Polymer Crystallinity

Overview of the lectures in polymer physics Topics: The amorphous postulate The crystalline democracy thermal transitions and properties Mechanical properties Rubber elasticity Polymer blends and IPNs Polymer composites and nanocomposites Polymer processing and rheology Lecurer: Patric Jannasch contribute of Chemistry, theatrical role of Polymer & Materials Chemistry patric.jannasch@polymat.lth.se Solid-State Properties Different drawing string conformations in diametrical phases unformed Dissordered, mixed state Semi-crystalline part ordered, partly folded state Increasing crystallinity PS PMMA polyvinyl chloride PE PP p. 153 1  strand conformations and entropy Which dynamic chain has the in high spiritsest (conformational) entropy, S? a) b) c) S = k lnW d) The Amorphous State Randomly spiral interpenetrating shackles Entanglements at sufficiently high molecular warhead Not all good deal is occupied: sluttish vol ume concept Diffusion of bittie molecules Segmental and chain mobility strongly dependent on temperature and free volume Amorphous high molar mass polymers brush off be in the glassy state, rubbery state or prevail state going from low to high temperature spaghetti analogy p.

154 2 Chain Entanglements Sufficiently long molecules Critical molecular charge face on chain flexibility Restrict conflate Mc particular molecular weight for formation of enduring entanglements Me molecular weight between entanglements Mc ? 2Me Flexible chains take for high Mc, aromatic main chains give low Mc The m olecular weight of commercial polymers sign! ificantly above Mc p. 154 Reptation manakin in the melt state How do polymers move in the involved state? guess of De Gennes long range movements of chains curving motion indoors a virtual tube frictional resistance by entanglements successful in predicting viscous properties of entangled polymer melts p. 156 3 The starter Transition Different theories isoviscous state (1012 Pa s) - isofree volume...If you want to get under ones skin a full essay, order it on our website: OrderCustomPaper.com

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