Location: Bioproducts ResearchTitle: Compression molded cellulose fiber foams
|Glenn, Gregory - Greg|
|Orts, William - Bill|
|SHOGREN, RANDALL - World Centric|
|Wood, Delilah - De|
Submitted to: Cellulose
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2023
Publication Date: 3/1/2023
Citation: Glenn, G.M., Orts, W.J., Klamczynski, A.P., Shogren, R., Hart-Cooper, W.M., Wood, D.F., Lee, C.C., Chiou, B. 2023. Compression molded cellulose fiber foams. Cellulose.
Interpretive Summary: Fiber foam is a new material that could help replace plastic products but it can not be molded using traditional equipment designed for plastics. ARS scientists have developed a compression molding process for molding fiber foam into finished products. The compression molding method produces a foam with a smooth, attractive skin while preserving the foam structure of the interior. Molded foam products with different densities and strength were produced. These renewable products could be used in packaging and other products currently made with plastics.
Technical Abstract: Cellulose fiber foams are of growing interest as a part of the circular economy where renewable, biodegradable/compostable materials replace nonrenewable, nondegradable plastic products. The ability to mold fiber foams into shapes is important for making products. Here we describe a compression molding technique that was used to mold wet cellulose fiber foam. The wet fiber foam was made from aqueous fiber mixtures and sodium dodecyl sulfate (SDS) as a foaming agent. Polyvinyl alcohol (PVA) was added as a fiber dispersant and foaming aid in formulations with fiber concentrations greater than 7%. A blender and a planetary paddle mixer were used to make foam containing fiber concentrations ranging from 0.77% to 11% and from 14.1% to 23.3%, respectively. The wet foam compressive strength was positively correlated with the drying time, dry density, compressive strength, and modulus. A wet foam compressive strength greater than 1.5 kPa was required for compression molding foam panels. The process involved overfilling (135%) the mold before lowering the upper platen. As the platen contacted and compressed the foam, sufficient pressure was created for the foam to flow and fill void spaces. Excess foam liquid exuded through the platens as the foam structure collapsed primarily at the platen surface. Compression molding created foam panels with a smooth, dense fiber layer on the surface and a low-density foam interior. The dry foam densities ranged from 0.0062 to 0.075 g/cm3, porosity ranged from 95% to 99.6%, and thermal conductivity ranged from 0.0385 to 0.0421 W/mK.