Polymer Crystallinity

Overview of the lectures in polymer physics Topics: The amorphous tell The crystalline recite 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 set up conformations in diametrical phases uncrystallized Dissordered, mixed state Semi-crystalline part ordered, partly folded state Increasing crystallinity PS PMMA polyvinyl chloride PE PP p. 153 1  cut into conformations and entropy Which dynamic set up has the in high spiritsest (conformational) entropy, S? a) b) c) S = k lnW d) The Amorphous State Randomly turn interpenetrating fetter Entanglements at sufficiently high molecular onus Not all good deal is occupied: casual volume concept Dif fusion 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 blow over state going from low to high temperature spaghetti analogy p.

154 2 Chain Entanglements Sufficiently long molecules Critical molecular pack face on chain flexibility Restrict merge Mc particular molecular weight for formation of enduring entanglements Me molecular weight between entanglements Mc ? 2Me Flexible chains turn in high Mc, aromatic main chains give low Mc The molecular weight of c ommercial polymers importantly above Mc p. ! 154 Reptation manakin in the melt state How do polymers move in the involved state? scheme of De Gennes long range movements of chains curving motion deep down a virtual tube frictional resistance by entanglements successful in predicting viscous properties of entangled polymer melts p. 156 3 The trash Transition Different theories isoviscous state (1012 Pa s) - isofree volume...If you want to come back a full essay, order it on our website: OrderCustomPaper.com

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