A novel type of crosslinkable poly（aryl ether sulfone）（PAES） bearing an allyl pendant（PES-OAllyl） was synthesized by a grafting reaction of hydrophenyl-containing PAES（PES-OH） and allyl bromide. PES-OH was pre...A novel type of crosslinkable poly（aryl ether sulfone）（PAES） bearing an allyl pendant（PES-OAllyl） was synthesized by a grafting reaction of hydrophenyl-containing PAES（PES-OH） and allyl bromide. PES-OH was prepared by a demethylation reaction of a methoxyphenylated PAES（PES-OCH3） in the presence of pyridine/hydrochlo- ride. The PES-OCH3 was synthesized by an aromatic nucleophilic substitution of bis（4-chlorophenyl）sulfone and （p-methoxy）phenylhydroquinone. Both DSC and solubility investigation were used to study the crosslinking behavior of PES-OAllyl. After heat treatment, the glass transition temperature（Tg） value of PES-OAllyl sharply increased from 165 ℃ to 227 ℃. Meanwhile, PES-OAllyl changed from a soluble polymer to an insoluble thermoset. In addition, TGA（thermogravimetric analysis） result suggests that the thermal stability of the crosslinked product was improved. All the data prove that the crosslinked PES-OAllyl could be a potential solvent-resistance high-performance material.展开更多
Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstar...Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with formaldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.展开更多
The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in th...The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in the liquid state. The reaction kinetics,the reaction-induced elastic strain and the phase separation kinetics were monitored respectively by UV-Vis spectroscopy,Mach-Zehnder interferometry and laser-scanning confocal microscopy.It was found that phase separation in the bulk state was strongly inf...展开更多
Some polymers which are difficult to crosslink, even degrade, at room temperature can crosslink at high temperatures. Obviously, the irradiation temperature is closely related to the probability of radiation crosslink...Some polymers which are difficult to crosslink, even degrade, at room temperature can crosslink at high temperatures. Obviously, the irradiation temperature is closely related to the probability of radiation crosslinking or degradation reaction as well as the behaviors展开更多
Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on ...Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on the DSC curves of thermal condensation of FA and FA with THEIC in the presence of sulfuric acid.The peaks Ⅰ,Ⅱ(50—80℃),Ⅲ(110—130℃)and Ⅳ(150— 190℃)correspond to linear polycondensation of FA through head-to-tail condensation,head-to-head etherification,crosslinking dehydration reaction between methylene group and terminal hydroxy group of FA polymeric chain and to further crosslinking reaction at higher temperature,respectively.The reactivity of FA and THEIC increases sharply at 130—150℃ and THEIC is reacted completely at 150℃.Addition of THEIC raises the initial decomposition temperature of FA polymer by 60℃.展开更多
基金Supported by the National Natural Science Foundation of China(No.50973040)the Science and Technology Development Plan of Jilin Province, China(No.20090322)
文摘A novel type of crosslinkable poly（aryl ether sulfone）（PAES） bearing an allyl pendant（PES-OAllyl） was synthesized by a grafting reaction of hydrophenyl-containing PAES（PES-OH） and allyl bromide. PES-OH was prepared by a demethylation reaction of a methoxyphenylated PAES（PES-OCH3） in the presence of pyridine/hydrochlo- ride. The PES-OCH3 was synthesized by an aromatic nucleophilic substitution of bis（4-chlorophenyl）sulfone and （p-methoxy）phenylhydroquinone. Both DSC and solubility investigation were used to study the crosslinking behavior of PES-OAllyl. After heat treatment, the glass transition temperature（Tg） value of PES-OAllyl sharply increased from 165 ℃ to 227 ℃. Meanwhile, PES-OAllyl changed from a soluble polymer to an insoluble thermoset. In addition, TGA（thermogravimetric analysis） result suggests that the thermal stability of the crosslinked product was improved. All the data prove that the crosslinked PES-OAllyl could be a potential solvent-resistance high-performance material.
文摘Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with formaldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.
基金supported by the Ministry of Education (MONKASHO),Japan through the Grant-in-Aid on the Priority-Research-Area"Molecular Nanodynamics"and"Soft Matter Physics".The Grant-in-Aid for Scientific Research (No.20350107) is also gratefully acknowledged.
文摘The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in the liquid state. The reaction kinetics,the reaction-induced elastic strain and the phase separation kinetics were monitored respectively by UV-Vis spectroscopy,Mach-Zehnder interferometry and laser-scanning confocal microscopy.It was found that phase separation in the bulk state was strongly inf...
文摘Some polymers which are difficult to crosslink, even degrade, at room temperature can crosslink at high temperatures. Obviously, the irradiation temperature is closely related to the probability of radiation crosslinking or degradation reaction as well as the behaviors
基金This project is supported by the National Natural Science Foundation of China.
文摘Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on the DSC curves of thermal condensation of FA and FA with THEIC in the presence of sulfuric acid.The peaks Ⅰ,Ⅱ(50—80℃),Ⅲ(110—130℃)and Ⅳ(150— 190℃)correspond to linear polycondensation of FA through head-to-tail condensation,head-to-head etherification,crosslinking dehydration reaction between methylene group and terminal hydroxy group of FA polymeric chain and to further crosslinking reaction at higher temperature,respectively.The reactivity of FA and THEIC increases sharply at 130—150℃ and THEIC is reacted completely at 150℃.Addition of THEIC raises the initial decomposition temperature of FA polymer by 60℃.
