INTRODUCTION
A sock is an item of clothing worn on the feet. The foot is among the heaviest
producers of sweat in the body, as it is able to produce over 1 US pint (0.471)
of perspiration per day. Socks help to absorb this sweat and draw it to areas
where air can evaporate the perspiration. In cold environments, socks decrease
the risk of frostbite. The earliest known surviving pair of socks, dating from
300-500AD these were on the Nile in Egypt. In the twelve century cotton sock,
found in Egypt. The invention of a knitting machine in 1589 meant that socks,
could be knitted six times faster than by hand. Nonetheless, knitting machines
and hand knitters worked side by side until 1800 (Smith and
Pitts, 2009). The next revolution in sock production was the introduction
of nylon in 1938. Until then socks were commonly made from silk, cotton and
wool. Nylon was the start of blending two or more yarns in the production of
socks, a process that still continues.
Socks can be created from a wide variety of materials. Some of these materials
are cotton, wool, nylon, acrylic, polyester, olefins, (such as polypropylene),
or spandex. To get an increased level of softness other materials that might
be used during the process can be silk, bamboo, linen, cashmere, or mohair (Anonymous,
1996). Socks should be designed in the way to meet the customer pleasure
in accordance with fashion and needs, have high use performance without losing
post-production properties and their fiber properties which used especially
for health shouldn’t affect negatively human health. (Tatsuya,
2001).
The quality in socks can vary depending on many factors. These can be summarized
as; the type and properties of the used thread, knitting conditions and machine
properties, finishing method and the used finishing materials and the form giving
operation applied on socks (Onder and Candan, 2005).
In addition to this, basic properties expected from socks during usage are
resistance against abrasion, elasticity, constant post-washing dimensions, thermo-physiological
properties and physiological comfort. Providing optimum heat, damp and air passing
are expected from socks through physiological comfort. And with thermo-physiological
comfort, perceiving the fabric comfort on the skin and feelings providing sensations
of warm, cold, wet and touch positively are understood (Ozdil,
2008).
Knitted fabrics not only posses stretch and provide freedom of movement but
they also have good handle and comfort. That is why knitted fabrics are commonly
preferred for sportswear, casual ear, underwear and socks. The comfort provided
by clothing depends on several factors, one of them being thermal comfort. It
is known that fiber type, yarn properties, fabric structure, finishing treatments
and clothing conditions are the main factors affecting thermo-physiological
comfort (Li, 2001). A state of comfort can only be achieved
when the most complex interactions between a range of physiological, psychological
and physical factors have taken place in a satisfactory manner. Hence, the comfort
provided by clothing depends on such factors as softness, flexibility, moisture,
diffusion, air permeability, thermal comfort, etc. (Marmarali
et al., 2009).
Human thermal comfort depends on a combination of clothing, climate and physical
activity. The warmth of a fabric is due to insulation provided by air trapped
between fibers and yarns. Fabrics from straight filament yarns remove heat rapidly
by conduction when placed next to the skin and in such a way produce a so-called
cool feel or handle. This phenomenon occurs just for a moment because the skin
adapts rapidly to mild stimulations. Fabrics from hairy yarns feel warm on contact
with the skin due to the insulating air held between the fabric fibers and the
skin (Ogulata 2007).
With the aim of making comfortable socks, we not only used cotton yarns but
also a new industrial method of making yarns of conductive fibers with traditional
fibers such as cotton or polyester. These fibers have a good influence on humans
because they are naturally antibacterial and biodegradable, have a high moisture
absorption capacity, softness, brightness UV protective properties, good mechanical
and physical performances and antiphlogistic, antiallergic properties (Ucar
and Yýlmaz, 2004).
Wearing safety footwear without suitable antibacterial socks, can lead to severe
foot irritation and discomfort. The main purpose of anti-bacterial socks is
to eliminate bacteria which multiply in the presence of dirt, moisture and heat
which cause infections of the foot body odor and allergies. The average person
loses upto 250 mL of water a day from their feet in the form of perspiration.
Anti-bacterial socks being largely constructed of cotton which is hydrophilic
and will conduct moisture away from the body (Gomathi,
2009).
