A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble ac...A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU parti-cles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI iso-cyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction be-tween HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.展开更多
A phosphorus-containing bio-based epoxy resin(EADI)was synthesized from itaconic acid(IA)and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide(DOPO).As a matrix,its cured epoxy network with methyl hexahydrophthalic a...A phosphorus-containing bio-based epoxy resin(EADI)was synthesized from itaconic acid(IA)and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide(DOPO).As a matrix,its cured epoxy network with methyl hexahydrophthalic anhydride(MHHPA)as the curing agent showed comparable glass-transition temperature and mechanical properties to diglycidyl ether in a bisphenol A(DGEBA)system as well as good flame retardancy with UL94 V-0 grade during a vertical burning test.As a reactive flame retardant,its flame-resistant effect on DGEBA/MHHPA system as well as its influence on the curing behavior and the thermal and mechanical properties of the modified epoxy resin were investigated.Results showed that after the introduction of EADI,not only were the flame retardancy determined by vertical burning test,LOI measurement,and thermogravimetric analysis significantly improved,but also the curing reactivity,glass transition temperature(T g),initial degradation temperature for 5%weight loss(T d(5%)),and flexural modulus of the cured system improved as well.EADI has great potential to be used as a green flame retardant in epoxy resin systems.展开更多
文摘A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU parti-cles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI iso-cyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction be-tween HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.
基金financially supported by the National Natural Science Foundation of China(51203176)the National Basic Research Program of China(2010CB631100)+3 种基金the Natural Science Foundation of Ningbo(2012A610095)the China Postdoctoral Science Foundation(2013M-540504)the Postdoctoral Science Foundation of Zhejiang Province(Bsh1201011)the Director Funds of the Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences(Y20224-QF06)
文摘A phosphorus-containing bio-based epoxy resin(EADI)was synthesized from itaconic acid(IA)and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide(DOPO).As a matrix,its cured epoxy network with methyl hexahydrophthalic anhydride(MHHPA)as the curing agent showed comparable glass-transition temperature and mechanical properties to diglycidyl ether in a bisphenol A(DGEBA)system as well as good flame retardancy with UL94 V-0 grade during a vertical burning test.As a reactive flame retardant,its flame-resistant effect on DGEBA/MHHPA system as well as its influence on the curing behavior and the thermal and mechanical properties of the modified epoxy resin were investigated.Results showed that after the introduction of EADI,not only were the flame retardancy determined by vertical burning test,LOI measurement,and thermogravimetric analysis significantly improved,but also the curing reactivity,glass transition temperature(T g),initial degradation temperature for 5%weight loss(T d(5%)),and flexural modulus of the cured system improved as well.EADI has great potential to be used as a green flame retardant in epoxy resin systems.
