Research On The Film Formability And Dissolution Of Pretreated Corn Stalks In Ionic Liquid

Biological resources are renewable, biodegradable and abundant which make them become the most potential source for development of green alternative energy sources. Corn straws have potentiality to develop into source due to its rich in mount and high content of cellulose. However, corn stalks are difficult to dissolve in common solvents due to the crystal structure of cellulose and the bind among the cellulose, hemicellulose and lignin in corn straws. Therefore, it is an important task, in using cellulose, which is to find proper pretreatment methods and suitable solvent for cellulose. In this paper, corn straws were pretreated with ethanol-water and then dissolved in synthetic ionic liquid [AMIM]C1. After that, regenerated cellulose membrane and regenerated cellulose composite membrane were made. Finally, the recyclability of ionic liquid [AMIM]Cl was explored. Main contents and results are as follows:(1) The result of ethanol-water pretreatment was the best when the experimental conditions were 65%for ethanol concentration,8:1 for liquid to solid ratio,180? for holding temperature and 2h for holding time. SEM results indicated that pretreatment didn't damage structure of cellulose in corn straws. TGA spectrums showed that the content of hemicellulose and lignin removed after the pretreatment. XRD diffraction pattern showed that the pretreatment didn't change crystal form of cellulose. Additionally, the FT-IR and thermal stability analysis were also used to get mechanisms of pretreatment by analyzing the lignin in black liquor.(2) The ionic liquid [AMIM]Cl was synthesized in laboratory and detected using FT-IR. The highest yield of [AMIM]Cl was 94.8% when the experimental temperature was 45? and the synthesis time was 8h. [AMIM]Cl was used for dissolving the pretreated corn straws. It is found that the maximum dissolving ration of cellulose was 10.1% when the melting temperature was 90? and the melting time was 8h. SEM results showed that the structure of regenerated corn stalk cellulose was destroyed. TGA indicated that the thermal stability of regenerated corn stalk cellulose decreased slightly. XRD illustrated that the crystal form of cellulose changed from cellulose I to cellulose II. FT-IR showed that the structure of lignin was saved well.(3) Ionic liquids [AMIM]Cl was used to dissolved pretreated corn straws to preparation regenerated cellulose membrane. Corn straws were added to preparation regenerated cellulose composite membrane. Optical microscopy images showed that the regeneration membrane surface was smooth; SEM indicated that surface structure of corn straws regenerated cellulose membrane was dense and the inside structure was layered. TGA showed that the thermal stability of corn stalks regenerated cellulose membrane was good.(4) Ionic liquids [AMIM]C1 was recovered by distillation devices under reduced pressure. The recovery rate was 97.1% after repeated four times. For every recovered ionic liquid were used to dissolve corn stalks and produce regenerated cellulose membrane. The results showed that the recovered ionic liquid remained the same performance to pretreated corn straws.