Scholarlink

<p>High temperature resistant, flame retardant polymers with great mechanical durability can be achieved by using various reinforcements, but new class of materials without any use of fillers that cannot compromise on the mechanical properties are highly warranted in industrial applications. In order to achieve a filler free co-polymeric material with high T<sub>g</sub>, mechanical strength and flame retardant property, a new completely bio-based tetrafunctional guaiacol derivative (TG) was synthesized from guaiacol and employed as a phenolic precursor for developing high-performance thermosetting systems. Tetrafunctional guaiacol based benzoxazine (TG-ffa) was prepared via Mannich condensation of TG with furfurylamine and paraformaldehyde, while tetrafunctional phthalonitrile (TG-PN) was obtained through the nucleophilic substitution reaction of TG with 4-nitrophthalonitrile. The chemical structure of both precursors was confirmed by FTIR, <sup>1</sup>H-NMR and HRMS analyses. The copolymeric blends of TG-ffa and TG-PN were formulated at different weight ratios to explore synergistic thermal and mechanical behavior. Differential Scanning Calorimetry (DSC) shows that TG-ffa exhibited a curing temperature of 225&#xa0;°C, which effectively reduced the curing temperature of TG-PN upon blending without the use of additional catalysts. The 50:50 wt% copolymeric blend resulted the lower curing temperature of 202&#xa0;°C and 270&#xa0;°C for benzoxazine and phthalonitrile segments, respectively. Also, high glass transition temperature (T<sub>g</sub>) of 357&#xa0;°C, a decomposition temperature (T<sub>max</sub>) of 551&#xa0;°C and a char yield of 70% obtained for the 50:50 wt% copolymeric blend. The flexural strength and flexural modulus of both poly(TG-ffa) and copolymeric blends were studied. Among the copolymeric blends the highest values of flexural strength of 344&#xa0;MPa and flexural modulus of 176&#xa0;MPa were observed for 50:50 wt% of copolymeric blend. The flame-retardant behaviour of poly(TG-ffa) and copolymeric blends possess the V-0 rating under UL-94 test. Further the low dielectric constant value of 2.90 k and tan δ value of 0.0189 has been observed for the poly(TG-ffa 75%+TG-PN 25%).</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Bio-derived Guaiacol-Phthalonitrile and Benzoxazine Thermosets for Exceptional Thermo-Mechanical Stability and Flame Resistance

  • 期刊论文

  • 发表日期：

    2026年6月2日

查看全文
  • Subasri Appasamy,
  • Mohamed Mydeen Khaja Najimudeen,
  • Harinei Srinivasan,
  • Alagar Muthukaruppan

摘要

High temperature resistant, flame retardant polymers with great mechanical durability can be achieved by using various reinforcements, but new class of materials without any use of fillers that cannot compromise on the mechanical properties are highly warranted in industrial applications. In order to achieve a filler free co-polymeric material with high Tg, mechanical strength and flame retardant property, a new completely bio-based tetrafunctional guaiacol derivative (TG) was synthesized from guaiacol and employed as a phenolic precursor for developing high-performance thermosetting systems. Tetrafunctional guaiacol based benzoxazine (TG-ffa) was prepared via Mannich condensation of TG with furfurylamine and paraformaldehyde, while tetrafunctional phthalonitrile (TG-PN) was obtained through the nucleophilic substitution reaction of TG with 4-nitrophthalonitrile. The chemical structure of both precursors was confirmed by FTIR, 1H-NMR and HRMS analyses. The copolymeric blends of TG-ffa and TG-PN were formulated at different weight ratios to explore synergistic thermal and mechanical behavior. Differential Scanning Calorimetry (DSC) shows that TG-ffa exhibited a curing temperature of 225 °C, which effectively reduced the curing temperature of TG-PN upon blending without the use of additional catalysts. The 50:50 wt% copolymeric blend resulted the lower curing temperature of 202 °C and 270 °C for benzoxazine and phthalonitrile segments, respectively. Also, high glass transition temperature (Tg) of 357 °C, a decomposition temperature (Tmax) of 551 °C and a char yield of 70% obtained for the 50:50 wt% copolymeric blend. The flexural strength and flexural modulus of both poly(TG-ffa) and copolymeric blends were studied. Among the copolymeric blends the highest values of flexural strength of 344 MPa and flexural modulus of 176 MPa were observed for 50:50 wt% of copolymeric blend. The flame-retardant behaviour of poly(TG-ffa) and copolymeric blends possess the V-0 rating under UL-94 test. Further the low dielectric constant value of 2.90 k and tan δ value of 0.0189 has been observed for the poly(TG-ffa 75%+TG-PN 25%).