The choice of diisocyanate and polyol significantly affects the properties of the synthesized polyurethane. Polyurethanes are formed by the reaction between diisocyanates and polyols, which results in the formation of urethane linkages. The properties of the final polyurethane product depend on the molecular structure, functionality, and molecular weight of the diisocyanate and polyol used.To conduct a comparative study on the properties of polyurethane synthesized using different combinations of diisocyanate and polyol, we can follow these steps:1. Selection of diisocyanates and polyols: Choose different types of diisocyanates e.g., aromatic diisocyanates like TDI and MDI, and aliphatic diisocyanates like HDI and IPDI and polyols e.g., polyester polyols, polyether polyols, and polycarbonate polyols for the study.2. Synthesis of polyurethanes: Prepare polyurethane samples by reacting the selected diisocyanates and polyols in different combinations. Ensure that the reaction conditions e.g., temperature, catalyst, and stoichiometry are consistent for all the samples.3. Characterization of polyurethanes: Analyze the synthesized polyurethane samples using various characterization techniques to determine their properties. Some of the important properties to consider are: a. Mechanical properties: Tensile strength, elongation at break, and modulus can be determined using tensile testing. Hardness can be measured using a durometer or a Shore hardness tester. b. Thermal properties: Differential scanning calorimetry DSC can be used to determine the glass transition temperature Tg and melting temperature Tm . Thermogravimetric analysis TGA can be used to study the thermal stability and decomposition temperature of the samples. c. Chemical resistance: Expose the polyurethane samples to various chemicals e.g., water, acids, bases, and organic solvents and observe any changes in their properties, such as swelling, weight loss, or degradation. d. Morphology: Analyze the microstructure of the polyurethane samples using scanning electron microscopy SEM or atomic force microscopy AFM to understand the phase separation and distribution of hard and soft segments.4. Comparison and analysis: Compare the properties of the synthesized polyurethanes and analyze how the choice of diisocyanate and polyol affects their properties. For example, aromatic diisocyanates generally result in polyurethanes with higher mechanical strength and rigidity, while aliphatic diisocyanates lead to polyurethanes with better UV resistance and color stability. Similarly, the choice of polyol can affect the hydrolytic stability, chemical resistance, and mechanical properties of the polyurethane.5. Conclusion: Summarize the findings of the study, highlighting the key relationships between the choice of diisocyanate and polyol and the properties of the synthesized polyurethane. This information can be used to guide the selection of diisocyanate and polyol for specific applications and to design polyurethanes with tailored properties.