Micro‐injection molding of CNT nanocomposites obtained via compounding process

Abstract

Many research efforts have gone in the production of carbon nanotubes (CNT) composites for functional and structural applications and many processing methodologies have been experimented. Twin-screw extrusion appears to be the most suitable way from the perspective of production scale up and commercialization of these composites. At the same time, micro-injection molding process is considered as the key manufacturing technology for the mass production of miniaturized components and devices. Despite the massive literature about nanocomposites and microinjection molding process, few articles focus on the interaction between the compounding process and the following micro-injection molding transformation processes. This article aims at analyzing the influence of the screw configuration used in compounding process on the rheological and technological properties of the resulting nanocomposites. Two different combinations of screw elements have been tested to incorporate CNTs in two different resins: LCP (liquid crystal polymer) and POM (polyoxymethylene) typically used in micro-injection molding. The effects of the process set up have been observed studying first the rheology and then the moldability of nano-compounds microinjected ribs with high aspect ratio. The nanofiller dispersion has been evaluated via light and transmission electron microscopy. The results confirm that, the screws show different capacity at promoting the dispersion of the nanofiller, which affects the moldability of micro-injected CNT nanocomposites. The viscosity of the polymer seems a critical factor as well, because it influences first the dispersion of CNT bundle during extrusion and then the injection moldability of the composites in the micro-channels

Mechanical characterisation and replication quality analysis of micro-injected parts made of carbon nanotube/polyoxymethylene nanocomposites

“…MCR 300) using plate/plate geometry (diameter of 25 mm), at 190℃. The results 37 suggest that the level of dispersion of the nanotubes, for both the compounds, is sufficient for the formation of an interconnected structure (network).…”

Micro milling of polymeric micro injected specimens with randomly oriented carbon nanotube fillers

“…Before machining the micro features, several tests were performed on the materials before and after moulding and the results are presented in Bongiorno et al (2017). Rheological analyses confirmed that no degradation of the material occurred and pointed out that the dispersion of CNTs in POM composites was adequate to achieve the network formation.…”

Fabrication of Poly(Vinylidene Fluoride)/Graphene Nano-Composite Micro-Parts with Increased β-Phase and Enhanced Toughness via Micro-Injection Molding

“…Therefore, polymer based micro-nano composites with high performance, multi-functionality and suitable for micro-injection molding are urgently needed [11]. In this situation, the micro-injection molding of carbon nanotubes (CNTs) composites, including polycarbonate/CNTs, polylactide/CNTs, liquid crystal polymer/CNTs, etc., for functional and structural applications have been studied [12][13][14][15][16].…”