The effectiveness of anti-static footwear is compromised if the hosiery socks
do not also conform to acceptable anti-static requirements. For this purpose
we use anti-static, an innovative fiber that has a layer of copper bonded to
it. Anti-Static fiber is strategically placed in order to conduct static electricity
away from the body, through the sock to the shoe (Baumgartner,
2000).
Copper is an essential nutrient in the human body. It also effectively kills
many species of bacteria, fungus and viruses. It has been used for health, wellness
and antimicrobial purposes for thousands of years, dating back to the ancient
Egyptians. Copper plays an important role in the healthy function of many systems
and organs within the body, including the nervous and immune systems and the
heart, brain and skin. In the medical arena, researchers have also documented
copper’s value in stimulating the production of hemoglobin (red blood cells),
collagen and other key proteins that help stabilize skin layers, promote wound
healing. In cosmetic applications copper improves the look and appearance of
skin and get rid of smelly feet. This patented non-toxic, antimicrobial and
antifungal technology helps eliminate fungi, bacteria causing odor on the sock
as well as improving the regeneration and appearance of the skin (http://www.Antimicrobialcopper.com).
The objects of this investigation is to determine the functional properties
including thermal properties and anti-microbial behavior of socks manufactured
using not only traditional cotton or polyester yarns but also yarns of new kinds
of conductive fibers such as copper fibers. The functional properties influenced
by both material type and knitted structure parameters. The effect of socks
constructions parameters on their functional properties for plain and rib knits
was discussed.
MATERIALS AND METHODS
The weft knitted samples were produced on circular hosiery weft knitting machine as the yarns are running continuously around the fabric. Five samples were produced using plain (s. Jersey) structure; another five samples were produced using Rib (1x1) structure. The raw materials used are traditional yarns (cotton or polyester) or mixed yarns (cotton, polyester and conductive yarns) which should be taken to reduce or eliminate the buildup of electrical charges and enhance the thermal conductivity and anti-microbial behavior of produced socks. These "conductive" yarns are knitted with the base yarns in a different percentage to obtain the required functional properties.
Fibrous base material: Variation in fiber properties can lead to significant variation in the finished product. The fiber type, denier, length, cross-sectional shape, surface texture and finish all influence the quality of the final end-use product. The type of conductive fibers which is used to produce the samples are composed of polyamide 66 with a layer 0.2 μm thick of conductive copper sulphide fused by chemical process into the outer skin of the fiber which has a reddish brown color in its final form. The layer of copper sulphide is intimately integrated into the polymer ensuring a permanent resistance to the usual wear conditions and various chemical treatments. They can be used to bring into focus the following:
| • |
Excellent conductivity level: 105 ohm cm-1 |
| • |
Excellent textile characteristics |
| • |
Excellent antibacterial properties |
Table 1 shows the properties of copper sulphide grafted onto nylon fibers which were used to produce the samples.
Yarns specifications: There is a relationship between the origin and
structure of the yarns used to make a fabric and its physical and functional
properties. The method of construction can also affect the fabric behavior.
To produce the weft knitted samples, different types of the yarns were used.
The basic yarns (type) are cotton or polyester used alone or mixed with conductive
yarns in a different percentage according to the construction of the textile
material, the conditions of process, the use and the functional properties obtained.
| Table 1: |
Properties of copper sulphide grafted onto nylon fibers |
 |
| Table 2: |
Specifications of utilized yarns |
 |
| Table 3: |
Specifications of the socks samples |
 |
| Conductive material: Copper sulphide grafted onto nylon |
The specifications of these utilized yarns are summarized in Table
2.
Manufacturing methods: It is important to know the fabrics constructions and their properties to choose them for the purpose which they are most suitable. All samples were produced on circular hosiery weft knitting machine (Diameter 3", Gauge 12 with 6 Feeders).
The specifications of the samples which were produced could be seen in Table 3. The difference between the samples depends on the various yarn constructions, the ratio of conductive material and the structure.
