Properties of Thermoplastic Vulcanizates Based on Rubbers of Various Polarity and Polypropylene
Results of studying of service properties of thermoplastic elastomers based on blends of polymer of various-polarity are presented. The composition was in accordance with previous researches devoted to establishment of principles of mixing and structure formation of thermoplastic vulcanizates (TPV) based on polypropylene (PP), isoprene rubber (IR) and butadiene acrylonitrile rubber (NBR), the ratio of polymer components PP/IR/NBR was 30/60/10. To improve the dispersion of elastomer phase in thermoplastic as well as polar rubber in non-polar rubber at the elastomer phase the combination of compatibilizing additives (maleinic polypropylene and polyethylene-co-vinyl acetate consequently) were in use. Satisfying stability of developed TPV to liquid aggressive medias (water, standard liquid «B», standard oil №3, motor oil) and high stability to thermal- and photo-oxidative degradation were shown. The maximal level of properties deterioration after thermal-oxidative degradation at 100°С and 120 °С during 72 h wasn’t overcome 15 %. After photo-oxidative degradation at light aging chamber Helios Italguartz Inve’96 with ultraviolet lamp DRT-400 during 600 h at 40 °С and illumination 20000±500 lux the properties deterioration was no more than 20 %. Tests at artificial climate chamber with ultraviolet radiating QUV-80-spray, imitated the natural material aging process under the conditions of atmosphere aggressive factors (sun radiation, rain, dew) during 192 h according «G» regime showed that the tensile strength level decrease wasn’t overcome 6 %, relative elongation at break - 13 %.. «G» regime included the repeating stages: 8 hours at 60 °С, ultraviolet radiation corresponded to double intensity sun radiation at summer midday (UVA 340 lamps of radiation power 1,55 Wt./m<sup>2</sup> and wave length 340 nm); 15 minutes under water irrigation; 3 hours 45 minutes at 50 °С under the conditions of humidity condensation.