Master of Science, University of Akron, 2023, Polymer Engineering

Understanding the quasi-crystalline structure of carbon black (CB) has been an important area of research for decades. The dispersion of CB in rubber is influenced by the continuous graphitic planes on its surface that lead to agglomeration of filler. The first objective of this work was to establish a method for repeatable and accurate quantification of crystallinity in CB. We used X-Ray diffraction (XRD) and Raman spectroscopy and developed equations for measurement of the % crystallinity of CB. A comparison of Raman and XRD data revealed lower % crystallinity from XRD. A correction was made to crystallinity measurements from Raman spectroscopy to include amorphous carbon in CB. Next, we considered two treatment methods of as received CB -the ball milling process and the heat treatment process in limited air atmosphere -to control the graphitic nature and the crystal structure of CB. The ball milling process had minimum effect on crystallinity of CB but greatly increased the amount of surface oxygen. The heat treatment process significantly enhanced the fraction of graphitized CB and increased the defect density of CB particles. The treated CB grades were compounded with styrene-butadiene rubber (SBR) for tire tread application and compound properties were measured. A major emphasis was given on dispersion and dynamic properties of the rubber compounds. In conjunction, the mechanical and thermal properties and cure characteristics were evaluated. The dynamic properties revealed information on filler flocculation, Payne effect (energy losses), and rolling resistance. It was found that high surface area, high structure CB had poor dispersion in rubber compounds especially after filler treatment by the above two methods compared to low surface area, low structure grades of CB. The ball-milled CB produced an average of 46.5% reduction in rolling resistance and a significant reduction in Payne effect compared to control CB. An increase of CB crystallinity resulte (open full item for complete abstract)

Committee: Sadhan C. Jana (Advisor); Li Jia (Committee Member); Mark D. Soucek (Committee Chair) Subjects: Materials Science

Master of Science in Engineering, University of Akron, 2019, Mechanical Engineering

With the rapid technology development these days, silicone rubber has become an important material to support our lives from house to industrial scale applications. Moreover, tire industries also considering the superior properties of silicone rubber in their product in applications that require high-temperature resistance to perform. This demand leads material science researchers to search for solutions by intensively studying the potential of nanotechnology to boost the mechanical performance of the materials to make them suitable to perform in extreme and specific conditions. Therefore, this research aims to explore an electrospinning method as a process to generate second phase materials with purpose to reinforce in a form of nanofibers into a room temperature vulcanized (RTV) silicone rubber together with study of the mechanical properties of reinforced RTV silicone rubber such as rolling resistance and the static friction of the material. The reinforcement process by electrospinning method was conducted by using polyether-based thermoplastic polyurethane as the reinforcement material that exhibits excellent temperature flexibility, abrasion resistance and strength to reinforce directly to the liquid silicone rubber to generate several specimens with a different composition ratio of matrix and reinforcement phase in the composite. Furthermore, the experiment was carried out by measuring the rolling resistance properties by using a wooden roller based device inspired by the invention of Dr. Alan Gent [1] and static friction of the material by using the inclined surface coefficient of friction tester to understand the influence of TPU on the RTV silicone rubber.

Committee: Shing-Chung "Josh" Wong (Advisor); Jiang Zhe (Committee Member); Kwek-Tze Tan (Committee Member) Subjects: Engineering

Master of Science, The Ohio State University, 2019, Mechanical Engineering

To measure the exact fuel consumption of a vehicle, it is essential to determine the total road load being imparted on it. One of the main methods to calculate road load is by performing a coast-down test. In order to get accurate results, there must be an understanding of the impact that each component has on the vehicle/tire. Rolling resistance is one of the primary forces acting against the motion of the vehicle. The major factors that contribute to rolling resistance losses are tire design and operation, ambient conditions and road design. Current standards tend to assume that the impact of a specific road surface in a coast-down test is a constant parameter. However, after performing multiple coast-down tests in the same track, this will cause the road surface texture to degrade. Even with a small degradation, this will possibly affect the results since the rolling resistance coefficient is increasing as well as the road load affecting the vehicle. This thesis provides a framework for road surface degradation due to coast-down testing during a span of one and a half years. First, an overview of road surface texture and its impact on fuel consumption is introduced. Surface texture is composed by 4 wavelengths, each one affecting in different ways the vehicle/tire interaction. This thesis focuses on the two smallest wavelengths -macrotexture and microtexture. Advantages and disadvantages of different methods for measuring road surface are discussed. Then, experimental data was collected with an optical profilometer in a coast-down track before and after it was repaved. This thesis aims to quantify the degradation that each wavelength experienced and to analyze the data as thorough as possible. Also, additional measurements were collected to study the impact of weather effect in the long run. By assuming a linear degradation, a mathematical model is developed to estimate the surface texture value. With more tight fuel consumption and emission regulations, it (open full item for complete abstract)

Committee: Giorgio Rizzoni (Advisor) Subjects: Mechanical Engineering