6.2.2 Basic Morphology of Polymer Crystals “ Single crystals” have one lattice > "Polycrystalline samples?" are aggregates of many single crystals Crystal Habits >a: lamellar(薄片状) b: platy c: tabular d: isometric e: prismatic e f: acicular 9 g: needle-like d >k: fibrous(纤维状) Macromolecular crystals are often lamellar or fibrous
6.2.2 Basic Morphology of Polymer Crystals ¾ Crystal Habits: ¾ a: lamellar (㮴⡷⣦) b: platy c: tabular d: isometric e: prismatic f: acicular g: needle-like ¾ h: fibrous (㓔㔤⣦) ¾ “Single crystals” have one lattice ¾ Macromolecular crystals are often lamellar or fibrous. ¾ “Polycrystalline samples” are aggregates of many single crystals 11
(1)Lamellae( FE)Crystallized from Dilute Solution Polyethylene(聚乙烯 T~80°C T~70°C
(1) Lamellae (⡷Ღ)Crystallized from Dilute Solution ¾ Polyethylene (㚊҉✟) Tc ~ 70 qC Tc ~ 80 qC 12
Orientations of polymer chains in lamellae PE chains are perpendicular to the lamellar surface Note: the lamellar thickness is 10 nm the chain length is >1000 nm >PE chains must be folded back and forth within the lamella!
Orientations of polymer chains in lamellae ¾PE chains must be folded back and forth within the lamella! Note: the lamellar thickness is ~10 nm, ¾PE chains are perpendicular to the lamellar surface. 13 the chain length is > 1000 nm
PEO(聚氧乙烯)-b-PS(聚苯乙烯) > Polyoxymethylene(聚甲醛) diblock copolymer .lum
¾ Polyoxymethylene (㚊⭢䟋) ¾ PEO(㚊≗҉✟)-b-PS(㚊㤟҉✟) diblock copolymer 14
The Structure of lamellae Growth sector Dominant fold boundaries orientation Unit·cell Fold surface RA Tight fold Fold length L 非平面 p Helical or zig-zag 31107 Growth faces conformation 空锥形
The Structure of Lamellae 15 䶎ᒣ䶒 オ䭕ᖒ