Improving Interfacial Adhesion of PLA/Lignin Composites by One-Step Solvent-Free Modification Method

To clarify the effects of lignin as a biodegradable filler added into the PLA matrix,PLA/lignin composites with or without silane coupling agent ofγ-(2,3-epoxypropoxy)propy trimethoxysilane(KH560)were prepared by a one-step solvent-free modification method.The effects of KH560 as a compatibilizer on the morphology,chemical structure,crystallization behavior,thermal degradative behavior as well as mechanical strength of the PLA/lignin composites were analyzed in detail.It was found that,after modification by KH560,the fractured surfaces of composites became smooth,suggested sufficient bonding between the lignin and PLA in the composites with KH560 coupling agent molecules.This result further proved by 1H NMR and ATR spectra of the composites that lignin and PLA formed stable chemical bonds with KH560.Due to the toughening effect of KH560,mainly affect the molecular chain mobility,the thermodynamic properties of LG-KH560/PLA composites were all reduced.When compared to the conventional solution modification method of adding silane coupling agents into PLA/lignin,the composites were synthesized via a single-step reactive extrusion modification procedure in this work showed relatively low tensile strength,which mainly because the existence of the free radicals due to coupling agents result in the composite’s deterioration and subsequent weakening of the tensile properties.

新能源电池领域导电剂技术的研究与产业化

二次电池已经被广泛开发并应用于各种领域,如大规模储能、便携式电子设备和电动汽车。作为锂离子电池的重要组成部分,主要通过构建导电网络来增加和保持电极的电子导电性,从而有效改善电池的电化学性能。导电剂虽然在锂离子电池成本的占比较小(2%左右),但相比于数十万亿级别的锂离子电池产业,导电剂也随之成为了千亿级别的产业。目前,主流导电剂为炭黑类、导电石墨类、气相生长碳纤维(VGCF)、碳纳米管和石墨烯。其中,炭黑类、导电石墨类和VGCF作为传统导电剂,其在活性物质间可形成点、线接触式导电网络;碳纳米管和石墨烯属于新型导电剂材料,其可分别形成线、面接触式导电网络。相对于单一导电剂,复合导电剂可使不同导电剂之间产生协同效应,从而表现出更优异的性能,因此新型导电剂与传统导电剂是高度统一的关系,在成本及性能的综合考量下,未来导电剂体系将逐步从单一化走向多元复合化。此外,我国导电剂长期依赖进口,近年来一些优秀企业在制备方法和分散技术方面逐步打破工艺壁垒,加速国产化进程。本工作将讨论碳纳米材料作为导电剂用于电池领域并改善电池电化学性能的相关工作,并进一步讨论导电剂的产业化现状前景。要点:(1)总结了导电剂对锂离子电池性能的影响。(2)介绍了导电剂的分散技术。(3)归纳了导电剂的制备方法。(4)讨论了导电剂的产业化现状和前景。

抗溶胀型聚酰亚胺气体分离膜的制备及其研究进展

膜分离技术具有绿色、高效、低能耗等特点.聚酰亚胺膜具有优异的气体分离性能及机械性能,但在分离高压天然气及生物气时,聚酰亚胺膜易被CO2溶胀塑化,导致膜的选择性下降.近年来,已经报道了多种可用于提高聚酰亚胺膜抗溶胀的技术.本文介绍了由于CO2渗透引起的聚合物膜塑化机理,并详述了热退火、热交联、化学交联、热重排、与纳米材料共混及与聚合物共混等用于抑制聚酰亚胺膜塑化的方法,提出了用于天然气及生物气分离的膜材料,未来的主要研究方向是开发同时具备高气体渗透性及高抗CO2塑化的聚酰亚胺膜材料.