Toughening Mechanism Analysis of Recycled Rubber-Based Composites Reinforced with Glass Bubbles, Glass Fibers and Alumina Fibers

Abstract

Recycling of materials attracts considerable attention around the world due to environmental and economic concerns. Recycled rubber is one of the most commonly used recyclable materials in a number of industries, including automotive and aeronautic because of their low weight and cost efficiency. In this research, devulcanized recycled rubber-based composites are designed with glass bubble microsphere, short glass fiber, aluminum chip and fine gamma alumina fiber (γ-Al2O3) reinforcements. After the determination of the reinforcements with matrix, bending strength and fracture characteristics of the composite are investigated by three-point bending (3PB) tests. Halpin–Tsai homogenization model is adapted to the rubber-based composites to estimate the moduli of the composites. Furthermore, the relevant toughening mechanisms for the most suitable reinforcements are analyzed and stress intensity factor, KIc and critical energy release rate, GIc in mode I are determined by 3PB test with single edge notch specimens. In addition, 3PB tests are simulated by finite element analysis and the results are compared with the experimental results. Microstructural and fracture surfaces analysis are carried out by means of scanning electron microscopy (SEM). Mechanical test results show that the reinforcement with glass bubbles, aluminum oxide ceramic fibers and aluminum chips generally increase the fracture toughness of the composites.

Conductive and Ferromagnetic Syntactic Foam with Shape Memory and Self‐Healing/Recycling Capabilities

“…The uneven fracture surfaces shown in Figure S15 (Supporting Information) also hint that the initial crack, initiated somewhere at the bottom surface, bifurcated and changed its path before reaching the top. However, adding the HGMs [ 28 ] slightly decreased the fracture toughness and made the syntactic foam more brittle. This brittleness is also evident from the relatively smoother surface shown in Figure S16 (Supporting Information) and the number of oscillations in the stress‐strain curves in Figure 3a.…”

New Modified Thin PDMS Membranes for IMS Detection of Volatile Chemical Agents

“…In the IMS instruments in the gas inlet port, prior to the Ni-63 ionization chamber there is placed Polydimethylsiloxane PDMS membrane, which is impermeable to the water vapor and on the other hand permeable to the tested volatile organic agents. Membrane permeability P depends on the Diffusion and Solubility of tested compounds P = D x S To increase the Diffusion D there are required relatively thin PDMS membranes, which also has to be mechanically strong and resistant to the varied pressures [1,2]. We have decided to test different mechanical porous supports (Figure 1), which will be modified with PDMS/ Hexane (Sylgard 184) 10% w/w solution to obtain after drying and hot temperature curing (120 ˚C for 2 hours) films with thicknesses in the range of 3-5µm only.…”