An addition-curable hybrid phenolic resin containing silicon and boron with improved thermal stability

• Published in: Polymer degradation and stability Vol. 189; p. 109599
• Main Authors: Du, Youpei, Xia, Yu, Luo, Zhenhua, Yuan, Wenjie, Xu, Kongli, Wang, Qian, Zhou, Heng, Guo, Ying, Li, Hao, Zhao, Tong
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.07.2021; Elsevier BV
• Subjects: Addition cure; Boron; Condensates; Condensation; Condensation resins; degradation; Epoxy resins; Esterification; formaldehyde; NMR spectroscopy; Novolacs; nuclear magnetic resonance spectroscopy; Phenolic resin; Phenolic resins; Resins; Silicon; Synergistic effect; Synergistic hybrid; Thermal stability; Weight; X ray photoelectron spectroscopy; Phenolic resin; Synergistic hybrid; Thermal stability; Addition cure
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2021.109599

•Vinyltrimethoxysiloxane (VTMS) acting as both silicon source and addition-cure group was successfully introduced into phenolic resin.•The characterization of FT-IR, Raman, SEM/SEM-EDX, XPS, and solid-state NMR spectroscopy to develop a detailed understanding to confirm the effectiveness of borosilicate synergy in improving thermal stability of hybrid phenolic resin.•The formation of B-O-Si, B-O-C, and Si-O-C structures make the three-dimensional continuous oxide framework composed of B-O-B-O-Si-O-Si networks strongly bond to the aromatic phenolic resin skeleton, endowing the resin with remarkable thermal stability.•The enriched hemispherical boron-silicate glass acted as a protective barrier to resist heat flux to the resin matrix, endowing the resin with excellent thermal stability. In this work, an addition-curable hybrid phenolic resin containing silicon and boron was synthesized via the addition-condensation reaction between 4-hydroxyphenylboronic acid and formaldehyde to obtain boron hybrid novolac resin (BN), which was followed by esterification with vinyltrimethoxysilane. Boron and silicon were introduced into the phenolic resin skeleton by forming C-B-OH, B-O-C, B-O-Si, and Si-O-Ph bonds, so the hybrid resin not only realized uniform molecular-level dispersion of hybrid elements but also achieved addition curing via the presence of vinyl groups. The hybrid resin's residual weight in an N2 atmosphere at 800°C was improved to 81.02%. The high residual weight arose from the formation of a three-dimensional continuous oxide framework composed of B-O-B-O-Si-O-Si. In addition, we characterized the pyrosis production of the materials with the combination of FT-IR, Raman, SEM/SEM-EDX, XPS, and solid-state NMR spectroscopy to develop a detailed understanding of the synergistic effects of boron-silicon modified phenolic resin.