The Effect of Cure Variations on Chemical and Functional Properties of Resin Bonded Friction Materials
Several resin-bonded friction materials were used to establish the interrelationship between the resin-cure state and the functional properties. Pyrolytic gas chromatography (PGC) was used to measure the cure state of the resin and the Friction Assessment Screening Test (FAST) was used to characterize the friction and wear behavior of the materials. A phenolic resin, an oil-modified phenolic resin, and two different cashew resins were used as binders for simple resin-asbestos composites as used in brake linings. Both the PGC and functional properties of these materials showed systematic variations with changes in cure conditions of the resin. For all resins studied, a linear or bilinear relationship was found to exist between the PGC measured cure state of the resin and wear as measured by the FAST machine. A chemical kinetic model was successfully applied to relate both sample wear and a characteristic PGC peak of the resin to a unique function of cure time and temperature.