Sustainable and self-regulating out-of-oven manufacturing of FRPs with integrated multifunctional capabilities

Abstract

With the ever increasing demand for energy reduction to stimulate sustainable development, new energy efficient manufacturing processes for advanced fibre-reinforced plastics (FRPs) are of great interest to overcome limitations of conventional autoclave or oven based manufacturing processes including high energy consumption and size restrictions. Herein, a highly energy efficient and safe out-of-oven curing method is presented by integrating a pyroresistive surface layer with intrinsic self-regulating heating capabilities, into a composite laminate. This surface layer consists of a nanocomposite film based on graphene nanoplatelets (GNPs) and high density polyethylene (HDPE) and possesses self-regulating Joule heating capabilities, which can be used to cure epoxy based composites at a desired temperature without the risk of over-heating.Moreover, the thermoplastic nature of the surface layer enables easy fabrication with good flexibility for complex shapes. Compared to state-of-the-art out-of-autoclave oven curing, the proposed out-of-oven Joule heating approach consumed only 1% of the energy required for 2 curing, with no effect on mechanical performance and glass transition temperature (Tg) of the final composite. Moreover, the integration of the self-regulating heating layer offers additional functionalities to the cured composites, like strain or damage sensing as well as the potential of de-icing without affecting the internal structure and performance of the laminate. The presented smart heating layer provides a novel solution for sustainable manufacturing as well as real-time structural health monitoring (SHM) throughout the components' life for multifunctional composite applications in the field of renewable wind energy and aerospace.

The effect of conductive network on positive temperature coefficient behaviour in conductive polymer composites

“…Benefiting from a large variety of polymer matrices and conductive fillers available, conductive polymer composites (CPCs) can be easily fabricated with desired properties, fulfilling a broad spectrum of requirements in various applications. By combining different polymer matrices and conductive fillers, not only the electrical and mechanical properties of CPCs can be tuned and tailored to specific target requirements, but other functionalities can also be introduced such as sensitivity to a number of external stimuli including strain [1][2][3], humidity [4], temperature [5][6][7], liquid [8] and damage [9][10][11].…”

Instabilities driven by frontal polymerization in thermosetting polymers and composites

“…For the fiber volume fraction φ = 0.15, we solve the set of PDEs described by (6) to study the effects of convective heat loss on thermal instabilities associated with the FP-based manufacturing of carbon/DCPD composites. Figure 9 presents snapshots of the temperature (blue curves) and degree-of-cure (red curves) distributions and spatial distribution of the maximum temperature (black curves) for hP/S = 110 kW/m 3 .K and for T 0 = 15 o C (Fig.…”

“…Traditional manufacturing approaches for the fabrication of fiber-reinforced thermosettingpolymer-matrix composites rely on the bulk polymerization of the matrix phase and often require costly, time-consuming processes where the manufactured part is subjected to long and complex pressure and temperature cycles [1,2,3,4]. These traditional manufacturing processes are expensive in terms of time, energy, carbon footprint, and infrastructure costs associated with autoclaves and heated molds [5,6,7,8,9]. To address these challenges, frontal polymerization (FP) was recently demonstrated as a faster, energy-efficient alternative to composites manufacturing [10].…”

Enhanced PTC Effect in Polyamide/Carbon Black Composites

“…With the rapid development of functional and intelligent devices, there is an increasing demand for new materials, which can respond to external stimuli like strain [ 1 ] humidity [ 2 ], damage [ 3 ], or temperature [ 4 ]. Combining different polymers with conductive fillers, electrical, mechanical, or chemical properties can be tailored and tuned for the desired requirements.…”