Masters Theses
Date of Award
5-1989
Degree Type
Thesis
Degree Name
Master of Science
Major
Textiles and Clothing
Major Professor
Kermit E. Duckett
Committee Members
Randall R. Bresee, Donald Bogue
Abstract
The tensile and flexural properties of point-bonded cotton and polyester blended nonwoven fabrics were studied to examine the effects of binder level and processing factors. Fabrics were thermally stabilized by point-bond calendering. Four base-fiber/binder-fiber ratios were chosen. Three levels of bonding temperatures (408 °K, 422 °K, 436 °K) along with three levels of crush edge pressures (65, 130, 195 kN/m) were used to bond the webs. In an attempt to understand the heat transfer kinetics involved in thermal bonding, two bonding speeds (10 m/min, 20 m/min) were included.
The fabrics were characterized in terms of their specific stress, specific work of rupture and elongation at maximum stress (%), and flexural rigidity. The results indicated that fabrics stabilized using an embossed roll calender give tensile loading levels that were independent of crush edge pressures but increased significantly with embossed roll temperature. The effect of delivery speed of the fabric through the calender on the maximum levels of loading is significant in both the machine direction and cross direction. The strengths of the fabrics produced at the lower of the two delivery speeds are greater than those of, otherwise, comparable fabrics. The influence on strength from crush edge pressure or temperature becomes less pronounced at lower levels of binder.
SEM photomicrographs are used to show the extent of binder fiber melting and thus the degree of bonding throughout the total 111 thickness of the fabric at various processing conditions.
The anisotropic orientation of the structural elements within the fabric have a major effect on the strength of the nonwoven fabric when loaded in different directions. The fabric strength along the machine direction is, on the average, somewhat more than twice as great as the fabric strength along the cross direction. This is attributed to the machine direction orientation of the fibers, which is an inherent characteristic of the carded webs. This orientation, in turn, leads to greater number of load supporting fiber elements for machine direction loading.
Generally, elongation in the cross direction is slightly greater than the elongation in the machine direction. The results also showed that the stiffness of the fabric increases with the temperature as a result of more complete bonding at higher bonding temperatures and, consequently, a reduction in fiber element movement.
Recommended Citation
Ranganathan, Srinivasan, "Physical characterization of thermally point-bonded cotton/polyester nonwovens. " Master's Thesis, University of Tennessee, 1989.
https://trace.tennessee.edu/utk_gradthes/13056
