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- ItemEffect of geometrical constraint condition on the formation of nanoscale twins in the Ni-based metallic glass composite(Milton Park : Taylor and Francis Ltd., 2014) Lee, M.H.; Kim, B.S.; Kim, D.H.; Ott, R.T.; Sansoz, F.; Eckert, J.We investigated the effect of geometrically constrained stress-strain conditions on the formation of nanotwins in -brass phase reinforced Ni59Zr20 Ti16 Si2 Sn3 metallic glass (MG) matrix deformed under macroscopic uniaxial compression. The specific geometrically constrained conditions in the samples lead to a deviation from a simple uniaxial state to a multi-axial stress state, for which nanocrystallization in the MG matrix together with nanoscale twinning of the brass reinforcement is observed in localized regions during plastic flow. The nanocrystals in the MG matrix and the appearance of the twinned structure in the reinforcements indicate that the strain energy is highly confined and the local stress reaches a very high level upon yielding. Both the effective distribution of reinforcements on the strain enhancement of composite and the effects of the complicated stress states on the development of nanotwins in the second-phase brass particles are discussed.
- ItemUnderstanding the Coupling Effect between Lignin and Polybutadiene Elastomer(Basel : MDPI, 2021) Hait, Sakrit; De, Debapriya; Ghosh, Prasenjit; Chanda, Jagannath; Mukhopadhyay, Rabindra; Dasgupta, Saikat; Sallat, Aladdin; Al Aiti, Muhannad; Stöckelhuber, Klaus Werner; Wießner, Sven; Heinrich, Gert; Das, AmitFrom an environmental and economic viewpoint, it is a win–win strategy to use materials obtained from renewable resources for the production of high-performance elastomer composites. Lignin, being a renewable biomass, was employed as a functional filler material to obtain an elastomer composite with a higher degree of mechanical performance. In the presence of a suitable coupling agent, an elevated temperature was preferred for the reactive mixing of lignin with polybutadiene rubber (BR). It is quite fascinating that the mechanical performance of this composite was comparable with carbon black-filled composites. The extraordinary reinforcing behavior of lignin in the BR matrix was understood by an available model of rubber reinforcement. In rubber composite preparation, the interfacial interaction between polybutadiene rubber and lignin in the presence of a coupling agent enabled the efficient dispersion of lignin into the rubber matrix, which is responsible for the excellent mechanical properties of the rubber composites. The rubber composites thus obtained may lead to the development of a sustainable and cost-effective end product with reliable performance. This novel approach could be implemented in other type of elastomeric materials, enabling a genuine pathway toward a sustainable globe.
- ItemMorphology and Physico-Mechanical Threshold of α-Cellulose as Filler in an E-SBR Composite(Basel : MDPI, 2021) Chowdhury, Soumya Ghosh; Chanda, Jagannath; Ghosh, Sreedip; Pal, Abhijit; Ghosh, Prasenjit; Bhattacharyya, Sanjay Kumar; Mukhopadhyay, Rabindra; Banerjee, Shib Shankar; Das, AmitIn the current context of green mobility and sustainability, the use of new generation natural fillers, namely, α-cellulose, has gained significant recognition. The presence of hydroxyl groups on α-cellulose has generated immense eagerness to map its potency as filler in an elastomeric composite. In the present work, α-cellulose-emulsion-grade styrene butadiene rubber (E-SBR) composite is prepared by conventional rubber processing method by using variable proportions of α-cellulose (1 to 40 phr) to assess its reinforce ability. Rheological, physical, visco-elastic and dynamic-mechanical behavior have clearly established that 10 phr loading of α-cellulose can be considered as an optimized dosage in terms of performance parameters. Morphological characterization with the aid of scanning electron microscope (SEM) and transmission electron microscopy (TEM) also substantiated that composite with 10 phr loading of α-cellulose has achieved the morphological threshold. With this background, synthetic filler (silica) is substituted by green filler (α-cellulose) in an E-SBR-based composite. Characterization of the compound has clearly established the reinforcement ability of α-cellulose.