Bağdagül Karaağaç

Use of ground EPDM wastes in EPDM-based rubber compounds: With and without compatibilization

Ethylene-propylene-diene monomer rubber (EPDM)-based ground wastes (W-EPDM) are reutilized as rubber matrix in plug material compounds for automotive applications. Production scraps of target product are ground to 35, 40 and 60 mesh in ambient conditions. Effect of particle size and the amount of W-EPDM is studied. A new trial product of maleated ethylene-propylene rubber (EPM) and bitumen are used to improve interphase adhesion of the waste and the virgin EPDM. Cure characteristics, physico-mechanical and aging properties of all compounds are determined. Micro structure of the vulcanizates is studied for explaining dispersion and interaction between different phases. Reutilization of W-EPDM causes some reasonable deterioration in cure characteristics and mechanical properties of the product. However, some systematic and alternative recipes for plug materials are suggested considering cost and environmental benefits.

Interphase Modification and Compatibilization of Rubber Based Blends

Blending of two or more elastomers is carried out for several purposes. The properties of an elastomer blend depend strongly on its state of compatibility and miscibility. In this chapter, recent advances on development of interphase modification and compatibilization of rubber-based blends are summarized. Current trends in compatibilization of rubber/rubber blends, TPEs and other rubber/thermoplastic blends, natural polymer blends, rubber-based blends with and without filler modification are discussed in detail. Finally, new challenges and opportunities of rubber-based blends are given.

Investigating Effect of Chrome Tanned Leather Scraps in Ethylene Propylene Diene Monomer Rubber

Nowadays, amount of chrome tanned leather scraps (CTL) of leather industry is increasing rapidly due to decreasing interest on CTL utilization in related areas. These kind of wastes cause considerable negative environmental effects and therefore CTL producers should find new recycling and/or disposing routes for them. It is speculated that CTL may be a valuable additive in rubber based materials thanks to its similar bending properties. In this study, it is aimed to evaluate rheological, thermal, mechanical, morphological, and aging properties of CTL loaded EPDM based rubber compounds. CTL wastes are incorporated into EPDM in various ratios by using a banbury mixer and two roll mill, subsequently. Rheological measurements show that CTL incorporation does not cause considerable losses in compound properties. Higher glass transition temperatures of CTL containing composites are attributed to restricted chain mobility of EPDM in the composites. Cheap CTL incorporation significantly improves the tear resistance of EPDM before and after thermal aging due to fibrous nature of leather.

An alternative antioxidant for sulfur-vulcanized natural rubber: Henna

Oxidative aging of natural rubber (NR) leads to the deterioration in the physical and mechanical properties. Using various antioxidants during compounding is a common way to improve the aging resistance of NR. The most widespread used antioxidants are phenolic and amine-based synthetic antioxidants and 2,2,4-trimethyl-1,2-dihydroquinoline in rubber industry. However, synthetic antioxidants cause some environmental problems during their production and tend to be replaced by natural alternatives. In this study, henna has been evaluated as a natural antioxidant in NR-based rubber compounds for efficient and conventional sulfur vulcanization systems. Performance of henna was evaluated in terms of rheological, mechanical, aging, and temperature scanning stress-relaxation properties of the compounds. It has been concluded that henna could be used as an alternative antioxidant for sulfur vulcanization of natural rubber matrix, compensating little deteriorations in vulcanizate properties. Short- and long-term performances of henna were also found to be related to vulcanization system.