Study On Preparation And Properties Of Rare Earth Complex/Polyethylene Functional Films

Linear low-density polyethylene is widely used in agricultural greenhouse film because of its low price,easy processing and good mechanical properties.Rare Earth Complexes have potential applications in chemical,biological and agricultural fields due to their special structure and light conversion properties.In this thesis,LLDPE was used as matrix to prepare the rare earth complex/polyethylene functional films,and the properties of the films were characterized.Two complexes of Eu?GI?3Phen and Eu?LI?3Phen were prepared with Eu³⁺as the central ion,with monostearate monoitaconate diglyceride?GI?,monolaurate diethanolamide monoitaconate diglyceride?LI?as the first ligand,and o-philoline?Phen?as the second ligand.The results of infrared spectra analysis show that the two rare earth complexes have been synthesized successfully,and the fluorescence spectra show that Eu?GI?3Phen has ultraviolet absorption band at 275 nm and emission band at 617 nm,Eu?LI?3Phen has ultraviolet absorption band around 292 nm and emission band around 615 nm.TGA results show that the thermal properties of the two rare earth complexes are stable and can be processed by thermal reaction at 190 ^oC.LLDPE was melt-extruded with Eu?GI?3Phen and Eu?LI?3Phen,respectively,and europium rare earth complex/polyethylene LLDPE-g-Eu?GI?3Phen and LLDPE-g-Eu?LI?3Phen grafted films were prepared.The results show that Eu?GI?3Phen and Eu?LI?3Phen have no significant influence on the melting temperature,crystallization temperature,crystal form,and mechanical properties of the samples.The fluorescence analysis showed that the fluorescence intensity of polyethylene grafted films increased with the increase of Eu-rare earth complex concentration in the grafted films,and the fluorescence quenching phenomenon occurred when the concentration of Eu?GI?3Phen in LLDPE-g-Eu?GI?3Phen films was more than 2.0 wt%.The water contact angle test of the grafted film showed that the contact angles of LLDPE films were effectively reduced by the Eu rare earth complex.The accelerated dripping test at 60 ^oC showed that the dripping time increases with the increase of Eu-rare earth complex concentration,Eu?LI?3Phen with stronger ligand polarity and smaller molecular structure has more effect on prolonging the dripping time.Rare earth complex/polyethylene films were prepared by blending and grafting GI,EDM and Eu?GI?3Phen at different ratios.The results of DSC and mechanical properties showed that the thermal and mechanical properties of LLDPE were not affected by blending and grafting.Fluorescence analysis showed that the film fluorescence intensity of LLDPE/Eu?GI?3Phen with concentration of 2.5 wt%Eu?GI?3Phen decreased by 97.8%,and that of LLDPE/Eu?GI?3Phen/EDM with concentration of 1.5 wt%Eu?GI?3Phen and 0.6 wt%EDM decreased by 96.0%The fluorescence intensity of LLDPE-g-Eu?GI?3Phen films with concentration of 2.5 wt%and 1.5 wt%Eu?GI?3Phen decreased by 20.5%and 69.5%respectively.The water contact angles test showed that the films added to EDM has a smaller contact angle.The accelerated dripping test at 60 ^oC showed that the grafting could effectively inhibit the migration of rare earth complexes,decrease the fluorescence intensity and increase the retention rate.LLDPE-g-Eu?GI?3Phen films added to EDM have the longest dripping time of 12 days.