Fiber Reinforced Polyester Resins Polymerized by Microwave Source

Abstract

Polyester resin based composite materials are widely used in the manufacture of fiberglass boats. Production time of fiberglass laminate components could be strongly reduced by using an intense energy source as well as microwaves. In this work a polyester resin was used with 2% by weight of catalyst and reinforced with chopped or woven glass fabric. Pure resin and composite samples were cured by microwaves exposition for different radiation times. A three point bending test was performed on all the cured samples by using an universal testing machine and the resulting fracture surfaces were observed by means of scanning electron microscopy (SEM). The results of mechanical and microscopy analyses evidenced that microwave activation lowers curing time of the composite while good mechanical properties were retained. Microwaves exposition time is crucial for mechanical performance of the composite. It was evidenced that short exposition times suffice for resin activation while long exposure times cause fast cross linking and premature matrix fracture. Furthermore high-radiation times induce bubbles growth or defects nucleation within the sample, decreasing composite performance. On the basis of such results microwave curing activation of polyester resin based composites could be proposed as a valid alternative method for faster processing of laminated materials employed for large-scale applications.

A laser scanning vibrometer for the monitoring of stiffness and density defects in fibre-reinforced plastics

“…8 So, in order to detect the material stiffness changes, vibrational tests can be employed as an alternative to flexural ones. The elastic modulus of the composite sample MW irradiated with a dose of 1.5 s/g re-increases, despite the decreasing trend shown by MW1.0 and MW1.3.…”

“…The tested polyester-glass composite samples contained different amounts of defects, intentionally induced by a microwave source during their cure reaction (8). The experimental data have been compared with those of traditional destructive tests (density measurements, electronic microscopy flexural test (FT) and simple vibration).…”

Gravity Effects of Curing Angle on Laminated Composite Structures: A Review on Novel Study

“…In accordance with the increase in the amount of initiator, the reaction rate increases while the gelation time decreases. It is realized that microwave energy can be applied to shorten the curing time [17]. The mechanical properties of a glass fiber-reinforced polyester composite that cure with microwave energy are comparable with those cured for 10 days of self-curing.…”

“…Epoxy resin cured by conventional oven-curing takes prolonged duration [17,62,68,71]. It is because the heat diffuses from the surface to the core of the material depending on the heat transfer rate.…”

“…A proper curing system can further enhance the performance. Conventionally, composites are cured via thermal treatment by transferring energy via conduction, convection, and radiation [17,18]. The raw materials in the composites, namely, reinforcement and matrix, are of the low thermal conductivity and thus requires longer curing duration.…”