This trend results in an encouragement to use and develop fibers that can be obtained or manufactured from renewable sources like natural fibers as a substitute for conventional synthetic fibers that are based on petroleum. Even cotton fiber is now considered as non eco-friendly fiber as it requires large quantity of chemicals, pesticides along with water. Unconventional natural fibers such as hemp, ramie, flax, sisal, kenaf, etc.can be used as an alternate to cotton and other synthetic fibers. These alternative fibers include banana fiber obtained from pseudo-stem of banana plant, pine apple fibers obtained from leaves, sugarcane fibers obtained from the sugarcane stalks, etc. and some other bast fibers obtained with almost no use of pesticides and chemicals include hemp, ramie, flax, sisal, kenaf, etc. . These fibers are present in abundance all over India but still neglected everywhere. These fibers have potential to become useful textile fibers. Along with abundant availability,these fibers possess characteristics like elegance in aesthetic appeal, comfort in wear and many other utility performances as peruse in different applications including clothing.Woven designed fabrics with eco-friendly fiber are more in demand.
Nowadays consumers are fashion and health-conscious so that they switch towards the eco-friendly fabrics. One of the most important aspects of clothing and apparels is comfort. Clothing comfort is mainly associated with three common aspects such as psychological, tactile and thermal. Psychological comfort is mainly related to the aesthetics of the clothing and fashion trends prevailing in a particular society and has no dependence on fabric’s properties quantitatively.It deals with the mechanical properties and surface characteristics of fabric. However, thermal comfort is a measure of fabric’s ability to maintain wearer’s skin temperature and deals with fabric’s transmission behaviors,namely thermal insulation or conductivity, water vapor or liquid water transmission and air permeability.In this research, efforts are being made to explore the possibilities of producing high-quality apparel fabric from unconventional natural fibers under industrial production environment. A comparative study was made on the low-stress mechanical properties, fabric hand and thermal comfort of banana, hemp, linen and ramie fabrics and their respective union fabrics with cotton. Union fabrics are the fabrics where the fiber content is different in the warp and weft direction. For this research, the four unconventional fibers namely banana, hemp, linen and ramie are used.
Cotton is used as reference fiber for comparison of respective fabric properties. Yarn samples of 30 Ne were developed from the above mentioned five fibers under industrial production conditions and accordingly used for fabric development. The moisture vapor diffusion rate through the fabric is determined using LABTHINKMVTR tester that works according to the simple dish method, similar to ASTM E96-80. The test sample is placed over a water dish having 33 cm2 area and 7.5 cm diameter. The test conditions were maintained at 80% humidity and38˚C temp inside the instrument. Dry air is circulated at an interval of 10 min. Avibration-free turntable platform that can accommodate eight dishes rotates atuniform speed. All dishes are exposed to the same average ambient condition during the test. The rate of moisture vapor loss is calculated in units’g/m2/24 hr. A higher MVTR value advocates a greater passage of moisture vapor through the material. The Kawabata Evaluation System was used to measure fabric low stress mechanical properties at standard conditions prescribed for apparel fabric.
KES system consists of four different modules for different testing e.g. KES-FB1 for tensile and shear tests, KES-FB2 for bending tests, KES-FB3 for compression properties testing and KES-FB4 for testing surface properties. Total 16 parameters describing fabric mechanical properties were evaluated from the instrumental outputs.The “primary hand values” contributing to specific comfort aspects of the fabric and then “total hand value” were calculated by the software using Kawabata equation. The air permeability of different unconventional fiber fabrics and their respective union fabrics with cotton were studied to ascertain their physiological comfort.The outcomes of the test are listed in Table 3. The results show that pure linen fabrics permit more air to pass through them, compared with pure cotton and all union fabrics. The trend is followed by hemp, ramie and then banana.The reason for higher permeability in case of pure fabrics of unconventional natural fiber fabrics can be attributed to less hairiness in these yarns due to longer fiber length than cotton. These fibers are smoother, circular and coarser than cotton fibers also favor an easy passage to air through the yarn. Also the larger diameter of banana yarn gives high cover of the fabric which prevents transmission of air through the banana fabric.