Development of a new structural prepreg: characterisation of handling, drape and tack properties

This paper describes a case-study in the development of a new type of woven glass/epoxy prepreg for use in marine and civil infrastructure applications. Experimental tests were performed on the prepreg at different levels of matrix cure between 1% and 59% to determine the condition that provides the optimum handling, drape and tack properties at room temperature. Bias extension testing was used to characterise the shear resistance and residual stress, bending stiffness tests to assess the drape, and peel tests to determine the tack of the prepregs. A low level of cure (<20%) provided the prepreg with excellent handling and drape properties due to the low complex viscosity of the resin. However, the low cure level resulted in the prepreg having insufficient tack. A high level of cure (59%), on the other hand, provided poor handling, drape and tack properties. The optimum level of cure was found to be approximately 30%, which combined an acceptable level of handling, low residual stress, high drape and good tack. Based on this research, a new type of prepreg is being produced in commercial quantities in Australia for domestic use and overseas export.