Dispersion copolymerization of acrylonitrile‐vinyl acetate in supercritical carbon dioxide

Abstract

Dispersion copolymerization of acrylonitrilevinyl acetate (AN-VAc) had been successfully performed in supercritical carbon dioxide (ScCO 2 ) with 2,2-azobisisobutyronitrile (AIBN) as a initiator and a series of lipophilic/ CO 2 -philic diblock copolymers, such as poly(styrene-r-acrylonitrile)-b-poly(1,1,2,2-tetrahydroperfluorooctyl methacrylate) (PSAN-b-PFOMA), as steric stabilizers. In dispersion copolymerization, poly(acrylonitrile-r-vinyl acetate) (PAVAc) was emulsified in ScCO 2 effectively using PSAN-b-PFOMA as a stabilizer. Compared with the precipitation polymerization (absence of stabilizer), the products prepared by dispersion polymerization possessed of higher yield and higher molecular weight. In addition, the particle morphology of precipitation polymerization was irregular, but the particle morphology of dispersion polymerization was uniform spherical particles. In this study, the effects of the initial concentrations of monomer and the stabilizer and the initiator, and the reaction pressure on the yield and the molecular weight and the resulting size and particle morphology of the colloidal particles were investigated.

Synthesis of polyacrylonitrile copolymers as potential carbon fibre precursors in CO2

“…[7][8][9] AN was also copolymerised in CO 2 with vinyl acetate, methyl acrylate, and 2-chlorostyrene; the resulting copolymers were prepared in moderate yields. 10,11 Subsequently, Teng processed the polyacrylonitrile homopolymer obtained in CO 2 , while Shen et al studied its surface properties, including the total surface free energy, in addition to the related Lifshitz-van der Waals and Lewis acidbase components. 8,12 In contrast to PAN prepared by conventional methods, the surface free energy of the PAN prepared in supercritical CO 2 increased as the molecular weight decreased.…”

Free‐radical solution copolymerization of the ionic liquid monomer 1‐vinyl‐3‐ethylimidazolium bromide with acrylonitrile

“…Copolymer's composition can greatly influence the performance of precursors and carbon fibers, 1,2 and many comonomers have been reported in the literature. [3][4][5][6][7][8][9][10] Hydrophilic comonomers can promote the diffusion between water and a solvent and effectively improve the mechanical properties of precursors and the resulting carbon fibers. [11][12][13][14][15] Thus, we tried to find a new comonomer with excellent hydrophilicity, such as a polymerizable ionic liquid.…”

“…Polyacrylonitriles (PANs) are the most successful and promising precursors for making high‐performance carbon fibers. Copolymer's composition can greatly influence the performance of precursors and carbon fibers,1, 2 and many comonomers have been reported in the literature 3–10. Hydrophilic comonomers can promote the diffusion between water and a solvent and effectively improve the mechanical properties of precursors and the resulting carbon fibers 11–15.…”