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Improving the curing process and thermal stability of phthalonitrile resin via novel mixed curing agents
Author(s) -
Wu Zuoqiang,
Han Jianhua,
Li Nan,
Weng Zhihuan,
Wang Jinyan,
Jian Xigao
Publication year - 2017
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.5328
Subject(s) - curing (chemistry) , phthalonitrile , thermogravimetric analysis , differential scanning calorimetry , thermal stability , materials science , polymer chemistry , bisphenol a , melting point , chemistry , composite material , organic chemistry , phthalocyanine , physics , thermodynamics , epoxy
High curing temperature (including post‐curing temperature) and long curing time of phthalonitrile resins make them thermally stable but difficult to process. In this paper, novel mixed curing agents ( CuCl /4,4′‐diaminodiphenylsulfone ( DDS ) and ZnCl 2 / DDS ) were firstly designed for solving these problems. Bisphenol‐based phthalonitrile monomer ( BP ‐Ph; melting point: 228–235 °C) was synthesized and used as the curing precursor. Differential scanning calorimetry results indicated that BP ‐Ph cured with CuCl / DDS and ZnCl 2 / DDS exhibited curing temperatures close to the melting point of BP ‐Ph with curing ending temperatures of 225.4 and 287.1 °C, respectively. Rheologic investigations demonstrated obvious curing reactions of BP ‐Ph occurred with the mixed curing agents at 220 °C. Thermogravimetric analysis showed that BP ‐Ph cured by CuCl / DDS or ZnCl 2 / DDS maintained 95% mass at 573 or 546 °C, respectively, at a post‐curing temperature of 350 °C for 2 h. Reasonable long‐term thermo‐oxidative stability was also demonstrated. When the post‐curing temperature decreased to 290 °C, char yield at 800 °C of BP ‐Ph cured by CuCl / DDS was 77.0%, suggesting the curing procedure can be milder when using mixed curing agents. © 2017 Society of Chemical Industry