Preparation Of Functional Polyurethane Elastomer Composites And Application On Laminated Glass

As a widely used functional polymer material,polyurethane is characterized by its wide range of adjustable properties,high strength,high elasticity of rubber and rigidity of plastic.It has been widely used in the fields of biomedicine,architecture,automobile and textile.In recent years,our country has made great progress in the field of polyurethane raw materials and products,but there is still a certain gap with foreign countries in laminated glass field.Laminated safety glass is made of two pieces of glass by hot pressing with a layer of functional polymer film.When it is damaged by external force,it can avoid the splashing of glass fragments,keep the integrity of glass and prolong the service life.Polyurethane elastomer（TPU）not only has high impact strength and mechanical properties,but also has the advantages of high light transmittance,excellent toughness,environmental stability and hydrolysis resistance.It has high bonding strength with substrates such as polymethyl methacrylate（PMMA）and polycarbonate（PC）.Therefore,it is a superior laminated glass intermediate membrane material.However,our country’s polyurethane laminated glass intermediate film still mainly depends on imports,represented by KRYSTALFLEX^?series TPU.There is still a gap between domestic polyurethane intermediate film and foreign products,mainly in bonding strength,application reliability and so on.At the same time,the research on laminated safety glass in our country is developing towards the direction of functionalization and thinness.In this thesis,the aliphatic polyurethane elastomer with excellent properties was prepared and modified by cellulose nanocrystalline.The problems such as low bonding strength and impact strength of the polyurethane elastomer were improved,and the control mechanism of the polyurethane composite was explained,which provided a theoretical basis for its application in the field of laminated safety glass.By functional design,the fluorescence properties and self-repairing properties of polyurethane elastomer were endowed,and the fluorescent safety laminated glass was prepared.This study lays the foundation for the practical application of polyurethane elastomer in the field of functionalized laminated glass.The specific research content is as follows:（1）By changing the ratio of isocyanate to polyol,the amount of catalyst,the type of solvent and the isocyanate index,the hydrogen bonding degree and the microphase separation structure of the polyurethane elastomer were adjusted.The optimum raw material ratio of aliphatic polyurethane elastomer was investigated,and an aliphatic polyurethane elastomer with better mechanical strength and light transmittance than 501-type TPU laminated glass intermediate film was prepared.At the same time,the laminated glass with aliphatic polyurethane elastomer as an intermediate film was prepared by hot pressing.The impact resistance of the laminated glass was investigated and compared with the laminated glass prepared by PVB laminated film and 501-type TPU laminated glass intermediate film.Although the bonding strength and impact resistance of the laminated glass are still inferior to PVB laminated film and 501 TPU interlayer,after simple surface pretreatment of aliphatic polyurethane elastomer during hot pressing,the properties of the laminated glass are better than those of the laminated glass made from PVB film and 501 TPU film.（2）In order to improve the bonding strength and impact properties of polyurethane elastomer,the polyurethane-cellulose nanocomposite and its laminated glass were prepared by using cellulose nanocrystalline as filler.The mechanism of the nano-fillers in the polyurethane matrix was investigated by FT-IR,XRD,DMA and SEM.Through research and experiment,the composite material with excellent mechanical and adhesive properties was obtained.Its maximum mechanical strength can reach 53 MPa,the maximum adhesive strength can reach 3.4 MPa,which is 150%and 280%higher than the unmodified polyurethane film,respectively,and some properties are better than the foreign KRYSTALFLEX^?series TPU.At the same time,the composite material also has excellent tear resistance and bearing capacity.The laminated glass can resist multiple impact of steel balls without spatter,which is much better than the laminated glass made of PVB laminated film.The polyurethane nanocomposite material will be an excellent sandwich glass intermediate membrane substitute material.（3）The polyurethane-perovskite quantum dot（Cs Pb Br₃-PU）elastomer composites were prepared by functional design based on the previous work.It has not only sensitive fluorescence properties,but also excellent mechanical properties.The problems of poor stability and difficult forming process of Cs Pb Br₃ quantum dots are solved.In addition,the superior self-healing properties of the composite were proved by mechanical properties and morphological characterization.Based on these excellent integrated properties,the Cs Pb Br₃-PU composite material will be widely used in many fields,such as intelligent anti-counterfeiting,photoelectric display and so on.（4）In order to apply the fluorescent polyurethane composite（HPU）prepared above to the field of laminated glass,a kind of acrylic copolymer（PA）was synthesized and the best preparation system was determined.On this basis,the fluorescent safety laminated glass based on sandwich structure（glass/PA/HPU/PA/glass）was prepared by hot pressing（85℃）,which solved the problem of low temperature bonding of HPU composites.Under UV irradiation,the laminated glass can achieve fast reversible fluorescence response（<0.5 s）.Furthermore,the superior stability of fluorescent safety laminated glass was characterized by fluorescence spectrum.The impact resistance of laminated glass was evaluated by drop-ball impact test.Under multiple impact of the steel ball,the glass cracks were uniformly dispersed and no splashing occurs.Based on these excellent integrated properties,the smart safety laminated glass studied in this paper can be applied in the fields of architecture,automobile and optical devices.