Özet:

In this study, the effect of mold release agent on the Environmental Stress Cracking of plastics under injection molding application has been investigated for crack and craze initiation. During this investigation, a great number of plastic injection and tests have been performed. In the last years, polycarbonate which is used as a polymer in this study has attracted great attention due to its advantages such as high durability, impact resistance, and is more economical. Moreover, polycarbonate is also preferred in the Defense Industry for electronic applications that capitalize on its collective safety features and being a good electrical insulator and having heat-resistant and flame-retardant properties. During the plastic injection production process, despite advance knowledge of plastic manufacturing, plastics parts experience failure due to severe causes. One of them, Environmental stress cracking (ESC), which occurs when metallurgical, environmental, and mechanical conditions are combined. Furthermore, a plastic resin is degraded by a chemical agent in the presence of stress. So, the effects of the chemical agent and mechanical stresses result in cracking after some time. In the first step of this study, the effects and causes of Environmental stress cracking have been examined. It has been determined that how chemical agents’ consequence critical plastic component failure. Moreover, contamination of chemical agents is an accelerating agent to plastic parts considering crack growth, also other main reasons of the plastic failure have environmental stress cracking is stresses which are existing during molding processes as residual stresses and mechanical stresses have been questioned. In the second stage of this investigation, molding release agents that are selected for questioning cause environmental stress cracking as a chemical agent because mold release agents are used widely in the industry by manufacturers. In this study, plastic parts that have different mechanical properties, are manufactured while using different molding release agents, and craze initiation and propagation stages have been observed experimentally. Observation depends on test equipment which is designed according to strain levels. As a result, environmental stress cracking is one of the main failures for plastic injection parts as the plastic killer and chemical agents such as molding release agent is a factor for increasing crazes grow more rapidly.

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