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Top 10 List Polymer products change our life significantly. Ties (Synthetic rubber) Non-sticky pan (Teflon) Polyethylene Stocking (Nylon) Polystyrene PVF PMMA Silicone Rayon Piping (PVC) We will review this list in the end of this course. Show and Tell. Compact Disk Zipper bag
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Top 10 ListPolymer products change our life significantly • Ties (Synthetic rubber) • Non-sticky pan (Teflon) • Polyethylene • Stocking (Nylon) • Polystyrene • PVF • PMMA • Silicone • Rayon • Piping (PVC) We will review this list in the end of this course
Show and Tell • Compact Disk • Zipper bag • PVC tubing • Soda bottle • Jacket for ski • Rayon • Rubber
History of Polymers 1927 – PVC 1934 – PE ICI 1934 – Nylon Du Pont Nobel Prize winners 1953 Herman Staudinger 1974 Paul Flory
Top 2 High-volume Polymers • Polyethylene • 50M tons/yr (2003) • packaging, consumer goods, pipe, durable equipment and industrial machinery • PVC • 27M tons/yr (2002) • Building 56%; Packaging 15%; Consumer goods 10%; Electronics industries 9%; Agriculture 5%; Others 5%.
Applications of some polymers • (PVC) : bottles, window frames, pipes, flooring, wallpaper, toys, car seats, guttering, cable insulation, credit cards, and medical products such as blood bags, IV tubing and much more.
Definition • Polymer: A substance composed of molecules with many repeating units (> 10,000) • (segments, monomers, repeating units, sub-units…) • Monomer: Staring material from which polymer is formed • Dimer, trimer, oligomer • Monomer vs polymer (one-unit vs many units) • Macromolecules = large molecules (such as proteins, synthetic polymers, etc) Basic Definition and Nomenclatures
Natural Polymers • Proteins • enzymes, muscles, tissue, hair, wool, silk • Carbohydrates • polysaccharides, starch, cellulose, rayon (reconstituted cellulose) • Nucleic Acids - DNA, RNA
Classification by Use • Plastics • HDPE, LDPE, Lexan, plexiglass, teflon, polystyrene • Fibers • Nylon, orlon, kevlar, rayon • Elastomers • rubber, spandex, poly(urethane) foam • Coatings • paints, varnishes, enamels, formica, Poly(urethane) • Adhesives • glues, cement, "scotch tape", epoxy, Hair spray
Adhesives • Adhesives are polymer-based formulations used to bond two surfaces together. Adhesives can be either reactive (form chemical bonds) or adhere by physical (van der Waals, ionic, etc) bonds. • Modern adhesives are classified either by the way that they are used or by their chemical constituents. • Anaerobics - used to bond metal surfaces together when air is excluded. They are generally based on acrylic resins. • Cyanoacrylates - reactive cyanoacrylic adhesives that cure in the presence of moisture. They solidify in seconds. • Toughened Acrylics - general use, strong acrylic-based adhesive. It's applied as a two-part, resin/catalyst system. • Epoxies - adhesives consisting of epoxy resin and hardener. These one-part, or two-part adhesives are extremely strong and versatile. • Polyurethanes - fast-cure, two-part adhesives used for bonding glass-reinforced plastics. • Modified Phenolics - phenolic resins for bonding metal to metal, or metal to wood. They require pressure and heat to cure. • Hot Melts - semi-crystalline polymers that bond physically. Joints form quickly, but are not very strong. • Plastisols - poly(vinyl chloride) based dispersions that require heat to harden. Once set, the joint is tough and resilient. • Rubber Adhesives - solutions or latexes of rubber that solidify by loss of solvent. Do not give load-bearing joints. • Poly(vinyl acetates) - PVA emulsions for use in bonding porous surfaces. Used in the packaging industry. • Pressure Sensitive Adhesives - used for labels and tapes. They don't solidify, rather stay in the rubbery flow regime.
Polymer Nomenclature In most cases [poly + monomer name] Trade names & Acronyms Examples: PMMA and Nylon PMMA = Poly(methyl methacrylate) = PLEXIGLASSTM NylonTM (Du Pont)
Examples - Homopolymers • Polyethylene • Polypropylene • Polytetrafluoroethlyene • Polystyrene • PMMA • PVC • PVA • PEG • PET • Nylon Assignment: Chemical structure, Tg, modulus, applications Due: next Monday
Classification of Polymers • Thermoplastics (“heat/pressure” + “deformable”) • Deformable, processible as viscous melt • Hard at its use temperature • Liner chain structures • 2 kinds • Crystalline/sem-crystalline polymers (Tm) • Amorphous polymer (Tg): PS, PC, PMMA • Thermosetting (“Heat” +”cross-linked”) • Sets = cross-linked = cured • Network or cross-linked architechure • Degrade rather than melt upon heating • Ealstomers: crosslinked rubbery polymers • Stretchable, recoverable • Low cross-link density