MATERIAL STATE MODELING DURING COMBINED RAMPAND ISOTHERMAL CURE CYCLES FOR POLYMERCOMPOSITES USING SHEAR RHEOMETRY AND THERMALANALYSIS

摘要

This paper presents viscosity and degree of cure modeling for a commercial carbon fiber prepregrn(977-2 UD) in combined ramp and isothermal cure cycles. Since the degree of cure (DOC) is anrnimportant parameter in polymer composite viscosity modeling, first DOC for combined ramprnand isothermal cure cycles was modeled. The experimental data for DOC modeling was obtainedrnusing a Differential Scanning Calorimeter (DSC) and the baseline issue of the DSC heat flowrncurves was addressed. Once the DOC was modeled and complex viscosity of the prepreg wasrnobtained using an Encapsulated Sample Rheometer (ESR), a viscosity model was applied to therncomplex viscosity data. Finally the data and the models for both DOC and viscosity wererncompared. The results showed that the models closely followed the experimental data. Thernviscosity and the degree of cure models can be used as a tool to provide a direct estimation of thernmaterial state during cure in composite processing.