Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University , Chengdu 610064, China.
ACS Appl Mater Interfaces. 2015 Jan 28;7(3):1780-6. doi: 10.1021/am507409d. Epub 2015 Jan 14.
Ammonium polyphosphates (APP) modified with piperazine (PA-APP) was used to improve the flame retardancy of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) aerogels, which were prepared via an environmentally friendly freeze-drying method. The thermal stabilities of the samples were evaluated by thermogravimetric analysis (TG); the flammability behaviors of samples were investigated by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CC) tests. TG test results showed that the 5% weight loss temperature (T5%) of PVA/MMT/PA-APP was 10 °C higher than that of PVA/MMT/APP. In combustion testing, all of PVA/MMT/PA-APP aerogels achieved V-0 ratings and have a higher LOI values than the unmodified PVA/MMT aerogel. Moreover, the aerogel with 1% PA-APP5, which means that the content of piperazine is 5% in PA-APP, decreased the cone calorimetry THR value to 5.71 MJ/m(2), and increased the char residue to 52%. The compressive modulus of PVA/MMT/PA-APP was increased by 93.4% compared with PVA/MMT/APP because of the increase in interfacial adhesion between matrix and PA-APP fillers. The densities of the PVA/MMT/PA-APP samples were slightly lower than those of the unmodified aerogels because of reduced shrinkage in the presence of PA-APP. All the tests results indicated that the incorporation of PA-APP not only improved the thermal stability and flame retardancy of aerogels but also maintained their mechanical properties.
用哌嗪（PA-APP）改性的多聚磷酸铵（APP）被用于改善通过环保的冷冻干燥法制备的聚乙烯醇（PVA）/蒙脱土（MMT）气凝胶的阻燃性能。通过热重分析（TG）评估了样品的热稳定性；通过极限氧指数（LOI）、垂直燃烧试验（UL-94）和锥形量热仪（CC）试验研究了样品的可燃性行为。TG 测试结果表明，PVA/MMT/PA-APP 的 5%重量损失温度（T5%）比 PVA/MMT/APP 高 10°C。在燃烧测试中，所有的 PVA/MMT/PA-APP 气凝胶均达到 V-0 等级，且 LOI 值高于未改性的 PVA/MMT 气凝胶。此外，添加了 1% PA-APP5 的气凝胶（即 PA-APP 中哌嗪的含量为 5%），将锥形量热法 THR 值降低至 5.71MJ/m2，并将炭残留量增加至 52%。与 PVA/MMT/APP 相比，由于基体与 PA-APP 填料之间界面附着力的增加，PVA/MMT/PA-APP 的压缩模量增加了 93.4%。由于 PA-APP 的存在，PVA/MMT/PA-APP 样品的密度略低于未改性气凝胶。所有测试结果表明，PA-APP 的加入不仅提高了气凝胶的热稳定性和阻燃性能，而且保持了其力学性能。
