# Structure and Properties of Self-Reinforced Polytetrafluoroethylene-Based Materials

## TL;DR

This paper explores how self-reinforced polytetrafluoroethylene composites can be made using recycled materials, improving their mechanical and thermal properties.

## Contribution

The study introduces a novel approach to using polymer waste in creating high-strength self-reinforced PTFE composites.

## Key findings

- Using recycled PTFE increased the elasticity modulus of composites to 2.0–3.1 GPa.
- The crystallinity of the materials ranged from 41–68%, with crystallite sizes of 30–69 nm.
- Processing method of waste PTFE significantly affects the thermal and mechanical properties of the composites.

## Abstract

A promising direction in polymer material processing is the development of self-reinforced polymer composites (SRPMs), representing a relatively new group of composite materials. The self-reinforcement method allows for materials of one polymer to be combined with different molecular, supramolecular, and structural features. The high adhesive and mechanical properties of SRPMs are due to the formation of a homogeneous system with no inter-phase boundary. Moreover, self-reinforcement considers the possibility of using polymer waste to create high-strength composites, which reduces the environmental load. In the current work, the phase composition, structure, and properties of SRPMs based on polytetrafluoroethylene (PTFE) were studied. SRPMs were prepared by mixing industrial and regenerated PTFE powders and then subjected to pressing and sintering. Two types of regenerated PTFE were used for the SRPM preparation: a commercial PTFE of the TOMFLONTM trademark and mechanically grinded PTFE waste. The degree of crystallinity of the obtained materials (41–68%) was calculated by XRD analysis; the crystallite size was determined to be 30–69 nm. Thermal analysis of the composites was carried out by the DSC method in the temperature range of 25–370 °C. The characteristics of thermal processes in self-reinforced composites correlate with the data from structural studies of XRD and FTIR analyses. The results of dynamic mechanical analysis showed that the introduction of regenerated PTFE powder into an industrial one increased the elasticity modulus from 0.6 GPa up to 2.0–3.1 GPa. It was shown that the phase state of the SRPMs depended on the method of processing polymer waste (the type of regenerated PTFE) that determined the heat resistance and mechanical properties of the obtained composite material.