Characteristics of tire-road wear particles (TRWPs) and road pavement wear particles (RPWPs) generated through a novel tire abrasion simulator based on real road pavement conditions.

Microparticles such as tire-road wear particles (TRWPs) and road pavement wear particles (RPWPs) are generated by the friction between tire tread and road surface. TRWPs and RPWPs on roads are dispersed through traffic and transferred to rivers and seas via runoff to accumulate in sediments. However, research on the generation of both TRWP and RPWP has rarely been conducted. In this study, the generation of both TRWP and RPWP was investigated using a novel tire abrasion simulator equipped with paved road and bus tire, and their contributions to the generation of microparticles were examined. Two types of model paved roads, asphalt and concrete pavements (AP and CP, respectively), were applied. TRWPs generated from the simulator exhibited morphologies very similar to those on real roads. The abrasion rate for the CP was 2.8 times higher than that for the AP. The wear particle size distributions peaked at the size ranges of 63-106 µm and 212-500 µm for the AP and CP, respectively. Totals of 84 wt% and 89 wt% of the wear particles were distributed in size ranges of 38-212 µm for the AP and 106-1000 µm for the CP. The tire wear particle (TWP) contents in the total wear particles of 38-500 µm were 21.7 wt% and 30.0 wt% for the AP and CP, respectively, and decreased as the particle size decreased. The weight of RPWP was higher than that of TWP in TRWP. Contributions from road pavement to the generation of wear particles of 38-500 µm were 3.6 and 2.3 times higher than those from tire tread for the AP and CP, respectively, and the contribution increased as the wear particle size decreased.

Characteristics of particulate matter from asphalt pavement and tire of a moving bus through driving tests in city road and proving ground.

Non-exhaust PM emissions from vehicles in real road have been conducted, but heavy vehicles have rarely been tested. In this study, PM2.5 and PM10 samples were directly collected from a tire of a moving bus and the composition was analyzed to investigate the sources of PM emissions. Driving tests were conducted at a proving ground (PG) and a city road (CR). PM2.5 emissions considerably increased when the lateral force of the tire increased and the vehicle accelerated. The PM emission rate was higher in the PG test than in the CR test because of the harsher driving conditions at PG. The emission rates of PM10 in the PG and CR tests were higher than those of PM2.5 by approximately 6 and 11 times, respectively. In the PG and CR tests, the proportions of tire wear particles (TWPs) were 4.9% and 2.1% in the PM2.5 samples, and 6.8% and 8.2% in the PM10 samples, respectively. Furthermore, TWPs with PM (TWPPM) were generated by other sources: secondary production of TWPPM by fragmentation of TWPs and resuspension of TWPPM on the road. The contributions of other sources to TWP2.5 generation were at least 6% and 57% in the PG and CR tests, respectively, whereas that to TWP10 generation was at least 3.5% in the CR test. Iron derived from brake abrasion and mineral particles was observed in the PM samples, and the Fe concentrations were higher in the PM10 samples than in the PM2.5 samples by over 9 and 18 times for the PG and CR tests, respectively. Sulfur sources, such as TWPs, exhaust gas, and bitumen, were observed in the PM samples. Based on our findings, we recommend that road wear particles should be removed from roads to reduce PM emissions upon driving.

Enhancing Stiffness and Oil Resistance of Fluorosilicone Rubber Composites through Untreated Cellulose Reinforcement.

Fluorosilicone rubber, essential in automotive and aerospace owing to its excellent chemical resistance, plays a pivotal role in sealing technology, addressing the industry's evolving demands. This study explores the preparation and properties of fibrillated cellulose-reinforced fluorosilicone rubber composites to enhance their stiffness and oil resistance. Fibrillated cellulose sourced as a wet cake and subjected to processing and modification is incorporated into a fluorosilicone rubber matrix. The resulting composites are analysed by tensile and compression tests, along with compressive stress-relaxation testing in air and in an oil-immersed environment. The findings demonstrate significant improvements in the mechanical properties, including an increased Young's modulus and elongation at break, whereas the tensile strength remained uncompromised throughout the testing procedures. Morphological analysis of the fracture surfaces revealed a remarkable interfacial affinity between the fibrillated cellulose and rubber matrix, which was attributed in part to the modified fatty acids and inorganic nanoparticles. The presence of fibrillated cellulose enhanced the stress-relaxation characteristics under oil-immersion conditions. These results contribute to the domain of advanced elastomer materials, with potential for applications requiring enhanced mechanical properties and superior oil resistance.

Effect of Cyclic Shear Fatigue under Magnetic Field on Natural Rubber Composite as Anisotropic Magnetorheological Elastomers.

With the development and wide applicability of rubber materials, it is imperative to determine their performance under various conditions. In this study, the effect of cyclic shear fatigue on natural-rubber-based anisotropic magnetorheological elastomer (MRE) with carbonyl iron particles (CIPs) was investigated under a magnetic field. An anisotropic MRE sample was prepared by moulding under a magnetic field. Cyclic shear fatigue tests were performed using a modified electromechanical fatigue system with an electromagnet. The storage modulus (G') and loss factor in the absence or presence of a magnetic field were measured using a modified dynamic mechanical analysis system. Under a magnetic field, fatigue exhibited considerable effects to the MRE, such as migration and loss of magnetised CIPs and suppressed increase in stiffness by reducing the energy loss in the strain cycle. Therefore, the G' of the MRE after fatigue under a magnetic field was lower than that after fatigue in the zero field. The performance of the MRE, such as absolute and relative magnetorheological effects, decreased after subjecting to cyclic shear fatigue. In addition, all measured results exhibited strain-dependent behaviour owing to the Payne effect.

Reduction of VOC emission from natural flours filled biodegradable bio-composites for automobile interior.

Various experiments, such as the thermal extract (TE) method, field and emission cell (FLEC) method and 20 L small chamber, were performed to examine the total volatile organic compound (TVOC) emissions from bio-composites. The TVOC of neat poly(lactic acid) (PLA) was ranged from 0.26 mg/m(2)h to 4.11 mg/m(2)h with increasing temperature. For both PLA bio-composites with pineapple flour and destarched cassava flour, the temperature increased from 0.30 mg/m(2)h to 3.72 mg/m(2)h and from 0.19 mg/m(2)h to 8.74 mg/m(2)h, respectively. The TVOC emission factors of all samples increased gradually with increasing temperature. Above 70°C, both PLA-P and PLA-C composites had higher TVOC emission factors than neat PLA due to the rapid emission of natural volatile organic compounds (VOCs), such as furfural (2-furancarboxyaldehyde). PLA composites containing 30 wt% flour had high 1,4-dioxane reduction ability, >50%. The TVOC of poly(butylene succinate) (PBS) was emitted rapidly from 50 °C to 90 °C due to succinic acid from the pyrolysis of PBS. The TVOC emission factors of PLA bio-composite and PBS bio-composites were reduced using the bake-out method (temperature at 70 °C and baking time 5h). The initial TVOC emission factors of the PLA and PBS bio-composites with pineapple flour and destarched cassava flour were reduced by the baking treatment using FLEC. The TVOC factors from PLA and PBS decreased until 5 days and were commonly maintained a relatively constant value after 5 days using 20L small chamber. The decrease in TVOC emission showed a similar trend to that of the TE and FLEC method. This method confirmed the beneficial effect of the baking treatment effect for polypropylene and linear density polyethylene (LDPE).