Inverse Gas Chromatography Characterization Of Polymer Properties

The mechanical properties of materials with two or more components are strongly influenced by the properties of the interface or interphase on the other. In case where there is no chemical bonding between the components, and the surface of the material is smooth, the interaction between the components is of physical nature and the strength of the dispersive and acid-base interaction forces is essential for the adhesion between the components and therefore for the properties of the material.For a specific design of interfaces (and interlowphases) it is essential to know the surface thermodynamics of the components. Inverse gas chromatography (IGC) at infinite dilution is a straightforward and very sensitive technique for the characterization of polymer systems. The IGC is based on interactions of known probe molecules with an unknown sample that serves as stationary phase of a chromatographic column. From these interactions, sample properties can be concluded. This paper characterized several polymers before and after surface modificaion using Inverse gas chromatography, the surface properties of the polymer including dispersive content of surface energy, as well as the surface Acid-base properties of the polymer were estimated, and are expected to predict the effect of the modification.The surface of high molecular weight polyethylene partical was modified by horseradish peroxidase catalyzed grafting reaction with acrylamid and acrylic acid as monomer in the presence of hydrogen peroxide. The surface property of polyethylene before and after grafting modification was compared by inverse gas chromatography. The behavior of the polymers was compared by means of dispersive contributions of the surface free energy, which is a measurement of dispersive interactions, as well as the K_A, and K_B values describe the ability of a polymer surface to act as electron acceptor or donor. The results showed that the γ~d_s increased after grafting, and the virgin PE surface exhibits an amphoteric character though more strong acidity, the grafted PE showed a predominantly basic surface.The surfaces of high performance fibers including ultrahigh molecular weight polyethylene, PBO and Kevlar fiber were treated with 65% nitric acid, surface propertiesof the polymers was compared by comparing the dispersive contribution of surface free energy yds values and the K\ and Kb values describing the surface of acid base properties of the fibers. It was found that the yds value increased after acid treatment and the treated PE fiber showed an acidic surface, while the surfaces of PBO and Kevlar both showed a predominantly basic surface, the change of the surface acid base properties are expected improve the adhesion ability of fibers with the resin.The crystalline behaviors of polymethyl methacrylate grafged Cyanate resin was studied by using inverse gas chromatography probe technique, including crystallinity, melting temperature and melting range of temperature. The effect of the molecular length of linear alkane probes on the results was discussed, results showed the micro-phase seperation of the modified cyanate resin influedce the crystalline behacior greatly, the molecular chain length of linear alkanes probes had no effect on the determination of melting point and melting range of temperature, but had a greater influence on the determination of crystallinity of the copolymer. Crystallinity of the copolymer decreased after modification and decrease with the incerease of molecular chain length of linear probe.