Research On PVA Slow-release/Controlled-release Packaging Film

As an environmentally friendly high-molecular compound, polyvinylalcohol (PVA) has many good performances, such as excellent filmforming, excellent water degradation and biodegradation. It could beapplied to the field of pharmaceutical industry, agricultural production,food industry, environmental protection, etc, and it can be considered as anew polymer material with development potential. many areas of greatpotential for development of new polymer materials. At present, PVA isoften used as film-forming material, carrier material or compounded withother materials in practice. This paper directly mixed PVA1799and PVABM-I(PVA1788) together with different proportions to prepare PVAslow-release/controlled-release packaging film. Wish that this kind of filmcouid be used as a novel sustained-release film in the actual production.In this study, PVA slow-release/controlled-release packaging film wasprepared by sol casting method. In the preparation of this film, there weremany factors that influenced its performance. This paper respectivelydiscussed the following factors: layer thickness, mass fraction for PVA,plasticizers, mold release agent, dry-curing and film-forming process.Basic on the preparation of PVA slow-release/controlled-releasepackaging films, this study made its performance testing, comparison andcharacterization as follows: including the sol viscosity, basic mechanicalproperties, light transmission properties, air permeability of differentproportions of PVA and so on. Use Thermogravimetry(TG) to analyse itsweight loss performance, use Scanning Electron Microscopy(SEM) to testits swelling properties and dissolution stability, finally use one-dimensionalmethod and two-dimensional method to test the film,s release rate.The results showed that: the optimal preparation conditions of PVAslow-release/controlled-release film were25μm for the layer thickness,about14%mass fraction for PVA,2.0%volume fraction for plasticizer(glycerin),1%~2%mass fraction for mold release agent (SDS), alsostrictly control the drying temperature, air velocity and external humidity,dry temperature should be controled between60℃and70℃.With the increase of mass fraction of PVA BM-I, the tensile strength and elongationat break were decreased, tear strength was increased. PVA release film with30%PVA BM-I had the highest haze and the lowest air coefficient. Thesustained release of PVA release film was caused by PVA BM-I,swater-soluble and PVA1799,s swelling. In one-dimensional test mainfactors that affected release property of the film were the formula andthickness, which formula was the most important factor. Intwo-dimensional test, choose different materials as contents for thedetermination, and their slow-release rule were basic consensus.