Purification and Characterization of Silica from Sugarcane Bagasse Ash as a Reinforcing Filler in Natural Rubber Composites

Abstract

This work studied the chemical composition, cure characteristics, and morphological and mechanical properties of natural rubber (NR) compounds filled with silica, which was derived from bagasse ash (BA). The BA filler underwent various preparation processes (untreated, hydrochloric acid (HCl)-treated, and HCl/ammonium fluoride (HCl/NH4F) extracted). The results revealed that the main functional group of the BA was silica. After purification by HCl and HCl/NH4F, the silica content increased from 77.2% to 90.6% and 97.0%, respectively. Longer cure times and lower crosslinking were obtained after purifying the silica. Treatment of silica with HCl/NH4F improved the tensile strength and compression set when added at 15 parts per hundred rubber (phr) loading. Purification with HCl and HCl/NH4F acted as an obstacle to rubber-rubber crosslinking, but helped to moderate the filler-filler interaction. The elongation range for the NR containing the BA silica in this work was 900% to 1,100%. The use of HCl/NH4F-extracted silica in NR vulcanizates had no effect on the lightness, while the untreated and HCl-treated silica displayed decreased lightness. The silica from BA is recommended for use as reinforcing filler in NR compounds if treated with HCl followed by NH4F extraction before use. The optimal loading of the treated silica was 15 phr.

Eco‐friendly polymer composites: A review of suitable methods for waste management

“…In this context, the extraction of silica from residues can enhance the reinforcement characteristics of crop‐derived. [ 257,258 ] Fernandes and co‐workers [ 259 ] have replaced commercial silica in epoxy resins composites by rice husk ash‐based silica. Authors observed that values of tensile strength and elastic modulus were quite similar, being 20 wt%, when compared to commercial and residue fillers.…”

Influences of purification and surface treatment of sugarcane bagasse ash on mechanical properties of natural rubber composites

“…The results agree well with the literature reporting the increase in the percentage of small particles (<40 μm) after the acid/base purification. [ 20 ] In addition, the purification process reduced the pH value of BA from 8.9 to 7.4 indicating the decrease in basicity as a result of the removal of alkali metal oxides. Nevertheless, the densities of the BA and PBA were not significantly different.…”

“…[ 19 ] The results revealed the low reinforcement of BA in both NR and SBR vulcanizates which could be explained by the large particle size of BA particles resulting in a low degree of rubber‐filler interaction. Since it is reported that purification process can significantly reduce the particle size of ash, [ 20 ] it is interesting to investigate the effect of purified BA (PBA) on reinforcement of rubber.…”

“…Recently, PBA obtained from the acidolysis by HCl and followed by the ammonium fluoride (NH 4 F) extraction has been characterized and employed as a filler in NR. [ 20 ] After the purification, the increase of specific surface area and the presence of hydroxyl groups on the PBA surface have been revealed. However, the influence of surface treatment on the reinforcement of PBA in NR has never been disclosed.…”

Plant-derived silica nanoparticles and composites for biosensors, bioimaging, drug delivery and supercapacitors: a review

“…Acid pretreatment in autoclave removes metal ions and induces the hydrolysis of organic substances. Bagasse ash filler treated with HCl/NH 4 F gives silica of 77%–97% purity (Huabcharoen et al 2017 ). SEM images of the sugarcane bagasse, bagasse ash and silica nanoparticles from sugarcane bagasse are shown in Fig.…”