Tang K.P.M., Chau K.H., Kan C-W, Fan J.T.
The Hong Kong Polytechnic University, HK
Keywords: fabrics, in-plane wicking, sweat rate, transplanar wicking, transport, water absorption
The water absorption and transport properties of fabrics are important in determining the thermophysiological comfort of apparel and health-care products, especially for sportswear and protective clothing. In the textile industry, a number of water absorption and transport tests have been developed. Some can provide only general characterization of surface hydrophobicity/hydrophilicity, others require delicate equipment (e.g. spectrophotometer, tomography device, Nuclear Magnetic Resonance spectrometer, MRI scanner). Despite this, existing testing methods do not simulate the end-use conditions of fabric, could not differentiate the direction of water spread and could only apply to certain types of fabrics. Against these research background, a new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking property of fabrics based on gravimetric and image analysis technique. FFWTT (as shown in the attached PDF Figure 1) can be divided into two parts: (i) sample stage and (ii) water supply part. On top of the stage, the testing specimen was placed in-between two layers of standard material for examining the direction of water spread. A compression loading was placed above the sample to ensure even contact between the layers. For the water supply part, syringe pump was utilized which enables constant rate of water supply. The syringe pump and the sample stage were connected by a silicone tube acting as a sweat gland. For the measurement parameters, the amount of water absorbed, the water spreading area and the water content of each layer was measured. By dividing the amount of water absorption in the top filter paper with the bottom one, an index called ‘Transplanar ratio’ denoting the transplanar wicking property of samples was additionally measured. When majority of water was transported to the top filter paper, it demonstrates excellent transplanar wicking property of the fabric whereas a large spreading area of fabric implies excellent in-plane wicking property. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument. The uniqueness and advantages of FFWTT include: (a)The rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities, (b)Capability of simulating the wearing condition with differential stress levels, (c)Capability of tracing the direction of water transport with the ability to estimate the amount of water left on skin when sweating, (d)Versatility in terms of the types of fabrics can be tested (including hydrophobic fabrics, towels, diapers, moisture management fabrics or fabrics having very high water absorption rate), (e)water was supplied from the bottom to the back side of the sample to minimize the gravitational effect on absorption, (f)Efficient, and (g)Simple setup
Journal: TechConnect Briefs
Volume: 3, Biotech, Biomaterials and Biomedical: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 141 - 144
Industry sector: Medical & Biotech
Topic: Personal & Home Care, Food & Agriculture
ISBN: 978-0-9988782-0-1