Suspension Polymerization of Thermally Expandable Microspheres Using Cinnamonitrile and Diethyl Fumarate as Crosslinking Agents

Abstract

Thermally expandable microspheres (TEMs) were synthesized via suspension polymerization using acrylonitrile as the major monomer. Methyl methacrylate and methacrylonitrile were used as supporting co-monomers, and 1,4-butanediol dimethacrylate was used as a crosslinking agent. In addition, cinnamonitrile (CN) and diethyl fumarate (DEF) were investigated as monomers to improve the expansion performance of the TEMs. However, the expandability of the TEMs using CN was diminished. When TEMs were prepared with DEF as the crosslinking agent, the expandability was highly affected. From the thermomechanical analysis of TEMs with various crosslinking agents, DEF showed better performance as crosslinking agent, yielding increased expansion properties. This is the first report using DEF as a TEM crosslinking agent.

Preparation of small particle diameter thermally expandable microspheres under atmospheric pressure for potential utilization in wood

“…The specific expansion temperature could be measured only for Group 1~2 and Group 12~14. As shown in Table 1, the expansion temperature of Group 1~2 was around 120 C, while that of the Group 12~14 was approximately 112 C. This temperature was far below those in other studies, 19,28,35 which was beneficial for the utilization of TEMs in wood. As for other groups, the exact expansion temperature could not be evaluated exactly, and the expansion temperature ranges of 120~150 and 120~140 C were obtained for Group 3~11 and Group 15~23 respectively, because these TEMs expanded gradually during a long temperaturerising period rather than at a specific temperature immediately.…”

“…They found that once the content of cross‐linking agent increased, the TEMs with a harder shell and worse expansion properties would be produced. Moreover, Kim et al 28 prepared TEMs using dimethyl fumarate (DEF) as the cross‐linking agent, and reported that DEF could improve the expansion properties of TEMs.…”

Thermally expandable microspheres with high expansion ratios: Design of core and shell for largest size change

“…[5][6][7][8] In fundamental research, TEMs have seen application in many next-generation materials and devices, including adhesives, microfluidic pumps, sensors, biomedical devices, and other soft robots. [9][10][11][12][13][14] To actualize TEMs' potential to contribute to nextgeneration materials and manufacturing, both new TEM compositions and fundamental design parameters must be determined. 4,[15][16][17] To this end, our interest in soft actuation methods led us to initiate a set of experiments to determine whether we could (1) use a monomer and copolymer never before used to make TEMs; and (2) systematically modulate reagents and reaction parameters to create a microsphere with heightened expansion.…”

“…TEMs are prepared via suspension free-radical polymerization. Others have shown this process is amenable to a variety of monomers, 1,4,9,23 crosslinkers, 2,3,24 and blowing agents. 24,25 Likewise, the expansion properties of TEMs have been studied.…”

Study on preparation and process of poly(MMA‐St) thermally expandablecore‐shellmicrospheres

“…2,3 Therefore, thermally expandable microspheres are widely used as light-weight fillers to improve thermal insulation, sound insulation, and electrical insulation. 4 They are used as foaming agents for thermoplastic materials, 5 in coatings, in printing inks, in 3D wallpaper, in the textile industry to produce three-dimensional patterns, 6 in adhesives, 7 and in microfluidic pumps. 8 When the surface of microspheres is functionalized, they are used to prepare conductive thermally expandable microspheres.…”