Preparation and Characterization of Blocked PAPI with Sodium Bisulfate
Preparation and Characterization of Blocked PAPI with Sodium Bisulfate
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硫酸氢钠封闭 PAPI 的制备及表征
DOI：
10.1163/156856111x618506
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发表时间：
2012-06
影响因子：
2.3
通讯作者：
中科院分区：
文献类型：
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作者：
摘要采用硫酸氢钠作为封端剂，对多亚甲基多苯基异氰酸酯（PAPI）进行了封端。通过改变搅拌速度，研究了封端异氰酸酯乳液的粒径分布速率及影响乳液稳定性的因素。此外，使用多种方法表征封端异氰酸酯。为了确定制备封端异氰酸酯的最佳搅拌速度，采用激光粒度分析仪和热重分析仪分别测定了封端异氰酸酯乳液的粒径分布率和稳定性。实验结果表明，封闭率为96.77%，在搅拌速度为400 r/min时，封闭型异氰酸酯乳液的分散性最好，稳定性最高。采用XPS、FTIR、DSC、TGA等分析手段对封端产物进行了表征，并对封端异氰酸酯进行了定量分析。采用XPS、FTIR、DSC和TGA等分析方法对产物的各组分进行了定性分析。结合定量分析，仪器分析的阻断率为86.18%。这低于通过化学分析测量的阻断率的96.77%的值。本工作可为研究人员区分封端异氰酸酯的组分提供参考，并提供一种测定封端率的仪器分析方法。
Abstract In this work sodium bisulfate was used as a blocking agent to block polymethylene polyphenylisocyanate (PAPI). The particle size distribution rate and the factors influencing the stability of the blocked isocyanate emulsion were studied by varying the stirring speed. Furthermore the blocked isocyanate was characterized using a variety of methods. In order to determine the best stirring speed for preparing blocked isocyanate, a laser particle size analyzer and thermo gravimetric analysis were used to the measure particle size distribution rate and the stability of the blocked isocyanate emulsion, respectively. Experimental results show that blocked rate was 96.77%, and that the blocked isocyanate emulsion dispersion was best, and had the greatest stability, at the stirring speed of 400 r/min. Different solvents were used to wash the blocked isocyanate emulsion and the freeze-dried product. Analysis by XPS, FTIR, DSC and TGA were used to characterize the blocked products, and the blocked isocyanate was also quantitative analyzed. Results from XPS, FTIR, DSC and TGA analytical methods were able to qualitatively analyze the various components of products. Combining these results with the quantitative analysis the blocked rate of instrument analysis was found to be 86.18%. This was lower than the value of 96.77% for the blocked rate measured by chemical analysis. This work could provide a reference for researchers to distinguish the components of blocked isocyanates and provide an instrument analysis method for measuring the blocked rate.