Measurements of manufactured samples: Several tests were carried out in order to evaluate the functional properties of produces socks, these tests include mechanical and physical properties tests:
| • |
Thickness test: The thickness samples were measured
by the Teclock tester under a pressure 0.2 kg f cm-2 according
to the ASTM D1777-96 (2011) e1 |
| • |
Bursting strength test: This test was carried out for
all samples by using the strip method according to the ASTM
D3786/D3786M-13 (1996) |
| • |
Air permeability test: This test was carried out for
all samples, according to the ASTM D737-04 (2012) |
| • |
Water resistance test: This test was carried out for
all samples, according to the ASTM D570-98 (2010) |
| • |
Thermal resistance test: This test was carried out
for all samples, according to the ASTM D1518-11a (1996) |
| • |
Fabric weariness or abrasion tester: This test was
carried out for all samples, according to the ASTM D3885
(2007) |
| • |
Determination the growth rate of bacteria (E. coli
and S. aureus) and fungi (T. viridae and A. niger)
test: This test was carried out for all samples, according to the AATCC
Test Method 30 (2013) |
RESULTS AND DISCUSSION
Since, the main aim of this work is to design comfortable healthy socks with better functional properties, different fabric types with various constructions parameters were made. Test results were addressed and discussed in order to optimize the socks design parameters.
Bursting strength: Figure 1 shows the effect of conductive fibers ratio (%) on bursting strength values (kg f cm-2) for experimental samples No. (2, 3, 5, 7, 8 and 10).
It is observed that, as shown in Fig. 1, there is a direct relation between the conductive fibers ratio (%) in the fabric and its bursting strength values. As the conductive fibers ratio (%) increases, the bursting strength values increase in produced samples.
|
| Fig. 1: |
Effect of conductive fibers ratio (%) on bursting strength
values (kg f cm-2) for experimental samples |
To get a mathematical relationship between the conductive fibers ratio (%) in the plain knitted samples on the bursting strength values (kg f cm-2), a linear regression technique was used to get this relationship. The following equation is applied on the (kg f cm-2) values:
Where:
| Y |
= |
Bursting strength values (kg f cm-2) |
| X |
= |
Conductive fibers ratio (%) |
As R = 1, the correlation is considered too high which means that the regression
equation is reliable for prediction of the bursting strength values (kg f cm-2)
in the conductive fibers ratio (%) range using plain knitted structure.
To address a mathematical relationship between the conductive fibers ratio (%) in the rib knitted samples on the bursting strength values (kg f cm-2), a linear regression technique was used to get this relationship. The following equation is applied on the (kg f cm-2) values:
Where:
| Y |
= |
Bursting strength values (kg f cm-2) |
| X |
= |
Conductive fibers ratio (%) |
As R = 1, the correlation is considered too high which means that the regression
equation is reliable for prediction of the bursting strength values (kg f cm-2)
in the conductive fibers ratio (%) range using Rib knitted structure.
Figure 2 shows the values of bursting strength values (kg
f cm-2) of sample No. 1 which presented the composition of 100% cotton
plain structure, sample No. 2 which presented the composition of blended plain
fabric (50% polyester +50% conductive material), sample No. 4 which presented
the composition of blended plain fabric (50% cotton+25% polyester+25% conductive
material), sample No. 6 which presented the composition of 100% cotton rib structure,
sample No. 7 which presented the composition of blended rib fabric (50% polyester+50%
conductive material) and sample No. 9 which presented the composition of blended
rib fabric (50% cotton+ 25% polyester+25% conductive material).
|
| Fig. 2: |
Bursting strength values (kg f cm-2) for different
composition samples |
Because of polyester is a strong and flexible material and extremely tear-resistant and is more elastic than cotton, Fig. 2 indicates that blended composition (50% polyester+50% conductive material) for both plain and rib structures causes the best “more” bursting strength properties than all others compositions by using the same other manufacturing parameters.
Based on the results obtained in Fig. 1-2
and by applying the statistics regression, signify that:
| • |
Polyester has better bursting strength properties than cotton |
| • |
Conductive fibers ratio (%) has a significant effect on bursting
strength values for tested samples. As the conductive fibers ratio (%) increases,
the bursting strength values increase in produced samples |
| • |
Rib structure causes better “more” bursting strength
properties than plain structure by using the same conductive fibers ratio
(%) because it is production by two sets of needles being alternately set
or gated between each other and it is theoretically twice the thickness
and half the width of an equivalent plain fabric but it has twice as much
width-wise recoverable stretch |
Air permeability: This test was carried out for all samples; Fig. 3 shows the effect of conductive fibers ratio (%) on air permeability values (cm3 cm-2 sec-1) for experimental samples No. (2, 3, 5, 7, 8 and 10).
