Preparation And Application Of Thermal Expansion Microcapsules

In this paper,the preparation and application of thermal expansion microcapsules are systematically studied,and the mechanism of the topography and swelling properties of thermal expansion microcapsules are analyzed,and high-temperature and low-temperature thermal expansion microcapsules are successfully synthesized.The foamed ABS and foamed EVA composites were prepared using microcapsules and AC as foaming agents,respectively,and the influence mechanism of foaming agents on the surface quality and cell structure of foamed products was studied.Get the following conclusions:1.Increasing the homogenization time is conducive to the synthesis of microcapsules with more regular morphology;the homogenization rate is too large to make the morphology of the microcapsules irregular.Among them,when the homogenization time is 10-14min;the homogenization rate is 7000-8250 r/min,the microcapsules have better microscopic morphology,and the particle size distribution is narrower.2.The increase of sodium chloride content,dispersion concentration,water-oil ratio is beneficial to the synthesis of microcapsules with regular morphology,and excessive cross-linker content is disadvantageous to the morphology of microcapsules.Among them,when the sodium chloride content is 15.1 wt%,the dispersant concentration is 1.09 mol/L,the water to oil ratio is 5:1,and the crosslinker content is not more than 0.87 wt%,the appearance of the microcapsules is more regular and the pellets The narrow distribution of the diameter.3.Under the conditions of ideal process and component content,when the content of foaming agent is 25wt%;its swelling performance is relatively stable,thermal expansion microcapsules are successfully synthesized,its appearance andappearance are regular,and it has a regular core-shell structure,and the expansion temperature 201 ?.4.Increasing the glass transition temperature of the polymerized monomer can increase the expansion temperature of the microcapsules;raising the boiling point of the core foaming agent can significantly increase the expansion temperature of the microcapsules.5.Using acrylonitrile,hydroxypropyl methacrylate as monomer and isooctane as the blowing agent to prepare high-temperature thermal expansion microcapsules,the content of blowing agent is 28.5-39.9wt%,and the content of crosslinker is 0.87wt%.When the synthesized microcapsules have good thermal expansion properties,the expansion temperature range is 180-209?.6.Acrylonitrile,hydroxypropyl methacrylate,methyl acrylate as the monomer,and n-hexane as the blowing agent to prepare the low-temperature thermal expansion microcapsule,the content of the blowing agent is 28.5-39.9 wt%,and the content of the crosslinking agent is added.The thermal expansion performance of the microcapsules synthesized at 0.58 wt% is good,and the microcapsules can maintain a stable state after being thermally expanded,and the expansion temperature of the microcapsules is 81-116?7.Foam products prepared by using high-temperature microcapsules as foaming agents have a good surface quality,and the formed cells are not easily deformed and have a uniform size.Under the injection molding conditions,the surface quality of the microcapsule/ABS foamed sample was good,the gloss was 52.3;the surface quality of the AC/ABS foamed sample was poor,the gloss was only 8.7,the cell size uniformity is poor,and the cells are easily deformed.8.The low-temperature thermal expansion microcapsules/EVA foamed specimens under molding conditions have good surface quality,glossiness of 72.9,,cell size and distribution of particles are uniform,morphology is regular and not easily deformed;The surface quality of AC/EVA foam samples was poor,the surface gloss was 66.1,and the cell distribution was uniform.However,the cells were easily affected by the flow of the matrix material,and some of the cells were deformed.