Effects of free formaldehyde emission reduction by ammonia fuming on physical and strength properties of particleboards made from formaldehyde based resins

Abstract

Particleboards made using formaldehyde adhesives cause substantial emission of free formaldehyde over time. Free formaldehyde is harmful to the user’s health and it also weakens internal bonds of particleboards in use. Emissions levels of formaldehyde lie between 0.8 to 2.2 g/m3 of indoor air in particleboards constructed homes. This study was carried out to quantify the amount of free pormaldehyde in particleboards from Raiply Ltd in Eldoret, suggest possible ways to reduce the emissions and determine the effect of the treatment on physical and mechanical  properties of the particleboards. Five samples were selected randomly and, different sections of the boards were prepared and soaked in distilled water for different times. Samples fumed with ammonia at different  durations from 15 to 60 minutes were subsequently soaked for 1 to 24 hours to determine water absorption. High Pressure Gas Chromatography (HPGC) was used to quantify free formaldehyde present in each leachate. Ammonia treated and untreated samples were tested for both physical and
mechanical properties at the Kenya Bureau of Standards. The study revealed that fuming particleboards with ammonia reduces the amount of free formaldehydes, on average, by 100%. Ammonia fuming reduces particleboards thickness swelling by between 14.01 and 11.5% and water
absorption by between 95.6 and 90.5%. the fuming increased MOE of particleboards from 2689.9 to 3405.3 kN/mm and MOR from 10.3 N/mm to 9.3 N/mm. Ammonia fuming should therefore be used to reduce free formaldehyde emission indoor. It’s recommended that further studies be
carried out to determine long-term effect of ammonia fumes on particleboards.

Key words: Particleboards, ammonia fuming, formaldehyde adhesives and emission