Preparation Of High Sound Insulation Laminated Glass Interlayer Films

In recent years,more and more attention has been attracted to noise pollution,which may cause hearing loss,sleep disorder and other symptoms.Several materials have been adopted to eliminate noise,among which,the sound insulation materials with damping and shock-absorbing functions takes the dominant part.As an excellent damping material,Polyvinyl butyral(PVB)has been widely used in laminated glass depending on its strong adhesion,high transparency and impact resistance.Compared with the traditional glass,even if the laminated glass is broken,the fragments will be stuck to the interlayer film,which effectively prevents the occurrence of accidents such as fragment puncture and ensures personal safety.PVB laminated glass has been widely used in high-rise buildings,military industry and daily life.Common deficiency of traditional sound insulation materials,is the unsatisfactory sound insulation in the low frequency region,especially for blocking human noise(200-700 Hz)due to the mass law.Yet it is not a good solution to increase the thickness of glass because of weight limits,which is not conducive to installation and transportation.Therefore,it is a challenge to develop a light and simple sound insulating laminated safety glass.Hence,two kinds of PVB composite laminated glass with sandwich structure and their interlayer films were prepared by means of electrospinning and hot pressing in this work.Then,the sound insulation of PVB composite interlayer film,the transmittance and impact resistance of composite laminated glass were characterized.The specific research contents are as follows:(1)Polyamide 6(PA6)nanofiber membrane was prepared by electrospinning technology,and the obtained membrane was embedded into PVB film by hot pressing to prepare glass/PVB/PA6/PVB/glass sandwich structure composite laminated glass.The effects of the morphology and thickness of electrospun PA6 nanofibers on the sound insulation of the interlayer film have been discussed in detail.The sound insulation mechanism of the electrospun fibers in the composite interlayer film has been elucidated.The results show that the sound insulation of the composite film is significantly improved in the low frequency region,the transmission loss(TL)of 200-500 Hz can reach a maximum of 3.5 d B higher than that of pure PVB film and the average passing through sound energy is reduced by 47%.Then the excellent transmittance and impact resistance of the composite laminated glass were characterized,which laid the foundation for the preparation of the sound insulation laminated glass.(2)Based on the previous work,PA6 was replaced with piezoelectric polyvinylidene fluoride(PVDF)and multi-walled carbon nanotubes(MWCNTs)were introduced.The reinforcement of MWCNTs on the electrical properties of electrospun PVDF nanofiber membrane was confirmed by using spectroscopy,conductivity testing and other characterization techniques.The relationship between the piezoelectricity of PVDF fibers and the sound insulation of PVB/PVDF composite interlayer film has been systematically studied.The results show that the higher piezoelectricity of the electrospun PVDF fibers,the higher TL value of the composite interlayer film.The enhancement of TL can be reached a maximum of 3.6 d B than pure PVB film and the average passing through sound energy is reduced by 48%,which indicated the effective block out of human noise.The mechanism of piezoelectric fibers in sound insulation has been analyzed in detail.The ultraviolet absorption spectrum,falling ball impact test and other characterization methods confirmed that the transmittance of composite laminated glass can be reached nearly 80%,the shear strength exceeds 3 MPa,and the breakage rate remains within 3% after multiple impacts,which fully meets the application requirements and provided a new strategy for the research and development of sound insulation materials.