title: Making positive use of the fibrillation of lyocell fibres in composite materials

authors: Graupner, Nina

abstract: The present study investigates the influence of surface fibrillation of lyocell fibres on the adhesion and resulting properties of short fibre-reinforced polypropylene (PP) and polylactide (PLA) composites. Fibrillation was shown to reduce the tensile strength and elongation at break of the fibres, while not affecting Young's modulus. It was demonstrated that fibrillation improved adhesion significantly compared to non-fibrillated (untreated) fibres, and the critical fibre length determined by microbond tests was reduced. Despite the reduced tensile strength of the fibrillated lyocell fibres, the tensile strength of the composites was increased by a factor of 1.15 for PP and 1.62 for PLA compared to composites produced with untreated fibres. The Young's modulus of the composites was increased using fibrillated fibres by a factor of 1.41 for PP and 1.20 for PLA. The impact strength was also improved by using fibrillated fibres by a factor of 1.38 for PP-based and 1.23 for PLA-based composites. Surface fibrillation of lyocell offers interesting application possibilities, particularly for short fibre-reinforced materials, as the higher specific fibre surface reduces the critical fibre length of lyocell, leading to improved stress transfer from the matrix to the fibre. These fibres seem particularly promising to enhance the mechanical properties of short-fibre reinforced composites for 3D printing applications.

text: Making positive use of the fibrillation of lyocell fibres in composite materials The present study investigates the influence of surface fibrillation of lyocell fibres on the adhesion and resulting properties of short fibre-reinforced polypropylene (PP) and polylactide (PLA) composites. Fibrillation was shown to reduce the tensile strength and elongation at break of the fibres, while not affecting Young's modulus. It was demonstrated that fibrillation improved adhesion significantly compared to non-fibrillated (untreated) fibres, and the critical fibre length determined by microbond tests was reduced. Despite the reduced tensile strength of the fibrillated lyocell fibres, the tensile strength of the composites was increased by a factor of 1.15 for PP and 1.62 for PLA compared to composites produced with untreated fibres. The Young's modulus of the composites was increased using fibrillated fibres by a factor of 1.41 for PP and 1.20 for PLA. The impact strength was also improved by using fibrillated fibres by a factor of 1.38 for PP-based and 1.23 for PLA-based composites. Surface fibrillation of lyocell offers interesting application possibilities, particularly for short fibre-reinforced materials, as the higher specific fibre surface reduces the critical fibre length of lyocell, leading to improved stress transfer from the matrix to the fibre. These fibres seem particularly promising to enhance the mechanical properties of short-fibre reinforced composites for 3D printing applications.

year: 2023-07-01

title: Fair Trading: Misleading or deceptive conduct by Lindsay Trotman & Debra Wilson [Book Review]

authors: Manyam, Joel

subjects: unfair competition

abstract: The article reviews the book "Fair Trading: Misleading or Deceptive Conduct," by Lindsay Trotman and Debra Wilson.

text: Fair Trading: Misleading or deceptive conduct by Lindsay Trotman & Debra Wilson [Book Review] The article reviews the book "Fair Trading: Misleading or Deceptive Conduct," by Lindsay Trotman and Debra Wilson.

year: 2007

title: Kōauau auē, e auau tō au e! The Kōauau in Te Ao Māori.

authors: Komene, Jo'el

subjects: Kōauau

abstract: In recent years there has been a revival of interest in traditional Māori musical instruments, including the kōauau. This thesis studies kōauau informed by a Māori framework, giving weight to traditional Māori knowledge and practices, emphasizing the spiritual dimensions of the instrument in its origins and its functions. The thesis defines the kōauau and how it is distinct from other taonga pūoro in its physical characteristics. It then presents the traditions associated with the kōauau which link its origins to the atua and their natural world, especially Raukatauri, together with other traditions from many rohe throughout Aotearoa.  The thesis describes the traditional tools and methods of construction, the role of atua in the construction process, materials used for kōauau, how they were embellished, and their use as adornments. The techniques for playing kōauau are analyzed, and there is a discussion of the occasions on which kōauau were played, and the purposes of performing on kōauau. The thesis also presents the texts of several traditional waiata kōauau. A number of traditional kōauau in storage at the Auckland Museum were able to be examined to confirm and extend documentary evidence about materials, construction methods, and embellishment. The discussion also comments on the quot;voicesquot; for those kōauau in the museum collection that could be sounded. The decline in kōauau performance during the twentieth century is outlined, and there is a summary of successful efforts in the later twentieth century to revive taonga pūoro, including kōauau. The thesis brings together in concise form much scattered information so that current and future performers with kōauau are able to give full consideration to its place in te ao Māori.

text: Kōauau auē, e auau tō au e! The Kōauau in Te Ao Māori. In recent years there has been a revival of interest in traditional Māori musical instruments, including the kōauau. This thesis studies kōauau informed by a Māori framework, giving weight to traditional Māori knowledge and practices, emphasizing the spiritual dimensions of the instrument in its origins and its functions. The thesis defines the kōauau and how it is distinct from other taonga pūoro in its physical characteristics. It then presents the traditions associated with the kōauau which link its origins to the atua and their natural world, especially Raukatauri, together with other traditions from many rohe throughout Aotearoa.  The thesis describes the traditional tools and methods of construction, the role of atua in the construction process, materials used for kōauau, how they were embellished, and their use as adornments. The techniques for playing kōauau are analyzed, and there is a discussion of the occasions on which kōauau were played, and the purposes of performing on kōauau. The thesis also presents the texts of several traditional waiata kōauau. A number of traditional kōauau in storage at the Auckland Museum were able to be examined to confirm and extend documentary evidence about materials, construction methods, and embellishment. The discussion also comments on the quot;voicesquot; for those kōauau in the museum collection that could be sounded. The decline in kōauau performance during the twentieth century is outlined, and there is a summary of successful efforts in the later twentieth century to revive taonga pūoro, including kōauau. The thesis brings together in concise form much scattered information so that current and future performers with kōauau are able to give full consideration to its place in te ao Māori.

year: 2009