Preparation And Physical Properties Of PMMA-PU Interlayers At The Interface Of Organic-inorganic Glass Laminates

Organic-inorganic glass laminate sare transparent composites,where the inorganic glasse sare adhered with transparent organic materials by the interlayers.These glass laminates combine excellent properties of high strength and weather resistance forin organic glasses with superior performance of light-weight and impact resistance for transparent organic materials,providing ideal materials for the aircraft windshields.So far,the main problem of organic-inorganic glass laminates is the interface delamination,which deteriorates its reliability and longevity.In this thesis,the interlayer properties were taken into consideration.PMMA-PU composite materials were prepared by the simultaneous polymerization method.The component composition and functional monomers were studied with respect to the structure and properties of PMMA-PU composites.The PMMA-PU gradient materials were prepared by the solution-diffusion method.The PU prepolymerization has been investigated in detail to clarify its effects on the structure and properties of gradient materials.Using the above two kinds of composites as the interlayers,the organic-inorganic glass laminates have been prepared by using the hot-pressing technique,and the relationships between the optical,mechanical and hygrothermal properties of glass laminates and the interlayers have been revealed to provide the theoretical basis for the development of high performance organic-inorganic glass laminates.In the case of PMMA-PU composites,the composition and crosslinking agent had major effects on the composite properties,while the other functional monomers had minor effects.With increasing the main components,the composite transparency increased significantly.As PMMA was the main component,the impact resistance of composites was significantly improved with the increase of PU content,whereas the tensile property and thermal resistance were somewhat reduced.Meanwhile,the densification of composite surfaces was improved,and the domain size decreased gradually from the maximum value of 3 mm.When the PMMA/PU ratio was 8:2,the excellent properties were achieved,including the transparency of 91.9%,the tensile strength of 37.7 MPa,the impact strength of 19.3 kJ/m2,the Shao's hardness of 86.4? as well as the elastic modulus of 3.0 GPa.For the composites with main PU component,the tensile strength and hardness increased with increasing the PMMA content,and the densification of composite surfaces was improved,accompanied with the reduced domain size.The dynamicthermomechanical analysis indicated that the glass transition temperature of different phases approached each other with the increase of minor components,and the elastic modulus increased with the increase of PMMA content.As for the PMMA-PU gradient composites,the formation of gradient zone was closely related to the PU prepolymerization temperature and time.With the increase of PU prepolymerization temperature and time,both transparency and impact strength increased firstly and then decreased.The optimal prepolymerization was performed at65 ?C for 4 h.In this case,the excellent properties of gradient composites included the transparency of 80.1% and impact strength of 177.8 kJ/m2.The Shao's hardness was84.3? for the PMMA side and 73? for the PU side.Moreover,the directional zone with compositional gradient was clearly found in the microstructural observation.For the glass laminates with composite interlayers and gradient interlayers,the optical property had a relationship with the PU content of interlayers similar to that of interlayer,but the shear strength firstly increased and then decreased.The organicinorganic glass laminates exhibited the excellent properties with 85% PU,including the transparency of 88.7% and the shear strength of 2.81 MPa.In the hygrothermal experiments,the transparency of glass laminates decreased with the increase of aging time,and the shear strength increased successively.When the PU content was 80% for the gradient interlayer,the transparency reached 82%,and the shear strength increased from 1.22 MPa to 2.26 MPa.The hygrothermal performance of glass laminates was better for the gradient interlayers compared with the composite interlayers.