Effects of small range color (Pigment) concentration levels in combination with gamma sterilization on plastic injection molded parts

Color (pigment) concentration levels play a significant role in changing the mechanical properties of an injection molded part. Higher concentration levels could result in functional failure of the parts [1]. A general rule of thumb, concentration levels between 3-5% or 5-10% are being used across different industries to achieve the required color. The above concentration levels are considered as small range concentration levels in this manuscript. Effects of sterilization (radiation) plays an important role on the plastic injection molded parts. The combination of gamma radiation sterilization and color concentration is very useful to the medical devices and food processing Industry. An experimental study is conducted to find out the effects of both small range color concentration and gamma radiation sterilization on the mechanical properties such as tensile strength, strain at yield and break on the Injection molded parts. In this study, Injection molded specimen made up of PP (polypropylene) and Acrylonitrile Butadiene Styrene (ABS) which are exposed to gamma sterilization of 25 kGy (kilo gray) dose are considered as it common normal dose used for plastics [8]. Depending upon the specific polymer and additives involved. There is no impact on tensile strength, while the strain at yield and at break shown an considerable decreasing trend with increase in the percentage of pigments in case of PP(polypropylene). There is no trending observed in case of ABS resin. Outcomes may influence performance and should be evaluated in advance by functional testing. Hence product designers may need to assess the impact of these small pigment concentration levels in combination with the sterilization effect with respect to the base resin and need to specify the acceptable pigment concentration levels in combination with sterilization in their product drawings or in product specification documents.