Facile preparation of biodegradable poly(γ-butyrolactone) via base-assisted ring-opening polymerization

Abstract

(Co)poly-γ-butyrolactone (pGBL) is a thermoplastic material of high interest to replace common plastics with a more sustainable alternative due to its biodegradability, re-monomerizability and opportunity to be obtained from renewable feedstocks. Mild methods to produce pGBL by ring-opening polymerization (ROP) have only been developed in the last decade. Unfortunately, these methods involve the use of sophisticated catalysts, very low temperatures or relatively diluted mixtures. To develop a more environmentally, economically and industrially relevant pGBL synthesis process, the aim was to increase the ROP temperature to be applicable for large scale reaction and optimize the base/alcohol system to circumvent the use of sophisticated organic or rare earth metal catalysts. To that end, the strong base potassium tert-butoxide in combination with benzyl alcohol or with polyols such as 1,4-benzenedimethanol or glycerol was used for the ROP. This simple system gives access to high GBL conversions and medium to high molecular weight (co)polymers.