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With an organic/inorganic hybrid nature, silicone elastomers are amongst the most versatile engineering materials, exploited in a wide range of applications either as end-products or in manufacturing processes. In many industrial machines, silicone components are exposed to in-service conditions, such as high or low temperatures, contact with functional fluids, mechanical loading, and deformations, which can adversely affect these components and reduce their lifespan, leading to machine failure in turn. The present study investigates the behaviour of a silicone component of a manufacturing equipment and the variations in the part’s properties due to in-service conditions (temperature, exposure to heat transfer fluid, and mechanical deformation) to develop a monitoring tool. An experimental design was employed to study the main and the interaction effects of temperature (22 °C, 180 °C), medium (air, synthetic heat transfer fluid), and strain (0%, 200%) on the silicone component’s properties. Results showed that while the chemistry of the component remains intact, its thermal and in particular mechanical properties are largely influenced by the in-service conditions. Consequently, leading to a physical rather than a chemical failure of the component and limiting its service life. Statistical analysis revealed that high temperature and the exposure to the heat transfer fluid have the most sever effects. Moreover, these two manufacturing parameters were found to have a significant interaction with one another, whose effect cannot not be neglected.

The high-volume manufacture of fiber-reinforced composites faces a huge challenge because long resin curing times put a low ceiling on the total output of parts produced per year. To translate the benefits from using epoxy in large-volume production platforms, cure cycle times of less than 1 min must be achieved. In this work, we report solvate ionic liquids (SILs) as simple and efficient rapid curing catalytic additives in epoxy systems. Ultrafast curing was observed at low levels of 1−5% of SIL in epoxy resin, and the cure rate is enhanced up to 26-fold without compromising the mechanical and thermal properties. Further investigations revealed that enhancement in the cure rate is dependent on the type of SILs employed, influenced by the metal center, the ligands around the metal, and the identity of the counter anion. The relative Lewis acidity of each of the active complexes was calculated, and the rapid cure effect was attributed to the activation of the epoxide moiety via the Lewis acidic nature of the SIL. Making epoxy thermosets rapidly processable enables enormous benefits, finding applications in a whole variety of transformation methods that exist for traditional glass and metals.

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In this article, the effect of hygrothermal aging on the painted surface finish of unidirectional and fabric carbon fibre composite laminates, with and without surfacing film was investigated. The results highlighted the importance of ensuring that the composite surface directly beneath the paint layer is made from a uniform material with a consistent thickness in order to minimise surface defects from occurring during aging. The surfacing film was found to minimise the print through development on the painted unidirectional and twill composite surfaces. However, the surfacing film layer was found to intermingle with the carbon fibre plies during cure, which resulted in an uneven film thickness that caused increased levels of orange peel. The twill laminate painted surface produced high levels of print through and surface waviness that was caused by the large resin rich regions located within the tow intersections at the surface which enlarged due to thermal expansion and swelling of the matrix with hygrothermal aging. It was also noted that the small resin rich regions between the individual carbon fibres on the unidirectional composite surface were sufficiently large to print through the painted surface.

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