Production of biomaterials from cork: Liquefaction in polyhydric alcohols at moderate temperatures

• Cork dust can be converted into a liquid material for preparation of bio-polymers.
• Liquefaction of cork can be performed under acidic or alkaline conditions.
• With the acid catalyst only lignocellulosic components of cork are liquefied.
• In the alkaline environment cork suberin is also liquefied.
• The highest liquefaction yields are obtained with the mixture of glycerol and PEG.

The aim of this study was to develop polymers in a liquid solution, from renewable bio-resources, usable as intermediate materials in the preparation of plastics, adhesives or coatings. The liquefaction of cork with glycerol was investigated at 150 °C, 180 °C, and 200 °C under acidic (sulphuric acid) or alkaline conditions (sodium hydroxide). Cork appears as a two-component material, containing suberin and lignocelluloses. In the presence of sulphuric acid, only the liquefaction of the lignocellulosic components was achieved, leading to liquefaction yield of less than 47% at all investigated conditions. The inverse phenomenon was observed with sodium hydroxide. Suberin was almost completely liquefied, but an increase of temperature and/or sodium hydroxide content was necessary to improve the liquefaction of lignocelluloses. Addition of polyethylene glycol to glycerol to a certain extent caused the conversion of suberin under acid conditions leading to liquefaction yield up to 93%. Therefore, it was demonstrated that it is possible to use cork dust, a less valuable by-product, for the production of various basic chemicals and/or polymers with a high added value.

Figure optionsDownload as PowerPoint slide