Protection from extreme environment has always been a critical requirement of textile industry. Clothing that protect from water, extreme winter, intensive heat, open fire, high voltage, propelled bullets, toxic chemicals, nuclear radiations, and biological toxins etc. are some of the examples. These clothing find applications as sportswear, defence wears, firefighting wears (fire entry suits), bullet proof jackets, and other professional wears.

Apart from clothing, even structures that can protect from above exposures are required to be created using protective textiles. Shelters- temporary or permanent such as army tents, stadium roofs, exhibition arena are some of the examples. Textile materials used in composites for various structural uses are also required to have certain protective properties.

Challenges

The protective textile try to combine both the fabric characteristics such as flexibility, softness, drape, handle  and breathability with critical protective characteristics mentioned above. This is a challenge because, applying any coating or modifying fibres for obtaining protective function tend to sacrifice that very fabric qualities which are dear to a textile technologist and a customer. 

Therefore, a balance where desirable textile attributes are preserved while achieving adequate protection is always a topic of intense research worldwide.

Developments at our group

Inherently fire retardant polyester filaments

Such materials are very important in creating protective clothing for use in chemical-nuclear-biological warfare, firefighting, and other heat intensive jobs. Many approaches have been used around the world in producing such fibres through modification during polymerization or melt spinning route. However, melt additive during spinning route is normally not commercially used as it tends to lower the mechanical properties of the resultant fibre. Our gourp has found an unique approach of adding phosphorous based compounds to PET up to 10% by weight loading in the fibres. These fibres can be easily drawn at high draw ratios to give high strength nearly equivalent to PET fibres without additive. The Limiting Oxygen Index (LOI) values for these fibres were as high as 27.5 in knitted filament form (i.e. open structure).

Breathable Coatings

Textile that allow water vapours to pass but protect from rain or water find varied applications in many many areas. Many commercial products are today available, however, creating breathable coating which can provide very high rates of water vapor transmission (WVTR) to allow comfortable feeling to the wearer is still a challenge. Microporous films or coatings with hydrophobic-hydrophilic segmented polymer are known methods of creating such structures. However, due to hydrophobic nature of the polymers used, WVTR values are normally restricted. Hydrophilic films are a better choice but they suffer from the limitation that they are soluble in water, and therefore, are not durable. Our group is working on integrating certain hydrophillic polymer systems based on substituted polyacrylamides with known textile surfaces that can provide durable protective coating while giving very high values of WVTR.

Heat Managing Outer-layer Structures

Textile structures for extreme winter clothing  is normally composed of several layers. these layers provide insulation and at times manage the flow of winds so that they do not penetrate the textile structures. Use of fur inside and bird feathers in between are often used or providing insulation from low outside temperatures. However, very little attention has been given for optimizing the structure of outermost layer of such garments. Our group has investigated certain structures for outer most layer which allow better capturing of heat from the Sun while minimizing loss of captured heat from the surface under windy conditions. Use of these layers was found to raise the fabric temperature by several degrees compared to standard structures.