Highly moisture-resistant epoxy composites: an approach based on liquid nano-reinforcement containing well-dispersed activated montmorillonite

Abstract

The effects of butyl glycidyl ether (BGE) activated montmorillonites (BGE-MMTs) on moisture-resistant characteristics of epoxy-based composites were evaluated. The activated MMTs were prepared by intercalating BGE into the inter-layer surfaces of octadecyl ammonium modified MMTs (O-MMTs) under ultrasonication, and in the form of liquid nano-reinforcement. It showed advantages of low viscosity, excellent dispersibility and high chemical reactivity in the epoxy matrix. The enhancements in tensile and flexural properties of BGE-MMTs/epoxy composites confirmed the well dispersion of BGE-MMTs in epoxy matrix and the strong interfacial adhesion between the two components. More importantly, the well-dispersed BGE-MMTs in epoxy matrix led to significant enhancement in the moisture-barrier properties of epoxy composites. In comparison with that of neat epoxy, the moisture diffusion coefficient of BGE-MMTs/epoxy composites significantly decreased from 10.1 Â 10 À6 to 0.3 Â 10 À6 cm 2 s À1 . The enhancement in moisture-barrier properties was ascribed to the exfoliated two-dimensional lamellar structure of MMTs extending the effective penetration paths of water molecules into tortuous forms. A model concerning moisture diffusion in BGE-MMTs/epoxy composites was suggested.Fig. 15 The curve for the relative diffusion paths l/l 0 versus BGE-MMT content in epoxy composites.This journal is

Fabrication of High Gas Barrier Epoxy Nanocomposites: An Approach Based on Layered Silicate Functionalized by a Compatible and Reactive Modifier of Epoxy-Diamine Adduct

“…As is well known, layered nanomaterials have been widely utilized as functional fillers to fabricate gas barrier nanocomposite [ 9 , 10 , 11 , 12 , 13 , 14 ]. In the present case, the gas permeability test was conducted on neat DGEBA/D400 epoxy resin, Na-MMT/DGEBA composite, T5000-D400-MMT/DGEBA nanocomposite and DDA-MMT/DGEBA nanocomposite respectively.…”

“…Numerous attempts have been made to improve the gas barrier properties of epoxy resin, such as copolymerization or blending modification technology, multilayer composite technology, surface coating technology, and nano-filler modification technology [ 5 , 6 , 7 , 8 , 9 ]. Among them, the incorporation of layered nanomaterials with high aspect ratios, e.g., montmorillonite (MMT) [ 10 , 11 ] and graphene oxide (GO) [ 12 , 13 ], has been proved to be an efficient method, which could make the pathways of gas-penetrant molecules much longer and more tortuous, thus prolonging the diffusion time of gas molecules throughout the polymer. However, the bottlenecks which remain to be overcome are the poor dispersion of nano-layers, and weak interfacial interactions with polymeric resins due to the incompatibility between inorganic fillers and organic matrices [ 14 ].…”

Performance improvement in carbon fiber reinforced polymer-based composites

“…的理论与方法 提出了多维度/多尺度协同增强/增韧/阻隔的新 方法和原理, 通过纳米杂化材料在微米纤维间、纤维 /树脂间的"搭桥效应"及其化学反应性, 构建以纳米 杂化材料为桥接点的三维立体交联结构的三相材料 体系(图6(d)) [33] , 同时以RVE模型为基础建立非规则 几何形态杂化纳米材料增强机制的有限元分析方法 (图6(a)~(c)) [46] , 预测和分析纳米杂化材料的多尺度 增强机制, 并基于Fick定律、Nielsen理论等提出了纳 米杂化材料的多尺度阻隔机理 [29] , 最终为实现复合 材料的高性能化提供理论基础 [21,45,52] . [53,54] , 建立了纳米纤维原位相分离 非均相增韧的模型 [55] , 阐明了增韧、增强与耐热协同 效应的实现机制 [56,57] , 解决了层间增韧与树脂基体 的流动性、渗透性和浸润性之间的矛盾 [19] , 发展了一 种 新 的 层 间 同 步 增 韧 增 强 CFRP 的 制 备 方 法 .…”

“…其中"双界面"指碳纤维与上 趋于一致. 同时ACC团队大量基础研究表明 [21,22] , 纳 [21,29,30] 的 研 究 都 表 明 , 树脂与纤维的弹性模量存在一个"相对匹配机制" [31] , 即高模量的树脂基体与纤维之间的界面结合更优, 通过有效增强界面应力传递并抑制界面裂纹扩展而 进一步提高了复合材料整体力学性能(包括横向力学 性能). 基于上述"模量过渡层"的发现和基本原理, ACC团队特别针对高模量碳纤维(M40J, M55J)的模 量高和断裂伸长率低的特征, 明确提出了复合材料 界面相模量过渡"新界面"的概念, 最新研究成果发 表于Composites Science and Technology [32] .…”

“…即通过在 合 材 料 中 纤 维 上 浆 剂 层 形 貌 及 厚 度 尺 寸 的 科 学 方 法 [34] , 发展了荧光纳米粒子同步荧光成像与界面增 强的协调理论. [30,42~48] ; (3) 二维纳米增强体, 如有机官能化 蒙脱土(MMT-BGE)、 聚多巴胺包覆石墨烯(GO-pDop) 等 [29,49,50] , 建立了不同维度纳米增强体表面化学改性 的 控 制 方 法 ; 并 采 用 TEM mapping 、 原 位 Raman mapping [21,51] 等手段建立对各种纳米增强体在复合材 料中的分散状态等相关特性进行表征的系统方法. 如…”