Polymer Crystallinity

Overview of the lectures in polymer physics Topics: The amorphous pass on The crystalline articulate thermal transitions and properties Mechanical properties Rubber elasticity Polymer blends and IPNs Polymer composites and nanocomposites Polymer processing and rheology Lecurer: Patric Jannasch prove of Chemistry, theatrical role of Polymer & Materials Chemistry patric.jannasch@polymat.lth.se Solid-State Properties Different drawstring 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  delve conformations and entropy Which dynamic range of a function has the in high spiritsest (conformational) entropy, S? a) b) c) S = k lnW d) The Amorphous State Randomly gyrate interpenetrating set up Entanglements at sufficiently high molecular commitment Not all good deal is occupied: lit e volume 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 thawing state going from low to high temperature spaghetti analogy p.

154 2 Chain Entanglements Sufficiently long molecules Critical molecular freight face on chain flexibility Restrict rate of flow Mc particular molecular weight for formation of motionless entanglements Me molecular weight between entanglements Mc ? 2Me Flexible chains check high Mc, aromatic main chains give low Mc The molecular weight of commercial polyme! rs significantly above Mc p. 154 Reptation manakin in the melt state How do polymers move in the involved state? surmise of De Gennes long range movements of chains curving motion inwardly a virtual tube frictional resistance by entanglements successful in predicting viscous properties of entangled polymer melts p. 156 3 The trumpery Transition Different theories isoviscous state (1012 Pa s) - isofree volume...If you want to give way a full essay, order it on our website: OrderCustomPaper.com

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