PP/POE thermoplastic elastomer prepared by dynamic vulcanization and its flame retardant modification

Flame retardant thermoplastic elastomer (TPE) with excellent mechanical properties and thermal oxidative aging resistance was prepared by dynamic vulcanization technology with ethylene-octene copolymer (POE) and polypropylene (PP) as raw materials. The paper first discussed the effect of the amount of vulcanizing agent on the properties of PP/POE TPE. Based on the study of tensile strength, elongation at break, cross-section morphology, processability and aging properties of TPE, it was found that the TPE prepared with 0.6 phr of bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) and 40/60 of PP/POE had the best properties. Then silicone powder (GM) is added to the traditional low-halogen bromine-phosphorus flame retardant system for flame retardant modification. The results show that the addition of GM can effectively enhance the stability of the carbon layer, prevent the material from dripping during combustion, and increase the residual carbon content of TPE at 800°C. When 3 phr of GM is combined with a bromine-phosphorus system. The comprehensive performance is the best, the limiting oxygen index (LOI) of TPE increased to 29.8%, reaching the V-0 level. At the same time, the processing fluidity and aging resistance of TPE materials have also been improved.

INFLUENCE OF ANYLES D, L- CAMPHORA ON THERMAL OXIDATING STABILITY OF BUTADIENE RUBBER BASED ELASTOMER

The influence of aniles DL-camphor as N-[(1RS)-camphane-2-ylidene]-2-methylaniline, N-[(1RS)-camphane-2-ylidene]-2-ethylaniline and N-[(1RS)-camphane-2-ylidene]aniline on vulcanization and resistance of butadiene nitrile rubber based elastomers to thermal oxidative aging was studied for the first time. The prospects of using aniles DL-camphor as anti-aging agents have been established. The best effect is achieved when using N-[(1RS)-camphane-2-ylidene]-2-methylaniline in combination with an effective vulcanisation system including sulfur donors tetramethylthiuram disulfide, 4,4'-dithiodimorpholine, and N-cyclohexylbenzothiazole-2-sulphenamide.

Comparative Study of Thermal-Oxidative Aging and Salt Solution Aging on Bitumen Performance

The aging of bitumen is detrimental to the durability and service life of asphalt pavement. Previous studies found that bitumen was suspected to be aged by not only thermal oxidation but also solution immersion. This research aims to compare the effect of thermal-oxidative aging and salt solution aging on bitumen performance. For this purpose, a thin film oven test (TFOT) and pressure aging vessel aging (PAV) were selected as thermal-oxidative aging, and 10% NaCl aging and 10% CaCl2 aging were selected as salt solution aging. The morphology, oxygen content, physical properties, low-temperature properties, and high-temperature properties of bitumen were analysed by employing scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS), physical tests, a bending beam rheometer (BBR), and a dynamic shear rheometer (DSR). Test results show that both thermal-oxidative aging and salt solution aging had similar influencing trends in the oxygen content, physical, low-temperature, and high-temperature properties of bitumen but had different changes in morphology. The aging degrees caused by four kinds of aging methods were obtained based on the summed values of the absolute aging factor of all parameters: PAV > 10% NaCl > TFOT > 10% CaCl2. The conclusions could provide a theoretical basis to establish a standard for the solution aging of bitumen.