Science & Engineering

Material Science: Polymers

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1. What structural parameters influence the melting point of a polymer? + Factors Affecting the crystalline melting point 1 InterMolecular Bonding/Interactions: 2 The Effect of Chemical Structure: 3 Chain Flexiblity: 4 Copolymerisation: Polymer science and technology By Robert Oboigbaotor Ebewele – Pressure Tm(P) = Tm(o) + sm’P – Molecular Mass 1 1 R 2 — – – Moleclar Asymmetry: Symmetry of the structural unit ellevates, asymmertry depresses the melting point. – Co-polymers & Tg & Tm: Advertisements

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Science & Engineering

Material Science: Glass

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Strengthening Mechanisms in Amorphous Materials Many silicate glasses are strong in compression but weak in tension. By introducing compression stress into the structure, the tensile strength of the material can be increased. This is typically done via two mechanisms: thermal treatment (tempering) or chemical bath (via ion exchange). In tempered glasses, air jets are used to rapidly cool the top and bottom surfaces of a softened (hot) slab of glass. Since the surface cools quicker, there is more free volume at the surface than in the bulk melt. The core of the slap then pulls the surface inward, resulting in […]