Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium

Carbohydr Polym. 2014 Dec 19:114:149-156. doi: 10.1016/j.carbpol.2014.07.077. Epub 2014 Aug 13.

Abstract

This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications.

Keywords: Graft copolymerization; Lactic acid; Starch; Supercritical carbon dioxide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Dioxide / chemistry*
  • Carbon Dioxide / metabolism
  • Lactic Acid / chemistry*
  • Lactic Acid / metabolism
  • Polyesters
  • Polymerization*
  • Polymers / chemistry*
  • Polymers / metabolism
  • Spectroscopy, Fourier Transform Infrared / methods
  • Starch / chemistry*
  • Starch / metabolism
  • X-Ray Diffraction

Substances

  • Polyesters
  • Polymers
  • Carbon Dioxide
  • Lactic Acid
  • poly(lactide)
  • Starch