Synthesis And Characterization Of Mechanoresponsive Hyperbranced Polyurethane Via Covalently Embedding Mechanophore(Spiropyrane)

Mechanical properties of the polymer is one of most important properties of polymer materials, and molecular structure of the polymer is an important factor affecting its mechanical properties, the study of the relationship between polymer structure and its mechanical properties is very meaningful. In this paper, based on diol structural of spiropyran molecules, we synthesized a series of response polyurethane, using of Spiropyran's force response. We could study molecular structure, polyurethane photochromic behavior and the mechanical properties. These polyurethane of spiropyran can not only predict the macroscopic material size of the force, but also analyze the impact of the microscopic structure of the polyurethane molecule intermolecular force transmission chain from the microscopic.In this paper, using the current maturity method, we designed spiropyran group and successfully synthesized spiropyran glycol molecules. By NMR structural characterization of the synthesized product, we proved that diol structural spiropyran are located on both sides of its C-O bond. The spiropyran is effective force photochromic group. By UV spectroscopy to study the light response of the spiropyran diol.In this thesis, using of mature prepolymer method, a series linear polyurethane was synthesized(IPDI-PTMG-SP, IPDI-PBA-SP, TDI-PTMG-SP, TDI-PBA-SP, MDI-PTMG-SP, MDI-PBA-SP), By infrared, gel permeation chromatography, differential scanning to characterize the structure and thermal properties of polyurethane; By tensile testing, UV tests to characterize the tensile properties of the polyurethane, the force response. By combining different types of linear polyurethane, we found MDI-PBA-SP linear polyurethane has good mechanical properties and force response. Through studying the microscopic mechanism of behavior of linear polyurethane containing spiropyran, we found a linear molecular structure of linear polyurethane is important to intermolecular force transmission. Entangled linear polyurethane molecular chains can effectively pass on the force, so that it has good mechanical properties and force response.According to the analysis of linear polyurethane containing spiropyran, this paper use MDI and PBA as raw materials, combined with the prepolymer method and A2+B3 Synthesis of copolymer, we synthesized a series of hyperbranched polyurethane of SP(including MDI:PBA's ratio was 5:4, 5:3, 2:1). By infrared, gel permeation chromatography, differential scanning to characterize the structure and thermal properties of polyurethane; By tensile testing, UV tests to characterize the tensile properties of the polyurethane, the force response. The study found that hyperbranched polyurethane branched structure is an important factor in their mechanical properties and the response force. The higher the degree of branching of the hyperbranched polyurethane, the shorter the distance between the branch points, the less entangled molecular chains, the harder Intermolecular forces effective transfer, the smaller the force of the C-O bond, therefore hyperbranched polyurethane have less force response and mechanical properties.We analysis force response of linear and hyperbranched polyurethane polyurethane, and found that the relationship between the structure and, microscopic force transfer, the macroscopic mechanical properties of the polyurethane molecule. Because the linear polyurethane and hyperbranched polyurethane molecular structure were different, and the efficiency of its microscopic force transmission were different, thus the mechanical properties and power response of the linear polyurethane were generally better than hyperbranched polyurethane. Therefore, spiropyran of power response is expected as probe molecules, from the molecular chain point of view help us to understand the process of force transfer in the material, and further understand the relationship between structure and properties.