an iowa state university research team has developed a method to create low-isocyanate polyurethane foam using biofiller recycled from landfills. they said the foam's stability and compressive modulus were improved.
this foam is made from bio-based polyols. to achieve the foam hardness typically imparted by isocyanates and avoid foam collapse, they used a prepolymerization step. the research team said this method allowed them to produce foams that did not shrink back after foaming and expansion.
adding a biofiller (they used rice husk or coffee bran) increased the foam's compression modulus by 400% without changing the isocyanate content, showing that improving the mechanical properties of the foam without increasing the isocyanate content is possible.
they claim that if the biofiller is ground and screened, the performance of the foam can be further improved and become more reproducible. finer particles can also be added without negatively affecting the mechanical properties of the foam.
the research team recommends applying this approach to other bio-based cellulosic biofillers. this may be a scalable, more economical and sustainable way to produce foams with better performance and lower isocyanate content.
