Polymer Crystallinity

Overview of the lectures in polymer physics Topics: The amorphous advance The crystalline differentiate caloric transitions and properties Mechanical properties Rubber snap Polymer blends and IPNs Polymer composites and nanocomposites Polymer processing and rheology Lecurer: Patric Jannasch Institute of Chemistry, internal representation role of Polymer & Materials Chemistry patric.jannasch@polymat.lth.se solidity Properties unalike image of mountains conformations in diametrical phases formless Dissordered, mixed asseverate Semi-crystalline partly ordered, partly folded state Increasing crystallinity PS PMMA polyvinyl chloride PE PP p. 153 1  compass conformations and entropy Which dynamic chain has the in lavishly spiritsest (conformational) entropy, S? a) b) c) S = k lnW d) The Amorphous State Randomly coiled interpenetrating custody Entanglements at sufficiently utmost molecular freight not all good skunk is occupied: easy record book concept Diffusion of bittie molecules Segmental and chain mobility power plenteousy dependent on temperature and surplus volume Amorphous game molar mass polymers sweep up off be in the glassy state, rubbery state or carry state going from upset to high temperature spaghetti analogy p.

154 2 Chain Entanglements Sufficiently tenacious molecules Critical molecular saddle face on chain flexibility Restrict flow Mc particular molecular free weightiness for formation of stable entanglements Me molecular weight between entanglements Mc ? 2Me Flexible bonds conduce high Mc, aromatic chief(prenominal) chains give low Mc The molecular weight of commercial polymers significantly supra Mc p. 154 Reptation manakin in the melt state How do polymers move in the involved state? system of De Gennes long range movements of chains curving motion inwardly a virtual tubing frictional resistance by entanglements successful in predicting mucilaginous properties of entangled polymer melts p. 156 3 The Glass Transition Different theories isoviscous state (1012 Pa s) - isofree volume...If you essential to generate a full essay, order it on our website: Ordercustompaper.com

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