Formulation and Characterization of Prototype Particleboards using selected Crop Residue and Starch from Cassava Peels as a Binder

Abstract

Particleboards are formulated from lignocellulose material bound with adhesives. Conventional lignocellulose material used is wood particles and adhesive is formaldehyde-based resin. Due to reduction of tree cover, wood has become scarce leading to search for alternative lignocellulose material. Crop residues, as a lignocellulose material, pose disposal problems due to their low biodegradability, hence disposed off mainly by burning. Crop residues are lignocellulose materials of low nutritional value for use as livestock feed. Conventional formaldehyde-based resins hydrolyse in water to form formaldehyde. Epidemiological studies have shown that formaldehyde are carcinogenic and thus harmful. Efforts to reduce the health hazard effects of the formaldehyde-based resins in the particleboard formulation have included, among others, the use of chemical scavengers for formaldehyde and use of an alternative binder. In this study, single layer particleboards were made from cassava peels starch and selected lignocellulose materials. This was done by in-situ chemical oxidation of cassava peels starch and hydrolysis of lignocellulose sources from crop residue followed by condensation polymerization to form composite material. The resultant composite material was moulded to form particleboards. Crop residues used in this study included bagasse, maize straw and rice husks. The residues were sampled from farm and disposal sites in Kirinyaga, Kisumu and Narok Counties. Sawdust was used as a control for the source of lignin. Lignin content was determined following the Klason method. Cassava peel starch adhesive used in this study was analyzed for pH. Na+, Zn2+, Ca2+ and Mg2+ in starch and crop residues were determined using atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF). The mineralogical content of particleboards was determined using X-ray Diffractometer (XRD). Structure elucidation of compounds in raw materials and particleboards was determined by the use of fourier transform infra- red (FTIR) and nuclear magnetic resonance (NMR). Data obtained from this study were subjected to statistical analysis using Tukey one way analysis of variance (ANOVA). Particleboards were formulated and tested per American Standard for Testing and Materials (ASTM D1037). Average densities for particleboards was between 0.608 gcm- 3 to 0.627 gcm-3, moisture content of 9.51 % to 9.85 %, deionized water absorption (WA) ranged from 61.33 % to 83.87 % and thickness swelling (TS) 18.23 % and 23.43 %. Modulus of Elasticity (MOE) for particleboards was between 2364.2 Nmm-2 to 33329.92 Nmm-2, Modulus of rupture (MOR) ranged from 13.55 Nmm-2 to 14.83 Nmm- 2, internal bonding (IB) ranged from 1.613 Nmm-2 to 2.370 Nmm-2. Elemental analysis for both starch sources and polyphenolic materials for Na+, Zn2+, Ca2+ and Mg2+. Na+ and Zn2+ was less than 1 %. Ca ranged from 4.55 to 13.46 % and Mg ranged from 5.95 to 6.55 %. FTIR and NMR analysis for starch and polyphenolic materials showed that peaks of –OH and -COOH decreased as those of -C-O-C- increased. Particleboards formulated in this study have similar characteristics to medium density fiberboards. They can thus be used for making furniture and doors.