Study On The Effect Of Inorganic Packing To Fruits And Vegetables Heavy Packaging Film

For the characteristics of fruit and vegetable heavy packaging films bearing high weight and poor permeability and moisture, LLDPE and LDPE were used as the substrate, lamellar wollastonite and fibrous sepiolite which had less influence on the mechanical properties of film were used as inorganic filler, to prepare the film with better mechanical properties and good permeability and moisture. Wollastonite and sepiolite particles were modified respectively by hydrochloric acid and KH-550 with active of silane coupling agent. The characterization of modification effect was discussed through the IR spectra and SEM. At last mechanical performance, moisture and permeability performance of film with modified filler (not processing, coupling agent treatment, acid and coupling agent processing) were tested.The results show that, with the increase of the content of LDPE, the melting point of blending film gradually reduced and the mechanical properties of the film decreased. At last the content of LDPE is 25%. The surface of inorganic packing changed from hydrophilic into lipophilic after the silane coupling agent process, which strengthen the connection with organic resin. When coupling agent content was 1% of the packing, the mechanical properties of the film was the best. CaO and MgO that contained in wollastonite and sepiolite disappeared after acid treatment. At the same time acid treatment smalled particle size, increased internal passageways, enlarged pore diameter and facilitated gas and water through.Along with the increase of packing content, the mechanical properties of the films filled with different modified packing fillers gradually decreased, but permeability and moisture of the film had increased. Coupling agent treatment improved the mechanical properties of the film and weakened the performance and moisture. The mechanical properties, permeability and moisture of the film after acidification treatment were superior to coupling agent handled film. When the content of untreated wollastonite was 12phr, the gas permeability of O2 and CO2 were increased by 62.8% and 82.9%, the moisture permeability was increased by 48.5%.While to the wollastonite, the gas permeability of O2 and CO2 were increased by 55.2% and 84.2%, the moisture permeability was increased by 81.6%.The wollastonite and sepiolite were blended composite to make fresh-keeping film. When the ratio of acidized wollastonite and sepiolite was 5:5, the mechanical properties of the film and permeability reached the maximum. While moisture permeability performance increased as the increases of sepiolite. When the content of compound packing was 6phr, the mechanical properties of the film and moisture content had improved compared with film filled with single filler. Using different one-way tension on the film, the mechanical properties of the film was improved and can also upgrade the performance of the film and moisture. The gas permeability of O2 increased by 44.2% and the moisture permeability coefficient increased by 43.4%.According to different fruits and vegetables required for optimal ventilation ratio, plastic wrap filled with suitable mineral, which had suitable breath, was chosen to pack the fruit and vegetables. The weightlessness rate of cucumber, the content of soluble solids, the content of chlorophyll, the content of Vc, respiration intensity and sensory evaluation was tested. As the extension of storage time, the loss of water and nutrients and the respiratory intensity were reduced effectively by mineral-filled film. The film was balanced relatively after the gas concentration, which can form a gas adjustment environment for fruit and vegetable, so that can delay the mature fruit and vegetable aging and maintain good storage quality.