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PET/AlOOH纳米复合材料的制备及性能研究
【作者】 张萍；
【导师】 夏延致；
【作者基本信息】 青岛大学 ， 材料学， 2008， 硕士
【摘要】 采用原位聚合法制备PET/AlOOH纳米复合材料,将纳米AlOOH的乙二醇溶胶加入到制备PET的中间产物对苯二甲酸乙二醇酯(BHET)中,在液态下均匀混合,再经过缩聚反应制得PET/AlOOH纳米复合材料,对制得的复合材料进行了结构表征及性能分析研究。通过红外测试,发现纳米AlOOH确实存在PET基体中,证实制备出PET/AlOOH纳米复合材料。且通过TEM图像可以看出AlOOH的粒径在二十纳米左右,均匀分散在PET基体中,没有形成团聚。通过TG测试对PET和PET/AlOOH纳米复合材料的热降解动力学进行的分析研究表明,PET/AlOOH纳米复合材料初始阶段的降解活化能降低,其它阶段的活化能明显提高。这说明,在降解过程中的高温阶段,AlOOH使复合材料降解变得困难。通过DSC对非等温结晶动力学的研究表明,由于复合材料中AlOOH表面接枝了一定量的PET大分子,引起部分交联结构,严重限制了PET大分子的活动,因此复合材料中的AlOOH对PET的结晶起到阻碍作用。通过CONE对材料的燃烧性能研究表明,虽然PET/AlOOH纳米复合材料的点燃时间较普通PET缩短,但是AlOOH的加入明显降低了复合材料的热释放速率、热释放速率峰值及峰值出现时间、总热释放量,因此AlOOH可以在一定程度上延缓复合材料的燃烧过程,具有阻燃性能。通过扫描电镜对残炭进行了研究,可以看出纯PET燃烧产物的炭层比较薄产生的泡比较大;PET/AlOOH纳米复合材料的燃烧产物形成的炭层比较厚,产生的泡很小。通过裂解色谱研究了其阻燃机理,PET/AlOOH纳米复合材料裂解产物比纯PET明显的少,说明阻燃剂的引入是聚酯分解不彻底,减少可燃性物质的生成。
【Abstract】 PET/AlOOH nanocomposites were synthesized via the in-situ method.Firstly, terephthalic acid was reacted with excess ethylene glycol to form bis(hydroxyethyl) terephthalate(BHET);Second,the boehmite(AIOOH) was added into the BHET and mixed homogeneously with it,then concurrent with polycondensation of BHET to produce the PET matrix.The characterization and properties of PET/AlOOH nanocomposites prepared by in-situ method were investigated.The composites examined by FT-IR showed to be boehrnite,which indicated that boehmite had been added into PET matrix.The TEM image showed that the boehrnite particles ranged from about several to tens nanometers in diameter.The nanoparticles were dispersed well in PET matrix.The kinetics of thermal oxidative degradation of pure PET and PET/AlOOH nanocomposites were investigated by TGA.The results showed that nano AlOOH enhanced the activation energy of different degradation steps except the initial step of degradation,which showed that nano AlOOH made the degradation of PET become difficult at high temperature.The nonisothermal crystallization kinetics of pure PET and PET/AlOOH nanocomposites were examined by DSC.The results showed that these boehmite particles made the crystallization capability of PET decline.Because the crosslink structure of PET/AlOOH nanocrnpsite dramatically restricted the movement of PET chains so as to cause the decrease of crystallization capability.The flame retardancy was investigated by CONE.Although the initial ignition time of PET/AlOOH nanocomposite were shorter than that of pure PET,the heating release rate, peak of heating release rate and its time,total heating release of PET/AlOOH nanocomposites were all lower than those of pure PET.So the boehmite could retard the burning processes of PET/AlOOH nanocomposite.The carbon layers under SEM,the char of pure PET was very thin and the hole was bigger. The char of PET/AlOOH was very thick and the hole was smaller.The flame retardant can make more carbon formation during buming,so the carbon layer formed after addition of AlOOH.The existing of a lot of fine holes may be because of the action of AlOOH.