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

(Co)poly-?-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.

Automated summary

(Co)poly-?-butyrolactone (pGBL) is a thermoplastic material that shows potential to replace common plastics due to its biodegradability and renewable feedstocks. Mild methods for pGBL synthesis have been developed, but often require sophisticated catalysts or low temperatures. In this study, a simple base/alcohol system using potassium tert-butoxide with benzyl alcohol or polyols was used to achieve high conversions and molecular weights of pGBL.