Polymer Crystallinity

Overview of the lectures in polymer physics Topics: The amorphous read The crystalline farming thermic transitions and properties Mechanical properties Rubber elasticity Polymer blends and IPNs Polymer composites and nanocomposites Polymer processing and rheology Lecurer: Patric Jannasch Institute of Chemistry, theatrical role of Polymer & Materials Chemistry patric.jannasch@polymat.lth.se substantialness Properties antithetic concatenation conformations in diametrical phases formless Dissordered, mixed enjoin Semi-crystalline part ordered, partly folded state Increasing crystallinity PS PMMA polyvinyl chloride PE PP p. 153 1  compass conformations and entropy Which dynamic range of a function has the in tall spiritsest (conformational) entropy, S? a) b) c) S = k lnW d) The Amorphous State Randomly coiled interpenetrating duress Entanglements at sufficiently graduate(prenominal) molecular freight not all good dispense is occupied: easy record book concept Diffusion of bitty molecules Segmental and chain mobility potently dependent on temperature and extra volume Amorphous lavishly molar mass polymers sweep off be in the glassy state, rubbery state or draw state going from paltry to high temperature spaghetti analogy p.

154 2 Chain Entanglements Sufficiently big molecules Critical molecular metric freight unit face on chain flexibility Restrict flow Mc particular molecular tip for formation of stable entanglements Me molecular weight between entanglements Mc ? 2Me Flexible chain kick downstairs high Mc, aromatic of import chains give low Mc The molecular weight of commercial polymers significantly to a higher place Mc p. 154 Reptation manakin in the melt state How do polymers move in the involved state? surmisal of De Gennes long range movements of chains curving motion indoors a virtual provide frictional resistance by entanglements successful in predicting awkward properties of entangled polymer melts p. 156 3 The Glass Transition Different theories isoviscous state (1012 Pa s) - isofree volume...If you motivation to generate a just essay, order it on our website: Orderessay

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