Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8948348 | Polymer Testing | 2018 | 47 Pages |
Abstract
N,N,Nâ²,Nâ²-tetraglycidyl-4,4â²-diamino-diphenylmethane (TGDDM) is the most widely used epoxy matrix in aerospace/aircraft industries, however its cured product suffers from cyclization side reactions, inadequate toughness and water resistance, and relatively high dielectric constant, which are rooted in its amine-derived nature. In order to address those issues, a tertiary-amine-free, non-planar, fluorine-containing tetrafunctional epoxy (FCTE) was synthesized with high yield. When FCTE is mixed with DGEBA and cured with 4,4â²-diaminodiphenylsulfone (DDS), the cured epoxy shows excellent balanced properties. At 20â¯wt% FCTE loading, the cured mixed epoxy shows a tensile strength and impact strength of 82.5â¯MPa and 30.5â¯kJ/m2, respectively, which are higher than those of TGDDM (76.5â¯MPa and 11.6â¯kJ/m2). Molecular simulation, PALS measurement, and TMA characterization suggest that the improved mechanical properties could be related to the marginal side reactions and larger free volume. The introduced fluorine-containing units also lead to better water resistance and lower dielectric constant compared with TGDDM. Despite a marginal drop in Tg, thermal degradation temperature is greatly improved. In addition, when FCTE is used as the matrix for a polyimide fiber reinforced composite, the interlaminar shear strength is also higher, making it a better candidate for preparing high temperature, light weight, and low-k composites.
Related Topics
Physical Sciences and Engineering
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Authors
An Xing, Fei Bao, Jianwei Fu, Xuepei Miao, Tuan Liu, Hongyi Zhai, Xingzhong Cao, Yan Meng, Xiaoyu Li,