High performance thermoplastic matrix composite processing: dry powder prepregging, plasma treatment, consolidation/crystallization analysis

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Virginia Tech

The quest for developing high performance materials, originally responsible for the birth and growth of the composites industry, is now responsible for the drive to produce composites which outperform those used today. A great deal of this interest lies in the use of thermoplastic polymers as the composite matrix. Thermoplastics offer the potential of improved mechanical performance, greater solvent resistance, better impact tolerance, as well as cost saving processing attributes such as infinite shelf life, the ability to be recycled, short processing time and repairability. Unfortunately, these advantages come at the expense of a very high melt viscosity which makes the prepregging process, where the fiber and polymer are combined, very difficult. To overcome this and associated difficulties a detailed analysis of thermoplastic matrix composite processing is developed.

The primary area of focus involves the development of an electrostatic dry polymer powder prepregging facility. This unit is capable of the production of high quality towpreg from thermoplastic polymers and reinforcing fibers. Two approaches, statistical and stochastic, were employed to model the process of polymer deposition on the fibers in the prepregging process. These models are used to optimize the production of towpreg. A modification of the prepregging facility allows for the production of towpreg from very small (15 g) samples of polymer. This is extremely useful for analysis and performance verification of state of the art polymer systems.