Novel Improvements in Thermal and Hydrophobic Properties of Chitosan Reinforced by Rice Husk Ash

Abstract

Several bio-composites of chitosan (CS), as the hydrophilic natural polymer, were prepared by composition with 2, 5, 10 and 15 wt% of rice husk ash (RiHA), as the bio-based filler, via solution casting. These composites were obtained with the aim to improve the hydrophobicity, thermal stability, and degradation mechanism of pure chitosan. The resulting bio-composites were characterized by scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and FT-IR spectroscopy as well as XRD analysis. The SEM images showed amorphous morphology, irregular shape, and the number averaged size of 32 µm for the RiHA particles dispersed in the composites. Investigation of thermal properties of the RiHA-reinforced chitosan composites by TGA/DTG and DSC measurements has revealed some improvements in the thermal behavior of chitosan by the RiHA filler. For instance, the composite made of 15 wt% filler was found to be thermally more stable as it degrades at significantly higher temperatures than the composites containing other portions of the filler. Unlike the other samples that are degraded in three-steps, the weight loss of the composite having 15 wt% of RiHA occurs in two steps. Additional experiments showed that the composites are more hydrophobic than virgin chitosan and the hydrophobicity of the samples is increased by increasing their RiHA component.

Rice husk ash: Economical and high-quality natural-based reinforcing filler for linear low-density and high-density polyethylene

“…The rice sample belonged to the Hassani type grown in the north of Iran. The RiH was obtained via local mill, washing several times with distilled water to remove any adhering materials and then drying at ambient temperature for 48 h. The dried RiH was converted to the favorite sample by smashing, sieving (200 mesh size), washing again with distilled water, and then drying at 110°C for 4 h. 40 RiHA was produced via combustion of RiH according to the reported method in the previous works. 40,41 On the other word, the prepared rice husk was pyrolyzed in a muffle furnace for 1 h at 600°C to receive the desirable RiHA.…”

“…The RiH was obtained via local mill, washing several times with distilled water to remove any adhering materials and then drying at ambient temperature for 48 h. The dried RiH was converted to the favorite sample by smashing, sieving (200 mesh size), washing again with distilled water, and then drying at 110°C for 4 h. 40 RiHA was produced via combustion of RiH according to the reported method in the previous works. 40,41 On the other word, the prepared rice husk was pyrolyzed in a muffle furnace for 1 h at 600°C to receive the desirable RiHA. 40 The L.O.I parameter (loss on ignition) of rice husk ash was investigated by heating 3 g of the sample at 1000°C for 1 h in air to remove the moisture, volatiles, and the co-existing unburned carbon.…”

“…40,41 On the other word, the prepared rice husk was pyrolyzed in a muffle furnace for 1 h at 600°C to receive the desirable RiHA. 40 The L.O.I parameter (loss on ignition) of rice husk ash was investigated by heating 3 g of the sample at 1000°C for 1 h in air to remove the moisture, volatiles, and the co-existing unburned carbon.…”

“…The RiH sample contained 8.2 ± 0.3 wt% of the volatile compounds. 40 Determining the components present in RiHA…”

Characterization and in vitro Biocompatibility of Binary Mixtures of Chitosan and Polyurethanes Synthesized from Chemically Modified Castor Oil, as Materials for Medical Use

“…Therefore, highly biocompatible antibacterial agents such as quaternary ammonium salts and natural polymers as the chitosan (Ch) could be used. The latter is one of the most abundant polymers in nature; chitosan is biocompatible and possesses antimicrobial activity [4][5][6]. However, films prepared from Ch exhibit poor mechanical strength and are brittle [7], which limit its use in biomedical applications.…”