Synthesis and characterization of novel bio-based benzoxazines from eugenol
Synthesis and characterization of novel bio-based benzoxazines from eugenol
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DOI：
10.1039/c3ra46582a
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发表时间：
2014-01
期刊：
影响因子：
3.9
通讯作者：
P. Thirukumaran;A. Shakila;Sarojadevi Muthusamy
中科院分区：
文献类型：
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作者：
P. Thirukumaran;A. Shakila;Sarojadevi Muthusamy
聚苯并恶嗪是具有尺寸和热稳定性的酚醛类材料，并且它们在聚合过程中不释放副产物。本研究以可再生资源丁香酚、多聚甲醛和多种芳香二胺为原料，合成了一类含苯并恶嗪的单体。通过红外光谱、核磁共振氢谱和碳谱分析证实了单体的结构，证明了其分子结构中存在含丁香酚基团的苯并恶嗪环。通过加热经由开环聚合使单体聚合/固化，如FT-IR和差示扫描量热法（DSC）所示。这通过恶嗪环（942 cm-1）峰的消失得到证实。从170 °C至250 °C观察到与固化相关的放热峰。通过热重分析（TGA）和动态力学分析（DMA）研究了聚苯并恶嗪的热性能和力学性能。对应于5%和10%重量损失的温度分别为240至295 °C和290至340 °C。在800 °C、氮气气氛下，完全固化的材料的成炭率可达36.5%。DMA分析表明，PBz-SUL和PBz-PHE的玻璃化转变温度高于PBz-DDS和PBz-OXY。
Polybenzoxazines are phenolic-like materials that possess dimensional and thermal stability, and they release no by-products during their polymerization. In this study, a new class of benzoxazine-containing monomers has been prepared from renewable resource (eugenol, a natural phenol obtained from clove oil), paraformaldehyde and various aromatic diamines. The structures of the monomers were supported by Fourier Transform Infrared (FT-IR), 1H-NMR and 13C-NMR spectral analysis, proving the existence of the benzoxazine ring containing eugenol moiety in its molecular structure. The monomers were polymerized/cured via ring-opening polymerization by heating as indicated by FT-IR and Differential Scanning Calorimetry (DSC). This is confirmed by the disappearance of the peaks due to oxazine ring (942 cm−1). The exothermic peak associated with curing was observed from 170 °C to 250 °C. The thermal and mechanical properties of the polybenzoxazines were investigated through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The temperatures corresponding to 5% and 10% weight loss is from 240 to 295 °C and from 290 to 340 °C, respectively. The completely cured materials could achieve char yields up to 36.5% at 800 °C in nitrogen atmosphere. DMA revealed that the glass transition temperatures of PBz-SUL and PBz-PHE were higher than that of PBz-DDS and PBz-OXY.