A comparative machinability analysis of polyimine vitrimer, epoxy and polycarbonate polymers through orthogonal machining experiments

Abstract

End-of-life management of fibre-reinforced thermoset composites is challenging due to the difficult-to-recycle reinforcements and the irreversibly polymerised thermoset matrix; therefore, researchers proposed the vitrimers as a sustainable alternative to thermosetting polymers. Although the early results of the material scientists are promising, the machinability of vitrimers has yet to be explored. Therefore, this paper aims to present a comparative machinability study of polyimine vitrimer, pentaerythritol-based epoxy (PER) and polycarbonate polymers through orthogonal machining experiments. Reflecting on the temperature-dependent properties of vitrimers, the starting temperature of the cutting tool was varied between room temperature and an elevated temperature above 155 °C. The cutting tool was heated by a 2000-W hot air gun until the surface temperature of the cutting tool, monitored by a VariocamHD thermographic IR camera (with Jenoptik IR 1.0/60 LW lens) and checked by a Fluke 51 II thermometer with a type K thermocouple, was permanently above 155 °C for 5 min. The cutting force was measured by a Kistler 9257B dynamometer, and the machined surface was characterised by a Mitutoyo Surftest SJ-400 surface roughness tester and Keyence VHX-5000 (with VH-Z20UT VH lens) microscope. The analysis of variances (ANOVA) results show that the sustainable vitrimer polymer is an appropriate substitute for thermosetting epoxy polymers, especially at low cutting temperatures.

Optimising Recycling Processes for Polyimine-Based Vitrimer Carbon Fibre-Reinforced Composites: A Comparative Study on Reinforcement Recovery and Material Properties

“…In this study, carbon fibre-reinforced polymer (CFRP) composites were fabricated. A polyimine-type vitrimer system [22,23] was applied (called VITRIMAX T130) as a matrix material, and it was acquired from the supplier Mallinda Inc. (Denver, CO, USA). The two-component system consists of an epoxy resin part and an amine functional polyimine hardener part; the combined system's viscosity is 54.8 Pa•s at 50 • C. The mixing ratio of the imine and epoxy was 2.5:1.…”