Synthesis of xylan-graft-poly(l-lactide) copolymers via click chemistry and their thermal properties

详细信息    查看全文

• 作者：Yukiko Enomoto-Rogers ; Tadahisa Iwata ; ^{atiwata@mail.ecc.u-tokyo.ac.jp}
• 关键词：Hemicellulose ; Xylan ; Polylactide ; Graft copolymer ; Click chemistry
• 刊名：Carbohydrate Polymers
• 出版年：2012
• 出版时间：14 February, 2012
• 年：2012
• 卷：87
• 期：3
• 页码：1933-1940
• 全文大小：952 K

文摘

Di-O-(6-azidohexanoyl)-xylan-graft-poly(l-lactide)s (XylC6N₃-g-PLLAs) were prepared by grafting propargyl-terminated poly(l-lactide) onto di-O-(6-azidohexanoyl)-xylan (XylC6N₃) via click chemistry. Di-O-(6-azidohexanoyl)-xylan (XylC6N₃) was prepared via two steps from xylan extracted from eucalyptus kraft pulp with aqueous sodium hydroxide solution. Propargyl-terminated poly(l-lactide)s (PLLA) with three different molecular weights were synthesized via ring-opening polymerization of l-lactide using propargyl alcohol as initiator and tin (II) octanoate (Sn(Oct)₂) as catalyst. XylC6N₃ and propargyl-terminated PLLAs were treated with N,N,N?N?N?pentamethyldiethylenetriamine (PMDETA) and copper(I) bromide, and the graft copolymers XylC6N₃-g-PLLAs were obtained. DSC measurements revealed that the glass transition temperatures (T_g) of the copolymers decreased compared to that of XylC6N₃, suggesting that the grafted PLLA side-chains act as an internal plasticizer for xylan. TGA measurements revealed that XylC6N₃-g-PLLAs had higher decomposition temperatures than those of XylC6N₃ or PLLA, and that the decomposition temperatures of the copolymers increased with decrease in the number of PLLA side-chains grafted to the xylan main-chain.