James Michael Bier

Effect of oxidative treatment on the secondary structure of decoloured bloodmeal

Bloodmeal can be decoloured using peracetic acid resulting in a material with a pale-yellow colour which only needs sodium dodecyl sulphate, water and triethylene glycol to extrude into a semi-transparent bioplastic. Fourier-transform infrared (FTIR) spectroscopy using Synchrotron light was used to investigate the effect of peracetic acid treatment at various concentrations on the spatial distribution of secondary structures within particles of bloodmeal. Oxidation caused aggregation of helical structures into sheets and acetic acid suppressed sheet formation. Decolouring with peracetic acid led to particles with a higher degree of disorder at the outer edges and higher proportions of ordered structures at the core, consistent with the expected diffusion controlled heterogeneous phase decolouring reaction. The degradation of stabilizing intra- and intermolecular interactions and the presence of acetate ions results in increased chain mobility and greater amorphous content in the material, as evidenced by reduction in Tg and greater enthalpy of relaxation with increasing PAA concentration.

An ecoprofile of thermoplastic protein derived from blood meal Part 2: thermoplastic processing

PurposeThe purpose of this research was to develop a nonrenewable energy and greenhouse gas emissions ecoprofile of thermoplastic protein derived from blood meal (Novatein thermoplastic protein; NTP). This was intended for comparison with other bioplastics as well as identification of hot spots in its cradle-to-gate production. In Part 1 of this study, the effect of allocation on the blood meal used as a raw material was discussed. The objective of Part 2 was to assess the ecoprofile of the thermoplastic conversion process and to compare the cradle-to-gate portion of the polymers life cycle to other bioplastics.MethodsInventory was collected to aggregate nonrenewable primary energy use and greenhouse gas emissions. Data were collected from a variety of sources including published papers, reports to government agencies, engineering models and information from a single blood meal production facility. Several assumptions regarding the thermoplastic conversion process were evaluated by way of a sensitivity analysis.ResultsThe allocation procedure chosen for the impacts of farming and meat processing had the greatest effect on results. Excluding farming and meat processing, blood drying had the greatest contribution to nonrenewable energy use and GHGs, followed by the petrochemical plasticizer used. Other assumptions, such as scarcity of water or inclusion of pigments, although significant when considered for blood meal conversion to NTP alone, were found not to be significant when production of blood meal was included in the analysis. Qualitative differences were observed between NTP and other bioplastics. For example, the profiles of some other bio-based polymers were dominated by fermentation and polymer recovery processes. In the case of NTP, it is the production of the raw material used that is most significant, and thermoplastic modification has a relatively low contribution to GHGs and nonrenewable energy use.ConclusionsFor a truly attributional scenario, production of any ruminant animal products does have an associated GHG. Deriving this for blood meal on a mass-based allocation seems to indicate that NTP is less favorable than other cradle-to-gate bioplastic production systems from a global warming perspective.On the other hand, the motivation for developing the material in the first place was to make use of an existing waste product. If it is assumed that the magnitude of blood meal production is independent of fertilizer or plastics demand and, instead, reflects demand for major products such as meat, further development of NTP is justified.

The Role of Extrusion Conditions on the Mechanical Properties of Thermoplastic Protein

Abstract Mechanical properties of Novatein thermoplastic protein compounded at different extrusion temperatures and processing water contents have been examined in a factorial experiment. Thermoplastic proteins are moisture sensitive and can be prone to thermal degradation during processing. Processing water was varied between 30 and 45 parts per hundred parts bloodmeal while the extrusion temperature was varied between 120 and 150 °C to identify a processing window suitable for process scale up. To resolve any effects processing water had on protein-protein interactions from its plasticising effect, injection molded specimens were mechanically tested both as molded and after conditioning at controlled temperature and humidity. Despite all conditioned samples having approximately the same moisture content, mechanical properties were different. Tensile strength and modulus decreased with increasing processing water at the same equilibrium moisture content. DMA and WAXS suggested this was due to changes in chain mobility within the amorphous phase of the material, rather than conformational change towards a more ordered state. Properties of unconditioned specimens were mostly dependent on the plasticising effect of different amounts of processing water remaining in the material after injection molding. Extrusion temperature had very little effect on mechanical properties, suggesting that Novatein is robust enough to handle some temperature variations during processes such as injection molding.