复旦大学：《高分子物理》课程电子讲义_Chapter 6 Condensed States of Polymers

Chapter 6 Condensed States of Polymers 6.1 Polymer Melts and glasses 6.2 Crystalline States of polymers 6.2.1 Chain Conformations in Crystals 6.2.2 Basic morphology of Polymer Crystals 6.2.3 Polymer crystallization Models、 Thermodynamics、 Kinetics 6.3 Oriented States of Polymers 6.4 Liquid Crystalline polymers

Chapter 6 Condensed States of Polymers 6.1 Polymer Melts and Glasses 6.2 Crystalline States of Polymers 6.3 Oriented States of Polymers 6.2.1 Chain Conformations in Crystals 6.2.2 Basic Morphology of Polymer Crystals 6.2.3 Polymer Crystallization ModelsǃThermodynamicsǃKinetics 6.4 Liquid Crystalline Polymers 1

6.1 Polymer melts and glasses The transition from melt to glass is called glass transition(玻璃化转变) The transition from melt to solid(crystal) is called solidification(crystallization) Temperature Viscoelastic liquid Glass () Crystallization Transition (glasses) Melting fast cooled slowly cooled I quI slow T i IT. fast Semi-crystalline Solid Glassy Solid >Tg: glass transition temperature(玻璃化转变温度) Tm: Melting point AT=T-T: undercooling T<T: crystallization temperature

6.1 Polymer Melts and Glasses (liquid) liquid glasses (glasses) slowly cooled fast cooled Tg slow Tg fast G T ¾ The transition from melt to glass is called glass transition (⧫⪳ॆ䖜ਈ) ¾ Tg : glass transition temperature (⧫⪳ॆ䖜ਈ⑙ᓖ) 2 Tm: Melting point Tc <Tm: crystallization temperature ¾ The transition from melt to solid(crystal) is called solidification(crystallization) 'T=Tm-Tc : undercooling

Glass Transition as a relaxation process Thermal history dependence of T. 1 fast cooling 2: slow cooling 185 liquid supercooled liquid 0.84 100h glass 2 Temperature dependence of the specific volume of PvA, measured during heating crystal Dilatometric(膨胀计法) results obtained after a quench to-20C, followed by 0.02 or 100 h of storage. (Kovacs, A.J. Fortschr. Hochpolym. Forsch. 1966, 3, 394)

Glass Transition as a Relaxation Process ¾ Thermal history dependence of Tg liquid V crystal glass 2 glass 1 1: fast cooling 2: slow cooling supercooled liquid Tg2 Tg1 Tm T Temperature dependence of the specific volume of PVA, measured during heating. Dilatometric (㟘㛰䇑⌅) results obtained after a quench to –20 qC, followed by 0.02 or 100 h of storage. (Kovacs, A. J. Fortschr. Hochpolym. Forsch. 1966, 3, 394) 3

6.2 Polymer crystallization Requisites for polymer crystallization Chemical regularity Homopolymer Copolymer block copolymer random copolymer ≯ Stereoregularity(立构规整度) Isotactic(等规 Syndiotactic(间规) Atactic(无规) (c)

6.2 Polymer Crystallization ¾ Requisites for polymer crystallization ¾ Chemical regularity ¾ Homopolymer ¾ Copolymer block copolymer random copolymer ¾ Stereoregularity (・ᶴ㿴ᮤᓖ) ¾ Isotactic (ㅹ㿴) ¾ Syndiotactic (䰤㿴) ¾ Atactic (ᰐ㿴) 4

6.2.1 Chain Conformations in Crystals Helix Conformations 1J1 62=31717273 ○器OO H31 repeating unit -CHCH3-CH2-CHCH3 isotactic Zig-zag Conformations Hydrogen bonding H2 syndiotactic

6.2.1 Chain Conformations in Crystals 21 31 41 42= 21 51 52 61 62= 31 71 72 73 81 83 91 92 32 31 H31 Helix Conformations Zig-zag Conformations H21 Hydrogen bonding syndiotactic repeating unit CHCH CH CHCH 32 3 isotactic 5

Why helix 0.12nI E PE H 0.2nm 0.25nm PP CH3: 0.2 nm

Why Helix ? H H 0.25 nm PE 0.12 nm PP CH3 : 0.2 nm 6 E r 0.2nm

Chain packing in crystal lattices c

Chain packing in crystal lattices LH RH LH LH LH LH RH RH RH 7

Chain packing in crystal lattices PE PP O ertherhembie

Chain packing in crystal lattices PE orthorhombic 8

Ap- Hydrogen bonding triclinic

triclinic Hydrogen bonding 9

i-Poly-1-butene it-PP tO65nm] ? 5 Trigonal Monoclinic

Trigonal i-Poly-1-butene Monoclinic 10