Influence of the glass transition of interlaminar particles on shear behaviour during cure of interlayer toughened thermoset composites

Abstract

This work investigates the effect of the glass transition of interlaminar toughening particles on the in-plane (G12) and out-of-plane (G13) lamina shear modulus during cure for an interlayer toughened prepreg system, Toray T800SC/3900-2B. The dependence of lamina G12 and G13 on temperature and degree of cure (DoC) of the resin was determined using Dynamic Mechanical Analysis (DMA). Lamina G12 is mainly governed by resin properties, whereas lamina G13 is additionally affected by particle glass transition in two different ways: first, the particle glass transition changes interlaminar microstructural characteristics such as interlayer thickness, packing morphology of particles and interlaminar particle volume fraction depending on the cure path in the pre-gelation stage, which subsequently influences lamina G13 in the post-gelation stage; in addition, the particle glass transition reduces particle shear modulus and interlayer shear modulus in the post-gelation stage, which consequently reduces lamina G13.