Preperation, Fabrication And Properties Of Acrylonitrile/Comonomer Copolymers Containing MicroPCMs

In this study, a series of polyacrylonitrile based copolymers were synthesized by deposition polymerization in water in order to produce melt processable PAN based copolymers and develop a new type of thermo-regulated fibers. The effect of various comonomers, microencapsulted phase change materials (MciroPCMs), hydrophilic substances and solid additives on the composition, thermal propertities, average molecular weight (M_η) and crystallinity of PAN based copolymers were studied. Results show that:(1) The feed ratios of the three kinds of PAN based copolymers are in line with those of compositions. The decomposition temperatures (T_d) of the copolymers are all higher than that of PAN. The decomposition temperature of poly(acrylonitrile-co-methyl acrylate) (AN/MA) increases with the increase of MA content. With the increase of co-monomer molar ratio, the decomposition temperature of poly(acrylonitrile- co-vinyl acetate)(AN/VAc) rises and then decreases, whereas, the decomposition temperature of poly(acrylonitrile-co-acrylamide)(AN/AM) decreases and then increases. The stabilities of the 3 kinds of copolymers follow that AN/MA>AN/VAc >AN/AM. With the increase of comonomer content, the melting temperature of AN/MA copolymer decreases more rapidly than that of the AN/VAc and AN/AM copolymers.(2) The number average molecular weights of AN/MA (molar ratio of 85/15) and AN/MA (90/10) copolymers produced with polymerization in water are 12,748 and 32,419 respectively, which are suitable for melt processing.(3) When the content of comonomer is 15 mol%, the melting temperature of AN/MA copolymer decreases to 174.4℃, which is lower than that of the other two kinds of copolymers; the decomposition temperature of AN/MA(85/15) copolymer increases to 320.9℃, which is higher than that of the other 2 kinds of copolymers.(4) With the increase of the content of MicroPCMs, the decomposition temperatures of the 3 kinds of copolymers increase while their crystallinities and melting temperatures decrease gradually.(5) With the increase of the content of hydrophilic substances, the decomposition temperature of the PAN based copolymers containing ethylene carbonate (EC) increases and then decreases and the melting temperature decreases gradually. The decomposition temperature of the copolymers containing polyethylene glycol (PEG) decreases and then increases and the melting temperature changes in opposite.(6) Lauryl alcohol maleic anhydride (LAM) increases the stability of the blends while, at the same time, decreasing the melting temperature and glass transition temperature. The AN/MA(85/15) blends added with 1～3 wt% LAM stable up to 220℃for 30 min.(7) Crystallization temperature of AN/MA(85/15) blends decreases with the increase of the content of di-octadecanol maleic (DOM) or boric acid (BA). The AN/MA blends show good stability at 220℃at the content of DOM or BA of 1 wt%.(8) When the AN/MA blends containing a stabilizer are melt processed, the processing temperature should be below 230℃.