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Synthesis and curing of amino‐containing benzoxazine as a novel hardener for diglycidyl ether of bisphenol‐A
Author(s) -
Ren Shitong,
Zhang Shaoyue,
Zhao Weibo,
Wang Wei,
Miao Xiangyan,
Song Wanqiang
Publication year - 2019
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.4572
Subject(s) - diglycidyl ether , curing (chemistry) , polymer chemistry , epoxy , polymerization , epoxide , bisphenol a , ether , materials science , bisphenol , cationic polymerization , steric effects , polymer , organic chemistry , chemistry , catalysis
Benzoxazines containing various additional functional groups have been extensively reported to improve the properties of polybenzoxazines. In this work, a novel amino‐containing benzoxazine (PDETDA‐NH 2 ) was conveniently synthesized from diethyltoluenediamine (DETDA), 2‐hydroxybenzaldehyde, and paraformaldehyde and was used as a hardener for diglycidyl ether of bisphenol‐A (DGEBA). The curing behaviors of PDETDA‐NH 2 and PDETDA‐NH 2 /DGEBA systems were studied by DSC, FT‐IR, and 1 H NMR. When curing, PDETDA‐NH 2 was firstly polymerized to N,O ‐acetal‐type polymer and then rearranged to Mannich‐type polymer at elevated temperature, while the addition reaction between amino and benzoxazine was discouraged because of the steric hindrance of alkyl substituents. During PDETDA‐NH 2 /DGEBA curing, it was found that the reactions happened in the order of addition polymerization of amino and epoxide, ring‐opening polymerization of benzoxazine, etherification between phenolic hydroxyl of the polymerized benzoxazine, and epoxide. Compared with DETDA cured DGEBA, PDETDA‐NH 2 cured DGEBA showed higher modulus, higher char yield, and much lower water uptake.