Reactive processing and characterization of PBAT with cellulose whiskers reinforced thermoplastic starch (nTPS)

• Grant number: 12/12237-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2012
• End date: July 31, 2013
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Alessandra de Almeida Lucas
• Grantee: Drieli Litsue Kondo
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

In a recent study developed our research group, nanocomposites of thermoplastic starch (TPS) containing 3, 4 and 5 wt% cellulose nanowhiskers (NWC) were processed. Better mechanical properties were obtained using 4% by weight of NWC, a value just above the previewed theoretical percolation threshold for the system (3.6% NWC). Subsequently, nanocomposites with TPS containing 1, 2, 4, 6 and 10% by weight of the TPS NWC (nTPS) were blended with poly (butylene terephthalate co-adipate) (PBAT) in a fixed proportion of 70/30 of PBAT/nTPS, by weight. Again, the best results were obtained when the nanocomposite TPS NWC contained 4%. The results were promising and the product and the process are being patented. Since no coupling agent was used in the PBAT / nTPS blends, the material did not show a strong and stable interface, typical of polymer blends is not compatible, due to the large difference hydrophilic / hydrophobic system.This research project is then proposed to study the reactive processing of the mixture PBAT / NTPS in the presence of maleic anhydride (MA). Initial studies performed in a torque rheometer is in progress by the student IC Drieli Kondo, candidate for the scholarship, who already has been dedicating to the project for about six months. The films will then be obtained in a single screw extruder coupled to a flat die. The mechanical properties (tensile strength, elongation at break and elastic modulus), thermal (stability, glass transition temperature, melting and crystallization) and barrier (permeability to water vapor) will be evaluated. The morphology of the systems will be investigated by Scanning Electron Microscopy (SEM). The rheological properties will be evaluated by rheometry using parallel plates (at low shear rates) and capillary (at high shear rates) geometries. The evidence for the occurrence of chemical reactions will be reviewed by Spectroscopy Fourier Transform Infrared (FTIR).This study is part of the project CAPES / Brazil-Network Nanobiotec No. 13 entitled "Consolidation of the Development Process Nanobiotecnológicos of Graduate Programs in Applied Chemistry, Chemical Engineering and Food Science of Bahia." This project integrates four universities: UFSCar, UFBA, UFMG and USP under the General Coordination of the Professor. Rosario Bretas and Local Coordination of Professor. Alessandra Lucas in DEMa / UFSCar. Importantly, the program does not include IC Scholarships for use in Brazil. (AU)