In the thesis, the influence of pattern geometry, the arrangement and pattern rotation, weft density,
and the use of polybutylene terephthalate (PBT) yarn on the auxetic potential of Jacquard woven
fabrics was investigated. Eleven Jacquard woven fabrics with different pattern geometries were
designed and produced. The fabrics were created using the Arahne computer-aided design system
and woven on a Jacquard weaving machine with the same cotton warp and identical constructional
parameters, while different weft yarns and weft densities were used. After weaving, dimensional
changes, density, thickness, air permeability, and tensile properties were determined before and
after heat treatment. The auxetic potential of the fabrics was evaluated by determining Poisson's
ratio based on tensile testing and image analysis.
The results showed that pattern geometry and shape significantly affected the auxetic behaviour
of the Jacquard woven fabrics, whereas the pattern rotation and arrangement of the pattern
elements had no significant influence. The use of polybutylene terephthalate (PBT) yarn in the
weft caused transverse shrinkage during heat treatment, resulting in the formation of a three
dimensional textured structure and an improved auxetic response. Among all the samples
investigated, the fabric with a uniformly distributed square geometry and PBT weft yarn exhibited
the best performance, achieving the highest negative Poisson's ratio and maintaining auxetic
behaviour over the widest strain range. Heat treatment also affected the density, athickness,
dimensions, and air permeability of the fabrics.
It was concluded that the development of functional auxetic Jacquard woven fabrics primarily
depends on an appropriate combination of pattern geometry and the use of polybutylene
terephthalate yarn, whereas the orientation of the pattern elements has no significant influence on
the development of the auxetic effect. The results obtained provide a basis for the further
development of auxetic textile structures intended for functional and technical textile applications.
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