聚合物共混物的超高效液相色谱-空间排阻色谱在线联用分离与表征

黏合剂和涂料行业中, 聚合物共混物表征是分析的难题, 分离技术的研究一直备受关注. 本文设计并搭建了超高效液相色谱-空间排阻色谱在线联用系统(UHPLC-SEC)， 采用羟基聚丁二烯(HTPB)考察了二维色谱系统的溶剂兼容性及正交性， 以苯乙烯-丁二烯嵌段共聚物(SBS)、 苯乙烯-异戊二烯嵌段共聚物(SIS)和聚甲基丙烯酸酯(PMMA)共混物研究了二维色谱系统的适用性. 结果表明, HTPB分子量及分布的UHPLC-SEC测定结果与SEC测定结果一致, 峰尖分子量(M_p)为3407 Da, 重均分子量(M_w)为6573 Da, 分散系数(PDI)为2.36, 相对标准偏差(RSD)均小于5.7%, 系统的溶剂兼容性和正交性良好. UHPLC-SEC法测得聚合物共混物中PMMA, SBS和SIS的M_p, M_w和PDI与单个聚合物的SEC测定结果的相对误差均小于7.1%. PMMA, SBS和SIS共混物在200 °C加热3 h后, PMMA 稳定不变, SBS和SIS组分明显降解. UHPLC-SEC在线联用方法对聚合物共混物的表征结果准确、 重复性好, 为聚合物配方产品的失效分析提供了一种重要且有效的手段.

Separation and Characterization of Polymer Blends Using Online Ultra-high Performance Liquid Chromatography-Size Exclusion Chromatography

The characterization of polymer blends is a difficult problem in adhesives and coatings industry， and the studies on the separation of complex mixtures are always popular. In this paper， an online ultra-high performance liquid chromatography-size exclusion chromatography（UHPLC-SEC） system was designed and set up. The solvent compatibility and orthogonality of the two-dimensional chromatography system were investigated using the hydroxyl polybutadiene（HTPB）. The applicability of the two-dimensional chromatography was studied in the separation and characterization of each fraction from the styrene-butadiene block copolymer（SBS）， styrene-isoprene block copolymer（SIS） and polymethacrylate（PMMA） blends. The results showed that the molecular weight and distribution of HTPB were determined by UHPLC-SEC， which were consistent with those determined by SEC. The peak molecular weight（M_p）， the weight average molecular weight（M_w） and the polymer dispersity index（PDI） of HTPB were 3407 Da， 6573 Da and 2.36， respectively， and the relative standard deviations（RSDs） were less than 5.7%. Moreover， the solvent compatibility and orthogonality of the system were good. Compared to the existing SEC method， the relative errors of M_p， M_w and PDI of PMMA， SBS and SIS fraction measured by UHPLC-SEC were all less than 7.1%. The PMMA remained stable after the mixture of PMMA， SBS and SIS was heated at 200 ℃ for 3 h， while SBS and SIS components degraded significantly. Due to the good accuracy and reproducibility of the UHPLC-SEC method in the characterization of the polymer blends， it is suitable for the failure analysis of the polymer formulations.