REACTIVE COUPLING OF FIBERS TO ENGINEERING THERMOPLASTICS

In order both to protect fibers from mechanical damage during processi ng and to promote fiber-matrix adhesion between constituents in a fibe r reinforced plastic, coupling agents are employed to chemically bond the reinforcing fibers to the polymeric matrix. In fiber reinforced th ermoplastic composites, the likelihood of covalent bonding is remote a nd it becomes necessary to rely on modification of interfacial tension to promote compatibility. The lack of covalent bonding, however, invi tes loss of long-term durability upon exposure to hostile environments . In this work, two examples of tailoring interfaces to create conditi ons for reactive coupling through covalent bonding between fiber reinf orcement and thermoplastic matrices are described. In one case, oligom ers of polysulfone and polycarbonate are grafted to E-glass fibers to promote chemical bonding to the corresponding thermoplastic. In a seco nd example, a partially stable thermotropic liquid crystalline polymer is used as a compatibilizing agent between a highly aromatic fiber an d a thermoplastic matrix.