SCIENCE AND TECHNOLOGY OF THERMOSET PREPREGS

Prepregs or pre-impregnated materials are semi-finished products which consist of a reinforcing material and a polymer and it is ready to form the final product, and while the polymer is a thermoset material, it is partially crosslinked. In other words, prepregs are mixtures of resins and reinforcing materials that can be easily molded. They have been widely used to produce structural composite parts. A large proportion of composite parts are being made by using prepregs. The processing parameters in the manufacture of prepregs are essential in the development and optimization of a prepreg. It is important to understand the prepreg system from processing, structure and property viewpoints. Although the prepreg materials have been used for a few decades but, no data have been published on their manufacturing conditions. We have done a comprehensive and a systematic work and focused on the manufacturing parameters. For this purpose we designed and manufactured a labscale prepreg production machine in order to be able to investigate production parameters. In this work, epoxy/glass and phenolic/glass prepregs have been prepared. It is very important to use a suitable formulated resin system and control the level of resin pre-cure to have a prepreg with optimum handling, drape and tack properties. Results show that as the temperature in heating column increases, the gel time decreases. The resin and volatile content of prepreg samples were measured. The range of pre-cure was observed to be between 5 to 40%. Processing characteristics, like resin flow and tack were measured at different levels of precures. Based on the results, a type of epoxy/glass and a type of phenolic/glass prepreg with optimum processing condition were produced. It has been shown that it is possible to go through science to technology by a systematic comprehensive work.

کلیدواژه ها:

epoxy ، phenolic ، glass ، prepregs ، flow ، pre-cure ، tack