Preparation of biopolymers from liquefied corn stover

The objective of the present study was to develop processes for liquefaction of solid biomass and explore the potential of making biopolymers from the liquefied biomass. In this study, corn stover was liquefied under acidic conditions, and several polymer materials were subsequently prepared from the liquefied biomass. Liquefaction was conducted using different organic solvents with sulfuric acid as catalyst at different temperatures. The effect of the ratio of solvent to solid biomass on liquefaction rate was also evaluated. Of the two organic solvents used in the liquefaction process, ethylene carbonate was found to be more effective than ethylene glycol in terms of liquefaction rate. The adequate processing conditions for the feedstock used were found to be organic solvent / corn stover ratio of 3, temperature 160℃, catalyst content 3%, and heating time 2.5 hours. The polyols from the liquefaction were separated and purified through a series of processes, such as dilution, pH value adjustment, filtration, evaporation, and ozonolysis. Processes for making biopolymers, such as polyester films, polyurethane foams and particleboards from the liquefied corn stover containing a high quantity of bio-polyols were evaluated. The film formation was based on the esterification reaction between the hydroxyl groups of the bio-polyols and the carboxyl groups. The foam was prepared through a reaction of the hydroxyl groups with diisocyanate. Polyesters made from the reaction between bio-polyols and anhydrides are shown to be a good adhesive for making particleboard.