基于纤维素纳米晶的成核效应制备高性能立构复合聚乳酸低温烧结制品  

Enhanced Properties of Low-Temperature-Sintered Stereocomplex-Type Polylactic Acid Products by the Addition of Cellulose Nanocrystals as Nucleating Agent

作　　者：李向力 章少华 何世文 白红伟[1] 傅强[1] LI Xiang-li;ZHANG Shao-hua;HE Shi-wen;BAI Hong-wei;FU Qiang(College of Polymer Science and Engineering,State Key Laboratory of Polymer Materials Engineering,Sichuan University,Chengdu 610065,China;Hangzhou Huasu Share Industry Co.,Ltd.,Hangzhou 310012,China)

机构地区：[1]四川大学高分子科学与工程学院,高分子材料工程国家重点实验室,四川成都610065 [2]杭州华塑实业股份有限公司,浙江杭州310012

出　　处：《塑料工业》2020年第8期136-140,共5页China Plastics Industry

基　　金：国家自然科学基金资助项目(51673133);四川省科技计划项目(2018JY0022)。

摘　　要：低温烧结成型是一种制备立构复合聚乳酸(SC-PLA)制品的新方法。然而,由于在SC-PLA初生粉末的烧结过程中,颗粒界面区的左旋聚乳酸/右旋聚乳酸(PLLA/PDLA)分子链难以充分扩散并结晶形成高含量可“桥接”界面的SC新晶体,导致颗粒间的黏结强度较低、制品性能不理想。为了突破界面区分子链相互扩散困难的限制,将PLLA接枝的纤维素纳米晶体(CNC-g-PLLA)均匀包覆在SC-PLA粉末颗粒表面,成功利用CNC-g-PLLA作为成核剂诱导分子链在其表面直接结晶形成大量的SC新晶体,进而实现了粉末颗粒界面的紧密黏合。结果表明,仅添加0.05%的CNC-g-PLLA即可使烧结制品的结晶度由42.1%大幅提高到56.1%,制品的耐溶剂性和拉伸强度均得到显著提升。Low-temperature sintering had been proposed as an innovative strategy for preparing stereocomplex-type polylactic acid(SC-PLA)products.However,the insufficient interdiffusion of poly(L-lactic acid)(PLLA)and poly(D-lactic acid)(PDLA)chains across the interfaces between adjacent SC-PLA nascent particles made it difficult to form numerous new SC crystallites capable of bridging and bonding the interfaces together during the sintering,thus leading to the weak interfacial strength and undesirable product properties.In order to break through the limitation of the insufficient chain interdiffusion across the interfaces,PLLA-grafted cellulose nanocrystals(CNC-g-PLLA)uniformly coated on the nascent particles surfaces had been used as a nucleating agent to directly nucleate the crystallization of PLLA and PDLA chains on their surfaces and finally sufficient amounts of SC crystallites were newly formed to firmly bond the interfaces.The results show when the addition of CNC-g-PLLA is only 0.05%,the crystallinity of the sintered product greatly increases from 42.1%to 56.1%.As a result,both the solvent resistance and tensile strength of the product are significantly enhanced.

关 键 词：聚乳酸 立构复合 纤维素纳米晶 烧结 低温 界面 

分 类 号：TQ323.4[化学工程—合成树脂塑料工业]