Synthesis of aromatic diamine-based benzoxazines and effect of their backbone structure on thermal and flammability properties of polymers

Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively (designated as BAPNCP, BAPBACP and BAPNPGCP, respectively), were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly(BAPNPGCP) were 8 °C and 7% higher than those of poly(BAPBACP). Meanwhile, the total heat release of poly(BAPNPGCP) was less than half of that for poly(BAPBACP), indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly(BAPNCP) gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.     

《高分子化学实验》课程的教学改革与学生实践能力培养

《高分子化学实验》课程是培养高分子专业人才的重要实践环节。本文就如何激发学生的学习兴趣和创造欲望、开设综合性实验项目、实验教学与科研相结合和改进实验考核方式等方面的措施,对《高分子化学实验》的教学内容和教学方法进行改革。旨在培养和提高学生的实践能力和创新能力,强化学生的综合素质和应用能力。     

PEI/PAA/APP三组分膨胀组装涂层阻燃改性苎麻织物

利用聚乙烯亚胺(PEI)的正电荷性及聚磷酸铵(APP)和聚丙烯酸(PAA)的负电荷性,通过层层组装技术在柔顺多孔的苎麻织物表面交替构筑了(PEI/PAA/PEI/APP)n膨胀型阻燃涂层,并对处理前后的苎麻织物的热稳定性和阻燃性等性质进行了表征.热失重分析(TGA)、微型量热仪(MCC)以及垂直燃烧测试(VFT)结果表明,阻燃处理后织物的热稳定性和阻燃性显著提高.同时与(PEI/APP)n试样相比,引入不同浓度的第3组分PAA在组装层数较少时通过增加PEI的电荷密度等作用可有效增加吸附量从而使上述性能有所提高,层数较高时由于APP和PAA的同性电荷紊乱,阻燃性的提升受到限制.     

新型生物基苯并嗪的合成及性能

以生物基糠胺、 酚酞和多聚甲醛为原料, 制备了一种新型生物基苯并噁嗪树脂——酚酞糠胺型苯并噁嗪树脂(PPTL-F-BOZ), 采用FTIR, ¹H NMR和 ¹³C NMR等手段对其单体PTL-F-BOZ的结构进行了表征, 并对其固化反应、 耐热和阻燃性能进行分析. 结果表明, 与传统的化石基双酚型苯并噁嗪——双酚A苯胺型苯并噁嗪(BPA-A-BOZ)相比, PTL-F-BOZ显示出较低的固化反应温度, 且糠胺中呋喃环的存在会增加聚合物的交联密度, 并减缓苯氧结构向苯酚结构的重排反应, 致使其在DSC曲线中出现了2个固化峰. PPTL-F-BOZ树脂具有较高的T_5%(质量损失5%的温度)和800 ℃的残炭率, 其极限氧指数(LOI)高达36.2%, 在垂直燃烧中达到V-0等级, 表现出优异的热稳定性和阻燃性能.     

虚拟仿真项目在高分子材料与工程专业实验教学中的实践

应用于实践性较强的高分子材料与工程专业实验教学中的虚拟仿真技术,是学生提高发现问题、解决问题和动手能力,培养高素质创新型人才的重要手段.本文探讨与实践"阻燃改性聚合物热氧化降解与燃烧过程测试"虚拟仿真实验教学项目的建设情况和在专业实验教学中的应用.其教学效果充分体现了在线实验教学的有效性和与传统实验教学模式的相容性,同...     

独立学院高分子材料与工程专业建设的实践与思考

独立学院是我国高教办学思路、体制、模式与机制的一次大胆创新,以其面向社会、市场自主办学,设置社会和市场所需要的学科专业,合理定位,注意学生就业等优势,在已有的高教发展体系与模式中,寻找到了自己的发展空间.本文以浙江大学宁波理工学院高分子材料与工程专业建设为例,通过增加硬件投入、加强师资队伍、优化培养方案、完善实践体系四...