12
S. Raja Balasaraswathi and R. Rathinamoorthy
process is responsible for these structural changes. Moreover, the surface of the recycled fibers seems to be duller and more deformed. These changes (strength reduction
and deformed surface) in the recycled fiber characteristics cause increased shedding.
The researchers analyzed and compared the shedding behavior of virgin and recycled
polyester fibers and found 2.3 times more shedding in the case of recycled polyesters
than virgin polyester [41].
In contrast, other researchers noticed lesser shedding in the case of recycled fibers.
Frost et al. studied the impact of recycled fiber contents on the shedding behavior
of the fabrics. They analyzed the shedding behavior of 100% virgin cotton, 20%
recycled cotton, 40% recycled cotton, 100% virgin polyester, 70% recycled polyester,
and 40% recycled polyester. In their study, they have found no significant difference
between the shedding of virgin and recycled cotton. They have reported that 70%
recycled polyester shed fewer fibers than the 40% recycled fibers. Further, results
showed that 70% recycled polyester sheds longer fiber than the other polyester fibers.
The reason behind this could be the higher elongation of recycled polyester at the
breaking point. Hence, they have concluded that the recycled fibers showed lesser
shedding as they tend to elongate rather than break [42]. The same result has been
obtained in the other study where virgin and recycled polyester fabrics are tested
for shedding. The researchers have reported higher shedding in the case of virgin
polyester than the recycled polyester [43]. Table 1 consolidates the previous analysis
performed with different fiber types.
4.1.2 Fiber Length (Staple/Filament)
Staple fibers and filament types are the two configurations of fibers. The staple
fibers are of shorter length whereas the filaments are of indefinite length [46]. The
slippage of staple fibers from the yarn structure is easy because of its shorter length.
During the spinning process, the twists are inserted to keep the fibers together. It
is common that during the twist insertion, fibers of shorter length slides toward the
sheath and the longer fibers move toward the core. Since the short fibers are on
the sheath it is easier to get disengaged from the yarn structure [41]. In the case
of staple fibers, even though the material is not damaged due to external actions,
there will be a release of shorter fibers [22]. However, in the filaments, the shedding
happens only after the breakdown of filaments due to external forces. This attributes
for higher shedding in the case of staple fibers when compared to filaments [41]. The
researchers have studied the shedding property of polyester knit, polyester woven,
and polypropylene woven and reported lesser shedding in the polyester knit sample
than the other two. This is attributed to the filament nature of fibers used in the
polyester knit whereas polyester and polypropylene woven fabrics were made of
staple fibers [45]. The other researchers who have noticed higher shedding in the
case of cotton than the polyester have concluded that it can be attributed to the staple
nature of cotton whereas the polyester fibers are filaments [23]. Yang et al. have also
claimed that the lesser shedding of polyester than that of acetate and polyamide is
due to the continuous filament nature of polyester [29]. Francesca et al. have noticed
S. Raja Balasaraswathi and R. Rathinamoorthy
process is responsible for these structural changes. Moreover, the surface of the recycled fibers seems to be duller and more deformed. These changes (strength reduction
and deformed surface) in the recycled fiber characteristics cause increased shedding.
The researchers analyzed and compared the shedding behavior of virgin and recycled
polyester fibers and found 2.3 times more shedding in the case of recycled polyesters
than virgin polyester [41].
In contrast, other researchers noticed lesser shedding in the case of recycled fibers.
Frost et al. studied the impact of recycled fiber contents on the shedding behavior
of the fabrics. They analyzed the shedding behavior of 100% virgin cotton, 20%
recycled cotton, 40% recycled cotton, 100% virgin polyester, 70% recycled polyester,
and 40% recycled polyester. In their study, they have found no significant difference
between the shedding of virgin and recycled cotton. They have reported that 70%
recycled polyester shed fewer fibers than the 40% recycled fibers. Further, results
showed that 70% recycled polyester sheds longer fiber than the other polyester fibers.
The reason behind this could be the higher elongation of recycled polyester at the
breaking point. Hence, they have concluded that the recycled fibers showed lesser
shedding as they tend to elongate rather than break [42]. The same result has been
obtained in the other study where virgin and recycled polyester fabrics are tested
for shedding. The researchers have reported higher shedding in the case of virgin
polyester than the recycled polyester [43]. Table 1 consolidates the previous analysis
performed with different fiber types.
4.1.2 Fiber Length (Staple/Filament)
Staple fibers and filament types are the two configurations of fibers. The staple
fibers are of shorter length whereas the filaments are of indefinite length [46]. The
slippage of staple fibers from the yarn structure is easy because of its shorter length.
During the spinning process, the twists are inserted to keep the fibers together. It
is common that during the twist insertion, fibers of shorter length slides toward the
sheath and the longer fibers move toward the core. Since the short fibers are on
the sheath it is easier to get disengaged from the yarn structure [41]. In the case
of staple fibers, even though the material is not damaged due to external actions,
there will be a release of shorter fibers [22]. However, in the filaments, the shedding
happens only after the breakdown of filaments due to external forces. This attributes
for higher shedding in the case of staple fibers when compared to filaments [41]. The
researchers have studied the shedding property of polyester knit, polyester woven,
and polypropylene woven and reported lesser shedding in the polyester knit sample
than the other two. This is attributed to the filament nature of fibers used in the
polyester knit whereas polyester and polypropylene woven fabrics were made of
staple fibers [45]. The other researchers who have noticed higher shedding in the
case of cotton than the polyester have concluded that it can be attributed to the staple
nature of cotton whereas the polyester fibers are filaments [23]. Yang et al. have also
claimed that the lesser shedding of polyester than that of acetate and polyamide is
due to the continuous filament nature of polyester [29]. Francesca et al. have noticed