Development, Structure And Performance Study On The Edible, Salt Tolerant And Super Absorbent Films

Super absorbent polymer is a extensively used functional material,in terms of safety, the research on this material for packing food and products are few.However,this material maybe can be used for food refreshing,condensing,thickening and so on.In order to obtain safe,edible,super absorbent material,the d-KGM/CHI films were prepared with mechanical blending,the CMC films were prepared with ester cross-linking,and the HCMC films were prepared with ester cross-linking on acid condition in this paper.The structure and performance of the edible,salt tolerant and super absorbent films prepared through these three novel ways were characterized with many modern instruments including FT-IR,XRD,SEM,DSC and etc. Main research results 1 A series of soluble d-KGM were prepared with non-homogeneous method using ethanol as solvent and Na2CO3 as modifier.The maximal water absorbency of d-KGM/CHI.HC1 blend films was 26(KC3),The maximal normal saline absorbency was 64(KC5).The analysis of the results of FT-IR,WXRD,SEM and DSC suggested that when the content of CHI.HC1 reached 40%,the strong hydrogen bond interaction among high polymers were generated,which made molecure chain combine much closer and displayed good compatibility.The analysis for mechanical property of films suggested that KC3 have the strongest Tensile strength(162Mpa) and breaking elongation(60.3%). Experiment results indicated that absorbing capacity of films have relation not only with the compatibility of d-KGM and CHI-HC1 but also with the crystallization of d-KGM. 2 The results of measurement of properties of six different CMC indicated that the intrinsic viscosity,the apparent viscosity and the optical transparency increased when viscosity-average molecular weight increased for the same kind of CMC. Among all the CMC films prepared with ester cross-linking method,the absorbing capacity of AH1 and PH7 relatively good.The premium condition for AHI:thermal treatment at 120~C for about 40min,QsaLt=155.The premium condition for PH7:thermal treatment at 1300C for about 20min,Qsa~t=130.However,thermal cross-linking of FH6, IH6,OM6 were weak and the absorbing capacity of FH6,IH6,OM6 were not strong. FH9 could not be executed with thermal cross-linking.Results of FT-IR,SEM and DSC analysis indicated that with simple double heating treatment,the -OH and -COOH of CMC material reacted,cross-linked,generated the three-dimensional network structure and then obtasined the strong absorbing capacity.The result of SEM suggested that the three-dimensional network structure of PH7 was more complete than that of AH1, because the viscosity-average molecular weight of PH7 and AH1 were almost the same but substituting degree of PH7 was higher.CMC material was environment-friendly, edible,biodegradable and without adding the cross-linking agent. 3 Among the HCMC film materials prepared with ester cross-linking on acid condition, the absorbing capacity of AH1 and PH7 were relatively strong.The premium condition for AHI:Qsalt＞120 and Qwater＜60 when adding volume reached 0.6%-1.5%(HI,H2, H3,H4) of the adding volume for AH1.The premium condition for PH7:Qsalt＞140 and Qwater＜100 when adding volume reached 0.6%-1.5%(H1,H2,H3,H4) of the add volume for PH7.However,the absorbing capacity of FH6,IH6,OM6,FH9 were relatively lower after acidifcation.The reaults of FT-IR,SEM and DSC analysis indicated that the -COOH of CMC gel increased after acidification and the cross-linking reaction between -COOH and-COOH group,-COOH and -OH group tended to react at 80~C thermal treatment,which made ether linkage of film materials increased,cross-linking intensity improved,and the complete three-dimensional network structure generated. The results of SEM of AH1 and PH7 indicated that the network structure of film materials prepared with Ester cross-linking method were less complete than were prepared with ester cross-linking on acid condition.This can be explained that the long-time thermal treatment of CMC in acid enviroment leaded to light degradation of molecule chain in the preparation of film materials with Ester cross-linking method, which was in accordance with DSC analysis.Compared to the ester cross-linking method, the ester cross-linking on acid condition method fulfill that film materials of high salt absorbing could be prepared with low-temperature cross-linking.