It is clear that, as shown in Fig. 3, there is difference in air permeability values according to the conductive fibers ratio (%) of produced samples. As the conductive fibers ratio (%) increases, the air permeability values increase in produced samples.
To get a mathematical relationship between the conductive fibers ratio (%) in the plain knitted samples on the air permeability values (cm3 cm-2 sec-1), a linear regression technique was used to get this relationship. The following equation is applied on the air permeability values:
Where:
| Y |
= |
Air permeability values (cm3 cm-2 sec-1) |
| X |
= |
Conductive fibers ratio (%) |
|
| Fig. 3: |
Effect of conductive fibers ratio (%) on air permeability
values (cm3 cm-2 sec-1) for experimental
samples |
As R = 0.9988, the correlation is considered too high which means that the regression equation is reliable for prediction of the air permeability values (cm3 cm-2 sec-1) in the conductive fibers ratio (%) range using plain knitted structure.
To address a mathematical relationship between the conductive fibers ratio (%) in the rib knitted samples on the air permeability values (cm3 cm-2 sec-1), a linear regression equation was used and applied on the air permeability values:
Where:
| Y |
= |
Air permeability values (cm3 cm-2 sec-1) |
| X |
= |
Conductive fibers ratio (%) |
As R = 0.9996, the correlation is considered too high which means that the
regression equation is reliable for prediction of the air permeability values
(cm3 cm-2 sec-1) in the conductive fibers ratio
(%) range using Rib knitted structure.
Figure 4 shows the values of air permeability values (cm3 cm-2 sec-1) of sample No. 1 which presented the composition of 100% cotton plain structure, sample No. 2 which presented the composition of blended plain fabric (50% polyester+50% conductive material), sample No. 4 which presented the composition of blended plain fabric (50% cotton+25% polyester+25% conductive material), sample No. 6 which presented the composition of 100% cotton rib structure, sample No. 7 which presented the composition of blended rib fabric (50% polyester+50% conductive material) and sample No. 9 which presented the composition of blended rib fabric (50% cotton+ 25% polyester+25% conductive material).
Because of cotton is breathable material while polyester does not breathe and doesn’t allow air to ventilate as well as cotton does, Fig. 4 indicates that, composition (100% cotton) for both plain and rib structures causes the best “more” air permeability properties than all others compositions by using the same other manufacturing parameters.
Based on the results obtained in Fig. 3-4
and by applying the statistics regression, signify that:
| • |
Polyester doesn’t allow air to ventilate as well as cotton
does |
| • |
Conductive fibers ratio (%) has a significant effect on air
permeability values for tested samples. As the conductive fibers ratio (%)
increases, the air permeability values increase in produced samples |
| • |
Plain knitted structure causes better “more” air
permeability properties than rib knitted structure by using the same conductive
fibers ratio (%). The existence of this decline is most probably a consequence
of the thicker structure of rib fabrics, where the transportation of air
through a thick fabric will be difficult while the open structure of the
plain fabric knitted gives the ability to the air to pass through fabric
without any obstacles |
|
| Fig. 4: |
Air permeability values (cm3 cm-2 sec-1)
for different composition samples |
Water absorption: Water absorption percentage of the fabrics were obtained according to the Eq. 5 and shown in Fig. 5. This test was carried out for all samples; Fig. 5 shows the effect of conductive fiber ratio (%) on the water absorption percentage (%) for experimental samples No. (2, 3, 5, 7, 8 and 10):
It is observed that, as shown in Fig. 5, there is a direct relation between the conductive fibers ratio (%) in the fabric and its water absorption time. As the conductive fibers ratio (%) increases, water absorption percentage (%) decreases in all produced samples.
