Polimer kompozitlerin termal özellikleri ve mekanik anizotropisi

The primary purpose of the study is to investigate the anisotropic behavior of different non-crimp stitched fabric (NCF) reinforced polyester and epoxy composites. Composite laminates were manufactured by vacuum infusion of resin into the fabric. Tensile and three-point bending flexural tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in NCF. In this study an important practical problem in fibrous composites, interlaminar shear strength as measured in short beam shear tests was discussed. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the stability and/or the instability of matrix-fiber interfaces. Infrared spectrum of composites were obtained by Fourier transform infrared spectroscopy (FT-IR). Thermal investigations on six selected type composites have been made. They differ with regard to the type of the resin matrix that have been reinforced with the different type of fiber. Changes in the specific heat capacity of composites have been determined by differential scanning calorimetry. Thermal conductivity measurements in through the thickness direction of composites were performed using a differential scanning calorimeter (DSC). Measurements were carried out over a wide range of temperatures. The thermal stability of composites in air atmosphere has been followed over a wide range of temperatures using thermogravimetric (TGA) and differential thermal analysis (DTA).