Starch-Based Composites Using Mature Fine Tailings as Fillers

• Author / Creator

  Moran Nava, Daniel A

• Mature fine tailings (MFT) are one of the major problems of the oil sands industry in Alberta, specifically due to the reclamation of the land filled with them. Stepping away from the most common approach of dewatering processes, this research is based on the manufacture of useful composite materials using MFT as filler to help mitigate the negative environmental effect of the oil sands industry. Thermoplastic starch was chosen as matrix because it is hydrophilic, easy to obtain, and there are several comparative studies of thermoplastic starch composites with different types of fibers and clays. Using glycerol as a plasticizer and MFT as filler for the synthesis of the composites, the morphology, water resistance and mechanical properties of the composites were studied while changing filler percentage. Changes in mechanical properties with temperature were also investigated through dynamic mechanical analysis. The MFT composites were compared to composites made with montmorillonite (MMT), cellulose nanocrystals (CNC) and Dean Stark solids (DS) as fillers. MFT composites showed a slight density increase of 0.06 g/ml after addition of 5% MFT, but the density always stayed in the same range as the rest of the composites. The water resistance of MFT and DS composites was similar and higher than the water resistance of MMT composites, but the improvement in water resistance was only 6% with the highest loading of filler. The total disruption of the starch granule after the composites preparation was proven through x-ray diffraction. Although there was not intercalation in MFT or DS composites, these showed similar and better mechanical properties than plasticized starch, with an increasing tensile and compressive modulus with increasing filler content. Despite the higher tensile modulus increase in intercalated MMT and CNC composites up to 5% filler, the MFT composites with filler contents higher than 5% achieved the same tensile modulus values, which is beneficial to MFT reduction, since more MFT is removed from the environment to make composites this way. MFT and DS composites also showed similar and better compressive modulus and strength than MMT composites and CNC composites. The dynamic mechanical analysis of the composites determined two thermal transitions in the composites related to a plasticizer rich phase and a starch rich phase, demonstrating the heterogeneity of the composites.

• Subjects / Keywords

  • Starch Composite
  • Clays
  • MFT

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3F47H619

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.