中国塑料 ›› 2023, Vol. 37 ›› Issue (10): 77-84.DOI: 10.19491/j.issn.1001-9278.2023.10.011

• 标准与测试 • 上一篇    下一篇

增容剂马来酸酐接枝聚丙烯接枝率的酸碱反滴定法测定误差分析

李朝1(), 贾元山2   

  1. 1.西安工业大学材料与化工学院,西安 710021
    2.西安新思路橡塑材料有限公司,西安 710025
  • 收稿日期:2023-05-09 出版日期:2023-10-26 发布日期:2023-10-23
  • 作者简介:李朝(1970—),工程师,研究方向为聚合物成型加工及改性,lizhao@xatu.edu.cn

Error analysis of determination for grafting ratio of compatibilizer maleic anhydride⁃grafted polypropylene through acid⁃base back titration

LI Zhao1(), JIA Yuanshan2   

  1. 1.School of Materials and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China
    2.Xi'an New Concept Rubber and Plastic Materials Co,Ltd,Xi'an 710025,China
  • Received:2023-05-09 Online:2023-10-26 Published:2023-10-23

摘要:

基于误差传递公式,对马来酸酐接枝聚丙烯(PP⁃g⁃MAH)接枝率的酸碱反滴定法测定建立了误差模型,讨论了取样量、HCl⁃异丙醇溶液浓度和接枝马来酸酐含量对接枝率测定误差的影响。实验室制备了PP⁃g⁃MAH,进行了红外光谱分析,分别以不同取样量、HCl⁃异丙醇溶液浓度对接枝物进行了接枝率测定;对比了不同马来酸酐含量PP⁃g⁃MAH的接枝率测定误差。结果表明,马来酸酐已接枝在PP分子链上;PP⁃g⁃MAH的沉析及对KOH的包裹效应是接枝率测定误差大、再现性差的主要原因;酸碱滴定溶液浓度减小、取样量增大可减小测定误差,HCl⁃异丙醇溶液浓度为0.01 mol/L时可取得最小测定误差;所制备PP⁃g⁃MAH在HCl⁃异丙醇溶液浓度为0.01 mol/L、取样量为0.2 g时,测定接枝率的相对标准偏差为32 %;所建误差模型可用于优化PP⁃g⁃MAH接枝率测试条件,减小测定误差。

关键词: 聚丙烯, 马来酸酐, 接枝率测定, 增容剂, 误差传递公式

Abstract:

Based on the error propagation formula, an error model was established for the determination of grafting ratio of PP⁃g⁃MAH through acid⁃base back titration. The effects of sampling amount, concentration of HCl⁃isopropanol solution, and content of grafted maleic anhydride on the determination error of grafting ratio were investigated. PP⁃g⁃MAH was prepared in the laboratory and analyzed by using infrared spectroscopy. The grafting ratio of samples was determined through acid⁃base back titration at different sample amounts and HCl⁃isopropanol solution concentrations. The determination errors of two different maleic anhydride contents of PP⁃g⁃MAH were compared. The results indicated that maleic anhydride was grafted onto the PP molecular chain. The precipitation of PP⁃g⁃MAH and the entrapment effect on KOH were considered as the main reasons for a large determination error and poor reproducibility of grafting ratio. The reduction of the concentrations of acid and base titration solutions and the increase of the sampling amount could reduce the determination error. The minimum determination error was achieved when the concentrations of acid and base titration solutions were 0.01 mol/L. The relative standard deviation of grafting ratio of the prepared PP⁃g⁃MAH was 32 % when the sampling amount was 0.2 g and the concentrations of acid and base titration solutions were 0.01 mol/L. The established error model can be used to optimize the test conditions for the grafting ratio PP⁃g⁃MAH and reduce the determination errors.

Key words: polypropylene, maleic anhydride, grafting ratio, compatibilizer, error propagation formula

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