Preparation And Property Of Konjac Gluconmannan Film And Sponge Material

In this paper, film and sponge material were prepared by tape casting andcryogenic induced phase separation with KGM as raw material. The molecularweight, purity, solubility in water and acid solution of KGM and the rheologicalproperties of KGM solution were studied. The rheological property of konjacglucomannan solution was studied in depth. Then the performance of the konjacglucomannan films and sponge were tested. Following results were obtained;(1) The measurement results of purity and viscosity-average molecular weightof KGM was96.18%and6.27×105respectively. Konjac glucomannan can be welldissolved in water, and can also be dissolved in a solution of hydrochloric acid,acetic acid and sulfuric acid. But degradation of KGM would appear in the acidsolution. The degradation would even result in the color change of the solution.Observing the dissolution through the microscope, and ultimately the smallamount of insoluble material would be left in solution. The rheology of KGMsolution showed the typical characteristics of a non-Newtonian fluid, the viscosityof the solution increased with the increasing concentration, and decreased as thegrowth of temperature and time.(2) The film of KGM was prepared by tape casting. The film formability wasstudied from selection from the mold, the degree of difficulty taking film from themould, improvement of water resistance. The results showed that the filmformability was best when KGM solution concentration was1.5%. The adding of0.8%glycerol, on the one hand, improved KGM film formability, on the otherhand improved the physical properties of the film. The water resistance of KGMfilm was improved after treatment by sodium hydroxide. the greater concentrationof sodium hydroxide, the better the water resistance. And when the sodiumhydroxide concentration was1.0%, the degree of deacetylation measured was 97.75%. The influence was small on film performance with the sodium hydroxideconcentration increasing. The best process was KGM solution was1.5%, glycerolwas0.8%, and treated with1.0%sodium hydroxide after film formed. Strength ofthe film was13.95MPa, elongation at break was7.94%, and the amount of waterabsorption was11.01g/g at this time.(3) KGM sponge was prepared by freeze-drying technology.1.5%KGM spongewas chosen though analyzing the mechanical properties and appearance of KGMsponge of different concentration. The orthogonal experimental designed tostudying solidification process of KGM sponge. The best condition was thesolidification temperature was45℃, the solidification time was6h, sodiumhydroxide concentration was3.0%. Then glycerin was used to handle sponge, forimproving the flexibility of KGM sponge. White non-variegate and intact no cracksponge was prepared after molding, solidification, softening three steps. Theinfluence of the treatment process was studied on KGM by the testing methodssuch as IR and TG. The sponge structure was observed by SEM. The pore structureof KGM sponge and the change of microscopic structure was observed and studied.The strength of soft KGM sponge was0.90MPa, elongation at break was28.18%,the water absorption capacity was22.63g/g, the air permeability was45.48%.Compared with alginate sponge, alginate non-woven fabric and viscose non-wovenfabric, the strength and moisture absorption of KGM were better than that threematerials.