Polyester composites reinforced with noncrimp stitched glass fabrics: Experimental characterization of composites and investigation on the interaction between glass fiber and polyester matrix

The primary purpose of the study was to investigate the anisotropic behavior of different noncrimp stitched fabric reinforced polyester composites. The effects of geometric variables on composite structural integrity and strength are illustrated. Hence, tensile, three‐point bending flexural and short beam shear tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in noncrimp stitched fabric. The remark, based on the observations while tensile testing, is that the stress–strain curves of polyester based composites were linear in the direction of fibers. However, in the matrix dominated orientations nonlinear relation between the stress and the strain was observed. Another aim of the present work was to investigate the interaction between glass fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the interaction between glass fiber and polyester and were interpreted in an attempt to explain the instability of polyester resin–glass fiber interfaces. It was concluded that the polymer was either deposited between adjacent fibers or as widely separated islands on the fiber surface. Infrared spectra of the cured polyester and its glass fiber composite were obtained by Fourier transform infrared spectroscopy. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers