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In this article, a new method to characterize the tear behavior of coated textiles using fracture mechanics is proposed. The energy dissipated in tearing (EDT) of as‐received and thermally aged samples of polyester fabric, polyvinyl acetate rubber coating, and textile‐coating composites was calculated and compared. The EDT of the coated fabric displayed a slightly smaller value than the fabric alone, whereas the EDT of the coating was found to be negligible when compared with the other two. The presence of the coating is believed to have a detrimental effect on the tearing behavior of the coated fabric as it hinders interfilament slippage. A master curve of EDT retention vs. aging time for noncoated and coated fabric samples was constructed using the time–temperature superposition principle and fitted using the Hill equation. Fourier transform infrared analyses carried out on aged fabric samples hinted at a possible chain scission process, whereas the crystallinity of fabric samples, calculated via differential scanning calorimetry, was found to decrease after thermal aging. Scanning electron microscopy images revealed an increase in surface roughness after aging that may reduce interfilament friction. These results, coupled to an increase in the adhesion strength between fabric and coating, are likely the cause of the reduction of EDT noticed in aged coated and noncoated fabrics compared with as‐received ones. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

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This article deals with the effect of fillers and additives content on the physical and mechanical properties of unidirectional pultruded glass/polyester composites. The physical characterization consisted of determining the void volume fraction (Vv), density, shrinkage ratio, coefficient of thermal expansion (CTE), and dynamic mechanical properties. The mechanical tests consisted of three-point-bending tests under static, impact, and fatigue loading. The low profile additive (LPA) has been found to compensate the cure shrinkage by microvoid formation. Dynamic mechanical analysis measurements show that the LPA slightly lowers the glass transition temperature Tg and increases the internal damping Tan ␦. The transverse coefficient of thermal expansion was found to be sensitive to the LPA content. Three-point bending tests show that the interlaminar shear strength (ILSS) is slightly sensitive to the fillers and LPA content, but the flexural strength is not affected. Impact test results on short beam shear and flexural specimens show the same behavior as in the static tests except that the LPA content has a detrimental effect on the flexural impact properties. The fatigue tests performed show that the effect of fillers is not significant, while the LPA effect is mixed. It seems that there is an LPA content for which the fatigue resistance is maximized. Finally, the wide range of behaviors and span-to-depth ratios investigated suggest that the ILSS as measured according to the ASTM 2344 recommendations can be largely misleading because of the unavoidable compressive yielding under the loading nose. For the materials investigated, higher span-to-depth ratio are more representative of the ILSS. POLYM. COMPOS., 27:71-81, 2006.

Tearing resistance is an important parameter for evaluating the reliability of textile structures, especially in the case of protective materials. In order to better understand the individual contribution of the different mechanisms involved in the tearing process, a study of the relation between the fabric and yarn properties characterizing these mechanisms and the tearing energy has been carried out. For that purpose, polyester fabrics with two types of weave patterns and various values of filling yarn density and linear density were characterized in terms of tongue tear energy, yarn and fabric modulus, breaking force and elongation at break, yarn slippage, and yarn jamming. Data for all tested fabrics relied on a unique master curve when the tearing energy was expressed as a function of the transverse yarn slippage force. This demonstrates the strong contribution of transverse yarn slippage to the tearing process, a mechanism which has generally been overlooked in previous works on tearing. Relationships between the tearing energy and the other properties characteristics of the mechanisms involved in tearing of woven textiles were also observed. These results build the path toward the development of models for the tearing energy of textile structures. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers