Preparing Of Thermally Expandable Microspheres Containing GMA And Studying On Their Expansion Characteristics

The thermally expandable microsphere is the new material which has shell/core structure and its shell is made up of copolymer in which there are low-boiling point organic solvents. Nowadays the foaming microsphere has received increasing attentions in actual transport, carry, environmental protection because of its lightweight and low pollution. Also it gives materials good functionality and aesthetics after heating. Therefore it has been widely used in the foaming, coatings, printing and other fields. When the glycidyl methacrylate was added to the foaming microcapsule which made the expandable microcapsule suitable to both low and high temperature without decreasing its foaming stability, and further it extends its use.In this paper, the influence of the different speed and time of the mixer, water-oil ratio to the thermally expandable microsphere, the initiator dosage and initiator combination, cross-linker dosage and species, foaming agent dosage and species combination, additives in the water phase were discussed. According to the better foaming performance, the better conditions of the basic prescription that mixing 15 minutes under 800 rpm/min, 3:1 water-oil ratio, 3:2 combination initiator dosage, 0.16% TM dosage were got.Thought about the limited applications of the foaming microspheres, the influence of different function monomers dosage such as methacrylic acid, acrylamide, butyl acrylate and GMA was studied. The results showed that GMA can improve the expandable property better than others. Besides, the proper GMA dosage was 7.9 percent of the oil content.At the same time, the effects of adding GMA to the thermally expandable microspheres were learned. They demonstrated that both high-temperature and low-temperature foaming microspheres which extended the practical application can be prepared by adjusting the ratio and dosage of the initiator, cross-linkers, foaming agents and other polymerization factors.In the end, the solvent resistance performance of the thermally expandable microsphere, the effect of storage time on foaming performance and actual foaming ratio were studied. From the test, the result that the thermally expandable microspheres have good resistance to xylene, isopropanol, acetone and cyclohexane was obtained. And the foaming microspheres showed fine tightness after six months. Though the tube experiment, the foaming ratio can be clearly demonstrated when the foaming microspheres were practical applied.