Characterization of cellulose degradation during accelerated ageing by SEC-MALS, SEC-DAD, and A4F-MALS methods
文摘
Size exclusion chromatography (SEC) is currently the method most frequently used for molar mass determination of cellulose, being applied to either derivatized cellulose in the form of tricarbanilates (CTC) or nonderivatized cellulose in solution of lithium chloride in dimethylacetamide or 1,3-dimethyl-2-imidazolidinone. In this work, we compared three methods of analysis of cellulose in paper subjected to accelerated ageing: size exclusion chromatography in combination with multiangle light scattering (SEC-MALS) detection, size exclusion chromatography in combination with diode-array detector and calibration using polystyrene standards (SEC-DAD), and asymmetric flow field–flow fractionation in combination with multiangle light scattering (A4F-MALS). Prior to separation, cellulose samples were derivatized with phenyl isocyanate to CTC and dissolved in tetrahydrofuran. Each of the methods provided different absolute values of molar mass, but pairwise correlations between them were linear with high correlation coefficients (r = 0.990–0.992). The highest molar mass values were obtained by the A4F-MALS method; SEC-MALS and SEC-DAD methods provided lower values, especially due to shear degradation of high-molecular cellulose chains. Keywords Cellulose Tricarbanilates (CTC) Degree of polymerization (DP) Size exclusion chromatography (SEC) Asymmetric flow field–flow fractionation (A4F) Paper degradation