Activated-Carbon-Supported Phosphotungstic Acid as Novel Heterogeneous Catalysts for Cationic Polymerization of β-Pinene

Abstract

Activated-carbon-supported phosphotungstic acid (HPW/C) catalysts were prepared and characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and the Brunauer–Emmett–Teller (BET) method. The catalytic performance of HPW/C for β-pinene polymerization was also investigated. The characterization results show that the Keggin structure of HPW does not change after being supported on the activated carbon. The tiny particles of HPW are distributed amorphously and uniformly on the surface of the activated carbon. HPW can interact strongly with surface oxygen-containing groups on the activated carbon. The immobilization of HPW leads to a decrease in the specific surface area and total porous volume of the activated carbon. The polymerization conditions were optimized as follows: loading amount 34.2 wt%; dosage of catalysts 0.6 g; reaction temperature 0–10°C; β-pinene 3 mL; solvent 7 mL; reaction time 2 h. Under these conditions, the polymer yield was up to 73.0%, and the number-average molecular weight was about 860.