DEVELOPMENT AND CHARACTERIZATION OF NANOPARTICLES MODIFIED UREA FORMALDEHYDE RESIN ADHESIVE

Abstract

ABSTRACT Urea formaldehyde resin lack in water resistance owing to the low stability of the amino-methylene bond making it susceptible to hydrolysis and thus limiting its use to interiors only. The aim of this study is to modify Urea Formaldehyde resin using nanoparticles derived from bamboo waste and its application in particleboard production. Biochar was produced from pyrolysis of waste bamboo at temperatures of 400 oC, 450 oC and 500 oC. Size reduction of the biochars produced was carried out using a ball mill for 1 hr. The particle size analysis showed that the particles were wide and dispersed having average sizes of particles between 40 to 60 diameter nanometer (d.nm). Physical properties of bamboo and nano biochar were evaluated, moisture content and volatile matter decreased with increase in pyrolysis temperature while ash content and fixed carbon increased with increase in pyrolysis temperature. Chemical properties were also evaluated, percentage carbon content of 54.82 %, 55.62 % and 56.48 % respectively increased with increase in pyrolysis temperature while percentage hydrogen and oxygen decreased with increase in pyrolysis temperature. The percentage nitrogen content was very low ranging from 0.22 to 0.24 % which implies very little pollution from NOx species that might be formed. Urea formaldehyde resin adhesive was synthesized using the alkaline-acid method and modified using the produced nano biochars. Physical and chemical properties of the neat and modified UF resins were evaluated. The viscosities of the modified resins increased to 152 cP, 151 cP and 154 cP respectively as against the neat resin which had a viscosity of 150 cP. The solid content also increased significantly ranging from 63-65 % for modified resins while the neat resin had a solid content of 60 %. Gel time, density and pH of both neat and modified resins did not change significantly with gel time ranging between 58 to 60 sec, densities of between 1.28 to 1.35 g/cm3 and pH ranging from 7.8 to 8.0. The neat and modified UF resins were used to produce particleboards using saw dust as filler. Physical and mechanical properties of the particleboards were evaluated, the densities of particleboards were within the range of 0.68 g/cm3 and 0.79 g/cm3 which implies that they were low density particleboards. Particleboard modified with sample UF2 showed the highest water resistance and least thickness swell of 32.13 % and 40.00 % respectively. It also showed the highest values in tensile strength of 25.16 MPa and elastic modulus of 19.83 MPa. Particleboards produced with sample UF3 gave the highest hardness of 44.9 HV and impact energy of 0.32 J. The findings presented demonstrate that nano biochar derived from bamboo wastes presents suitable properties that can be used in the modification of UF resin. Particleboard produced with the modified UF resin significantly improved in its water resistance, thickness swell, tensile strength and elastic modulus.