Final Technical Report

Abstract

Project Objective: Project objective is to (1) develop and test new technologies that harvest, transport, store, and separate corn stover to consistently supply clean, raw materials to downstream processors in the bioproducts industry, and (2) to engineer a fermentation system to meet performance targets for lactic acid and ethanol manufacturers. Executive Summary:The two main objectives of this project were: 1) to develop and test technologies to harvest, transport, store, and separate corn stover to supply a clean raw material to the bioproducts industry, and 2) engineer fermentation systems to meet performance targets for lactic acid and ethanol manufacturers. Significant progress was made in testing methods to harvest corn stover in a "single pass" harvest mode (collect corn grain and stover at the same time). This is technically feasible on small scale, but additional equipment refinements will be needed to facilitate cost effective harvest on a larger scale. Transportation models were developed, which indicate that at a corn stover yield of 2.8 tons/acre and purchase price of $35/ton stover, it would be unprofitable to transport stover more than about 25 miles; thus suggesting the development of many regional collection centers. Therefore, collection centers should be located within about 30 miles of the farm, to keep transportation costs to an acceptable level. These collection centers could then potentially do some preprocessing (to fractionate or increase bulk density) and/or ship the biomass by rail or barge to the final customers. Wet storage of stover via ensilage was tested, but no clear economic advantages were evident. Wet storage eliminates fire risk, but increases the complexity of component separation and may result in a small loss of carbohydrate content (fermentation potential). A study of possible supplier-producer relationships, concluded that a "quasi-vertical" integration model would be best suited for new bioproducts industries based on stover. In this model, the relationship would involve a multiyear supply contract (processor with purchase guarantees, producer group with supply guarantees). Price will likely be fixed or calculated based on some formula (possibly a cost plus). Initial quality requirements will be specified (but subject to 2 refinement).Producers would invest in harvest/storage/transportation equipment and the processor would build and operate the plant.Pilot fermentation studies demonstrated dramatic improvements in yields and rates with optimization of batch fermentor parameters. Demonstrated yields and rates are approaching those necessary for profitable commercial operation for production of ethanol or lactic acid. The ability of the biocatalyst to adapt to biomass hydrolysate (both biomass sugars and toxins in the hydrolysate) was demonstrated and points towards ultimate successful commercialization of the technology. However, some of this work will need to be repeated and possibly extended to adapt the final selected biocatalyst for the specific commercial hydroly...

Effect of the Chemical Structure of Compatibilizers on the Thermal, Mechanical and Morphological Properties of Immiscible PLA/PCL Blends

“…It is engineered specifically for extrusion and used as food packaging or consumer goods, such as plastic bowls and cups. [19] The PCL grade used was Capa 6500, produced by Perstorp, which is a nontoxic and biodegradable homopolymer with a deformation at break of over 700% and 17.5 MPa yield strength. The block copolymers added to immiscible PLA/PCL blends were kindly donated by Perstorp.…”

Tuning structural relaxations, mechanical properties, and degradation timescale of PLLA during hydrolytic degradation by blending with PLCL-PEG

“…Although PLLA is considered a relatively strong polymer, with yield strength of approximately 60 MPa and stiffness around 4 GPa [8,9], its mechanical properties are still insufficient for many load bearing applications, especially when compared with the permanent metals these polymers are often seeking to replace. For stents this means that to provide the required mechanical support, polymeric stents must incorporate significantly thicker struts than their metallic counterparts.…”

Mechanical response of poly(lactic acid)‐based packaging under liquid exposure

“…Recent technologies have widened the processing capabilities in the production of not only flexible packaging but also of rigid containers for longer service life products, such as beverages (plain water, soft drink, and fruit juices), edible oil, and health and beauty products. 1 PLA-based materials, however, have some limitations as packaging materials, especially because of the deterioration of their material properties, which can observed after prolonged exposure to the environment. [2][3][4] Moreover, interactions involving the packaging type, product constituents, and environment may impact the material degradability and can initiate changes in the thermal, chemical, and physical properties of the material.…”