Research On Preparation Of Polymer Films By Demulsification-induced Fast Solidification Method

Natural rubber has many excellent properties,such as high elasticity,high strength,high insulation ability,excellent wear resistance and so on.Natural rubber with excellent comprehensive mechanical properties cannot be replaced in this era of synthetic chemistry.As a classical research field in polymer science,emulsion has been extensively studied for many years.Emulsion is known to be thermodynamically unstable and prone to demulsification.However,through the conscious use of the emulsion instability,we hereby put forward a new practical concept as a new film-forming method,namely demulsification induced rapid curing(Demulsification-Induced Fast Solidification,DIFS)method.In this paper,using DIFS method in combination with dipping/dialysis and electrochemical methods,polymer membranes with excellent properties were prepared,hollow and phase change polymer capsules were also prepared.(1)Rubber films prepared by dipping/dialysis DIFS:The thickness of the rubber membrane can be accurately controlled by adjusting the dipping/dialysis time.Through the study of the diffusion ability of demulsifier,curing efficiency and the adjustment of dipping sequence,it was found that when Ca Cl₂ in dipping method and formic acid in dialysis method were used as demulsifier,the film quality was better and the efficiency was higher.The mechanical properties of rubber films prepared by dipping/dialysis DIFS were improved by vulcanization or adding fillers in the latex.In addition,the tensile strength of dipping films with Si O₂ increased from 0.82 to 1.36 MPa.Rubber films with fluorescent properties were prepared by dipping method using Eu(NO₃)₃ as demulsifier.After soaking in water for 7 days,the films still had a certain intensity of fluorescence emission.(2)DIFS combined with electrochemical methods:By adjusting the electrification voltage,the growth mode of the film under different substrates can be controlled,including diffusion mode,bubble mode and densification mode.Therefore,the morphology of the film can be regulated.In the diffusion mode,the thickness of the rubber film can be accurately controlled by adjusting the electrification time.The rubber film can be prepared on the surface of conductive substrate of any shape and size,and the patterned rubber film can be prepared by DIFS combined mask method and surface coating method.The rubber film prepared by DIFS combined with electrochemical method has a certain adhesion to the substrate,and the maximum strength was 0.26 MPa by shear tensile test.The mechanical properties of the film can be improved after latex modification,and the tensile strength of the rubber film prepared by vulcanized latex was observed to be the the highest,which is2.22 MPa.(3)Polymer hollow capsules:The polymer hollow capsules with controllable particle size and wall thickness were successfully prepared by DIFS method.Functional substances such as Fe₃O₄ and upconversion rare earth Er(III)and Yb(III)were successfully introduced into the capsule,which lead to incorporation of ferromagnetic or fluorescent properties.The paraffin phase change capsules with good thermal stability were also successfully prepared by DIFS method.