Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

Abstract

Abstract:This work was aimed at preparing polytetrafluoroethylene (PTFE) nanocomposites filled with graphene nanoplatelets and investigating how the graphene nanoplatelets and the preparation techniques influenced the physical properties. Graphene was incorporated up to 4 vol% of the total PTFE system by dry and solvent assisted blending. The powder compaction was evaluated using the Kawakita/Ludde model to describe the compressibility of the powder blends. The nanocomposite billets were prepared using cold compression moulding by applying preform pressures between 12.7 and 140 MPa and the preform billets were sintered at 380 °C using a specific sintering cycle. The changes in the physical dimensions, billet mass, density, and void content of the billets, pre and post sintering, were analysed with Experimental design software to evaluate the influence of the pre-compaction pressure and graphene loading. From the evaluation it was concluded that the ideal compaction pressure was at 12.7 MPa and the solvent assisted blending was superior to the mechanical blending method. Furthermore, the compression creep tests confirmed the ideal processing temperature and graphene loading range to improve the mechanical properties.2

Gas barrier properties of oxyfluorinated graphene filled polytetrafluoroethylene nanocomposites

“…The guidelines specified by van Rooyen et al [28] were used with regards to preparing the PTFE /graphene blends and how to fabricate the disc samples.…”

“…The preform disc samples were sintered using a programmable sintering oven (Carbolite HT, United Kingdom) which sequentially increased the temperature to 380 °C, held the temperature (380 °C) for a required period, and cooled the samples slowly to room temperature. The temperature profile for the sintering of the disc samples is described in more detail by van Rooyen et al [28]. Unfilled TFM 1700 disc samples were also prepared as reference samples using the same fabrication methods.…”

“…However, the dispersion of nanofillers like graphene into PTFE is difficult [27]. Researchers have recently shown how to improve the dispersion of graphene in PTFE through electrostatic self-assembly [27] and by using perfluorinated solvents [28]. Also, good chemical compatibility between the filler and the polymer matrix normally reduces the gas permeability even further [29].…”

Effect of tensile rates on thermal and mechanical properties of porous PTFE composites

“…In order to conquer defects of neat PTFE, several researchers have investigated enhance properties based on PTFE, such as creep resistance, abrasion resistance, and higher thermal stability Cai et al . fabricated graphene nanoplatelet (GNP)–PTFE nanocomposites through liquid phase exfoliation of graphite sheets in ethanol with tip sonication.…”

Performance properties and applications of polytetrafluoroethylene (PTFE)—a review

“…On further evaluation, for higher graphene loads, there seems an improved dispersion of particles by solvent blend method when compared to the mechanical blending method. The optimization of this ideal processing condition will guide in preparing PTFE/Nanocomposites [119].…”