Surface-Modified Cellulose Nanofibers-graft-poly(lactic acid)s Made by Ring-Opening Polymerization of l-Lactide
Surface-Modified Cellulose Nanofibers-graft-poly(lactic acid)s Made by Ring-Opening Polymerization of l-Lactide
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DOI：
10.1007/s10924-019-01398-y
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发表时间：
2019-04-01
影响因子：
5.3
通讯作者：
Sirisansaneeyakul, Sarote
中科院分区：
文献类型：
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作者：
Chuensangjun, Chaniga;Kanomata, Kyohei;Sirisansaneeyakul, Sarote
以软木和非木材纤维素纸浆为原料制备了表面具有高密度羧酸基的高结晶纤维素纳米纤维。制备方法采用2,2,6,6-四甲基哌替啶-1-氧（TEMPO）介导的天然纤维素原纤维在TEMPO/NaBr/NaClO水溶液体系中氧化，然后在醋酸缓冲液（pH 4.8）中用NaClO2氧化。tempo氧化纤维素纳米纤维（TOCNs）的羧酸盐含量为1.7mmolg(-1)，结晶度为67-69%，晶粒尺寸约为3nm。在极性非质子溶剂中，通过l-丙交酯开环聚合制备了高结晶tocn -接枝聚乳酸（PLA）纳米复合材料。研究了反应温度和l-丙交酯与羧酸盐表面基团的摩尔比对表面接枝效率的影响，以期改善纳米复合材料的结晶度和热性能。TOCN-g-PLA产品的结晶度比纯PLA的结晶度高59-66%。
Highly crystalline cellulose nanofibers with a high density of carboxylate groups only on the surfaces were prepared from both softwood and non-wood cellulose pulp. The preparation method used 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation of native cellulose fibrils in an aqueous TEMPO/NaBr/NaClO system and subsequent postoxidation with NaClO2 in acetate buffer (pH 4.8). The TEMPO-oxidized cellulose nanofibers (TOCNs) possessed a carboxylate content of 1.7mmolg(-1) and a crystallinity of 67-69% with a crystallite size of approximate to 3nm. The TOCNs were used to produce highly crystalline TOCN-graft-poly(lactic acid) (PLA) nanocomposites via ring-opening polymerization of l-lactide in a polar aprotic solvent. Effects of the reaction temperature and the molar ratio of l-lactide to carboxylate surface groups, on the efficiency of surface grafting were investigated to potentially improve the crystallinity and thermal properties of the nanocomposites. The crystallinity of TOCN-g-PLA products was 59-66% greater than the crystallinity of neat PLA.