Status : Verified
| Personal Name | Oyales, Mitch-Irene Kate G. |
|---|---|
| Resource Title | Influence of environmental aging on the fracture mechanism of carbon black (CB) reinforced natural rubber/ butadiene rubber (NR/BR) composites |
| Date Issued | 13 August 2024 |
| Abstract | Materials degradation is inevitable and can lead to product failure, incurring loss of product integrity, costs, and even loss of life. While the degradation of monolithic materials has been extensively researched, the failure mechanisms of composite materials remain relatively unexplored. This study investigates the influence of storage aging and defect size on the fracture behavior of rubber composites, specifically for tire sidewall applications. By establishing baseline failure characteristics of fresh composites, this research identifies changes in fracture mechanisms and features as degradation progresses. Carbon black (CB)-reinforced natural rubber/ butadiene rubber (NR/BR) composites were fractured via tensile load according to ASTM D 412. Fractographic analysis revealed consistent fracture initiation at the edge of dog-bone specimens, followed by the formation of distinct fractures, namely smooth zone, hackle marks, and rupture zone. The “cup-and-cone” fracture origin is indicative of localized shear that resulted to yielding and permanent plastic deformation before initiation of crack. Continued application of tensile load increased the concentrated stress at the origin equivalent to the ultimate tensile strength, initiating crack formation. The crack then propagated slowly through the material, creating a smooth region with faint tear lines. As the load increased, the crack propagation accelerated, forming hackle lines. This reduced the cross-sectional area of the material that could still carry the load, causing the bulk stress to approach its ultimate tensile strength and forming the rupture zone to complete the fracture. The measured ultimate tensile strength and fracture energy of the composites were 15.77 ± 0.58 MPa and 61.08 ± 6.47 J/mm3, respectively. Exposure to ambient conditions (20-28°C, 55-90% RH) for up to three years significantly degraded the fracture strength of the composites by 37%. While fractographic features remained simila |
| Degree Course | Ph.D. Materials Science and Engineering |
| Language | English |
| Keyword | Rubber; Degradation; Fractography |
| Material Type | Thesis/Dissertation |
Preliminary Pages
13.29 Mb
Category : F - Regular work, i.e., it has no patentable invention or creation, the author does not wish for personal publication, there is no confidential information.
Access Permission : Open Access