Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and the...Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.展开更多
Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution,which satisfies the needs of sustainable social development.In this study,a...Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution,which satisfies the needs of sustainable social development.In this study,a bio-based epoxy thermoset precursor(MGOL-EP) was synthesized from a naturally occurring magnolol through a facile and efficient one-step process.And the fully bio-based epoxy thermoset(MGOL-EP-SC) was obtained by self-curing without adding any other hardener.MGOL-EP-SC revealed an extremely high glass-transition temperature(T_(g)) of 265℃ and char yield of 53.2%(in N;),which were at the highest level among the fully bio-based epoxy thermosets reported so far.In addition,when the MGOL-EP was cured with 4,4’-methylenedianiline(DDM),T_(g)of the MGOL-EP/DDM was decreased by 61℃ and the other comprehensive performance had also been decreased,which was due to a reduction in biphenyl structure content and cross-linking density by adding the external curing agents.Moreover,the MGOL-EP-SC presented certain killing rate(48.4%) to Staphylococcus aureus.These findings provide a new design strategy for engineering high-performance and functional epoxy thermoset with high biomass content.展开更多
This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels...This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels-Alder(DA)/retro-DA reactions.The syntheses of new different aromatic bismaleimides with ester and amide bonds are presented.These maleimides have been protected using DA reaction and characterized by 1H NMR analysis to determine protection rate and diastereomer ratios.The retro-DA reactions of both aromatic and aliphatic DA adducts in presence of thiol molecules were studied.Kinetic analysis was monitored by 1H NMR and compared to model study.Finally,both aromatic and aliphatic bismaleimides-based polymers were synthesized with 2-mercaptoethyl ether and thermal properties of polymers were compared.The glass transition temperature values ranged from–20°C to 14°C and very good thermal stabilities were observed(up to 300°C).展开更多
基金This work was supported by the China Postdoctoral Science Foundation(China Fund[1998]6)that was entitled“Synthesis of Modified Starch Binder and Its Application in Foundry”.Authors would like to thank academician Jinzong YANG and lecturer Hua ZHANG for the kind analyses and discussions.
文摘Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.
基金supported by the National Natural Science Foundation of China (Nos. 51873027, 52073038 and 51673033)the Natural Science Foundation of Liaoning Province (No. 2019-ZD-0139)+1 种基金the Fundamental Research Funds for the Central Universities (No. DUT20TD114)the National Key Research and Development Program of China (No. 2017YFB0307600)。
文摘Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution,which satisfies the needs of sustainable social development.In this study,a bio-based epoxy thermoset precursor(MGOL-EP) was synthesized from a naturally occurring magnolol through a facile and efficient one-step process.And the fully bio-based epoxy thermoset(MGOL-EP-SC) was obtained by self-curing without adding any other hardener.MGOL-EP-SC revealed an extremely high glass-transition temperature(T_(g)) of 265℃ and char yield of 53.2%(in N;),which were at the highest level among the fully bio-based epoxy thermosets reported so far.In addition,when the MGOL-EP was cured with 4,4’-methylenedianiline(DDM),T_(g)of the MGOL-EP/DDM was decreased by 61℃ and the other comprehensive performance had also been decreased,which was due to a reduction in biphenyl structure content and cross-linking density by adding the external curing agents.Moreover,the MGOL-EP-SC presented certain killing rate(48.4%) to Staphylococcus aureus.These findings provide a new design strategy for engineering high-performance and functional epoxy thermoset with high biomass content.
基金The authors thank the Hutchinson Company for its financial support,Biobased Polymer Company for reactants supply.
文摘This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels-Alder(DA)/retro-DA reactions.The syntheses of new different aromatic bismaleimides with ester and amide bonds are presented.These maleimides have been protected using DA reaction and characterized by 1H NMR analysis to determine protection rate and diastereomer ratios.The retro-DA reactions of both aromatic and aliphatic DA adducts in presence of thiol molecules were studied.Kinetic analysis was monitored by 1H NMR and compared to model study.Finally,both aromatic and aliphatic bismaleimides-based polymers were synthesized with 2-mercaptoethyl ether and thermal properties of polymers were compared.The glass transition temperature values ranged from–20°C to 14°C and very good thermal stabilities were observed(up to 300°C).
