Preparation Of Thermosetting Epoxy Hollow Microspheres

Polymer hollow microsphere is a kind of spherical polymer material with special cavity structure.This material has the advantages of low density,large specific surface area and good thermal insulation,so it is widely used in the fields of electronics,chemical industry,biomedicine,analytical chemistry and daily life.Researchers at home and abroad have done a lot of research on the preparation and properties of polymer hollow microspheres,but the focus of their research is mainly on the general thermoplastic resin hollow microspheres(such as polystyrene hollow microspheres,polymethyl methacrylate hollow microspheres,etc.),there is little research on thermosetting resin hollow microspheres.Compared with thermoplastic resin,thermosetting resin has the advantages of good heat resistance and excellent mechanical properties,so it has higher research value for the preparation and study of hollow microspheres of thermosetting resin.Epoxy resin is one of the most widely used materials in thermosetting resin materials,but there is little research on the preparation and properties of epoxy resin microspheres.In this paper,epoxy resin solid microspheres were prepared by emulsion method using thermosetting epoxy resin as matrix.Thermosetting epoxy resin hollow microspheres were prepared by foaming method and double emulsion method.The preparation process of thermosetting epoxy resin hollow microspheres was studied systematically,and the effects of various factors on the morphology and structure of the products were analyzed.The prepared epoxy microspheres were characterized in detail.The details of the study are as follows:(1)Thermosetting epoxy resin solid microspheres were prepared by emulsion polymerization with thermosetting epoxy resin as matrix.The effects of diluent dosage,emulsifier type,emulsifier content,continuous phase type and oil bath temperature on the morphology and structure of epoxy resin solid microspheres were studied.The results showed that when the mass ratio of diluent to epoxy resin was 1:1,emulsifier OP-10 was 6 wt %,water was used as continuous phase and oil bath temperature reached 80 ?,epoxy resin microspheres had good spherical structure,smooth surface and solid structure;the volume average particle size D(50)of the microspheres was 14.4 ?m;the surface of the microspheres had abundant active groups-OH;the extrapolated thermal decomposition initial temperature of the microspheres was 412 ?.(2)Based on the study of epoxy resin solid microspheres prepared by emulsion polymerization,thermosetting epoxy resin hollow microspheres were prepared by foaming method in the emulsion.The effects of the content of flexible curing agent,the type of foaming agent,the content of foaming agent,the content of emulsifier and the temperature of oil bath on the morphology and structure of epoxy resin hollow microspheres were studied.The results showed that when the dosage of hexadecylamine was 6 wt %,the content of foaming agent H was 4 %,the content of emulsifier was 5 wt %,the oil bath temperature was 120 ?,the epoxy resin microspheres had hollow structure,its particle size was about 100 ?m and the wall thickness was about 20 ?m;the volume average particle size D(50)of the microspheres was 86.4 ?m;the extrapolated thermal decomposition initial temperature of the microspheres was 344 ? and the mass retention rate at 800 ? was 11.48%.(3)Based on the preparation of epoxy resin hollow microspheres by foaming method,thermosetting epoxy resin hollow microspheres were prepared by W/O/W double emulsion method.The effects of internal water phase content,external water phase temperature,epoxy resin prepolymerization time,emulsifier type,emulsion stirring speed and emulsion reaction time on the morphology and structure of epoxy resin hollow microspheres were studied.The results showed that when the content of internal water phase was 40 wt %,the epoxy emulsion was prepolymerized for 40 min,and reacted at 80 ? for more than 60 min,the epoxy resin microspheres were hollow structure with a particle size of 20 ?m and a wall thickness of about 5 ?m;the volume average particle size D(50)of the microspheres was 28.0 ?m;the extrapolated thermal decomposition initial temperature of the microspheres was 336 ?,and the glass transition temperature of the microspheres was 121 ?.