物理化学学报

所属专题: 热分析动力学和热动力学

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BaO·4B2O3·5H2O纳米材料的制备及其对聚丙烯阻燃性能的热分解动力学方法评价

苗静, 郭睿凤, 刘志宏   

  1. 陕西师范大学, 化学化工学院, 陕西省大分子重点实验室, 西安 710062
  • 收稿日期:2019-05-14 修回日期:2019-06-12 录用日期:2019-06-12 发布日期:2019-06-17
  • 通讯作者: 刘志宏 E-mail:liuzh@snnu.edu.cn
  • 基金资助:
    国家自然科学基金(21573142)资助项目

Preparation of BaO·4B2O3·5H2O Nanomaterial and Evaluation of Its Flame Retardant Performance to PP by Thermal Decomposition Kinetics Method

MIAO Jing, GUO Ruifeng, LIU Zhihong   

  1. Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China
  • Received:2019-05-14 Revised:2019-06-12 Accepted:2019-06-12 Published:2019-06-17
  • Contact: LIU Zhihong E-mail:liuzh@snnu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21573142).

摘要: 硼酸盐是一类抑烟、低毒和热稳定性较高的无机阻燃剂,但是通常制备得到的硼酸盐颗粒在微米尺度,在聚合物基质中很难分散,限制了其在工业上的应用。所以,开展硼酸盐纳米材料的制备及其阻燃性能的有效评价研究具有重要实际意义。关于硼酸钡作为纳米阻燃剂的研究还未见报道,本文采用水热法制备了硼酸钡BaO·4B2O3·5H2O纳米片和纳米带,并通过粉末X-射线衍射仪(XRD),傅里叶变换红外光谱仪(FT-IR),热重-差示扫描量热(TG-DSC)和扫描电镜(SEM)等手段对样品进行了表征。采用热重分析(TGA)、差示扫描量热(DSC)及极限氧指数(LOI)法对聚丙烯/BaO·4B2O3·5H2O复合材料的阻燃性能进行了研究;考虑到聚丙烯/BaO·4B2O3·5H2O纳米片和纳米带复合材料接近的TG失重和LOI,所以进一步通过非等温热分解动力学方法进行了评估。伴随着TG质量损失的减少,DSC在N2气氛下吸收热的增加,氧指数值的增加,以及热分解表观活化能的增加,制备样品BaO·4B2O3·5H2O的阻燃性能由块体到纳米带再到纳米片依次增强,这与样品尺寸依次减小一致。通过对燃烧后残渣的扫描照片分析,对其阻燃机理进行了探讨。另外,对聚丙烯/BaO·4B2O3·5H2O复合材料的力学性能也进行了研究。其中,聚丙烯/BaO·4B2O3·5H2O纳米片复合材料具有最好的阻燃性能和力学性能,可以发展作为一种潜在的实用阻燃剂。

关键词: 硼酸钡, 纳米材料, 制备, 阻燃性能, 力学性能, 热分解动力学方法

Abstract: Borate is considered one of the most important additives for improving the fire-resistance of combustible polymers because of its smoke suppression, low toxicity, and good thermal stability. However, the size of prepared borate is usually in the micrometer range, which makes it difficult to disperse in a polymer matrix, thus hindering its use as fire-retardant material. The preparation and application of borate nanomaterial as flame retardant is considered an effective method. However, the preparation of barium borate nanomaterials as flame retardant has not been reported. In this paper, nanosheets and nanoribbons with different sizes for a new barium borate BaO·4B2O3·5H2O are prepared by hydrothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), Thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and Scanning electron microscope (SEM). The flame-retardant properties of polypropylene (PP)/BaO·4B2O3·5H2O composites are investigated by thermogravimetric analysis (TG), differential scanning calorimetry (DSC) thermal analysis methods and limited oxygen index (LOI) method. Considering the near TG mass losses and the near LOI values for PP with 10% prepared BaO·4B2O3·5H2O nanosheet and nanoribbon, their flame-retardant properties need to be further evaluated by non-isothermal decomposition kinetic method. The apparent activation energy for this decomposition reaction was obtained from the slope by plotting ln(β/Tp2) against 1/Tp according to Kissinger's model. With the reduction of TG mass loss, increased heat absorption in DSC under N2 atmosphere, increased apparent activation energy Ea for the thermal decomposition of PP/BaO·4B2O3·5H2O composite as well as increased LOI value, the flame-retardant performance of prepared BaO·4B2O3·5H2O samples with PP gradually improved from bulk to nanoribbon to nanosheet. This can be attributed to the decrease in the size of BaO·4B2O3·5H2O samples because the smaller sample size leads to improved dispersion and increased contact area with the polymer. The flame-retardant mechanism is discussed by analyzing the after-flame chars of the PP/BaO·4B2O3·5H2O composite in SEM images, which show that the char layer is more compact and continuous for the PP/BaO·4B2O3·5H2O nanosheet composite. The influence of loading BaO·4B2O3·5H2O nanomaterials on the mechanical properties of PP is also tested using a universal material testing machine, in which the PP/BaO·4B2O3·5H2O nanosheet composite has higher tensile strength. The PP/BaO·4B2O3·5H2O nanosheet composite has the best flame-retardant and mechanical properties, which is promising to be developed for the application as flame-retardant material.

Key words: Barium borate, Nanomaterials, Preparation, Flame retardant performance, Mechanical property, Thermal decomposition kinetics method

MSC2000: 

  • O642