Some studies on sea water ageing of E GLASS/EPOXY resin composite with different fiber orientation

Abstract

This project deals with the studies done on sea water ageing of E glass/epoxy resin composite having different fiber orientation. In this project we are trying to find the effects caused by the sea water treatment on composite’s mechanical properties and change in properties due to different fiber orientation in composites. Here first of all we prepare the composites by usual hand lay up process taking woven fiber and epoxy resin along with a hardener as raw materials. The composite were made of several glass layers in order to acquire required thickness of ASTM standard. These were then cut into specific dimensions (according to ASTM standard) for samples to be tested for three point bend test in INSTRON. These samples were first heated at 50 degree Celsius in order to stabilize their weight. These were then rolled in aluminum foil in order to have minimum moisture absorption from atmosphere. The samples were then dipped in sea water kept at 60 degree Celsius for an increasing time period of 10 hours and upto 80 hours. After that the samples were taken out and their weight was taken in order to know the amount of water absorbed by the samples. The samples were then tested for 3 point bend test and fracture analysis was done by using SEM. The results of the weighing of the samples shows that water content goes on increasing upto some time of exposure to sea water after that the sea water content becomes constant. Moreover the sea water content does not depend on the fiber orientation. The results of the 3 point bend test shows that the ILSS value of the composites goes on decreasing as the time of exposure to sea water goes on increasing. Moreover as the fiber orientation is changed from 0 to 45 degree the ILSS value goes on decreasing for constant time of exposure. These results show that the sea water when gets absorbed does debonding between the matrix and fiber and then it starts doing the delamination process. If the time of exposure is more then sea water also weakens the fiber thereby causing breakage of fibers. This happens due to various salt ions present in the sea water. The hydroxyl ion which is present in sea water enters the fibers and replaces the originally present sodium ions thereby producing strains due to misfit. So we can conclude that sea water produces a very detrimental effect on composites along with the directionality.