Synthesis And Properties Of Poly(Urethane-Isocyanate) Network Polymers

In this article, a series of poly(urethane-isocyanurate) were prepared in the consecutive polycyclotrimerization method in the presence of epoxy and amine catalyst with aromatic diisocyanate and small molecule diol oligomer as raw materials. The structure and the mechanical properties of poly(urethane-isocyanurate) was studied by infrared spectroscopy (FTIR),chemical titration, gel permeation chromatography (GPC), differential scanning calorimeter (DSC), thermogravimetric analyzer (TG), dynamic mechanical thermal analysis (DMTA) and so on. The main work was as follows:The synthesis of poly(urethane-isocyanate) network. The polyurethane prepolymer with different R values was characterized by -NCO analysis, GPC test and IR test. The poly (urethane-isocyanate) structure was characterized by IR analysis. The results of dynamic mechanical properties (DMA) show that the glass transition temperature (Tg) is -47 ? and the storage modulus is between 106 and 109MPa with the increase of TDI addition. The results of thermodynamic performance (TG) show that the heat resistance of the material is not changed, and the residual carbon ratio is increased from 2% to 21% with the increase of TDI addition. The results show that with the increase of the amount of TDI, the tensile strength of the material increases from small to large, the elongation at break decreases from large to small and the hardness is hardened by softness. With the increase of R value, the tensile strength of the material under the same TDI concentration is correspondingly increased,and the elongation at break is reduced. SEM results show that with the increase of TDI addition, the internal structure of the material is more uneven,the mass cross point is increased, and the material section is more flat.The synthesis of modified poly(urethane-isocyanate) network. The structure of the modified network polymer was characterized by IR. And then its performance is characterized by DMA, TG, mechanical properties and so on. The results show that with the increase of TDI addition, the storage modulus and loss modulus of the material increase, the heat resistance of the material does not change greatly, the residual carbon ratio increases, the tensile strength of the material increases from small to large, The elongation at break is reduced from big to small, and the hardness is hardened by softness.Epoxy addition ratio has little effect on the thermal properties of the material.When the ratio of polyurethane oligomers and epoxy resin is 1: 1, the internal structure of the material is better, the performance of material is superior.The synthesis of fluorinated poly(urethane-isocyanate) networks.Through the analysis of end group -NCO, GPC test, infrared analysis of different fluorine rubber addition of fluorine-containing network for characterization. The results of dynamic mechanics show that the storage modulus and loss modulus change with the addition of fluorine in the terminal hydroxyl liquid. The thermodynamic properties show that the residual carbon content is from 0% to 10% as the addition of fluorine to the terminal hydroxy liquid increases. The mechanical properties show that the mechanical properties of the hydroxyl groups are better than that of the PTMG addition ratio of 1: 6.Based on the previous research on the synthesis of single modulus poly(urethane-isocyanate) network, the continuous change of the injection rate of the two components was controlled by high precision injection pump, and the polyurethane modulus gradient material was synthesized. By testing the dynamic mechanical properties and hardness of the material at different positions, it is proved that the polyurethane modulus gradient material with the same properties as the single modulus material is synthesized.