Chapter 15.5

Chapter 15.5 - Crystallization, Melting, Glass Transition...

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22 MSE 2090: Introduction to Materials Science Chapter 15, Processing of Polymers Crystallization, Melting, Glass Transition (III) The melting temperature increases with the rate of heating, thickness of the chain-folded crystalline lamellae, and depends on history of material, especially crystallization temperature. Melting involves breaking of the inter-chain bonds, therefore the glass and melting temperatures depend on: ¾ chain stiffness (e.g., single vs. double bonds) - rigid chains have higher melting temperatures ¾ size/weight of molecule - increasing molecular weight increases T m (range of M produces range of T m ) ¾ size, shape of side groups, side branches, cross- linking, defects, etc. Essentially the same molecular characteristics rise and lower both melting and glass transition temperatures.
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23 MSE 2090: Introduction to Materials Science Chapter 15, Processing of Polymers Crystallization, Melting, Glass Transition (IV) Dependence of melting and glass transition temperatures and polymer properties on molecular weight
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Chapter 15.5 - Crystallization, Melting, Glass Transition...

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