Mechanical testing and microstructure characterization of glass fiber reinforced isophthalic polyester composites

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Journal of Materials Research and Technology


The present work investigates the effect of material geometry in terms of material thickness on the mechanical properties of glass fiber reinforced isophthalic polyesters. The tensile strength, flexural strength, and Barcol hardness quantify the mechanical properties in this article. The experimental tests as per the ASTM standards show that the tensile strength and hardness increase with the increase in the thickness of laminates. The flexural strength is determined to decrease with the increasing thickness of laminates. The statistical analysis through ANOVA test shows that material thickness is a significant factor affecting the mechanical properties with 83.88, 70.37, 97.63 and 62.19% contribution toward the variance in the tensile strength, Young's modulus, flexural strength, and hardness respectively within the selected range of values for glass fiber reinforced isophthalic polyesters. The tensile failure mode analysis indicates that the increase in the thickness of laminates increases delamination failure. It is also found that the anisotropic behavior of the composites leads to an angular failure of the specimen in the tensile test. The random orientation of fibers leading to anisotropic behavior and increasing voids/decreasing interfacial bonding with the increasing laminate thickness is visualized in the microstructural studies through SEM images.

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