| abstract |
Composite materials and methods for their preparation are described herein. The composite materials can comprise (a) a polyurethane and (b) from 35% to 90% by weight, based on the total weight of the composite, of a particulate filler dispersed in the polyurethane. The polyurethane can be formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols. The one or more polyols that form the polyurethane comprise a high hydroxyl number polyol having a hydroxyl number of at least 250 mg KOH/g. In some cases, the one or more polyols that form the polyurethane can have a weight average equivalent weight of from 200 to 1100 amu. In some cases, the one or more polyols that form the polyurethane can include less than 5% by weight, based on the total weight of the one or more polyols that form the polyurethane, of one or more flexible polyols having a hydroxyl number of less than 150 mg KOH/g and a functionality of less than 3. |