Preparation of Crosslinked Poly(acrylic acid-co-acrylamide)-Grafted Deproteinized Natural Rubber/Silica Composites as Coating Materials for Controlled Release of Fertilizer

Abstract

The crosslinked poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber/silica ((PAA-co-PAM)-DPNR/silica) composites were prepared and applied as coating materials for fertilizer in this work. The crosslinked (PAA-co-PAM)-DPNR was prepared via emulsion graft copolymerization in the presence of MBA as a crosslinking agent. The modified DPNR was mixed with various contents of silica (10 to 30 phr) to form the composites. The existence of crosslinked (PAA-co-PAM) after modification provided a water adsorption ability to DPNR. The swelling degree values of composites were found in the range of 2217.3 ± 182.0 to 8132.3 ± 483.8%. The addition of silica in the composites resulted in an improvement in mechanical properties. The crosslinked (PAA-co-PAM)-DPNR with 20 phr of silica increased its compressive strength and compressive modulus by 1.61 and 1.55 times compared to the unloaded silica sample, respectively. There was no breakage of samples after 80% compression strain. Potassium nitrate, a model fertilizer, was loaded into chitosan beads with a loading percentage of 40.55 ± 1.03% and then coated with the modified natural rubber/silica composites. The crosslinked (PAA-co-PAM)-DPNR/silica composites as the outer layers had the ability of holding water in their structure and retarded the release of fertilizer. These composites could be promising materials for controlled release and water retention that would have potential for agricultural application.

The Effect of Silver Nanoparticles/Titanium Dioxide in Poly(acrylic acid-co-acrylamide)-Modified, Deproteinized, Natural Rubber Composites on Dye Removal

“…The procedure for preparing the poly(acrylic acid- co -acrylamide)-modified, deproteinized, natural rubber ((PAA- co -PAM)-DPNR) was carried out via emulsion-graft copolymerization of the comonomers of acrylic acid and acrylamide, according to previous work [ 11 ]. The DPNR latex was mixed with Terric16A using a mechanical stirrer at 100 rpm in a three-necked round-bottom reactor.…”

“…For the Freundlich adsorption isotherm, it can be used to describe the heterogeneous surface with multilayer adsorption. The Freundlich equation is shown in Equation (11):…”

“…In our previous work, deproteinized natural rubber was modified by grafting it with poly(acrylic acid- co -acrylamide) through emulsion-graft copolymerization in the presence of N′,N′-methylenebisacrylamide as a crosslinking agent [ 11 ]. This method is a water-based system with an environmentally friendly process.…”

Nutrient controlled release behaviors and plant growth of NPK encapsulated hydroxyapatite/alginate biocomposite toward agricultural and environmental sustainability

“…Inorganic particles/polymer composites have advantages over polymer blending systems because they act as polymer reinforcements. Recently, composites based on montmorillonite/chitosan [15], bentonite/carnauba wax [16], and poly(acrylic acid-co-acrylamide)-grafted silica/deproteinized natural rubber [17] were reported as CRF materials. The drive toward more sustainable agriculture has motivated research efforts to minimize and utilize biowastes.…”

Effect of Modified Natural Rubber on the Mechanical and Thermal Properties of Poly(Lactic Acid) and Its Composites with Nanoparticles from Biowaste

“…Poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber was selected for use as a toughening agent, and it was prepared according to a previous work [ 24 ]. Due to the polarity of poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber, it has been incorporated with other materials and successfully utilized in the functions of controlled-release fertilizer and dye removal [ 25 , 26 ]. Therefore, it is possible that it could serve as a toughening agent.…”