Preparation And Application Of Distiller’s Grains Based Polyurethane Material

Polyurethane materials have been widely used in biomedical applications,construction and construction applications,automobile,textile and other industries because of their excellent properties in hardness,elongation,strength and modulus.In order to solve the difficult problem of large scale use of petroleum based polyols in the process of polyurethane synthesis and the dual problems of environmental pollution and waste of resources caused by waste biomass,the waste residue of distiller’s grains is directly used as biomass polyol.After fermentation,the molecular weight of distillers grains is reduced,and their reactivity is improved,replacing the non renewable petroleum based polyols.The distillers grains based polyurethane foam was used as an adsorbent and immobilized carrier of mimic enzyme,combined with the adsorption and biodegradation characteristics of the material,so as to achieve the efficient adsorption and removal of organic dyes.In view of the complex preparation process of bio based polyols and the consumption of petroleum based polyols and chemical reagents in the reaction,the physical and chemical properties of distiller’s grains fermented by microorganisms were analyzed to explore the feasibility of its direct use as bio based polyols.The film-forming properties of distiller’s grains in polyurethane system were studied according to the results of hydroxyl value.The preparation process of distiller’s grains based polyurethane film was explored.The effects of catalyst,isocyanate index,distiller’s grains content and drying temperature on the properties of the film were determined by infrared spectroscopy,mechanical properties and differential scanning calorimetry.The results showed that the combination of catalysts could promote the dispersion and reaction of distiller’s grains.The isocyanate index is near R = 1.2,the viscosity of film solution is high,and the film-forming effect is ideal.The content of distiller’s grains has a significant effect on the performance of the membrane.Higher drying temperature can promote the further crosslinking of the membrane solution.Under the optimum conditions,triethanolamine and tin isooctanoate were used as catalysts,isocyanate index was r = 1.16,polyol substitution of distiller’s grains was 30%,and drying temperature was 120 ℃,the distiller’s grains based polyurethane film had excellent mechanical properties,water resistance and thermal stability.At this time,the tensile strength of distiller’s grains based polyurethane film is 9.43 MPa,the elongation at break is 168%,and the water solubility is only 4.5%.In view of the low bioavailability of polybasic alcohol in biological polyurethane foam,distiller’s grains are directly used as bio based polyols,which greatly improves the content of biomass in foams.The isocyanate,soft segment extender of hard segment was selected and designed to synthesize polyurethane foam with porous structure.The effects of isocyanate,chain extender,isocyanate index,distiller’s grains content,foam stabilizer and catalyst on foam properties were also investigated by infrared spectroscopy,mechanical properties,thermogravimetric analysis and scanning electron microscopy.The results show that the selection of isocyanate and chain extender has a significant effect on the foaming effect.The isocyanate index controls the crosslinking strength of the foam,the content of the lees changes the structure of the foam,the foam stabilizer stabiles the foam and regulates the cell hole,and the catalyst can adjust the synergy of the gel and the foaming reaction.With six methylene diisocyanate as isocyanate and chain extender as polyethylene glycol 400 and glycerol,a polyurethane foam with a porous structure was successfully synthesized.Under the optimal conditions,the isocyanate index R=0.72 and the polyol substitution amount of distillers grains are 60%.The tensile strength of the distilled lees based polyurethane soft foams is 103.7 k Pa,the elongation at break is 73%,the porosity is 95.6%,and the water absorption is 660%.On this basis,in order to investigate the adsorption and immobilization characteristics of the materials,the distillers grains based soft polyurethane foam was applied to the adsorption of organic dyes,and the enzyme was further simulated.hematin@Cu /GMP was immobilized on the soft polyurethane foam of distiller’s grains and adsorbed and degraded organic dyes.The adsorption of amino acids on the distillers grains based soft polyurethane foam follows a pseudo-second-order kinetic model.The total adsorption rate is determined by chemical adsorption,which is consistent with the Freundlich model.Adsorption may not be monolayer adsorption.After the enzyme was immobilized,the adsorption and degradation rate of amino black was greatly improved,and the carrier still maintained a high adsorption and degradation efficiency under different conditions and repeated use.In conclusion,distiller’s grains can be used as bio based polyols to replace some petroleum based polyols.The synthesized distiller’s grains based polyurethane material has excellent properties,which provides theoretical guidance and technical support for the resource utilization of waste biomass.