Composite materials and methods for their preparation are described herein. The composite materials can comprise a polyurethane and an absorptive filler. The polyurethane can be formed from the reaction of at least one isocyanate selected from the group consisting of diisocyanates, polyisocyanates, and combinations thereof, and one or more isocyanate-reactive monomers. The one or more isocyanate-reactive monomers can comprise at least one polyol and a first isocyanate-reactive monomer which includes one or more isocyanate-reactive functional groups and a moiety configured to associate with the absorptive filler.