A phosphine oxide-containing bio-based curing agent was synthesized by addition reaction between furan derivatives and diphenylphosphine oxide. The molecular structure of the as-prepared bio-based curing agent was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Dynamic mechanical analysis results indicated that with the increase of bio-based curing agent content, the glass transition temperature of epoxy/bio-based curing agent composites decreased, which was related to the steric effect of diphenylphosphine oxide species that possibly hinder the curing reaction as well as the reduction in the cross-linking density by mono-functional N-H. By the addition of 7.5 wt-% bio-based curing agent, the resulting epoxy composite achieved UL-94 V-0 rating, in addition to limiting oxygen index of 32.0 vol-%. With the increase of content for the bio-based curing agent, the peak of heat release rate and total heat release of the composites gradually decreased. The bio-based curing agent promoted the carbonization of the epoxy matrix, leading to higher char yield with good thermal resistance. The high-quality char layer served as an effective barrier to retard the diffusion of decomposition volatiles and oxygen between molten polymers and the flame. This study provides a renewable strategy for fabricating flame retardant and transparent epoxy thermoset.
To attain superior fire safety epoxy resins (EP), aluminum diethylphosphonate (AlPi) and nickel alginate were incorporated to EP in different proportions. The synergistic flame retardant effects between AlPi and nickel alginate on fire safety and mechanical properties of EP were investigated in detail. EP/AlPi 9.5 -Nickel Alginate 0.5 acquired the UL-94 V-0 rating with the highest limiting oxygen index value (28.9%). Besides, the thermal decomposition behaviors of the samples were researched by thermogravimetric analysis, implying that EP/AlPi-Nickel Alginate exhibited the better thermal stability and char-forming ability. Compared with EP, the peak heat release rate and total heat release were declined by 58.3% and 12.8%. And the addition of nickel alginate reduced the release of smoke. In particular, the incorporation of AlPi and nickel alginate increased the impact strength, flexural strength and glass transition temperature of EP. In perspective, the synergistic effect of bio-based nickel alginate and AlPi opens a practicable avenue in decreasing the fire risk and improving the mechanical properties of EP.
It is always a challenge to prepare multifunctional epoxy resins (EP) composites with excellent flame retardance, mechanical property and high transparency. In this work, a reactive flame-retardant (BDO) was synthesized from DOPO, 3,5-diamino-triazolz and thiophene-2-formaldehyde, and taken to prepare EP/BDO composites. Surprisingly, benefitting from the synergy of efficient flame retardant unit (DOPO structure), catalytic curing unit (triazole structure) and optical functional structure (thiophene-2-formaldehyde), the EP composites with excellent comprehensive performance was obtained. In detailed, after adding only 5 wt% BDO, the EP composites passed the UL-94 V-0 level, and the limiting oxygen index was increased to 33% from 22.5% of neat EP. At the same time, EP/BDO-5 showed obvious heat suppression and smoke suppression effects. Besides, EP/BDO-5 presented excellent mechanical strength , that the tensile strength and bending strength were increased by 25% and 30% compared with neat EP. Moreover, EP/BDO composites maintained the same good light transmittance as neat EP, and also presented enhanced T g and dielectric property . In addition, the dual phase flame-retardant mechanism was revealed through systematically analyzing residues after combustion and the gaseous phase products of flame retardant. The above results indicated EP/BDO composites with excellent comprehensive performance possessed a great potential application in high-performance composites fields.
危险品化学品经营许可证（带存储）