Influence of Incorporation of Starch Nanoparticles in PBAT/TPS Composites Films

Abstract

Films of PBAT/TPS (poly(butylene adipate-co-terephthalate)/thermoplastic starch) (starch plasticized with glycerol containing citric and stearic acids) without and with 0.6wt% starch nanoparticles were produced by extrusion. The presence of nanoparticles during the extrusion process led to a higher degree of starch gelatinization improving starch compatibility with PBAT.Nanoparticles modified the interaction between the different components of the PBAT/TPS composite. The hydroxyl groups of the starch nanoparticles interacted with starchamylose bymeans of hydrogen bonds. In addition, nanoparticles modified the structure of thePBAT rigid segment (BT): a shift of Tm ofBT towardlower temperatures anda slight shift of the relaxation of the BT segment to higher temperatures were observed. The incorporation of nanoparticles also had a reinforcing effect on<br />the PBAT/TPS matrix. The composite presented slight increases of Young?smodulus (E) and stress at break (b)without affecting the strain at break (b). The rate of biodegradability was improved with the use of starch nanoparticles. The composite showed faster deterioration than thematrix, showing the first changes in its tonality and breakdowns at only 6 days of burial in compost.<br /><br />