The Preparation Of Hydrophobic Oxidized Starch And Studied On Its Application In Food Packaging

This article mainly studied on the preparation and characterization of alkenyl succinic acid oxidation starch ester(OOS-starch), as well as its application in the paper with studying on the properties of oil-proof, hydrophobicity and mechanical property. The detail research content is as follows:1. The preparation and characterization of OOS starch. Prepare a series of OOS starch with continuous changed substitution degree by adding different amount of OSA. By analyzing the image of polarization microscope, it’s clear that it’s easier to disperse the OOS-starch in the water than oxidized starch. The FTIR shows the successful synthesis of continuous changed substitution degree due to the corresponding change in the intensity of ester bond absorption peak. Two different methods to obtain the substitution degree, one is calculation by H-NMR spectrum and the other is acid-base titration, were conducted and the result of substitution degree is similar. It is further confirmed that OSA molecules have been successfully grafted onto the oxidized starch molecules.2. The preparation and characterization of OOS-starch film and OOS-SiO2-starch film. The starch film was prepared by tape casting method with adding a certain amount of glycerin and nano-SiO2 into starch with different substitution degree. The properties of oil-proof, hydrophobicity and mechanical property of starch film were studied by contact angle, water vapor transmission coefficient, coefficient of oil permeability and tensile strength, elongation at break and young’s modulus and the results showed that the contact angle of OOS-SiO2 film is bigger than OOS-starch film which indicated the better oil-proof property because of the hydrogen bond formed between nano-SiO2 and OSA with starch to build a denser film. However, the film-forming property of starch will worsen after adding more than 6% OSA due to the appearance of big gap in the molecule structure. So the contact angle and oil-proof property of film will lower after adding more than 6% OSA. The tensile strength(TS), modulus of elasticity(Y) and ductility of OOS-starch film is bigger and better than OOS-SiO2 and decrease with the increase the amount of OSA. However, the elongation at break(E) of film showed the maximum value when the experimental sample is OSE-3. In a word, the OSE-3 sample has better properties of oil-proof, hydrophobicity and mechanical property in all samples.3.The influence on the paper property after using OOS starch oil-resistant agent. The effect of different adding concentration of OSA and starch, heating time and rotational speed of stirring on the paper properties of oil-proof and hydrophobicity was investigated by one factor test and also studied the influence of OS starch on the optical and mechanical property of paper. The best experimental data was obtained after analyzing the microstructure of SEM image, oil-proof value and dynamic contact angle. The paper after immersed in the starch that prepared by 3% OSA, 20% starch, heat 20 min and stir at the speed of 15mm/s has the properties of 8-level oil-proof value. The Cobb60 value is 17.6 which lowers 36% than the original paper(27.5) and dynamic contact angle is 33.27? and 90.81? which increases 68%(19.8?) and 20%(75.42?) Respectively, besides the surface roughness of paper had decreased along with the improvement of tensile strength and folding degrees. The paper meets the demand of permeation-proof and mechanical properties in the food oil-proof wrap paper.4. The influence of OOS/gelatin composite starch oil resistant agent on the paper property. The effect of the OOS/gelatin ratio on the oil-proof and mechanical property of paper was studied by one factor method and the result indicated that the maximum of oil-proof value can reach to 9 after immersed in the OOS/gelatin starch but the oil-proof value would decrease when the ratio is too high due to the deterioration of compatibility between gelatin and starch. Beside, because of forming the ionic and hydrogen bond with negative charge on the fiber during the process of sizing between gelatin/starch and surface, the fold degrees and tensile strength improved significantly.