Phosphazene Functionalized Silsesquioxane-Based Porous Polymer as Thermally Stable and Reusable Catalyst for Bulk Ring-Opening Polymerization of ε-Caprolactone

Abstract

The bulk ring-opening polymerization (ROP) of ε-caprolactone using phosphazene-containing porous polymeric material (HPCP) has been studied at high reaction temperatures (130–150 °C). HPCP in conjunction with benzyl alcohol as an initiator induced the living ROP of ε-caprolactone, affording polyesters with a controlled molecular weight up to 6000 g mol−1 and moderate polydispersity (Ð~1.5) under optimized conditions ([BnOH]/[CL] = 50; HPCP: 0.63 mM; 150 °C). Poly(ε-caprolactone)s with higher molecular weight (up to Mn = 14,000 g mol−1, Ð~1.9) were obtained at a lower temperature, at 130 °C. Due to its high thermal and chemical stability, HPCP can be reused for at least three consecutive cycles without a significant decrease in the catalyst efficiency. The tentative mechanism of the HPCP-catalyzed ROP of ε-caprolactone, the key stage of which consists of the activation of the initiator through the basic sites of the catalyst, was proposed.

Non-Flammable Epoxy Composition Based on Epoxy Resin DER-331 and 4-(β-Carboxyethenyl)phenoxy-phenoxycyclotriphosphazenes with Increased Adhesion to Metals

“…Phosphazenes are non-toxic and can even be used in pharmaceuticals [24][25][26]. Porous polymers based on phosphazenes are used in environmentally friendly sorption processes [27] and industrial catalysis [28], and some cyclophosphazenes even have an anti-corrosion effect towards metals, which is important in the manufacture of metal-containing composites [29].…”