FABRICATION AND MECHANICAL RESPONSE OF COMMINGLED GF PET COMPOSITES/

The mechanical properties and the response to mechanical load of conti nuous glass fiber reinforced polyethylene terephthalate (GF/PET) lamin ates have been characterized. The Laminates were manufactured by compr ession molding stacks of novel woven and warp knitted fabrics produced from commingled yams. The laminate quality was examined by means of o ptical and scanning electron microscopy. Few voids were found and the laminate quality was good. Resin pockets occurred in the woven laminat es, originating from the architecture of the woven fabric. The strengt h of the fiber/matrix interface was poor. Some problems were encounter ed while manufacturing the laminates. These led to fiber misalignment and consequently resulted in tensile mechanical properties that were s lightly lower than expected. Flexural failures all initiated as a resu lt of compression, and it is possible that the compression strength of the matrix material, rather than its tensile strength, might limit th e ultimate mechanical performance of the composites. Flexural failures for both materials were very gradual. The warp knitted laminates were stronger and stiffer than the woven laminates. The impact behavior wa s also investigated; the woven laminates exhibited superior damage tol erance compared with the warp knitted laminates.