Synthesis of an intrinsically flame retardant bio-based benzoxazine resin

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

Author
Hongqiang Yan. Author links open the author workspace.Opens the author workspaceOpens the author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceChuang Sun. Author links open the author workspace.a. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceZhengping Fang. Author links open the author workspace.a. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceXiaoqing Liu. Author links open the author workspace.b. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceJin Zhu. Author links open the author workspace.b. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceHao Wang. Author links open the author workspace.c. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace

a

Lab of Polymer Material and Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo, Zhejiang 315100, China

b

Ningbo Key Laboratory of Polymer Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences Institution, Ningbo, Zhejiang 315201, China

c

Centre of Excellence in Engineered Fibre Composites (CEEFC), University of Southern Queensland, Toowoomba, Queensland 4350, Australia

Highlights

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An intrinsically flame retardant bio-based benzoxazine (DPA-PEPA-boz) was synthesized from renewable diphenolic acid.

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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.

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P-DPA-PEPA-boz had a limiting oxygen index (LOI) of 33.5% and achieved V0 level in UL94 test.

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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.

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