Preparation And Properties Of Polyurethane Acrylate-Polycaprolactone IPN Elastomer By 3D Printing

Intelligent material refers to the material imitating the life system,which can sense the excitation of the external environment(heating or cooling,current,light,water and etc.),change one or more performance parameters of the material in real time,and make the desired changes that can adapt to the changed environment.When the external stimulation is eliminated,the material can quickly return to the original state.Shape memory polymers(SMPs)are a kind of intelligent materials.SMPs for 3D printing refer to the preparation of three-dimensional objects that can change shape,have simple process and low cost by using 3D printing technology.Three dimensional objects can be physically or functionally intelligent under environmental stimulation.SMPs of 3D printing have been applied in aerospace,electrical automation,robotics,medical devices,drug delivery carriers and other fields,expand the application of 3D printing.Currently,SMPs research on 3D printing mainly focuses on deformation behavior and structural design of printed structures,which limits the potential application of 3D printing.Therefore,it is necessary to further develop the intelligence of 3D printing SMPs and enable it to have new functions,such as self-repair and photoluminescence,to make 3D printing SMPs more intelligent,so as to expand the application of 3D printing based on SMPs.This study intends to prepare a certain molecular weight of poly?-caprolactone(PCL)which can be used for selective regional photocuring technology(LCD 3D)printing.The prepared poly?-caprolactone has characteristics of low melting point,good biocompatibility,green non-toxic,excellent mechanical properties and blending compatibility.PCL was mixed with polyurethane acrylic resin(PUA)to prepare a photocurable resin system for LCD 3D printing technology.The dynamic ammonia ester bond and hydrogen bond between PCL and PUA and the shape memory performance of PCL were utilized.Elastomers with shape memory and self-healing function of PUA-PCL interpenetrating network(IPN)were obtained.In addition,a photoluminescent material was added to PUA-PCL photocured resin,such as:Poly(9,9-dioctyl fluorenyl-2,7-diyl(F8BT)monomer,2-[4-(diphenylamine)phenyl]-10,10-dioxide-9H-thioxanthracen-9-one(TXO-TPA),8-Hydroxyquinoline aluminum salt(Alq₃),were prepared with shape memory,self-healing properties and photoluminescence 3D printing smart materials.This study provides new ideas for the preparation of photoluminescent 3D shape memory materials,drug delivery materials and soft robot materials.In addition,the introduction of intelligent self-repair function enables 3D printed components to self-repair in time,prolonging the service life and stability of materials,providing more inspiration for the wide application of 3D printing in the future.The specific research contents are as follows:(1)The preparation of PCL was made by ring-opening polymerization of?-caprolactone,oxalic acid and photoinitiator 6976 as catalyst under UV irradiation.The structure and molecular weight of PCL prepared under different catalysts and technological conditions were studied.By regulating the molecular weight and properties of PCL,the PCL resin material suitable for LCD 3D printing was explored.(2)The PCL prepared in(1)above was mixed with PUA,the monomer acrylomorpholine(ACMO)was added as the diluent,and diphenyl(2,4,6-trimethylbenzoyl)phosphonic oxide(TPO)and 2-hydroxy-2-methylphenylacetone(1173)were prepared in a 1:1 ratio as the mixed photoinitiator of the system.Pua-pcl IPN elastomer with shape memory and self-healing function was obtained by uv curing.At the same time,3D objects with complex shapes were printed by LCD 3D printer("OK"gesture),and the good shape memory performance of PUA-PCL IPN elastomer was demonstrated.(3)The photoluminescent polymers F8BT,TXO-TPA and Alq₃ were added into the photosensitive resin system prepared above,systematically studied the effects of different photoluminescent materials and PCL content to the luminescence,mechanics,shape fixing rate and self-healing properties of intelligent elastomers.