Advanced Thermoplastic Composite Manufacturing by In-Situ Consolidation: A Review

Abstract

This article provides an overview of the evolution of the in-situ consolidation (ISC) process over time. This evolution is intimately linked with the advancements in each of the steps of the ISC manufacturing process, is additive in nature, and is limited by the orthotropic nature of composite materials and the physicochemical behavior of the thermoplastic matrix. This review covers four key topics: (a) Thermal models—simulation tools are critical to understand a process with such large spatial gradients and fast changes. Heating systems once marked a turning point in the development of industrial ISC systems. Today, lasers are the most recent trend, and there are three key issues being studied: The absorption of energy of light by the material, the laser profile, and the laser focusing. Several approaches have been proposed for the distributed temperature measurements, given the strong temperature gradients. (b) Adhesion—this refers to two subsequent mechanisms. In the first place, the process of intimate contact is one by which two surfaces of thermoplastic pre-impregnated composite materials are brought into contact under pressure and temperature. This enables closure of the existing gaps between the two microscopic irregular surfaces. This process is then followed by the healing or diffusion of polymer molecules across the interface. (c) Crystallinity—mostly influenced by the cooling rate, and strongly affects the mechanical properties. (d) Degradation—this refers to the potential irreversible changes in the polymer structure caused by the high temperatures required for the process. Degradation can be avoided through adequate control of the process parameters. The end goal of the ISC manufacturing process is to achieve a high product quality with a high deposition rate through an industrial process competitive with the current manufacturing process for thermoset composites.

Effect of in situ fibrillation on polyethylene/poly(ethylene terephthalate)/multiwalled carbon nanotube electromagnetic shielding foams

“…The mechanism of in situ fibrillation is because the local shear or tensile stress of the polymer matrix is greater than the deformation resistance of viscoelastic fiber‐forming phase, changing the crystal structure of fiber from triangular to hexagonal, thus weakening the cohesion between adjacent chains. [ 37 ] The fibrillated PET can improve the microfoaming effect of the PP matrix and optimize MWCNT dispersion.…”

Processing and Mechanical Properties of Basalt Fibre-Reinforced Thermoplastic Composites

“…With increasing demand for lightweight, sustainable materials for metal-replacement in various industries, the global thermoplastic composite market has been projected to reach USD 16.3 billion by 2023 [ 12 ]. Thermoplastic composites can be recycled and welded, allowing composites to be part of a circular economy and also offer the possibility of forming large composite structures in a shorter timeframe [ 13 , 14 , 15 ]. However, the research for thermoplastic composites is less established than that for thermoset composites due to issues such as fibre-matrix compatibility, high processing temperatures, and processing difficulty [ 13 , 14 , 15 , 16 ].…”

Star-Branched Polyamides as the Matrix in Thermoplastic Composites

“…The use of thermoplastic matrices in the manufacturing of composites has been recently discussed in the literature to increase process rates [ 4 , 5 , 6 , 7 ]. These matrices can melt and solidify in very short times, which translate into very low cycle times and greater economic profitability.…”