Synthesis and characterization of maleic anhydride-grafted orange waste for potential use in biocomposites

Abstract

The purpose of the study was to develop a less hydrophilic, and therefore more useful, material from orange waste produced in large quantities by the food industry. A new derivative of industrial orange waste was synthesized via esterification with maleic anhydride. The reaction was confirmed via Fourier transform infrared spectroscopy (FTIR), and the degree of substitution of the hydroxyl groups was 0.39 ± 0.01, as determined by a back-titration method. A major change in physical structure was confirmed by scanning electron microscopy (SEM). The flake-like structure of orange waste changed to a sponge-like structure after the reaction, which involved an increased volume and a reduced density by approximately 40%. The sponge-like structure was represented as an agglomeration of particles with a low specific surface area of 2.18 m 2 /g and a mean pore diameter of 10.7 nm. Interestingly, the grafted orange waste seemed to become more hydrophobic, which was confirmed by a contact angle test; however, the material absorbed more water vapor. Thermogravimetric analysis (TGA) confirmed a thermally more uniform, though, less heat-resistant material. This work suggests a possible way of utilizing orange waste via synthesizing a renewable material with possible applications as a filler in biocomposites.

Biodegradable maleic–itaconic polymer‐coated phosphatic fertilizer improved phosphorous recovery in calcareous soil

“…(2001) also found the O–H functional groups within the same range. A smaller peak visible at 2970 cm −1 referred to the C─H stretches of sp 2 ‐hybridized carbons in maleic anhydride (Bátori et al., 2018). The absorption peak at 1734 cm −1 represents the stretching vibration of C═C.…”

“…Bátori et al (2018) found a similar peak at 1410 cm −1 and attributed it to OH bending vibration of the carboxyl group. Overall, the peaks confirm the presence of the molecular structure of vinyl acetate in the formulated polymers (Poly-A and Poly-B) in the present study.…”

“…The characteristic broad bellshaped peak at 3435 cm −1 indicated the O-H stretching vibrations in anionic polymers. Thomas et al (2001) referred to the C─H stretches of sp 2 -hybridized carbons in maleic anhydride (Bátori et al, 2018). The absorption peak at 1734 cm −1 represents the stretching vibration of C═C.…”