Study on Preparation of Alkali-lignin Polyurethane Film and Its Performance

摘要

Alkali lignin was used to substitute for part of polyethylene glycol (PEG) in the synthesis of alkali-lignin polyurethane (PU) films which can reduce the cost of production of polyurethane and validate the recycling of alkali lignin that turns waste into treasure. The alkali-lignin PU films were prepared from alkali lignin by solution casting with PEG and toluene diisocynate (TDI) in the solvent of N,N-dimethylformamide (DMF) under the presence of stannous octocte. To prepare PU with the optimum technique, NCO/OH ratio and alkali-lignin content, the two influence factors of PU performance were studied, respectively. The results showed that Young’s modulus, tensile strength, elongation at break and tear resistance were 0.39 GPa, 44.3 Mpa, 4.5 ％ and 6300 mN, respectively, under the conditions of NCO/OH ratio of 2.8 and 15 percent lignin content with the ratio of catalyst. The membrane materials were also studied with SEM and TGA. Experiments showed that the PU film has good chemical resistance and high working performances, too.