Study on the Mechanical and Thermal Properties and Shape Memory Behaviors of Blends of Bio-Based Polybenzoxazine and Polycaprolactone with Different Molecular Weights

In this research, blends of bio-based polybenzoxazine (V-fa) and polycaprolactone (PCL) with different molecular weights (Mn) (14,000, 45,000, and 80,000 Da) were prepared with varying PCL content from 10 to 95 wt%. The spectra measured using Fourier Transform Infrared Spectroscopy (FTIR) may indicate the presence of hydrogen bonding between two polymeric components. The thermograms obtained using a Differential Scanning Calorimeter (DSC) and dynamic mechanical analyzer (DMA) exhibited a shift in glass transition temperature (Tg), which indicated partial miscibility between V-fa and PCL. The thermograms obtained using a thermogravimetric analyzer (TGA) revealed that the addition of PCL led to an increase in the maximum decomposition temperature (Tdmax). The tensile strength and modulus decreased with an increase in PCL, thus indicating a decrease in brittleness. Interestingly, only the samples with an Mn of 80,000 Da were bendable. The blends with 80 wt% PCL were revealed to have shape memory behaviors with a shape fixity of approximately 81%. The shape recovery ratio of the blends with 95 wt% PCL was approximately 78%.