Research On Technology And Mechanism Of Cotton As A Kind Of Biomass Material Reducing Formaldehyde

Formaldehyde pollution is still one of significant problems in wood-based panel industry.Through analyzing the influences on formaldehyde releasing from cotton stalk and pineparticleboard composites by different ratios from cotton stalk particles to pine particles, andthrough analyzing the influences on formaldehyde releasing from plywood by different ratios ofcotton stalk powder as an additive, the mechanism of biological means of reducing formaldehydeemission in this thesis will be discussed. Meanwhile how cotton stalk absorb free formaldehydefrom the urea formaldehyde resin(UF) physically and chemically in order to get the result ofreducing formaldehyde emission will be investigated in this paper. And the research contents andconclusions are as follows:(1)As a kind of particleboard composites with UF as its adhesive, the cotton stalkparticleboard's formaldehyde amount is lower than the wood particleboard's. By experiments,results can be found that with the increasing amount of cotton stalks, the formaldehyde emissionwill be reduced gradually. When the ratio of cotton stalk particles to pine particles arrives at60:40, the effect of reducing formaldehyde releasing from the panels is obvious. Composites atthis ratio contain almost40.8percent lower free formaldehyde emission than woodparticleboards. Particleboard composites' physical and mechanical properties with different ratiosof cotton stalk particles to pine particles are between cotton stalk particleboards and woodparticleboards. Properties of composites, including IB, MOE and MOR will drop when the ratioof cotton stalk particles to pine particles is increased, and2h TS will go up. When the ratio ofcotton stalk particles to pine particles arrives at60:40, physical and mechanical properties canreach national standard.(2) When adding10percent of cotton stalk powder as an additive of UF, the plywood'sbonding strength is obviously increased and the formaldehyde emission is successfully reduced.Also, the bonding strength is higher and formaldehyde emission is lower than that of flour as anadditive of UF under the same situation.(3)The results of X-ray photoelectron spectroscopy show that SiO2particles which adhereon the surface of cottons can joint the free formaldehyde in UF resin to create the steady C-O-Sichemical bond. This gives another reason that cottons are available to reduce formaldehydereleasing in the view of chemistry.(4)Producing plywood has much economic effect when the additive content of cotton stalkpowder reaches10percent of UF, and its costs are2.77percent lower than that of flour, and itsprofit ratio of production can arrive at87.36percent when the physical and mechanical properties of the panels and amount of formaldehyde emission are taken into consideration. In addition,producing this kind of plywood can create much social and ecological benefits which can satisfythe needs of the enterprises and the society.