A binder is applied to fibers (600) to bind particles (602) to the fibers. The fibers have hydrogen bonding functional groups. The particles have functional groups capable of forming a hydrogen bond or a coordinate covalent bond. The binder comprises binder molecules, wherein the binder molecules have at least one functional group that forms a hydrogen bond or a coordinate covalent bond with the particles, and at least one functional group that forms a hydrogen bond with the fibers. A substantial portion of the particles that may be adhered to the fibers are adhered in particulate form by hydrogen bonds or coordinate covalent bonds to the binder, and the binder in turn may be adhered to the fibers by hydrogen bonds. Fibers containing particles bound by this method are easily densified.