Biodegradable Chitin Foam

About

The foam is made using chitin extracted from shellfish waste as well as other sources of chitin. Chitin is the second most abundant polysaccharide after cellulose and acts as the structural component of the exoskeleton of arthropods. Currently the most widely produced foams, polyurethane and polystyrene, are created from nonrenewable petroleum based sources. Manufacturing and working with petroleum based foams is very toxic to workers and damaging to the environment. Chitin based foams have neither of these drawbacks. Chitin extracted from shellfish waste can be a powder, flake, granule, or combination thereof. The chitin is then dissolved in an eco-friendly, water-based ionic liquid solution such as a solution of sodium hydroxide and urea. The chitin is then foamed either by mechanical, chemical, or physical blowing of the solution.

Surfactants, stabilizers, and/or cross-linking agents may be added to the dissolved chitin solution to facilitate the foaming process, stabilize the foamed product, and/or tailor the mechanical properties of the dried foam. The surfactants can be anionic, cationic, or nonionic. These surfactants, stabilizers, and cross-linkers may include but are not limited to sodium dodecyl sulfate, ammonium lauryl sulfate, sodium stearate, polysorbate 20/40/60, dodecyldimethylamine oxide, glycols, ethers, sulfates, carboxylates, xanthan gum, or glyoxal.

The foamed chitin solution can then be washed with water, or an organic solvent (e.g. ethyl alcohol), to allow the chitin to self-assemble while simultaneously removing excess salt from the ionic solution. The foamed chitin solution is then dried by a method including but not limited to air, oven, steam, vacuum, or pressure to result in a cellular, closed-cell, chitin polymer foam material.