HEAT-TRANSFER AND CURE IN PULTRUSION - MODEL AND EXPERIMENTAL-VERIFICATION

Though pultrusion has existed for nearly 40 years, factors affecting t emperature and resin reactivity are not completely understood. A model is tested to help explain the effects of die temperature, line speed and initiator concentration on curing inside a pultrusion die. The mod el includes radio frequency preheating, heat conduction, heat of cure, changing thermal properties with temperature and degree of cure, and hindered heat transfer due to shrinkage of the profile away from the d ie. The analysis is compared to experimental temperature measurements for a 1-in. (25-mm) round die, where die temperature, line speed, and initiator concentration were varied. Temperature predictions by the mo del are in good agreement with the data for many of the conditions tes ted. Considerable disagreement still persists, however, under processi ng conditions with faster line speeds and lower die temperatures.