analyzer (DMA).
基金supported by the National Natural Science Foundation of China(82101184)the Shenzhen Science and Technology Program(JCYJ20210324102809024 and RCBS20210609103713045)+3 种基金the Jiangsu Provincial Medical Key Discipline Laboratory(ZDXK202243)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX22_1288)the Nanjing Medical Science and Technique Development Foundation(YKK20070)the Shenzhen Medical Research Fund(A2303017).
文摘Hydrogels have emerged as appealing prospects for wound healing due to their superior biocompatible qualities.However,the integration of antibacterial active substances into hydrogels for effective wound repair remains challenging.Here,we present a novel double-network hydrogel for nasal mucosal injury repair with antibacterial and self-healing capabilities.This hydrogel is the result of mixing aldehyde polyethylene glycol(PEG)and a carboxymethyl chitosan(CMCS)-based hydrogel with a photocured methylacrylate gelatin(GelMA)hydrogel to envelop mesenchymal stem cell exosomes(MSC-Exos).CMCS is rich in amino groups and facilitates antibacterial repair.Given the dynamically reversible Schiff base connections between the amino group of chitosan and the aldehyde group of modified PEG,the hydrogel can be easily injected into the lesion site because of its excellent injection and shear thinning properties.GelMA introduces an additional network layer for the hydrogel,which enhances its strength and extends the duration of stem cell exosomes on the wound surface.On the basis of these characteristics,we provide evidence that this compound hydrogel can substantially increase cell proliferation and regeneration,inhibit scar hyperplasia,and stimulate angiogenesis in rabbit nasal septum mucosa trauma models.These results suggest that MSC exosome-loaded hydrogels(ME-Gel)have substantial clinical potential for the repair and regeneration of nasal mucosa after surgery or trauma.
