Preparation Of Micro-nano Multilayer Polycarbonate/polymethyl Methacrylate Optical Film

Microlayer coextruded polymer optical films can be selectively reflected in the sun's infrared thermal energy,reduce heat exchange in the house with the outside,while realizing the large transmission of visible light,so as to achieve energy-saving and lighting purposes,in the building doors and windows,automotive glass and other surfaces have been widely used.Limited to material cost,preparation technology and equipment,optical film can not be industrialized at present.In this paper,micro-nano multilayer PC/PMMA optical film can be prepared based on microlayer coextrusion technology and equipment.Through the membrane system design and simulation for the preparation of near-infrared high-reflection micro nano multilayer optical film to provide a theoretical basis,and the optical film formulation modification research.By adding nano-inorganic SiO2 and ultraviolet absorber UV-P,the modified formula of the optimum performance of optical film was explored.The achievements and contents of this subject acquired are as follows:(1)Selection of polymer materials with different refractive index of polycarbonate(PC)/polymethyl methacrylate(PMMA)through micro-nano multilayer and periodic superposition,a micro-nano multilayer optical film of near infrared region(780?1100nm)highly reflective,visible light region(400?760nm)high transmission can be designed.The feasibility of preparing the optical film by microlayer coextrusion device is also verified.Based on genetic algorithm,the largest film center wavelength value of infrared energy reflectivity is searched globally,and the total thickness of the optimal film is about 78?m.Simulation of the spectral characteristics of film shows that the multilayer film achieves high reflection of four peaks in the near infrared region,with a total reflectivity of 63.81%,and more than 80%transmittance in the visible light region.With the increase of incident angle,the total reflectivity is increased after the first decrease,the average total reflectivity is more than 50%,and the total reflectivity fluctuates less in the 77?79?m range of film thickness,which is maintained by more than 60%.(2)The micro-nano multilayer PC/PMMA optical film and pure PC and PMMA multilayer film were prepared based on the microlayer coextrusion technique.The error of optical properties is analyzed by using rheological knowledge.And the micro-nano multilayer PC/PMMA optical film with different thicknesses were obtained by the bidirectional tensile experiment of thin film.It is found that the tensile strength of micro-nano multilayer PC/PMMA optical film in the transverse longitudinal direction is greater than that of pure PC and PMMA multilayer film,and the elongation at break is between the two.The average visible transmittance of the PC/PMMA film prepared at the beginning was more than 75%,the maximum reflectivity of the near infrared region reached 19.5%.In the range of different thickness(40-100?m)films measured,the reflection peaks are offset with different thickness,maintaining a high reflectivity in general.The visible light transmittance increased with the increase of wavelength,and the average transmittance on the whole fluctuated at 75%.When the thickness of micro-nano multilayer PC/PMMA optical film is about 80?m,the comprehensive optical performance is the best.The maximum instantaneous reflectivity in the near infrared region reaches 33.8%,the average reflectivity is above 24%,and the average transmittance in the visible region is more than 78%.(3)The micro-nano multilayer PC/PMMA optical film under distinguishing content of nano-SiO2 particle were manufactured.The nano-SiO2 particles are evenly dispersed in the composite film matrix.With the increase of nano-SiO2 content,the tensile strength and elongation of composite film in the longitudinal direction are the first to increase and then decrease,and the thermal stability is improved in different degrees.When the content of nano-SiO2 is 0.5%,the tensile strength and elongation of composite film reach the maximum,and the comprehensive mechanical properties are the best.With the increase of nano-Si02 content,the reflection spectrum curve of film is moves up first and then moves down,the light transmittance of visible rays shows a small downward trend.When the nano-SiO2 content is 0.5%,the comprehensive optical performance of film is the best,the instantaneous reflectivity in the near infrared region reaches the highest peak of about 25%.the average reflectivity reaches 23.6%,and the overall visible light transmittance fluctuates up and down at 70%.(4)The micro-nano multilayer PC/PMMA optical film under distinguishing UV-P filling amount were manufactured.With the increase of UV-P filling amount,the average transmittance of composite film fluctuates up and down at 75%,the UV absorption capacity increases rapidly,has all absorbed UVB ultraviolet rays,almost absorbs most of UVA ultraviolet rays.When the UV-P fill amount is 0.8%,it can be almost separated by 99%UV rays within 380nm and 95%of UV rays within 400nm.When the UV-P filling capacity is 0.5%,the optical properties of the composite film are the best,can shield 99%of the UV rays within 380nm,and the average light transmittance reached a high level of 82.1%.