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Boric Acid as a Coupling Agent for Preparation of Phenolic Resin Containing Boron and Silicon with Enhanced Char Yield
Author(s) -
Yun Jin,
Chen Lixin,
Zhao Hui,
Zhang Xiaofei,
Ye Wenlong,
Zhu Defu
Publication year - 2019
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201800702
Subject(s) - char , boric acid , boron , yield (engineering) , silicon , materials science , pyrolysis , silane , solvent , chemical engineering , carbon fibers , fire retardant , polymer chemistry , nuclear chemistry , organic chemistry , composite material , chemistry , composite number , metallurgy , engineering
In this study, an innovative, facile, and low‐cost method is developed to prepare phenolic resin (PR) containing boron and silicon (BSiPR). BSiPR is synthesized by a solvent‐free, one‐pot method using boric acid as the coupling agent instead of silane, and methyltriethoxysilane as the silicon source. The results show that boron and silicon elements are introduced into PR via BOC and BOSi structures. The char yield of the resulting resin at 800 °C is improved to 76%. The reasons for higher char yield are investigated. The formation of BOC can reduce the content of phenolic hydroxyl, which helps to decrease the weight loss. B 2 O 3 is also formed at 400 °C, and it can prevent the release of carbon oxides. Moreover, thermally stable BOSi and SiO structures remain stable during the pyrolysis. In addition, the mechanical and ablative properties of fiber‐reinforced composites are also enhanced.