Processing and Characterization of Composites Curing by Microwave Irradiation

Abstract

The present study aimed to assess the curing of composites based on fiberglass and epoxy resin subjected to various microwave irradiation power level and time. The conditions studied were monitored in order to provide thermal images of different times during the irradiation, allowing the visualization of the temperature distribution over time on the test specimens . The heating profile tests resulted in samples that were later analyzed. Pores and voids content, density and thickness were also evaluated according to ASTM. The existing composite were then analyzed via optical microscopy.The samples obtained by thermal curing are less than the amount of pores and voids. Moreover, the cure via microwave required only twenty minutes to accomplish what has been produced in more than thirty hours of thermal curing.

Accelerated microwave curing of fibre-reinforced thermoset polymer composites for structural applications: A review of scientific challenges

“…Polymer/PPO-GNR However, several studies have conducted on successful (without degradation) accelerated curing of epoxy resins by means of controlled microwave heating [29,30,33,66,[90][91][92][93][94][95][96][97][98]. As reported in [99] microwave heating offers distinctive advantage of having a controlled selective and volumetric heating at a reduced duration compared to thermal rapid heating which is a time and energy consuming process.…”

“…Microwave heating is in the form of radiation in which energy is dissipated volumetrically as a result of the interactions between the material(s) and microwaves at molecular scale [85]. Microwave dielectric heating has been employed in a variety of applications such as vulcanisation of rubber [121], heating of foods [122,123] and bonding of composites [30,86,90,98]. Epoxies may be cured by absorbing microwave energy from a high frequency field and converting it to heat energy via molecular vibrations/rotations in the presence of an alternating field ( Figure 6).…”

“…Answering these questions would require scientific studies of microwaving mechanisms at molecular level at both epoxy bulk and epoxynanomaterial interface before a rapid process cycle is realised at full (macro) scale. Also, the presence of carbon fibres can prevent microwave penetration [29][30][31][32][33]94]. Overcoming the challenges with the exposure of dissimilar materials (e.g.…”

“…It therefore appears well-recommended to use for the curing of resins either in isolation or as part of reinforced composites during production, or as a means of curing sections of polymer bonds, and therefore for bonded joints. However, the mechanical performance of resins can deteriorate due to microwave exposure [29][30][31][32][33] and the presence of carbon fibres that prevent penetration, suggesting that microwave is not currently a reliable means for the manufacturing of high performance composite structures. These issues with the quality of microwave processed composites, in association with variabilities caused by curing parameters (e.g.…”

Predicting the suitability of microwave formulation using microwave differential thermal analysis (MWDTA)

“…In contrast to the use of microwave radiation as an analytical tool, a comparatively large volume of research has been undertaken to investigate the effects (and potential benefits) of using microwaves in a formulation capacity. For example, it has been shown that microwave radiation can affect the viscosity and gelatinisation of industrially utilised starch [8], be applied to synthesise novel maize protein-based functional materials [9], curing composites [10], enhancing rates of reaction [11] and considered for biodiesel production [12]. Possibly the most researched area of microwave-based formulation is regarding pharmaceutical applications where the limited physicochemical properties of compounds can be a significant barrier in the development of new medicines, thus requiring intervention, such as through alternative formulation methods including microwave heating, to enhance their properties.…”