拉曼峰强对比法测定PMMA/丙酮涂层液中丙酮含量

Determination of acetone content in PMMA/acetone coating solution by Raman peak contrast method

聚合物涂层膜中溶剂浓度的控制是成膜质量的一项重要指标。激光共焦扫描成像拉曼光谱仪在测量液体样品时具有高分辨率、不直接接触样品、操作便捷、快速等优点,适用于测试聚合物涂层液在干燥固化过程中溶剂的浓度。但是在测试过程中拉曼散射光的强度易受待测样品中溶剂背景噪音、折光率、检测器的稳定性以及散射池的结构等影响,为消弱或抵消这些影响,采用拉曼峰强对比法可以在一定程度上抵消非线性关系。笔者以聚甲基丙烯酸酯(PMMA)-丙酮涂层溶液为例,利用拉曼测试涂层膜中丙酮的含量。结果表明,拉曼对比法能有效地测定PMMA/丙酮涂层液中丙酮的含量,当丙酮质量分数从52%增加到100%时,丙酮质量分数(W_a)与两者的相对峰强比值(A1)呈线性关系,得到线性回归方程为A_1=-11.371 92+0.229 71·W_a,线性相关系数达到96%以上,具有良好的拟合度。

The control of solvent concentration in polymer coating membranes is an important index of film forming quality.The confocal scanning imaging laser Raman spectrometer has the advantages of high resolution,no direct contact with samples,convenient operation and fast speed in the measurement of liquid samples,and is suitable for testing the solvent concentration in polymer coating solution during drying and curing processes. But during the detection,the intensity of Raman scattering light can be easily affected by the background noise and refractive index of solvent in the sample to be measured,the stability of detector and the structure of scattering pool. In order to weaken or offset these influences,the Raman peak strength contrast method is employed to offset the nonlinear relation to a certain extent.In this paper,the content of acetone in polymethyl methacrylate（ PMMA）-acetone coating solution is detected by Raman spectroscopy.The results show that Raman contrast method can effectively determine the content of acetone in PMMA/acetone coating solution.When the mass fraction of acetone increases from 52% to 100%,the mass fraction of acetone（ Wa） will have a linear relationship with the relative peak-to-peak strength ratio（ A1）.The linear regression equation is obtained as follows： A1=-11. 371 92＋0. 229 71·Wa,the linear correlation coefficient outstrips 96%,representing a good fitness.