Biodegradable thermoplastic polyurethanes incorporating polyhedral oligosilsesquioxane.

Area of Science:

• Polymer Science
• Materials Science
• Biomaterials Engineering

Background:

• Biodegradable polymers often lack mechanical robustness and elasticity.
• Thermoplastic polyurethanes (TPUs) offer tunable properties but can be limited in biodegradability.
• Inorganic moieties like polyhedral oligosilsesquioxanes (POSS) can enhance polymer properties.

Purpose of the Study:

• To develop a novel hybrid biodegradable thermoplastic polyurethane (TPU) system.
• To investigate the effect of incorporating polyhedral oligosilsesquioxane (POSS) into the hard segments of TPU.
• To evaluate the mechanical properties, shape memory behavior, and in vitro degradation of the developed material.

Main Methods:

• Synthesis of a hybrid TPU system with poly(D, L-lactide) soft blocks and POSS-containing hard blocks.
• Dynamic mechanical analysis (DMA) to assess elasticity and transition temperatures.
• Wide-angle X-ray diffraction (WAXD) to study crystallinity and POSS crystallization.
• In vitro degradation studies over a two-month period.

Main Results:

• The hybrid TPU system demonstrated excellent elasticity above its glass transition temperature (T(g)), attributed to POSS crystallization.
• Increasing POSS content enhanced material rigidity and crystallinity.
• The highest POSS incorporation exhibited one-way shape memory with superior shape-fixing capabilities.
• In vitro degradation showed moderate water uptake and significant molecular weight reduction, with substantial mass loss after two months.

Conclusions:

• The developed POSS-enhanced biodegradable TPU offers a unique combination of elasticity, shape memory, and controlled degradation.
• POSS crystallization in the hard segments is key to achieving enhanced mechanical properties and shape memory effects.
• This novel material holds promise for applications requiring advanced biodegradable materials with tailored performance.