Synthesis of an intrinsically flame retardant bio-based benzoxazine resin

Published Date
Polymer
5 August 2016, Vol.97:418–427, doi:10.1016/j.polymer.2016.05.053

Author 

• Hongqiang Yan ^a,,
• Chuang Sun ^a
• Zhengping Fang ^a
• Xiaoqing Liu ^b
• Jin Zhu ^b
• Hao Wang ^c

• aLab of Polymer Material and Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo, Zhejiang 315100, China
• bNingbo Key Laboratory of Polymer Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences Institution, Ningbo, Zhejiang 315201, China
• cCentre of Excellence in Engineered Fibre Composites (CEEFC), University of Southern Queensland, Toowoomba, Queensland 4350, Australia

Received 28 February 2016. Revised 6 May 2016. Accepted 19 May 2016. Available online 20 May 2016. 

Highlights

• •
  An intrinsically flame retardant bio-based benzoxazine (DPA-PEPA-boz) was synthesized from renewable diphenolic acid.
• •
  The residual char of P-DPA-PEPA-boz after 400 °C was much higher than those of P-DPA-boz and P-MDP-boz under nitrogen and air atmospheres.
• •
  P-DPA-PEPA-boz had a limiting oxygen index (LOI) of 33.5% and achieved V0 level in UL94 test.
• •
  Thus, this study demonstrates the great potentials of the intrinsically flame retardant bio-based benzoxazine (DPA-PEPA-boz) in the application of high performance matrix resin and composite material.

Abstract

An intrinsically flame retardant bio-based benzoxazine (diphenolic acid pentaerythritol caged phosphate benzoxazine, DPA-PEPA-Boz) monomer was synthesized from bio-based diphenolic acid (DPA) using a four-step process. The monomer of DPA-PEPA-Boz was characterized by FT-IR, ¹H NMR and ¹³C NMR. The curing behavior of DPA-PEPA-boz was studied and compared with those of DPA based benzoxazine (DPA-Boz) and DPA ester derivative (MDP) based benzoxazine (MDP-Boz) without PEPA by means of non-isothermal differential scanning calorimetry. The results indicated that DPA-PEPA-Boz system showed a two-stage curing, assigned to the exothermic opening reactions of oxazine rings and P–O–C ring in PEPA respectively, while the DPA-Boz and MDP-Boz showed a one-stage curing. In addition, the effect of the introduction of PEPA on thermal and inflammable properties of the resin was evaluated. The residual char of the cured DPA-PEPA-Boz (P-DPA-PEPA-Boz) after 400 °C was much higher than those of cured DPA-Boz (P-DPA-Boz) and cured MDP-Boz (P-MDP-Boz) under nitrogen and air atmospheres. Meanwhile, total heat release (THR), peak heat release rate (PHRR) and heat release capacity (HRC) of P-DPA-PEPA-Boz were about half of those of P-DPA-Boz and P-MDP-Boz. P-DPA-PEPA-Boz had a limiting oxygen index (LOI) of 33.5% and achieved V0 rating in UL94 test. P-DPA-PEPA-Boz behaved as a very good intrinsic thermal and flame retardant bio-based benoxazine resin.

Graphical abstract

An intrinsically flame retardant bio-based benzoxazine (DPA-PEPA-boz) has been synthesized and behaved as a very good intrinsic thermal stable and flame retardant bio-based benzoxazine resin.

Keywords

• Diphenolic acid
• Bio-based polymer
• Benzoxazine
• Intrinsically flame retardant
• Synthesis

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• ∗ 
  Corresponding author.

© 2016 Elsevier Ltd. All rights reserved.

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