Thermal Decomposition Kinetics of Basalt Fiber-Reinforced Wood Polymer Composites.

Xian Zhang,Runzhou Huang

doi:10.3390/polym12102283

Xian Zhang, Runzhou Huang

Open Access

https://doi.org/10.3390/polym12102283

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Abstract

Thermogravimetric analysis (TGA) was used for the observation of the pyrolysis kinetics characteristics of high density polyethylene (HDPE)-based composites enhanced by a variety of basalt fibers (BFs) and wood flour (WF). The improved Coats-Redfern (C-R), Flynn-Wall-Ozawa (F-W-O), Friedman, and Kissinger methods were utilized to ascertain the specific apparent activation energy (Ea) of each component and composite material. The results indicate that BFs do not decompose under 800 °C, while the pyrolysis of WF and waste HDPE showed two significant weight loss zones (250–380 °C and 430–530 °C), relative to cellulose/hemicellulose and HDPE thermal degradation, respectively. The average Ea of WF/BF/HDPE composites over the entire pyrolysis process obtained by the modified C-R method fluctuated in a range of 145–204 kJ/mol and increased with the BF content, which was higher than that of WPC (115–171 kJ/mol). The value of Ea computed by the F-W-O method was significantly lower than that computed with the improved C-R method, which could validate the reliability of two methods by comparing with the literature. The Friedman and Kissinger methods were not applicable to this composite material reinforced by mixed fillers, so the obtained Ea values were quite different from the previous two methods. The changes in Ea showed that the addition of BFs could improve the average Ea and further enhance the thermal stability and flame resistance of the composites.

Highlights

Over the past few years, wood-plastic composites (WPCs), which show advantages with respect to biodegradability, low cost, superb mechanical and thermal insulation performance, and availability, have been regarded as a novel green renewable material exhibiting great potential for structural building applications [1,2,3,4]
The first stage is from 100 to 250 ◦ C, where the weight loss of wood materials was very small, because only a portion of the cellulose was dehydrated at lower temperature to produce dehydrated cellulose, which was a slow process
The second stage was from 250 ◦ C to 450 ◦ C, which is the main stage of samples pyrolysis

Summary

Introduction

Over the past few years, wood-plastic composites (WPCs), which show advantages with respect to biodegradability, low cost, superb mechanical and thermal insulation performance, and availability, have been regarded as a novel green renewable material exhibiting great potential for structural building applications [1,2,3,4]. An array of studies have assessed the applicability of both organic and inorganic fibers in polymers Among these fibers, mineral basalt fibers (BFs) have attracted intense research interest as a reinforcing material. The use of these fiber composites is hindered by serious drawbacks including high energy costs for production, inhalation health risks, non-recyclability, and lack of biodegradability [7,8]. In this context, BFs, as a natural reinforcing material in polymers, provide a promising alternative to WPCs. The fibers consist of SiO2 and Al2 O3 and are composed of natural ores via melting at ~1500 ◦ C and have a significant number of capabilities including

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