Roberto Frassine of the Politecnico di Milano Polymer Engineering Lab., Milano (Italy) has been using corn-cobs and straw, wheat straw and even seaweed as a source of cellulose for acetylation – a process which normally requires the highest quality dissolving pulp. The cellulose extraction and purification process involves Toluene/Ethanol extraction of waxes followed by bleaching first with alkaline peroxide and then with an acetic/formic acid/hydrogen peroxide mixture.
A final peroxide extract yields a pure cellulose with a DP rather lower than that obtained from wood. This was acetylated and dissolved in dichloromethane/methanol for electrospinning to nonwovens. At acetate concentrations of 7% and 10% the nonwovens were of good quality. A lab. scale batch reactor has now been built to allow 1.5kg batches of acetate to made for future experimentation.