The Surface Properties Of Fatty Acids And Its Application In Inorganic Filler Surface Modification

Inorganic fillers are widely used in mordern polymer industry. It is known that the addition of inorganic fillers to polymer materials changes the properties of composites. The composites added rare earth filler contained special optical, electrical, and magnetic properties. The dispersion of the inorganic fillers in the polymer materials is very important and determines the nature and properties of the composites. The reduction of particle size results in an increased dispersion in polymer materials. However, the reduction of particle size also results in an increased surface energy and the particles reveal a tendency to agglomerate in polymers. Agglomeration decreases the reinforcement effect of fillers and leads the deterioration of mechanical properties. The surface of inorganic fillers is hydrophobic and its compatibility with the polymers is poor. The nature and properties of composites is determined by the interaction between the fillers and polymer materials, so it is significant that the surfaces of inorganic fillers can be modified with organic compounds to reduce the surface energy of particles and improve compatibility between fillers and polymers. Fatty acids(FA), due to simultaneous containing carboxyl and alkyl group, were used as surface modifier.Inverse gas chromatography (IGC) at infinite dilution method was used to investigate the surface properties of nonvolatile materials and determine the molar adsorption free energy (△Ga) of probes on materials, the specific adsorption free energy (△GaSP) of polar probes on materials, the surface energy dispersive component (ysD) and the acceptor (KA) and donor (KD) parameters of materials. The main contents of this thesis were as follows:1. Introduction. Relevant literature were searched and cited in this part. The influences of addition of fillers on the nature and properties of composites were described; the defects of inorganic filler in application were briefly introduced; the applications of IGC method in the surface characterization of materials were described; and the purpose, significance and contents of this study were expounded.2. Study on the surface properties of FA by IGC. The retention time of probe molecular on FA were measured by IGC; the physicochemical parameters (△Ga、△GaSP, γsD, KA and KD) were calculated; the correlations between these physicochemical parameters and FA structure (carbon chain length and unsaturated degree) were discussed; the reasons were speculated, for the△GaSP value of n-alcohols on FA surface calculated by Papirer is positive.3. Study on the surface properties of samarium oxide modified with FA by IGC. The influences of FA on the Sm2O3surface were determined by IGC; the retention time of probe molecular on Sm2O3modified with FA were measured; the physicochemical parameters (△Ga、△GaSP, γsD,KA and KD) were calculated; the correlations between these physicochemical parameters and FA structure (carbon chain length and unsaturated degree) were discussed; the reasons were further speculated, for the△GaSP value of n-alcohols on FA surface calculated by Papirer is positive.The retention time of probe molecular on polymer (polyethylene, natural rubber and EPDM) were measured by IGC; the physicochemical parameters (△Ga、△GaSP, γsD, KA and KD) were calculated; the compatibility between polymer and Sm2O3were analyzed according to the physicochemical parameters; the reasons were verified, for the△Gasp value of n-alcohols on FA surface calculated by Papirer is positive.