PREPARATION AND CHARACTERIZATION OF EPDM RUBBER MIXTURE FOR A HEAT RESISTANT CONVEYOR BELT COVER

In this paper, the EPDM rubber-based dough recipe for a conveyor belt used in high temperature conditions was developed. As a first step, the silica loading effect on the mechanical and rheological properties was determined.  After selecting the proper coating dough recipe, dough properties were investigated for filler mica, instead of silica, and the influence of paraffinic oil was tested for both silica and mica fillers. The properties of the EPDM rubber blend were investigated with rheometer tests on the semi-finished materials and with mechanical and physical tests (tensile strength, elongation at break, density, hardness, abrasion, heat ageing tests) on the finished coating materials after a vulcanization process. Thermal degradation behaviors of materials were analyzed by the thermal gravimetric analysis (TGA) system, and determination of chemical structure was analyzed by Fourier transform infrared spectroscopy (FTIR). The physico-mechanical characteristics of EPDM rubber blends were increased with silica loadings. EPDM rubber demonstrates thermal resistance in the temperature range of 150oC – 160oC under normal conditions. As a result of the studies conducted, the heat resistance of the coating rubber material was raised to 200oC by adding silica and paraffinic oil with a higher flash point into the EPDM dough mixture formulae

Drying effects on the antioxidant properties of tomatoes and ginger

In this study, the effects of four different drying processes, sun drying (SD), oven drying (OD), vacuum oven drying (VOD) and freeze drying (FD) for tomatoes (Solanum lycopersicum) and ginger (Zingiber officinale) in terms of thiolic and phenolic contents have been studied. Thiol content, total phenolic content (TPC), ascorbic acid (AA) content, and cupric ion reducing antioxidant capacity (CUPRAC) were determined in fresh and dried samples. Glutathione (GSH) and cysteine (Cys) were determined as the thiol contents of tomatoes and ginger. Significant losses were observed in the contents of TPC, AA, GSH and Cys and CUPRAC values in all samples that were dried using the thermal method. There was a statistically significant difference in the losses of the TPC, AA, and thiol contents between the use of thermal drying and freeze drying (except Cys in tomatoes) methods. Freeze dried tomato and ginger samples have been found to have better antioxidant properties. (C) 2014 Elsevier Ltd. All rights reserved

Chemical Composition of Turkish Okra Seeds (Hibiscusesculenta L.) and The Total Phenolic Contents of Okra Seeds Flour

Okra is a common vegetable in most regions of Turkey and available all year-round, with a peak season during the summer months. In this study, the chemical composition and physical properties of matureokra seeds were investigated, firstly. Then, the unroasted okra seed flour (OSF)and roasted okra seeds flour(ROSF) (40 minutes at 1600C) were analyzed for total phenolic contents and DPPH radical scavenging activity.The results of flour samples showed that the greatest value of phenolics in OSF(157.80mgGAE100g-1flour) and ROSF(232.19mgGAE100g-1flour). The concentration that provided 50% radical scavenging (IC50) was determined as 360.25±2.01mgml-1 and 452.39±12.27mgml-1 for roasted and unroasted okra seed flour, respectively. Regarding physical and chemical composition, okra seeds and their flour could be recommended for a good source of protein, fat, mineral and phenolic acid, which can be help remove the stigma of "starvation food" for people and promote them as a healthy food source