To get a mathematical relationship between the conductive fibers ratio (%) in the plain knitted samples on the water absorption percentage (%), a linear regression technique was used to get this relationship. The following equation is applied on the water absorption time:
Where:
|
Y |
= |
Water absorption percentage (%) |
| X |
= |
Conductive fibers ratio (%) |
As R = -1, the correlation is considered too high which means that the regression equation is reliable for prediction of the water absorption percentage (%) in the conductive fibers ratio (%) range using plain knitted structure.
|
| Fig. 5: |
Effect of conductive fibers ratio (%) on water absorption
(%) for experimental samples |
To address a mathematical relationship between the conductive fibers ratio (%) in the rib knitted samples on the water absorption percentage (%), a linear regression equation was used and applied on the water absorption percentage (%):
Where:
| Y |
= |
Water absorption percentage (%) |
| X |
= |
Conductive fibers ratio (%) |
As R = -1, the correlation is considered too high which means that the regression
equation is reliable for prediction of the water absorption percentage (%) in
the conductive fibers ratio (%) range using rib knitted structure.
Figure 6 shows the values of water absorption percentage (%) of sample No. 1 which presented the composition of 100% cotton plain structure, sample No. 2 which presented the composition of blended plain fabric (50% polyester+50% conductive material), sample No. 4 which presented the composition of blended plain fabric (50% cotton+25% polyester+25% conductive material), sample No. 6 which presented the composition of 100% cotton rib structure, sample No. 7 which presented the composition of blended rib fabric (50% polyester+50% conductive material) and sample No. 9 which presented the composition of blended rib fabric (50% cotton+25% polyester+25% conductive material).
Because of polyester isn’t as comfortable as cotton because it keeps sweat close to your body, whereas cotton soaks up and then releases moisture. Unlike cotton, polyester does not breathe and is apt to stick to skin when an individual sweats, Fig. 6 indicates that, composition (100% cotton) for both plain and rib structures causes the best “more” water absorption properties than all others compositions by using the same other manufacturing parameters.
Based on the results obtained in Fig. 5-6
and by applying the statistics regression, indicates that:
| • |
Cotton has better absorbency properties than polyester |
| • |
Conductive fibers ratio (%) has a significant effect on water
absorption percentage (%) for tested samples as the conductive fibers ratio
(%) increases it will improve the water proof properties of the fabric |
| • |
Rib knitted structure causes better water absorption properties than plain
knitted structure by using the same conductive fibers ratio (%). The wick
ability rate of interlock structure makes it to have the higher water absorption
amount than the SJ. Rib knitted structure can take up the water with higher
amount and allow less air passage. These findings indicate that the rib
knitted structure can absorb a lot of sweat, perspiration moves fast from
skin to outside and as a result user can feel dry and more comfort. Furthermore,
rib structures demonstrated the highest water up-take capacity and very
high initial wicking rate. This performance is most likely due to the structures'
capability to act like a capillary system, rapidly removing and transporting
water through the structure. As the fabric becomes tighter, it will have
high water absorption capability due to the more fiber material contained
and the high fabric thickness accompanied with this fabric specification |
|
| Fig. 6: |
Water absorption(%) for different composition samples |
Thermal resistance: The thermal resistance of a batting or batting/fabric system is of considerable importance in determining its suitability for use in fabricating cold weather protective socks systems. The thermal interchange between the human and his environment is, however, an extremely complicated subject which involves many factors in addition to the insulation values of fabrics and battings. Therefore, measured thermal insulation values can only indicate relative merit of a particular material. This test was carried out for all samples; Fig. 7 shows the effect of conductive fibers ratio (%) on the thermal resistance values (Tog) for experimental samples No. (2, 3, 5, 7, 8 and 10).
It is observed that, as shown in Fig. 7, there is a direct relation between the conductive fibers ratio (%) in the fabric and its thermal resistance properties. As the conductive fibers ratio (%) increases, thermal resistance values increase in all produced samples.
To get a mathematical relationship between the conductive fibers ratio (%) in the plain knitted structure samples on the thermal resistance values, a linear regression technique was used to get this relationship. The following equation is applied on the thermal resistance values:
Where:
| Y |
= |
Thermal resistance values |
| X |
= |
Conductive fibers ratio (%) |
|
| Fig. 7: |
Effect of conductive fibers ratio (%) on thermal resistance
values (Tog) for experimental samples |
As R = 0.9796, the correlation is considered too high which means that the regression equation is reliable for prediction of the thermal resistance values in the conductive fibers ratio (%) range using plain knitted structure.
