Study On The Preparation And Properties Of Modified Layered Double Hydroxides/Chitosan Blend Film

In this paper, modified layered double hydroxides/chitosan (M-LDHs/CS) blend film, a degradable barrier packaging film, was prepared, and the properties of M-LDHs/CS blend film were inspected. The oxygen barrier property of chitosan films was inspected, and the processing was optimized; LDHs was modified, prepared M-LDHs; the M-LDHs/CS blend films was prepared by co-solution. The structure of blend films was characteriazed, and the mechanical properties, optics properties, oxygen barrier properties of the flims were inspected; and the effect of glycerol to blend films'structures and properties was inspected. The main conclusions in this paper were as follows:For the oxygen barrier property of chitosan films and modification of LDHs, the influence of the concentration of chitosan in acetic acid solution, stirring temperature and film forming temperature were investigated on the properties of blend films by the use of orthogonal experiment. As a result, the optimal process of preparing chitosan films had been obtained. The concentration of chitosan and acetic acid solution was 1.0% (m/v), stirring temperature was 60℃, and film forming temperature was 40℃. The oxygen barrier property of chitosan films was the best, the OTR was 3.598cm~3/m~2·24h·0.1MPa. LDHs was modified by citric acid, the analysis of XRD, FTIR, FE-SEM and TG showed: the M-LDHs was the best when the molar ratio of citric acid and LDO is 2:1.For the M-LDHs/CS blend films, with the increase of w(M-LDHs):w(CS), the oxygen transmission rate of the composite films was declined first, then increased. The optimal oxygen barrier property of blend film was when the ratio of w(M-LDHs):w(CS) is 15:100, which has been increased 42% than the pure chitosan film. At the same time, the tensile strength has been increased 22%. The blend films had a good transparency due to the light transmission rate was more than 90%. The oxygen barrier property, optics properties and mechanical properties of LDO/CS blend films were worse than M-LDHs/CS blend films. For the glycerol toughing M-LDHs/CS blend films, with the increase of glycerol content, the phase separation between M-LDHs and chitosan was become worse. With the increase of glycerol, tensile strength and breaking elongation were increased 14% and 19% compared to blend films without glycerol, separately, achieved the aim of toughing; the oxygen barrier property of M-LDHs/CS was declining, but the oxygen barrier property was still better than the pure CS film when the content of glycerol was 2% and the mechanical properties of the blend films was the best; light transmission rate was more than 91%, better than films without glycerol.