An acrylic resin system for in-situ pultrusion: Curing performances and rheology

In recent years, the use of low viscosity and in-situ polymerizable thermoplastic acrylic resins for advanced fiber reinforced composites has grown, specially to address the difficulty of fiber impregnation with high-melt viscosity thermoplastic polymers. The present work investigated the curing kinetics, chemo-rheology of an acrylic resin system for in-situ pultrusion, and proposed the corresponding constitutive models. First, the curing kinetics was studied with the differential scanning calorimetry experiments. The viscosity development was obtained by a rheometer as functions of the degree of cure (DOC) and temperatures. The gelation point was acquired from the intersection point of storage and loss modulus curves through dynamic mechanical analysis test, which occurs at DOC of 0.65 determined by the cure kinetics model. Through the dynamic mechanical analysis, a four step cure hardening modulus model (modified CHILE approach) was proposed. The aforementioned models were applied in a case study to evaluate the influence of process parameters on the DOC, viscosity and physical behavior of the acrylic resin system in the pultrusion die. Highlights: Material characterizations of an acrylic resin system are investigated. The cure kinetics and viscosity and elastic modulus models are proposed. A pultrusion case study is given.