Preparation Of Poly (Vinyl Alcohol) Composite Packaging Film With Chitosan Biguanidine Hydrochloride

PVA composite film of antibacterial performance were prepared by adding the organic antibacterial agent of chitosan biguanidine hydrochloride to the excellent compressive properties of PVA composite film. It can be better to protect the interior goods inhibiting the growth of microorganism,and reduce the waste caused by the corruption eventually.At the first step,the best process conditions of chitosan biguanidine hydrochloride which was synthesized using the chitosan and dicyandiamide as the raw material were discussed. It showed that the highest yield was 92.96% when the hydrochloric acid concentration was0.4mol/L, the molar ration of functional group(amino-group:cyano-group) was 1:5 and the reaction time was 20min.Afterwards,the molecular structure and antibacterial activity of chitosan biguanidine hydrochloride were observed with the FTIR and disc diffusion, the results show that the biguanide groups had been in the structure, and also the MIC was reduced about 50% comparing with chitosan. The growth and stability of E.coil and S. Aureus cells which was treated about 24h with the antibacterial agent were inhibited and disturbed respectively by the SEM.At the same time,the influence of process parameters on the final mechanical, barrier properties and cross-section structure of PVA composite films were investigated by electronic universal testing machine, XRD and SEM, respectively. The experiment results show that the tensile strength(TS) increased from 26.31MPa to 57.32 MPa, while the elongation at break(ES) presented the opposite trend decreasing form 50.29% to 28.70% with increasing the amount of chitosan, respectively. The trend of the oxygen permeability coefficient(Pg) and the water vapor permeability coefficient(Pv) was same as the TS, however the crystallinity decreased. In addition, the SEM pictures of cross-section of composite films displays not smooth,"fish scale" lamellar. Whereas, the mechanical properties presented an almost opposite trend compared with the previous with the addition of PVA,the TS and ES was 25.23MPa,50.28%, respectively. It was also observed that the barrier properties were getting worse and the crystallinity were increased. Meanwhile, the cross-section of films gradually appears the agglomeration. Besides, it only produce the intermolecular forces and hydrogen bonding between chitosan and PVA which were the two compounds of the films under the FTIR analysis. And also, the compressive performance was better by adding the glycerol and cross-linking agent, the toughness and resistance to water performance were improved, respectively.At last, The PVA composite film of antibacterial performance were prepared by adding the antibacterial agent to the composite films. Based on the bacteriostatic experiment, it was observed that the bacteriostasis were improved with the addition of the antibacterial agent, the bacteriostasis rate against with the E.coil and S.aureus was 98.86% and 99.12%,respectively. So the PVA composite film could protect the goods because of the good bacteriostasis.