Comparison of the mechanical characteristics of biocomposites of unsaturated polyester resin with cellulose extracted from corn silk and treated corn silk

Abstract

The purpose of this study is to extract cellulose from corn silk (CS) fiber and use it as a reinforcing filler in unsaturated polyester resin (UPR) matrix. In this study, the cellulose is characterized using a Fourier Transform Infrared Spectrometer (FTIR), and the resulting UPR/cellulose biocomposite's mechanical properties (such as flexural and impact testing) are assessed. Scanning electron microscopy (SEM) provided strong support for mechanical rather than a chemical bond between fiber and UPR. Additionally, the sodium hydroxide treated CS in UPR biocomposite and comparing it with neat UPR. The agricultural byproduct rich in cellulose corn silk is a natural polymer known for its structural strength and UPR has garnered attention as a biopolymer with notable flexibility, making it an appealing choice for plastic product manufacturing. However, the drawback of UPR lies in its inherent deficiency in both stiffness and strength. According to the FTIR data, extracted cellulose (CS) had fewer ketone (C = O) and hydroxyl (-OH) groups than virgin cellulose. It was shown that throughout the extraction process, hemicellulose and lignin were more eliminated, producing a more pure form of cellulose. When filled in UPR, cellulose and treated CS both caused the impact strength of UPR biocomposites to drop. For both treated CS and cellulose, it was shown that the flexural modulus and flexural strength increased as the filler amount increased to a definite percentage (12%) after which it decreased. The result revealed the tensile strength and tensile modulus achieved by 0% of fiber with 48 N/mm2 and 51 N/mm2 and highest at 12% of fiber with 54.3 N/mm2 and 68.8 N/mm2 for CS + UPR. And 53.4 N/mm2 and 69.6 N/mm2 for cellulose + UPR composite,, respectively. In comparison, the flexural characteristics of UPR/cellulose were marginally inferior to those of UPR/treated CS. However, the impact resistance showed a significant improvement, particularly with a cellulose loading of 12%. Hence, cellulose presents a greater potential for composite manufacturing due to its ability to maintain the ductile properties of UPR compared to treated CS. Moreover, processed CS and cellulose both can be used as reinforcing agents in polymers to increase their strength and stiffness.