高分子材料与应用（英文版）chapter5fibers.ppt

Chapter 5 Fibers,Contents,What’s Fiber History of chemical fibers The classification of chemical fibers Basic structure and properties Manufacturing technology Fiber products and their applications Fibers and The environment,What’s fiber,What’s fibers - definition 1. Soft and flexible, slim and long substance 2. A natural or man-made substance having a length at least 100 times its diameter 3. Is capable of being spun into a yarn or made directly into a fabric. 4. Chemical fibers are polymers,What’s fiber,Length (staple 25~48mm, filament 1000m) Diameter (0.1 m~100 m),What’s fiber,Property requirements for Fibers High tensile strength (tenacity) Pliable but low elongation Abrasion resistant High melting point (esp. for clothing) T m 200 oC (iron without damage) but 300 oC to enable spinning from melt T g 100 oC so fibers soften when ironed at 150 oC Creases removed Polymer Tg ( oC) Tm ( oC) PET 70 265 Nylon 6,6 60 265 PAN 105 320 PP -5 165,What’s fiber,Processing requirements for fibers Fibers are pulled (drawn) during spinning Melt spinning Wet spinning (polymer dissolved in solvent, filaments extruded into non-solvent) Dry spinning (polymer dissolved in solvent, solvent evaporates) Drawing orients amorphous regions, stronger fibers result Drawing makes fibers much stronger in direction of draw than across it (anisotropic),What’s fiber,Structural requirements for fibers Symmetrical, unbranched polymer High crystallinity promotes linear molecular alignment – this is critical High cohesive energy (intermolecular forces) Strong intermolecular forces promote High tenacity, fiber strength, low elongation,What’s fiber,History of chemical fibers,Motivation to manufacture man-made fibers Imitate natural fibers, eps. Silk Improve the properties of natural fibers, e.g. Cotton and linen wrinkled from wear and washings. Silk required delicate handling. Wool shrank, irritating to the touch, and eaten by moths. The early attempt The earliest attempt in 1664, by Hooke (English), The first patent for “artificial silk” was granted in England in 1855 to Audemar for the spinning process of cellulose solution . Sir Joseph W. Swan experimented with forcing a cellulose solution through fine holes into a coagulating bath.,History of chemical fibers,The first commercial production The first commercial man-made fiber was achieved by French chemist de Chardonnet in 1889. His fabrics of “artificial silk” caused a sensation at the Paris Exhibition. Two years later he built the first commercial rayon plant at Besancon, France, and secured his fame as the “father of the rayon industry.” The subsequent man-made fibers the American Viscose Company, formed by Samuel Courtaulds Co., Ltd., began its production of rayon in 1910. The first commercial textile uses for acetate in fiber form were developed by the Celanese Company in 1924.,History of chemical fibers,,,Facts,,,,,Facts,,,,,World man-made fibers production 1 unit = 1000 Tonnes,The U.S. production of fibers,Chemical fibers in the future,Innovation is the hallmark of the manufactured fiber industry. Manufacturing methods： high speed (over 10000m/min) integrated scale(300-350t/d/line) automation(computer-controlled processing) Products High performances (strength100cN/dtex) Smaller diameter (microfiber, 0.0001dtex-1dtex) Differentia (差别化) Special function (功能化：阻燃、导电、光导、抗 静电、抗辐射、灭菌、治疗作用) Intelligent fibers:(thermo-, optic-sensitive fibers, shape memory fiber),Classification of fibers,Natural fibers 天然纤维,Regenerated fibers 再生纤维,Synthetic fibers 合成纤维,Chemical fibers 化学纤维,Cotton棉 Wool羊毛 Silk 丝 Others: jute, and ramie麻,Cellulose纤维素 Viscose Rayon 粘胶纤维 Cellulose acetate 醋酯纤维 Cellulose triacetate纤维素三醋酯 Protein fibers casein 酪蛋白纤维 bean 大豆蛋白纤维 collagen 胶原蛋白纤维 甲壳素纤维 zein 玉米蛋白 arachin 花生蛋白 Starch 淀粉 PLA聚乳酸,Polyester聚酯 Polyamide聚酰胺 -Nylons -Aromatic -Kevlar -Nomex Acrylic 丙烯腈(copolymers of PAN and other vinyl polymers) Modacrylic 改性丙烯酸酯 Polyolifin 聚烯烃 -Polyethylene 聚乙烯 -Polypropylene聚丙烯 Elastomeric 弹性纤维 -Spandex (polyurethane)氨纶 Polyvinyl alcohol 聚乙烯醇 Polyvinyl chloride聚氯乙烯,,Natural Fibers,Man-Made Fibers,Natural Polymer Base,Synthetic Polymer Base,Basic structure,Polymers: (macromolecules) composed of covalent-bonded structural units (monomers) Types: Homopolymers Copolymers Block polymers,Basic structure,Polymers: Types: Linear Branched Network (cross-linked),Basic structure,Polymers: Chemistry Backbones: -C-C-, -C-O-C-, -C-N-C- Configuration Side groups: -H, -CH3, -OH,Basic structure,Polymers: Orientation and Crystallinity Highly oriented: large proportion of polymer chains are aligned with the fiber axis Crystalline regions: adjacent polymers are packed with spatial order Amorphous regions: no spatial order,Basic structure,Polymers: Intermolecular forces Difference in electronegativity of the two atoms forming a covalent bond. The larger the difference, the more polar the bond. Extremely large difference leads to ionic bond.,Basic structure,Polymers: Intermol。