2.15 Super Absorbent Materials
49
shorts and pants. Many researchers have applied super absorbent materials in fabric
to obtain a cooling effect [252–255].
Bumbarger et al. [256] used super absorbent material to produce a protective multilayered liquid-retaining composite to be used for protective garments, blankets and
compressors. Thomas and Bumbarger [257] produced a composite absorbent material
which when soaked in a liquid protects a person from extreme heat when the clothing
is worn close to the skin. This can also help in controlling body temperature by
providing warming or cooling as required. There are many companies such as Cooltek
[258] applying super absorbent materials to get a cooling effect when garments are
worn.
Hydroweave is one of the super absorbents introduced by AquaTex Industries
(USA). In Hydroweave, the fabric has a three-layer design consisting of hydrophilic
fibres (fibres that attract water) and hydrophobic fibres (fibres that reject water)
woven into a fibrous batting core. The batting is sandwiched between a breathable
outer shell fabric and a thermally conductive inner lining. When the Hydroweave
fabric is wet, the hydrophilic fibres become charged with moisture, and then, the
hydrophobic fibres evenly distribute and surround the charged fibres with air, creating
an ideal environment for evaporation. Figure 2.18 shows the way the super absorbent
materials function.
The Hydroweave material absorbs heat when the wearer’s skin is in contact with
the Hydroweave fabric and transfers to the outside environment by evaporation of
the water in the garment. As there is an even distribution of water-absorbent polymer
throughout the batting, the garment provides uniform cooling, and this can last for
several hours. This mainly depends upon the degree of garment contact with the skin,
climatic conditions, the level of physical activity and the type of outer clothing worn.
The cooling effect can be reduced by wearing underclothing that limits the contact
of the vest with the wearer’s skin. Apart from the cooling function, Hydroweave
provides the benefit of insulating the wearer from heat.
Despite the predicted advantages of PCM and water-absorbent materials to cool
the body, this investigation found no application of PCM or water-absorbent materials
for the thermal regulation of motorcycle helmets. The absence of application to
motorcycle helmets and their unique rider/user application in the tropics and high
heat climates raises the research question: ‘Can these materials be employed to
regulate heat transfer?’
2.16 PCM Salt Hydrate
Tan and Fok [259] conducted a conceptual study for the cooling of helmets using salt
hydrate PCM within the helmet. PCM materials were placed in a pouch with other
components to absorb the heat and which was placed in the helmet by removing a large
portion of the impact-absorbing polystyrene. It is acknowledged that this attempts to
reduce the temperature inside the helmet and provide cooling for the rider. Though
this work provides a potential solution to provide cooling to the wearer of the helmet,
49
shorts and pants. Many researchers have applied super absorbent materials in fabric
to obtain a cooling effect [252–255].
Bumbarger et al. [256] used super absorbent material to produce a protective multilayered liquid-retaining composite to be used for protective garments, blankets and
compressors. Thomas and Bumbarger [257] produced a composite absorbent material
which when soaked in a liquid protects a person from extreme heat when the clothing
is worn close to the skin. This can also help in controlling body temperature by
providing warming or cooling as required. There are many companies such as Cooltek
[258] applying super absorbent materials to get a cooling effect when garments are
worn.
Hydroweave is one of the super absorbents introduced by AquaTex Industries
(USA). In Hydroweave, the fabric has a three-layer design consisting of hydrophilic
fibres (fibres that attract water) and hydrophobic fibres (fibres that reject water)
woven into a fibrous batting core. The batting is sandwiched between a breathable
outer shell fabric and a thermally conductive inner lining. When the Hydroweave
fabric is wet, the hydrophilic fibres become charged with moisture, and then, the
hydrophobic fibres evenly distribute and surround the charged fibres with air, creating
an ideal environment for evaporation. Figure 2.18 shows the way the super absorbent
materials function.
The Hydroweave material absorbs heat when the wearer’s skin is in contact with
the Hydroweave fabric and transfers to the outside environment by evaporation of
the water in the garment. As there is an even distribution of water-absorbent polymer
throughout the batting, the garment provides uniform cooling, and this can last for
several hours. This mainly depends upon the degree of garment contact with the skin,
climatic conditions, the level of physical activity and the type of outer clothing worn.
The cooling effect can be reduced by wearing underclothing that limits the contact
of the vest with the wearer’s skin. Apart from the cooling function, Hydroweave
provides the benefit of insulating the wearer from heat.
Despite the predicted advantages of PCM and water-absorbent materials to cool
the body, this investigation found no application of PCM or water-absorbent materials
for the thermal regulation of motorcycle helmets. The absence of application to
motorcycle helmets and their unique rider/user application in the tropics and high
heat climates raises the research question: ‘Can these materials be employed to
regulate heat transfer?’
2.16 PCM Salt Hydrate
Tan and Fok [259] conducted a conceptual study for the cooling of helmets using salt
hydrate PCM within the helmet. PCM materials were placed in a pouch with other
components to absorb the heat and which was placed in the helmet by removing a large
portion of the impact-absorbing polystyrene. It is acknowledged that this attempts to
reduce the temperature inside the helmet and provide cooling for the rider. Though
this work provides a potential solution to provide cooling to the wearer of the helmet,