N00: Poster Session II (11:30am-2:30pm CST)

Hall BC

Innovative and sustainable technologies intended to prevent the harmful effects of sourcing, manufacturing, and disposing of synthetic plastics are rarely both biobased and biodegradable. Many biodegradable plastics will in fact not fully decompose in natural settings and despite the best recycling efforts, the most significant portion of the plastic produced annually escapes into the biosphere. In an effort to create a fully biobased and backyard-compostable plastic alternative, we recently reported a bioplastic formulation composed only of spirulina biomass, without the need for extraction or other energy-intensive treatments. The application of heat and pressure transforms the biomass into a rigid, thermoformable and backyard compostable biomatter plastic with mechanical performance rivaling polystyrene and polylactic acid. In this work, we investigate the mechanism governing the self-bonding of spirulina during thermomechanical processing by creating a representative analogue for biomatter plastics. We vary the ratios of pure carbohydrates, lipids, and proteins are physically combined and subject the produced biopolymer composites to heated compression molding to form materials with composition emulating that of our algal bioplastics. The effect of the varying macromolecular composition, and the contribution of each class of macromolecule to the polymer morphology and mechanical properties of the formed biomatter analogues are evaluated by mechanical testing and scanning electron microscopy (SEM). The varying ratio of protein to carbohydrates is utilized to compare the mechanical performance of biomatter analogues to several algal species. The bonding mechanism of the biomatter analogues is first assessed qualitatively during sequential reprocessing to isolate contributions of dynamic bonding. Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) are then utilized in combination with molecular dynamic (MD) simulations to quantitatively measure both secondary and primary bonding interactions between different macromolecular components of the analogue composites and a mechanism is proposed for self-bonding in biomatter plastics.