Abstract

Materials used in a sustainable building application must have low (or zero) embodied energy in order to contribute to the elemental objective in minimizing total carbon footprint. Traditional construction materials are primarily derived and manufactured using nonrenewable resources and, at the end of their useful lives, typically disposed of in landfills where they lie recalcitrant. To address this cradle-to-grave concern in material manufacture, use, and disposal, novel construction materials are being developed with a target of relying only on rapidly renewable resources, including waste streams. The proposed cradle-to-cradle biomaterials are fabricated by using natural fibers as reinforcement in a biodegradable polymeric matrix derived from polyhydroxyalkanoates (PHAs), naturally occurring aliphatic thermoplastic polyesters produced by microbes via bacterial fermentation in carbon-rich environments. The composite material produced exhibits comparable material properties to structural grade wood and is rapidly biodegradable in specific anaerobic conditions at the end of its useful life. Using anaerobic digester sludge from local wastewater treatment plants as the biodegradation medium, the material decomposes into biogas that consists mostly of inert gases and, of particular interest, methane, which can be captured and used either as a biofuel or as a closed-loop carbon source for the production of new PHAs. This paper documents biobased composite material development, durability issues, anaerobic biodegradation, and potential industrial applications.