Mild and rapid surface initiated ring-opening polymerisation of trimethylene carbonate from cellulose

Abstract

Surface initiated ring-opening polymerisation (SI-ROP) of trimethylene carbonate (1,3-dioxane-2-one, TMC) from cellulose surfaces has been studied for the first time. Specifically, organocatalytic systems employing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were implemented in the ROP of TMC, initiated by the hydroxyl groups on the cellulose chain, to form polymer grafts on the surface of filter papers. A sacrificial initiator was added to the reaction solution, resulting in the formation of free, unbound polymer formed in parallel to the surface grafting. The properties of the polymer grafted paper were studied utilising infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy and contact angle measurements. The free polymers were characterised with nuclear magnetic resonance spectroscopy and size exclusion chromatography. The grafting resulted in hydrophobic papers in as little as one minute and the ability to control the grafting length of the polymer from the surface was demonstrated by either altering the time of the polymerisation or the ratio of free initiator to monomer. This polymerisation route provides milder conditions than conventional metal-catalysed ROP, greatly reduces reaction times and thus is an attractive method for modification of natural biopolymers compared to previously described methods.