Study On The Preparation Of Novel Sugarcane Bagasse CMC/PVP Hydrogel

Gel is widely adopted in biomedical fields and other high-tech material science, especially in the study of drug release. For medical use, gel requires good biocompatibility, biodegradability, low toxicity and excellent mechanical properties.In this paper, using ultrasonic assisted treatment, Carboxymethyl Cellulose (CMC) is extracted and prepared from bagasse fiber, one of the commonly available biomass materials. The results of the above experiments are as following:(1) For bagasse cellulose extraction, in addition to the original alkaline hydrogen peroxide treatment, ultrasonic assisted extraction are introduced. Various experiments are conducted to find the best condition to operate the treatment. The optimum parameters are:ultrasonic intensity of200W, extraction processing time of70min, extracting temperature of80℃, the mixed solution H2O2and NaOH with concentration of0.7%and6%respectively. Under these conditions, the amount of cellulose extracted from bagasse can reach as high as87.54%, which is an8.69%increase to the original treatment.This is because ultrasonic treatment increases the reagent accessibility of bagasse fibers, thus greatly shortening the reaction time; it also increases the swelling capacity of the fibers:the hydrogen bonds are broken and lots of micro fibers are exposed, greatly expanding the contact area with the reagents, which leads to less NaOH and hydrogen peroxide usage.(2) In preparation of high viscosity carboxymethyl cellulose with ultrasonic assisted solvent method, effects of various conditions on the synthesis of CMC is tested. Finally, using orthogonal test, the optimum process conditions of the synthesis conditions turn out to be:the ultrasonic power is250W, NaOH dosage is10g, alkalization time is50min, alkalization temperature is30℃, the amount of chloroacetic acid is10g, etherification time is80min, etherification temperature is30℃, NaOH:ClCH2COOH (mass ratio) is1:1. The viscosity of CMC can reach above3000mPa.s when its concentration is0.2g·L-1.(3) Effects of different time, pH value, salt concentration and temperature on the viscosity of CMC solutions are tested:the viscosity of the solution decreased as time goes by. The viscosity of the CMC solution reaches maximum value in pH6～8.. The viscosity tend to decrease when NaCl salinity is increased, but for high viscosity CMC solutions, the viscosity increases at first, until mass fraction reaches3%. At lower temperatures, CMC solutions can keep a good viscosity, when temperature increases, the viscosity turns down.(4) Experiments on preparation of CMC/PVP hydrogel for drug application with by solution blending method are conducted. Tests on gel swelling ratio shows that the swelling rate of composite hydrogel with CMC:PVP=0.75:0.25is14times higher than that of the CMC:PVP=0:1hydrogel, with better diffusivity and higher permeability; SEM of the gel morphology shows that the composition CMC:PVP=0.75:0.25has larger aperture. Fourier transform infrared spectroscopy shows that the gel components are well blended. X-ray diffraction (XRD), differential scanning calorimetry (DSC) results show that the PVP amorphous structure is dispersed in the CMC molecular chain. The existence of PVP isolates large CMC molecules, preventing them from crystal growth, thus increasing the molecular chain flexibility. Therefore the gel can quickly absorb the tissue fluid out of the wounds, and has good air permeability.