Enhancement of Mechanical and Thermal Properties of Oil Palm Empty Fruit Bunch Fiber Poly(butylene adipate-co-terephtalate) Biocomposites by Matrix Esterification Using Succinic Anhydride

Samira Siyamak,Mohamad Zaki Ab Rahman,Wan Md Zin Bin Wan Yunus,Sanaz Abdolmohammadi,Nor Azowa Ibrahim

doi:10.3390/molecules17021969

Samira Siyamak, Mohamad Zaki Ab Rahman + Show 3 more

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https://doi.org/10.3390/molecules17021969

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Abstract

In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (EcoflexTM), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites’ performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites’ spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.

Highlights

Responding to globally growing socio-ecological concerns and aiming to diminish the sum of landfill waste and carbon footprints, the thermoplastic industry has focused on developing new environmentally friendly products through mixing biodegradable polymers with natural fibers [1].Different markets, including packaging, disposable non-woven hygiene products, consumer goods and agricultural tools exist for biodegradable polymers
With the addition of 40 of empty fruit bunch (EFB) fiber and with addition of 4 of succinic anhydride (SAH), the C=O peak of PBAT at 1,715 cm−1 shifted to a lower wave number, respectively
The C=O peak of PBAT even shifted to a lowest wave number by 7 cm−1 to 1,709 cm−1 after addition of 4 of SAH and 1 of dicumyl peroxide (DCP)

Summary

Introduction

Responding to globally growing socio-ecological concerns and aiming to diminish the sum of landfill waste and carbon footprints, the thermoplastic industry has focused on developing new environmentally friendly products through mixing biodegradable polymers with natural fibers [1]. Different markets, including packaging, disposable non-woven hygiene products, consumer goods and agricultural tools exist for biodegradable polymers (and biocomposites). Biodegradable polymers’ high cost compared to that of cheap petroleum-based non-biodegradable polymers, as well as their limited thermo-mechanical properties, are barriers that need to be addressed for biodegradable polymers in order to be commercially applied in the mass production of commodities. Melt blending biodegradable polymers with biofillers could effectively contribute to the improvement of thermo-mechanical properties as well as to the cost reduction, while at the same time keeping the overall biodegradability features. In order to obtain satisfactory interfacial adhesion, minimum size dispersed phases, and enhanced stress transfer among the components, a proper compatibilizer must be used to control the interfacial energy during the melt blending procedure [1]

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