Study of the dielectric and chemical properties of cellulose bio-based composites

• Published in: Industrial crops and products Vol. 214; p. 118493
• Main Authors: Khouaja, Asma, Koubaa, Ahmed, Ben Daly, Hachmi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-08-2024
• Subjects: Bio-based composites; Cellulose acetate biopolymer; Cellulose fibers; Dielectric properties; Surface chemistry; Thermal stability; Cellulose acetate biopolymer; Bio-based composites; Cellulose fibers; Dielectric properties; Thermal stability; Surface chemistry
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2024.118493

Injection molded cellulose bio-based composites have been effectively manufactured using cellulose acetate (CA), environmentally friendly triethyl citrate (TEC) plasticizer, and cellulosic fibers. This study investigated the surface chemistry, the thermal stability, and the dielectric properties of CA biopolymer and its bio-based composites. DSC result of plasticized cellulose acetate (PCA) showed that the glass transition temperature decreased from 191°C to 101°C and the melting temperature from 224°C to about 140°C after plasticization, which improves the processing of the biopolymer Fourier Transform Infrared (FTIR) spectroscopy was used to determine the chemical properties of the raw materials and the bio-based composites. The results showed a good plasticization effect of TEC plasticizer by the presence of ester bonds at 1734 cm−1 in PCA spectra. Chemical interactions between hydroxyl groups of the different components were also observed in the 3200–3600 cm−1 region. Dielectric analysis at different frequencies of cellulose bio-based composites showed enhanced dielectric properties compared to pure PCA polymer. Composites with 50 wt% cellulose fibers had values of ε' and tan δ of about 4 and 0.13 at 1 MHz, respectively. These properties decreased as the frequency increased from 1 MHz to 3 GHz, reaching values of 2.8 and 0.04, respectively. The increase in temperature from the frozen state induced an increase in the dielectric properties and showed a relaxation process that shifted to higher temperatures at higher frequencies.
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•Cellulose acetate was plasticized using triethyl citrate.•Cellulose enhanced the thermal and dielectric properties of biobased composites.•Dielectric properties increased with cellulose fiber content and temperature.•The dielectric constant has a linear relationship with cellulose content.•Cellulose composites can be used as high-temperature dielectric materials.