| The objective of this study was to obtain a complex active package film,prepared by coating chitosan on poly(vinyl alcohol) film,with properties of high-resistance, well-mechanics,biodegradation and antimicrobial.Relative molecular weight of three kinds chitosan used in this study were 4.68×10~5, 4.77×10~5 and 6.68×10~5 respectively,tested by Ubbelohde viscometer.Nephelometery combine with dilution-plate method showed the antibacterial activity of chitosan accurately,comparing whit inhibition zone and nephelometery. Flocculent precipitate occurred in LB with 0.01%chitosan during cultivation.This interesting phenomenon was not reported in literature.Chitosan showed high antibacterial activity against E.coli and S.aureus,with higher molecular weight showed better antibacterial activity.While 0.01%concentration of chitosan showed no good antibacterial.The best antibacterial condition of chitosan was 0.05%concentration against E.coli,and 0.025%concentration against S.aureus.PCS and TMC synthesised were white floccus,and had good solubility in neutral water.Antibacterial activity of PCS and TMC with 0.1%concentration against E.coli is well.Antibacterial activity of PCS and TMC had selectivity.Antibacterial activity of TMC against E.coli was better than against S.aureus.Complex film was prepared by coating chitosan on poly(vinyl alcohol) film in this paper.Physical properties of poly(vinyl alcohol)/chitosan complex film was tested with universal material testing machine.Elasticity modulus of complex film increased when concentration of chitosan increased.Elongation at break and tensile strength of complex film a little decreased,comparing with poly(vinyl alcohol) film.Water vapor permeablity of complex film was tested by PERMA TRAN-W 3/33. Water vapor permeablity of complex film was a little larger than poly(vinyl alcohol) film. Water vapor permeablity of complex film with chitosan-1 and chitosan-2 increased when concentration of chitosan increased.However,water vapor permeablity of complex film with chitosan-3 decreased when concentration of chitosan increased.Water vapor permeablity of complex film was affected by relative humidity of the air.Oxygen permeablity was tested by OX-TRAN 2/22.It showed that the oxygen barrier performance of poly(vinyl alcohol) film with chitosan was better than poly(vinyl alcohol) film.Antibacterial activity of complex film was tested by QB/T 2591-2003.It showed that complex film had good antibacterial activity against E.coli and S.aureus.Complex film with more chitosan showed the better antibacterial activity,chitosan-3-2%film showed the best antibacterial activity against E.coli and S.aureus,and the bacteriostatios ratio was 99%.Complex film prepared by coating method,showed the superiority union of poly(vinyl alcohol) and chitosan.Complex film maintained the high-resistance,goodmechanical property of poly(vinyl alcohol),and showed the best antibacterial activity as well. |
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