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In recent years, a few research studies have been published on the blending of unsaturated polyester and phenolic resins for the purpose of improving the fire properties of unsaturated polyester resins. However, there has been no published study on the cure and strain monitoring of unsaturated polyester/phenolic blends during composite manufacturing. In this study, non-crimp triaxial glass fabric preforms were infused with the unsaturated polyester/phenolic blends, and the strain developments inside the composites were monitored using fibre Bragg grating sensors, as the long and complex curing stages were progressing at different temperatures. Strain-free fibre Bragg grating sensors and also thermocouples were utilised for temperature monitoring and compensation in order to obtain true strain developments and residual strains. The results were associated with a study presenting the cure analyses of unsaturated polyester/phenolic blends. The unsaturated polyester and the phenolics were found to be incompatible and exhibited different curing mechanisms in the blends, which were also observable in the strain development results. This paper has been the first attempt to (i) process these novel resin systems in the vacuum infusion process and (ii) monitor the long, complex and high-temperature cure cycles and the strain developments in the vacuum infusion process using fibre Bragg gratings. [ABSTRACT FROM AUTHOR]

This study presents the cure kinetics and cure modelling of an ambient curing unsaturated polyester (UP) resin system for its cure simulation in the vacuum infusion (VI) process. The curing of the UP resin system was investigated using differential scanning calorimetry (DSC). The dynamic DSC test measurements were conducted to find out the ultimate heat of reaction and enable experimental conversion determination for the isothermal curing. The empirical autocatalytic cure kinetics model incorporating the Arrhenius law represented the cure behaviour. The results of the cure kinetics study, the cure model, the material properties and the boundary conditions were the inputs in PAM-RTM software for the simulation of the degree of cure and the exothermic temperature during the infusion and the room temperature curing stages. The simulation results were compared with experimentally measured data. A vacuum infusion (VI) experiment involving a non-crimp glass fibre preform was performed in order to monitor the curing using thermocouples and validate the temperature simulation result. It was shown that the degree of cure and the exothermic temperature of a room temperature curing thermoset resin system during the VI process could be predicted through the steps of this study. [ABSTRACT FROM AUTHOR]