Research On Urea-formaldehyde Resin/Stone Powder Composite Materials

In this paper, urea-formaldehyde resin as matrix and stone powder as filler, to prepare Organic inorganic composite materials. Because the main drawback of urea-formaldehyde resin is long curing time, the surface yellowing after curing,no gloss,brittle, and easy to fault and so on. These shortcomings has great relations with the curing agent system, so this experiment from urea-formaldehyde resin curing system to start. the choice of curing agent system is ammonium chloride as the main additive of two component curing agent,and respectively with citric acid, phosphoric acid, sulphuric acid, hydrochloric acid, nitric acid and Perchloric acid additive.The acid concentration is5%～10%.and in different adding amount, then measure curing time, suitable period and the apparent after resin curing. finally choose the nitric acid, phosphoric acid and citric acid curing agent system. Curing agent system is usede to urea-formaldehyde resin/stone powder composite material which ammonium chloride as the main additive with the6%nitric acid or10%phosphoric acid,and nitric acid, phosphoric acid respectively with Citric acid composition of multi-component curing agent.The result showed that, when using6%nitric acid curing agent system, and addition amount is12%of urea-formaldehyde resin, there is a best curing. curing time and applicable period can satisfy the requirements. The surface is smooth after curing, no crack. Though the research of urea-formaldehyde resin/stone powder composite material preparation process and final chose the proportion of urea-formaldehyde resin and stone powder is1:1.5, stirring time is60min.Chose PVA, sodium carboxy methyl cellulose, PVAc and PVF, adding to urea-formaldehyde resin/stone powder composite to modified toughness. And use the scanning electron microscopy (SEM) to analyze composite structure. The result show that,when use the PVAc as modifier and the adding amount of PVAc is6%, there have a best effect. This time impact strength, bending strength and hardness of the composite material all achieve maximum. And the impact strength is7.71kJ/m2, bending strength is12.35MPa, hardness is27.07D.