| High barrier packaging materials have wide range of applications, whichused for food and medicine packaging can extend their shelf life and prevent themigration of hazardous substances, also used for precision machinery parts,electronic parts and solar module may lengthen their performance life. One of themain approaches obtained the high barrier performance is to deposit the SiOxbarrier material on the surface of the plastic sheet material. Currently, themethods of depositing SiOxfilms include physical vapor deposition (PVD),plasma assisted chemical vapor deposition (PECVD), etc. There are a largenumber of cracks, pinholes and other defects in SiOxbarrier films prepared byPVD which is also easy to rattle. To aim at solving these problems, organic highmolecular epoxy resin (dicyclopentadiene dioxide cured by maleic anhydride-DCPD/MA) and SiO2targets are magnetron co-sputtered to prepareSiOx-(DCPD/MA)fcomposite barrier films. A SiOx-(DCPD/MA)fthin film isformed by combining flexible chain fragments of an organic polymer into theSiOxbarrier layer, which is effective to increase its toughness, the foldingresistance. The SiOx-(DCPD/MA)fthin film is synthesized by flexibleunsaturated Polymer chains including free radicals by Ar ion bombardment aDCPD/MA target and Si dangling bonds by Ar ion bombardment a SiO2target.The film structures and properties wre characterized.The deposition process andthe relationship between structure and properties were clarified, and themechanism of film improving barrier quality for substrate was explored. MSmonitoring techniques was used for diagnosis of plasma discharge characteristics.By obtaining material composition of sputtering DCPD/MA and SiO2respectively, the chemical reaction paths between particles of plasma atmospherewas studied.The study of deposition apparatus sputtering characteristics, the substratecharacteristics and the co-sputtering process show that the uniformity of thetarget width direction did not affect the uniformity of films prepared by thewinding apparatus. However, the target axial uniformity exerted a larger effect onfilms uniformity, especially sputterred from the DCPD/MA target. When the RFpower1KW, working pressure0.39Pa, winding speed2m/min, deposition time60min, and the deposited film thickness difference was up to60nmcorresponding target different axial positions. No filler substrates and substrateswith thermal stability acquired high barrier properties after depositing SiOx-(DCPD/MA)ffilm. Studies have shown that the power ratio, workingpressure, wind speed, deposition time are key process parameters affect the filmstructure and properties. Power ratio1, working pressure0.39Pa, winding speed2m/min, deposition time60min are the premium parameters for depositing filmswith good oxygen barrier and water blocking properties.Composition and structure of the SiOx-(DCPD/MA)ffilms were analyzedusing XPS, FTIR, and the morphologies of the films were characterized by TEMand AFM. Also, the impact of process parameters such as power ratio, windingspeed and deposition time on the film composition and structure were discussed.There are not only main Si-O-Si bond structures, but also Si-O-C bond structuresand the Si-H bond structures exist in the SiOx-(DCPD/MA)fcomposite film.There are also visible C=C, C=O double bonds as oxygen active sites in thefilm. Si-O-Si asymmetric vibration, bending vibration and cyclic vibrationincreased with power ratio increases. As the input RF power ratio between0.4-1,SiOxphase uniformly distributed in the film and the annular coupling existedbetween the phases of SiOxwith few large particles clusters. When power ratiowas greater than0.4, the SiOx-(DCPD/MA)ffilm was uniform and dense.Roughness of films decreased as power ratio increasing. The research showedthat excessive winding speed would result in shortening time of the substratethrough the discharge region, which made the SiOx-(DCPD/MA)ffilm barrierperformance deteriorate. XPS depth analysis showed that the polymer fragmentgrowing trend had the advantage over the SiOxparticles close to the area aroundthe PET substrate during the initial stage of film growth. Further, the changes ofgas permeation activation energy could assist a judgment of SiOx-(DCPD/MA)fcomposite film structure in the presence of nano-defect structure, of which sizewas between the0.30nm-0.40nm.State of plasma for the magnetron co-sputtering was tested using massspectrometry. The results showed that there were neutral particles, free radicalsand ions, and the first two were the majority for both single-target sputteringSiO2or sputtering DCPD/MA. There was no compounds dissociation forsingle-target sputtering SiO2, while there was the overall dissociation ofmolecular fragments for single-target sputtering DCPD/MA, and mainly in theform of free radicals. The plasma components of the latter were morecomplicated than that of the former. As the input DCPD/MA target powerincreasing, the number and species of particles and fragments also increased, andthe whole chain segment of ether and ester bond including oxygen graduallydissociate, which resulted in the forming of active oxygen uptake sites. During the course of preparing SiOx-(DCPD/MA)fcomposite films by magnetronco-sputtering, particles and segments were from the double targets and combinedeach other, of which silicon particles mainly in the form of silicon oxide such asSiO, SiO2joined with the polymer chain segment.Researches on the mechanical properties, gas barrier properties andcharacters of preventing the migration of heavy metals and organicmacromolecular of the PET substrate after depositing SiOx-(DCPD/MA)fcomposite film were carried out. PET after the composite film deposition hadimproved tensile property, and a significant change in the stress strain curveappeared with a double-stage two inflection point. The polymer chain forming acomposite structure improved the toughness of SiOxfilms significantly.SiOx-(DCPD/MA)f/PET had good barrier on the inert gases such as Ne and Ar,and large amount of active oxygen uptake site could significantly extend theoxygen lag time, also chemical barrier operated toward water vapor.SiOx-(DCPD/MA)f/PET composite films had an obvious role on the inhibition ofheavy metals and organic polymer migration to the package contents. Throughsandwich double-faced SiOx-(DCPD/MA)f/PET film, oxygen permeability (OTR)could be reduced to10-5magnitude. |
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