Crystallization and thermal performance of poly(acrylonitrile-co-alkyl acrylate) comb-like polymeric phase change materials with various side-chain lengths

Abstract

A series of comb-like poly(n-alkyl acrylate) and poly(acrylonitrile-co-alkyl acrylate) phase change materials (PCMs), denoted as PAn and PANAn, with alkyl carbon atoms varying from n=14, 16 to 18, are synthesized...

Side‐chain crystallization and phase transition of poly[styrene‐co‐(maleic anhydride)]‐g‐alkylamine comb‐like polymers

“…Figure 6(a) displays the WAXS results of SMA and SMAC n N comb‐like polymers. SMA showed an amorphous state at room temperature, while the SMAC n N comb‐like polymers exhibited a varied phase structure depending upon the side‐chain length 10,15,21,22,32 . At room temperature, an amorphous diffraction peak was seen for SMAC12N and SMAC14N, indicating that C12 and C14 alkyl chains stayed in the non‐crystalline structure, which is likely due to the lower T c (−5.1 °C) of SMAC14N.…”

“…Recently, a series of double-component comb-like polymers have been reported by our group with poly[ethylene-graft-(maleic anhydride)] (EMA), poly[styrene-co-(maleic anhydride)] (SMA), poly[(methyl vinyl ether)-alt-(maleic anhydride)] (PVEM), poly[acrylonitrile-co-(alkyl acrylate)] and poly [isobutylene-alt-(maleic anhydride)] (PIAM) as polymer main chain. 9,11,21,35,36 Interestingly, these double-component comblike polymers such as EMA-Cn, PVEM-Cn, PIAM-Cn and SMA-g-CnOH exhibit a chain packing manner different from that of the single-component ones. Also, PVEM-Cn and PIAM-Cn comb-like polymers required at least nine CH 2 units to satisfy the critical crystallization requirement for the pendent alkyl side chains.…”

“…This indicates that the chemical spacer between main chain and side chain affects the stacking mode of chain segments. Recently, a series of double‐component comb‐like polymers have been reported by our group with poly[ethylene‐ graft ‐(maleic anhydride)] (EMA), poly[styrene‐ co ‐(maleic anhydride)] (SMA), poly[(methyl vinyl ether)‐ alt ‐(maleic anhydride)] (PVEM), poly[acrylonitrile‐ co ‐(alkyl acrylate)] and poly[isobutylene‐ alt ‐(maleic anhydride)] (PIAM) as polymer main chain 9,11,21,35,36 . Interestingly, these double‐component comb‐like polymers such as EMA‐C n , PVEM‐C n , PIAM‐C n and SMA‐ g ‐C n OH exhibit a chain packing manner different from that of the single‐component ones.…”

“…Information on the packing structure, conformational variation and crystallization habit has been reported previously, 9–18 and the length of pendent side chains, the critical crystallizable carbon atoms and the rigidity of the backbone show an important contribution. The exhibited side‐chain crystalline packing of comb‐like polymers that originates from crystallizable alkyl side chains illustrates the main difference from linear polymers and main‐chain crystallization polymers, 17–19 and the hexagonal phase ( α H ) is a typical one, which is strongly regulated by the crystallizable carbon atoms and the polymer backbones 11,20,21 . For a flexible polymer skeleton such as polyethylenimine, 15 six carbon atoms per side chain are required to realize side‐chain crystallization, while for a rigid one such as poly( p ‐benzamide), polypyrrole, polyaniline and poly ( p ‐phenylene terephthamide), 16,22,23 ten or more carbon atoms are required.…”

“…The exhibited side-chain crystalline packing of comb-like polymers that originates from crystallizable alkyl side chains illustrates the main difference from linear polymers and main-chain crystallization polymers, [17][18][19] and the hexagonal phase (⊍ H ) is a typical one, which is strongly regulated by the crystallizable carbon atoms and the polymer backbones. 11,20,21 For a flexible polymer skeleton such as polyethylenimine, 15 six carbon atoms per side chain are required to realize side-chain crystallization, while for a rigid one such as poly(p-benzamide), polypyrrole, polyaniline and poly (p-phenylene terephthamide), 16,22,23 ten or more carbon atoms are required. In the meantime, the crystallinity of alkyl side groups along the various polymer backbones is different and the conformationally ordered/disordered state of the chain segments determines the manner of side-chain packing accordingly.…”