Cellulose as a functional additive to develop composite materials

  • Georg Graninger

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

The potential of cellulose, an abundant naturally occurring bio-polymer, as a reinforcing agent in thermoplastic matrices, and as a coating on glass fibre in a reinforced polymer composite to promote interfacial adhesion, is explored. The growing interest in bio-based cellulose, as a reinforcement for polymers, stems from their attractive combination of physical and chemical properties such as high aspect ratio, high elastic modulus (100-150 GPa) and tensile strength (7-10 GPa), low density (1.56 g/cm3), a crystalline structure and surface-rich chemistry.

Twin-screw extrusion is a facile and scalable process for continuous production. A detailed investigation of the influence of shear during continuous melt processing, on the dispersion of cellulose particles within different thermoplastic matrices, is conducted. Two different screw configurations, introducing different amounts of shear forces, are employed during twin-screw extrusion. The study reveals that inexpensive and readily available bio-renewable microcrystalline cellulose can be effectively dispersed and distributed due to fibrillation into cellulose nanoparticles during high-shear processing.

A detailed interface characterization of nanocellulose crystal-coated glass fibre reinforced composites, using atomic force microscopy, is presented, enabling the determination of stress transfer-enhancing capabilities of nanocellulose crystals.

The insight into the composition-processing-property relationships in cellulose composites makes an important contribution to the ongoing research into novel and sustainable composite applications.

Date of AwardJul 2024
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsNorthern Ireland Department for the Economy
SupervisorBiqiong Chen (Supervisor), Brian Falzon (Supervisor) & Stephen Hawkins (Supervisor)

Keywords

  • Extrusion
  • cellulose
  • cellulose composites
  • processing
  • coating
  • interface

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