Preparation And Modification Of Water-Blo Wn Rigid Polyurethane Foam

Nowadays building energy conservation has become the trend of the social development. Our government promulgate many policies on building energy efficiency to promote the development of construction industry. One of the most important in building energy conservation is insulation materials. Through the use of high rate energy saving preservation material, we can effectively realize building energy efficiency. As a kind of heat preservation material, rigid polyurethane foam has been widely used in the field of building energy efficiency, which has got very good effect.This paper used water as blowing agent to prepare rigid polyurethane foam, and emphatically expounds the several factors of influencing the performances of rigid polyurethane foam. When isocyanate index equal to 1.02, the compression strength reach peak. such as isocyanate index, water consumption and the catalyst. The increasing of water has great influence of the physical properties of the foam. The use dosage of the catalyst also can influence the pore structure of the foam. The paper use amine and tin as a mixed catalyst, and the water as blowing agent, to prepare rigid polyurethane foam.By through the study of diatomite which modified rigid polyurethane foam, we can find that with the increase of diatomite, the compression performance and impact performance of foam are increased firstly, and then began decreases. But the tensile properties has no marked change. Through the analysis of the foam structural, the thermal stability of foam has increase correspondingly, and the size stability become better, and the bibulous rate has also reduced. The coefficient of thermal conductivity of rigid polyurethane foam reach the lowest when the addition amount of diatomite is 15%, which is 20.8% decline. By the adding of diatomite as inorganic material can help to increase the flame retardant property of the foam.By study of the expansible graphite and diatomite compound modification of the foam, the performance and impact performance are much better than diatomite used by oneself, which the impact performance can reach 4 times than it. The flame retardant properties get much better with the addition of the expansible graphite, and the heat stability also has marked improvement. When the use content of the diatomite reach 13% and the expansible graphite is 3%, the heat conductivity coefficient of the foam is lowest, even lower than the diatomite used alone.By the study of addition micro silicon powder to modification rigid polyurethane foam can reach the result that the performance, impact performance and tensile strength all get better. And when the addition amount is 5%, the performance reach max which get to 0.46 MPa. The impact performance and tensile strength reached the highest when the addition amount is 10%. The impact performance is 8 times than the foam which add nothing, and the tensile strength is 3 times than it. The thermal stability also has increased correspondingly, and so is the dimensional stability and the heat preservation performance. When the addition amount of the micro silicon powder is 10%, the heat conductivity coefficient is the lowest.