Title

Oligomeric titanates as coupling agents for fiber-reinforced composites

Date of Completion

January 1989

Keywords

Chemistry, Polymer|Engineering, Chemical

Degree

Ph.D.

Abstract

Titanate coupling agents have been used in composites with a wide variety of fillers. It has been proposed that some titanium derived coupling agents react with substrate surface protons at an inorganic interface according to the following mechanism:$$\rm METAL{-}O{-}H + (RO){-}Ti{-}(R\sp\prime)\sb3\quad METAL{-}O{-}Ti{-}(R\sp\prime)\sb3 + R{-}OH$$^ Most of the current available titanates however do not have thermal stability at temperatures above 180$\sp\circ$C, and not enough evidence of their chemical structures or bonding onto an inorganic surface has been given in the literature.^ Oligomeric titanates similar to those of high performance thermoplastics have been found to interact more readily with both the resin and the functional groups on the glass surfaces, creating a high temperature stable coupling agent. A composite material of a high performance thermoplastic and its analog titanate coupling agent present several advantages over a thermoset/fiber composite.^ Synthesis (in situ) and characterization of a high performance titanate coupling agent has been achieved by initially treating glass fibers with a solution of TiCl$\sb4$ and subsequently displacing the chlorine atoms by reaction with hydroxyl terminated polysulfone oligomers.^ The engineering properties of short fiber reinforced composites prepared with the pretreated glass fibers have been evaluated. These properties were compared with those of the composites obtained using glass fibers treated with a commercial titanate coupling agent, and with those of the composites obtained using glass fibers without any kind of treatment. ^