Development of Pressure-Responsive PolyPropylene and Biochar-Based Materials.

Amir Noori,Mattia Bartoli,Alberto Frache,Erik Piatti,Mauro Giorcelli,Alberto Tagliaferro

doi:10.3390/mi11040339

Abstract

In this research paper, we reported the synthesis of biochar-based composites using biochar derived from exhausted tea leaves and polypropylene. The resulting materials were deeply characterized investigating mechanical (dynamic mechanical thermal analysis), thermal (thermogravimetrical analysis and differential scanning calorimetry), morphological (field emission scanning microscopy) and electrical properties vs. temperature. Furthermore, electrical conductivity was studied for a wide range of pressures showing an irreversible plastic deformation. An increment of one order of magnitude in the conductivity was observed in the case of 40 wt% biochar loading, reaching a value of 0.2 S/m. The material produced exhibited the properties of an irreversible pressure sensor.

Highlights

Tea production is one of the largest beverage commodities with an annual production of up to 4.6 Mton/y reached in 2010 [1]
Biochar has been used in many applications but one of the most attractive has been the production of composites [18]
In the field of industry, thermoplastic-based composites are largely used with an annual production of up to 29.5% of the overall production [21]

Summary

Introduction

Tea production is one of the largest beverage commodities with an annual production of up to 4.6 Mton/y reached in 2010 [1]. Few research efforts have been devoted to investigate the effect of biochar produced at high temperatures towards the enhancement of polymer conductivity [29] This field has conducted in-depth studies on using thermoset-based composites [30,31,32,33] or carbon nanotubes-based thermoplastic polymeric hosts [34,35,36,37,38] but it has neglected to consider thermoplastic and biochar at the same time. The use of a thermoplastic polymer matrix could be very useful for the production of irreversible resistive sensors that could detect the plastic deformation of the material at lower pressure ranges than thermoset-based sensors. Similar results could be achieved using high-tech and very expensive carbon-based fillers (e.g., carbon nanotubes [41] and graphene [42]) or high loading of high-quality carbon black [43,44]

Objectives

Methods

Results