To address a mathematical relationship between the conductive fibers ratio (%) in the rib knitted structure samples on the thermal resistance values, a linear regression equation was used and applied on the thermal resistance values:
Where:
| Y |
= |
Thermal resistance values |
| X |
= |
Conductive fibers ratio (%) |
As R = 0.9939, the correlation is considered too high which means that the regression equation is reliable for prediction of the thermal resistance values in the conductive fibers ratio (%) range using Rib knitted structure.
Figure 8 shows the values of thermal resistance values (Tog) of sample No. 1 which presented the composition of 100% cotton plain structure, sample No. 2 which presented the composition of blended plain fabric (50% polyester+50% conductive material), sample No. 4 which presented the composition of blended plain fabric (50% cotton+25% polyester+25% conductive material), sample No. 6 which presented the composition of 100% cotton rib structure, sample No. 7 which presented the composition of blended rib fabric (50% polyester+50% conductive material) and sample No. 9 which presented the composition of blended rib fabric (50% cotton+25% polyester+25% conductive material).
Because of copper fibers are thermal regulating, they hold body heat emanating from within and redirect this warmth back to the body, Fig. 8 indicates that, composition of blended fabric (50% polyester+50% conductive material) for both plain and rib structures causes the best “more” thermal resistance properties than all others compositions by using the same other manufacturing parameters.
Based on the results obtained in Fig. 7-8
and by applying the statistics regression, signify that:
| • |
Copper fibers have better conductive and thermal insulating
properties than polyester and cotton |
| • |
Conductive fibers ratio (%) has a significant effect on thermal
resistance values for tested samples. As the conductive fibers ratio (%)
increases, thermal resistance values increase in all produced samples |
| • |
Rib knitted structure causes better “more” thermal
insulation properties than plain knitted structure samples by using the
same conductive fibers ratio (%). This case can be explained by the high
bulk density; high weight per square meter and less still air in the unit
area of rib knitted structures. Moreover, in plain knitted structure the
thermal conductivity decreases. This could be referred to higher porosity
value and the less fabric weight of the plain knitted structure |
|
| Fig. 8: |
Thermal resistance values (Tog) for different composition
samples |
Fabric weariness or abrasion: This test was carried out for all samples; Fig. 9 shows the effect of conductive fiber ratio (%) on their weight loss values (%) after abrasion (100 cycles) for experimental samples No. (2, 3, 5, 7, 8 and 10).
It is observed that, as shown in Fig. 9, there is a direct relation between the conductive fibers ratio (%) in the fabric and its weight loss values (%) after abrasion. As the conductive fibers ratio (%) increases, weight loss values (%) after abrasion decrease in all produced samples.
To get a mathematical relationship between the conductive fibers ratio (%) in the plain knitted structure samples on the weight loss values (%) after abrasion, a linear regression technique was used to get this relationship. The following equation is applied on the weight loss values (%) after abrasion:
Where:
| Y |
= |
The weight loss values (%) after abrasion |
| X |
= |
Conductive fibers ratio (%) |
As R = -0.9494, the correlation is considered too high which means that the regression equation is reliable for prediction of the weight loss values (%) after abrasion in the conductive fibers ratio (%) range using plain knitted structure.
To address a mathematical relationship between the conductive fibers ratio (%) in the rib knitted structure samples on the weight loss values (%) after abrasion, a linear regression equation was used and applied on the weight loss values (%) after abrasion:
|
| Fig. 9: |
Effect of conductive fibers ratio (%) on their weight loss
values (%) after abrasion for experimental samples |
Where:
| Y |
= |
Weight loss values (%) after abrasion |
| X |
= |
Conductive fiber ratio (%) |
As R = - 0.9727, the correlation is considered too high which means that the regression equation is reliable for prediction of the weight loss values (%) after abrasion in the conductive fibers ratio (%) range using rib knitted structure.
