Fabrication of Poly(butylene succinate)/Carbon Black Nanocomposite Foams with Good Electrical Conductivity and High Strength by a Supercritical CO2 Foaming Process.

Zhou Chen,Junfeng Hu,Jiajun Ju,Tairong Kuang

doi:10.3390/polym11111852

Abstract

Lightweight, high-strength and electrically conductive poly(butylene succinate) (PBS)/ carbon black (CB) nanocomposite foams with a density of 0.107–0.344 g/cm3 were successfully fabricated by a solid-state supercritical CO2 (ScCO2) foaming process. The morphology, thermal and dynamic mechanical properties, and rheological behavior of the PBS/CB nanocomposites were studied. The results indicate that the CB nanofiller was well dispersed in the PBS matrix and the presence of a proper CB nanofiller can accelerate the rate of crystallization, improve the thermal stability, enhance the stiffness, and increase the complex viscosity of PBS/CB nanocomposites. These improved properties were found to play an important role in the foaming process. The results from foaming experiments showed that the PBS/CB nanocomposite foams had a much smaller cell size, a higher cell density, and a more uniform cell morphology as compared to neat PBS foams. Furthermore, the PBS/CB nanocomposite foams also possessed low density (0.107–0.344 g/cm3), good electrical conductivity (~0.45 S/cm at 1.87 vol % CB loading), and improved compressive strength (108% increase), which enables them to be used as lightweight and high-strength functional materials.

Highlights

To minimize environmental pollution and the depletion of fossil oils, biodegradable polymeric foams are increasingly being considered as a promising alternative to replace the petroleum-based polymeric foams [1,2,3,4,5,6]
The linear molecular chains and low molecular weight of poly(butylene succinate) (PBS) itself resulted in a low melt strength, which eventually led to the poor foamability of PBS foams [16]
To evaluate the filler’s dispersion in the PBS matrix, SEM was used to observe the fracture surface of PBS/carbon black (CB) nanocomposites

Summary

Introduction

To minimize environmental pollution and the depletion of fossil oils, biodegradable polymeric foams are increasingly being considered as a promising alternative to replace the petroleum-based polymeric foams [1,2,3,4,5,6]. Compared to PLA, PCL, PHAs, and other biodegradable polymers, PBS is regarded as the most promising biodegradable polymer materials due to its good processability and mechanical properties, better thermal and chemical stability, and lower materials cost [12,13,14,15] Due to these good characteristics, PBS materials were expected to produce high-performance biodegradable polymeric foams for various applications. Using crosslinking or a branching agent to modify the chemical structure of PBS materials was regarded as an efficient route to increase the PBS’s viscosity in many previous studies. Zhou et al modified PBS through reactive melt mixing with a chain extender to improve the molecular weight and polydispersity index (PDI), and the volume expansion ratio of the resulting PBS foams was found to reach up to 14.3 [15]

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