Лако-красочные материалы — производство

Inverse gas chromatography (IGC) is a method very well used by the adhesion community for obtaining thermodynamic and morphological information on a variety of materials such as fillers, pigments, colloids, fibers, powder, wood, and polymers [17,60,61,85-94]. The term ‘‘inverse’’ means that the stationary phase is of interest by contrast to conven­tional gas chromatography in which the mobile phase is of interest. Its success lies in the fact that it is simple, versatile, usable over a very wide range of temperature, and very low cost. IGC has a well established background for the assessment of and acid-base parameters for polymers and fillers. Such thermodynamic parameters can be further used to estimate the reversible work of adhesion at polymer-fiber and polymer-filler interfaces [95,96].

IGC is based on the interfacial interactions between molecular probes and the sta­tionary phase. Probes are injected at infinite dilution so that lateral probe-probe interac­tions are negligible and the retention is governed by solid-probe interactions only. The net retention volume, VN, is defined as the volume of inert carrier gas (corrected for the dead volume) required to sweep out a probe injected in the chromatographic column. At infinite dilution (zero coverage), AGa, the free energy of adsorption of 1 mole of solute from a reference state, is related to VN by

-AGa = RT ln (27)

&тло J

where R is the gas constant, T the column temperature, P0 the partial pressure of the solute, л0 the two-dimensional spreading pressure of the adsorbed film, and S and m the

specific surface area and mass of the stationary phase, respectively [97]. Dispersive and acid-base properties of materials (e. g., polymers, fibers, and fillers) are deduced from AGa or simply RT ln(VN) data.