Preparation and properties of biodegradable polyurethane scaffolds from poly(ε-caprolactone) triblock copolymers

An ideal tissue engineering scaffold should possess mechanical properties and biodegradability that are compatible with the host tissue. To address this issue, the ring-opening polymerization of ε-caprolactone (ε-CL) was conducted in conjunction with polyether polyols, poly(propylene glycol) (PPG) and poly(trimethylene ether) glycol (PO3G), to synthesize the triblock copolymers PCL-PPG-PCL and PCL-PO3G-PCL. Subsequently, biodegradable polyurethanes (PUs) were synthesized utilizing these triblock copolymers as the soft segments, while a PU incorporating poly(ε-caprolactone) (PCL) as the soft segment served as a control group. The influence of block polyols on the structural, morphological, mechanical, and degradation properties of the resulting materials was systematically investigated. The findings indicate that the PU from the triblock copolymers exhibited lower modulus, tensile strength, and hardness, a higher degradation rate compared to the PU from PCL. Additionally, these polyether-ester-based PUs demonstrated superior elastic recovery at strains exceeding 100% in comparison to the control PU sample. Biodegradable PUs were fabricated into porous scaffolds through electrospinning, and the mechanical properties of these scaffolds were tailored by adjusting the fiber diameters, achieving a modulus as low as 2 MPa. The biodegradable PUs developed in this study possess a low initial modulus and tunable mechanical properties, indicating their potential application in scaffolding.