Solid state bonding of graphite/thermoset composites via interchain transesterification reaction (ITR)

Thick section composite laminates are expensive and difficult to manufactur e because of problems with porosity, large reaction exotherms from epoxies and residual strains. The copolyester thermosets described here can elimina te these problems. Through interchain transesterification reactions, indivi dually cured prepreg plies of graphite reinforced copolyester can be bonded with each other in the solid state. ITR bonding is shown to produce well-c onsolidated laminates with less than 2% void volume and mechanical properti es comparable to those of current high-end polymer matrix composites. DMA t esting showed the glass transition to begin at 190 degreesC for a 45% fiber volume fraction composite. Tensile testing of 55% fiber volume composites at room temperature shaved modulus, strength and elongation to failure aver ages of 105.4 GPa, 1.02 GPa and 1.0% respectively.