Accelerated aging of elastomers in aqueous media


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Arts and Sciences, Department of Chemistry, Turkey

Approval Date: 2007

Student: EKREM İNALER

Supervisor: İSMAİL TEOMAN TİNCER

Abstract:

EPDM (Ethylene-Propylene-Diene Monomer)/PP (Polypropylene) based TPV (Thermoplastic Vulcanizate) was aged in a closed system at stabilized temperature and pressure at 80, 100 and 120oC in distilled water, detergent solution and shiner solution. The variation in properties of TPV upon aging were followed by using DSC (Differential Scanning Calorimetry), TGA (Thermogravimetric Analysis), tensile testing, Shore A rubber hardness testing. DSC analysis indicated that percent crystallinity of PP component in TPV increased at 100oC whereas crystal structure was deformed at 120oC. In addition to this, hardness test showed that the hardness of TPV remained almost constant in distilled water aging except 120oC water aging but TPV became softer in detergent and shiner solution upon all aging temperatures used in this study. Tensile testing confirmed the hardness analysis that the loss in mechanical properties of TPV was observed except 100oC water aging. TGA analysis showed that percent crystallinity increase causes enhancement in degradation temperature of EPDM/PP blend in air. It is detected that TPV is quite resistant to 80oC aging, but TPV loses its resistance to preserve its characteristics at 120oC aging. It is also determined that aging media is as important as temperature to evaluate the performance of TPV. Moreover, it is decided that the rate of aging directly proportional to detrimental rate is arranged in an order from the slowest to the fastest as distilled water, detergent and shiner solution media.