Biodegradable water hyacinth cellulose-graft-poly(ammonium acrylate-co-acrylic acid) polymer hydrogel for potential agricultural application

Kiplangat Rop; Damaris Mbui; Njagi Njomo; George N. Karuku; Immaculate Michira; Rachel F. Ajayi

Heliyon (Mar 2019)

Biodegradable water hyacinth cellulose-graft-poly(ammonium acrylate-co-acrylic acid) polymer hydrogel for potential agricultural application

Kiplangat Rop,
Damaris Mbui,
Njagi Njomo,
George N. Karuku,
Immaculate Michira,
Rachel F. Ajayi

Affiliations

Kiplangat Rop: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya; Corresponding author.
Damaris Mbui: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
Njagi Njomo: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
George N. Karuku: Department of Land Resource Management and Agricultural Technology, University of Nairobi, P. O. Box 29053- 00625, Kangemi, Nairobi, Kenya
Immaculate Michira: Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
Rachel F. Ajayi: Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa

Journal volume & issue: Vol. 5, no. 3
p. e01416

Abstract

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Swollen cellulose fibres isolated from water hyacinth were utilized in the synthesis of water hyacinth cellulose-graft-poly(ammonium acrylate-co-acrylic acid) polymer hydrogel (PHG). Acrylic acid (AA) partially neutralized with NH3 was heterogeneously grafted onto swollen cellulose by radical polymerization reaction using N,N-methylene-bis-acrylamide (MBA) as the cross-linker and ammonium persulphate (APS) as the initiator. The reaction conditions were optimized through assessment of grafting parameters such as grafting cross-linking percentage (GCP), percentage grafting cross-linking efficiency (%GCE) and water absorption tests. Characterization of the copolymer by Fourier Transform Infra-red (FTIR) spectroscopy revealed successful grafting of the monomer onto cellulose. Transmission electron microscopy (TEM) image of acetone-extracted PHG displayed micro-porous structure. The optimized product swelled in distilled water up to 165 times its own dry weight. The swelling was influenced by the pH and presence, nature and concentration of ions. The hydrogel had the capacity to retain moisture in soil, and degradation testing revealed a higher mass loss in cellulose grafted copolymer compared to the copolymer without cellulose. Degradation by soil microbial isolates showed significantly higher (P ≤ 0.05) accumulation of NH4+ in the cellulose grafted copolymer up to 0.05% (w/v) from 40 to 100 h, relative to similar amounts of copolymer without cellulose. The use of water hyacinth, a notorious weed in Kenyan waters, to produce cellulose-based polymer hydrogels has not been explored and yet, it could form an effective and beneficial way of utilizing this plant. A mechanism of graft polymerization reaction has also been proposed. The synthesized product can be applied in agriculture and other fields where biodegradability and effective utilization of water is essential.

Materials science

Published in Heliyon

ISSN: 2405-8440 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Science: Science (General); Social Sciences: Social sciences (General)
Website: https://www.cell.com/heliyon/home

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