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An investigation of the relationship between the performance of polybenzoxazine and backbone structure of hyperbranched epoxy modifiers
Author(s) -
Wang Xin,
Wang Jinyan,
Liu Cheng,
Jian Xigao
Publication year - 2018
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.5480
Subject(s) - materials science , epoxy , flexural strength , curing (chemistry) , dynamic mechanical analysis , composite material , izod impact strength test , hydrogen bond , network structure , flexural modulus , intramolecular force , phase (matter) , modulus , ultimate tensile strength , molecule , polymer , chemistry , organic chemistry , computer science , machine learning
Novel hyperbranched polyether epoxies (HBPEEs) with various backbone structures were synthesized using a one‐pot A 2 + B 3 approach. These highly effective HBPEEs were incorporated into polybenzoxazine (PBOZ) network at various concentrations without cure‐induced phase separation. Effects of backbone structure and loading amount on the curing behavior and mechanical and thermal properties of PBOZ/HBPEE hybrid were investigated. The general trend shows that the impact strength, flexural strength and storage modulus all first increase and then decrease with filler content. For the backbone structure study, HBPEE‐3, which has the highest proportion of benzene rings, can simultaneously improve impact strength, flexural strength and storage modulus. In contrast, HBPEE‐1 and HBPEE‐2, which have fewer benzene rings and smaller intramolecular cavities, perform worse in terms of mechanical and thermal properties. Both backbone structure and loading of HBPEEs play important roles in determining the crosslink density and structures of non‐phase‐separated network. In addition, the simultaneous improvement can be explained by enhanced crosslinking density, structure of modifier, reduced hydrogen bond network and higher fractional free volume according to dynamic mechanical and thermomechanical analyses. © 2017 Society of Chemical Industry