The effects of a magnesium-based layered composite on the flammability of a phenolic epoxy resin(EP)are studied.In order to produce the required composite material,first,magnesium hydroxide,aluminum salt and deionized...The effects of a magnesium-based layered composite on the flammability of a phenolic epoxy resin(EP)are studied.In order to produce the required composite material,first,magnesium hydroxide,aluminum salt and deionized water are mixed into a reactor according to a certain proportion to induce a hydrothermal reaction;then,the feed liquid is filtered out using a solid-liquid separation procedure;finally,the material is dried and crushed.In order to evaluate its effects on the flammability of the EP,first,m-phenylenediamine is added to EP and vacuum defoamation is performed;then,EP is poured into a polytetrafluoroethylene mold,cooled to room temperature and demoulded;finally,the magnesium-based layered composite is added to EP,and its flame retardance is characterized by thermogravimetric analysis,limiting oxygen index and cone calorimetry.The X-ray diffraction patterns show that the baseline of magnesium-based layered composite is stable and the front shape is sharp and symmetrical when the molar ratio of magnesium to aluminium is 3.2:1;with the addition of magnesium-based layered composite,the initial pyrolysis temperature of EP of 10%,15%and 30%magnesium-based layered composite decreases to 318.2°C,317.9°C and 357.1°C,respectively.After the reaction,the amount of residual carbon increases to 0.1%,3.45%and 8.3%,and the limiting oxygen index increases by 28.3%,29.1%and 29.6%,respectively.The maximum heat release rate of cone calorimeter decreases gradually.The optimum molar ratio of Mg:Al for green synthesis is 3.2:1,and the NO_(3)-intercalated magnesium-based layered composite has the best flame retardance properties.展开更多
New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solu...New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.展开更多
Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples posses...Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.展开更多
文摘The effects of a magnesium-based layered composite on the flammability of a phenolic epoxy resin(EP)are studied.In order to produce the required composite material,first,magnesium hydroxide,aluminum salt and deionized water are mixed into a reactor according to a certain proportion to induce a hydrothermal reaction;then,the feed liquid is filtered out using a solid-liquid separation procedure;finally,the material is dried and crushed.In order to evaluate its effects on the flammability of the EP,first,m-phenylenediamine is added to EP and vacuum defoamation is performed;then,EP is poured into a polytetrafluoroethylene mold,cooled to room temperature and demoulded;finally,the magnesium-based layered composite is added to EP,and its flame retardance is characterized by thermogravimetric analysis,limiting oxygen index and cone calorimetry.The X-ray diffraction patterns show that the baseline of magnesium-based layered composite is stable and the front shape is sharp and symmetrical when the molar ratio of magnesium to aluminium is 3.2:1;with the addition of magnesium-based layered composite,the initial pyrolysis temperature of EP of 10%,15%and 30%magnesium-based layered composite decreases to 318.2°C,317.9°C and 357.1°C,respectively.After the reaction,the amount of residual carbon increases to 0.1%,3.45%and 8.3%,and the limiting oxygen index increases by 28.3%,29.1%and 29.6%,respectively.The maximum heat release rate of cone calorimeter decreases gradually.The optimum molar ratio of Mg:Al for green synthesis is 3.2:1,and the NO_(3)-intercalated magnesium-based layered composite has the best flame retardance properties.
文摘New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.
基金This work was financially supported by the National Natural Science Foundation of China(No.20104008).
文摘Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.
