The effect of polytetrafluoroethylene particle size on the properties of biodegradable poly(butylene succinate)-based composites

Shudong Chen,Jialin Lin,An Huang,Hankun Wang,Lihong Geng,Xiangfang Peng,Binyi Chen

doi:10.1038/s41598-021-86307-x

Abstract

Poly(butylene succinate) (PBS)/polytetrafluoroethylene (PTFE) composites, including three types of PTFE powders, were prepared by melt blending using a HAAKE torque rheometer. Microcellular foams were successfully fabricated by batch foaming with supercritical fluids (scCO2). The effects of PTFE powder type on crystallization, rheological properties and foaming behavior were studied. PTFE L-5 and PTFE JH-220 powders showed good dispersion in the PBS matrix, and PTFE FA-500 powder underwent fibrillation during the melt blending process. All three PTFE powders gradually increased the crystallization temperature of PBS from 78.2 to 91.8 ℃ and the crystallinity from 45.6 to 61.7% without apparent changes in the crystal structure. Rheological results revealed that PBS/PTFE composites had a higher storage modulus, loss modulus, and complex viscosity than those of pure PBS. In particular, the complex viscosity of the PBS/P500 composite increased by an order of magnitude in the low-frequency region. The foamed structure of PBS was obviously improved by adding PTFE powder, and the effect of fibrillated PTFE FA-500 was the most remarkable, with a pore mean diameter of 5.46 μm and a pore density of 1.86 × 109 cells/cm3 (neat PBS foam: 32.49 μm and 1.95 × 107 cells/cm3). Moreover, PBS/P500 foam always guarantees hydrophobicity.

Highlights

Poly(butylene succinate) (PBS)/polytetrafluoroethylene (PTFE) composites, including three types of PTFE powders, were prepared by melt blending using a HAAKE torque rheometer
When fabricating PBS foams via supercritical carbon dioxide, the melt strength is too low to support the cells during cell growth, causing large cell sizes and collapsed c ells[10], which limits their wide application
The method of enhancing the melt strength or elastic modulus is the key to developing high-performance PBS foams, which can further broaden their application areas

Summary

Introduction

Poly(butylene succinate) (PBS)/polytetrafluoroethylene (PTFE) composites, including three types of PTFE powders, were prepared by melt blending using a HAAKE torque rheometer. Polymer foams are generally considered to be gas-filled composites, which are characterized by light weight, low density, shock absorption and excellent mechanical properties They can realize lightweight polymer materials without losing or while even improving the performance of materials[1]. Wu et al.[17] prepared PBS/halloysite nanotube (HNT) nanocomposite foams by melt compounding and s cCO2 foaming, indicating that HNTs obviously improved the foamability of the PBS matrix. These nanofillers aggregate during melt blending and are expensive, making them difficult to apply on a large scale in the preparation of high-performance foams

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Conclusion