Fig. 10 shows the values of weight loss values (%) after abrasion of sample No. 1 which presented the composition of 100% cotton plain structure, sample No. 2 which presented the composition of blended plain fabric (50% polyester+50% conductive material), sample No. 4 which presented the composition of blended plain fabric (50% cotton+25% polyester+25% conductive material), sample No. 6 which presented the composition of 100% cotton rib structure, sample No. 7 which presented the composition of blended rib fabric (50% polyester+50% conductive material) and sample No. 9 which presented the composition of blended rib fabric (50% cotton+ 25% polyester+25% conductive material).
Because of copper fibers and polyester have better durability properties compared with cotton, Fig. 10 indicates that, composition of blended fabric (50% polyester+50% conductive material) for both plain and rib structures causes the best “more” abrasion resistance properties than all others compositions by using the same other manufacturing parameters.
Based on the results obtained in Fig. 9 and 10 by applying the statistics regression, signify that:
| • |
Copper fibers and polyester have better abrasion resistance
properties compared with cotton |
| • |
Conductive fibers ratio (%) has a significant effect on the
weight loss values (%) after abrasion for all tested samples. As the conductive
fibers ratio (%) increases, weight loss values (%) after abrasion decrease
in all produced samples |
| • |
Rib knitted structure causes better abrasion resistance properties
than plain knitted structure samples by using the same conductive fibers
ratio (%). This case can be explained by the high bulk density; high weight
per square meter of rib knitted structures |
|
| Fig. 10: |
Weight loss values (%) after abrasion for different composition
samples |
| Table 4: |
Comparison of growth rate of bacteria and fungi |
 |
| +: Moderate growth rate, ++: High growth rate |
Determination the growth rate of bacteria (E. coli and S. aureus) and fungi (T. viridae and A. niger): The growth rate of bacteria (E. coli and S. aureus) and fungi (T. viridae and A. niger) were compared when grown on the ten test samples as substrates. The results are presented in Table 4. This test proves that the growth rate of organisms on copper or conductive fibers as a substrate is less, when compared with cotton and polyester. The natural antimicrobial effect of copper does not allow the multiplication of bacteria and fungi and ultimately proves to be both bacteria static and fungi static. The growth rate of microorganisms on Plain knitted structure is less when compared with rib knitted structure.
This test proves that copper effectively kills a broad spectrum of viruses, bacteria and fungus, from exposure to copper ions. Copper oxide releases ions that penetrate the harmful bacteria/fungus causing:
| • |
Membrane rupture, causing loss of basic nutrients and fluid |
| • |
Damage to microbe genetic material such as DNA and RNA |
| • |
It does not allow reproduction of bacteria/fungi |
CONCLUSION
This study presents a quantitative study of various functional properties carried out on different knitted fabric structures (Rib-Jersey) containing conductive fibers with various ratios (%) and aiming at the selection the most adequate fabric for socks applications. From the results obtained it can be concluded that the performance and functional properties of the studied fabrics is greatly affected by the ratio of conductive fibers (%) which significantly increased or decreased the values of the different comfort related properties evaluated.
Combinations of cotton, polyester and conductive fibers gave socks better functional properties than a single fiber type with greatest performance properties. On the basis of the results obtained it could be concluded that the cobber fibers ratio (%) in socks has a significant effect on improving the thermal conductivity, anti-microbial behavior, abrasion resistance, bursting strength and air permeability properties for both plain and rib structures. Based on the pervious in-depth analysis, it was observed that cobber fibers have good antimicrobial properties. This indigenous anti microbial property of cobber fibers makes it more suitable for foot wears such as socks as compared to ordinary fibers.
The results indicated that plain knitted structures have less thermal conductivity, abrasion resistance, water absorption, bursting strength properties and better air permeability, water vapor permeability properties and anti-microbial behavior than rib knitted structures by using the same conductive fibers ratio (%). This case can be clarified by the high amount of entrapped air inside the plain knitted structures because of its higher porosity value and their lower weight per square meter and thickness, respectively. In the other side, rib knitted structures the high bulk density; high weight per square meter and less still air in the unit area.
All previous findings are an important tool in the design of healthy comfortable socks.
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