Modern Polyurethanes: Overview of Structure Property Relationship

The intrinsic features of polyurethanes polymers - such as elasticity, clarity and tunable mechanical properties - are found to be key in industrial and personal care applications. Understanding structure-property relationships in polyurethanes is necessary when designing smart multifunctional materials for specific end-uses. Polyurethanes have a segmented structure of block copolymers where soft and hard segments form micro domains that may result in two-phase morphology. For example, a change in the molecular weight of the soft segment may affect phase separation that, in turn, dictates a very unique thermodynamic behavior of the polymer affects its mechanical characteristics. The nature of the building blocks and polymer morphology greatly affects film forming properties, stiffness, and polymer behavior under different thermal and physical conditions. This paper will review effects of the polymer structure on biodegradability and chemical resistance. Physical-chemical characteristics of the polymer to achieve shape memory or self-healing effects will also be discussed.