Effects of molecular weight of polycaprolactone on the thermal properties of V-fa/PCL blends added with cross-linking agent

Abstract

Abstract In this research, the blends between bio-based polybenzoxazine (V-fa) and polycaprolactone (PCL) with different molecular weights (Mn) of 14,000 and 80,000 Da were prepared at the PCL contents varied at 80, 90, and 95 wt%. γ-Aminopropyltriethoxysilane (KH-550) was used as cross-linking agent. The chemical structures of the polymer blends were characterized by Fourier Transform Infrared Spectrometer (FT-IR). The spectra revealed that hydrogen bonds between two polymers were observed. Moreover, the V-fa and PCL were cross-linked when KH-550 was applied. Thermal properties were determined by thermogravimetric analyzer (TGA). The results of the blends with KH-550 describes the temperature at maximum decomposition rate (Td, max) and char yield. In addition, at the same molecular weight, when the contents of PCL increased, Td, max was slightly increased from 426 to 429 °C, but char yield was decreased. However, these values had no significant difference when no KH-550 was used. Moreover, when bending the V-fa/PCL at a Mn of 80,000 Da, the sample was flexible and could be bent.