Urea-formaldehyde (UF) resin binder compositions modified with a starch are described. The binder compositions may include about 1 wt. % to about 10 wt. % of a starch. In addition, fiber reinforced composites are described. The composites may include organic or inorganic fibers and a polymer matrix formed from a binder composition. The binder composition may include a UF resin and about 1 wt. % to about 10 wt. % of a starch.

Particulate binder compositions made with amine-aldehyde resins and methods for making same are provided. The method for making the particulate binder composition can include spray-drying an amine-aldehyde resin having a total aldehyde compound to total amine compound molar ratio of about 1.55:1 to about 1.65:1 to produce a particulate binder composition. The particulate binder composition can have a fusion diameter of about 35 mm to about 70 mm.

A method of making a glass mat includes providing an assembly of glass fibers, applying a binder composition to the assembly of glass fibers, wherein the binder includes an organic resin, and curing the binder composition while dimensionally constraining the assembly of glass fibers. Dimensional constraining includes directly contacting a first major surface and a second major surface of the assembly of glass fibers between two substantially parallel surfaces. Further provided is a glass mat that includes an assembly of glass fibers, wherein the assembly of glass fibers are substantially randomly oriented with a tensile anisotropy of less than about 6 in any two directions. The glass mat has a decreased surface roughness and a decreased caliper compared to an equivalent glass mat having an assembly of naturally packed glass fibers with an equivalent fiber diameter size.