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Commodity Resins. MFG 355. Polyethylene (PE). Mer unit Polymer chain. Guilio Natta. Karl Ziegler. Polyethylene. LDPE High Pressure/High Temperature processing High “H” activation—branching HDPE Ziegler-Natta catalyst Little branching Highly crystalline LLDPE
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Commodity Resins MFG 355
Polyethylene (PE) • Mer unit • Polymer chain
Guilio Natta Karl Ziegler Polyethylene • LDPE • High Pressure/High Temperature processing • High “H” activation—branching • HDPE • Ziegler-Natta catalyst • Little branching • Highly crystalline • LLDPE • “Copolymer”—side chains prevent crystalization • Improve toughness, strength, ESCR • Crosslinked PE
High Pressure Process (LDPE) Pressures around 350 MPa Temp. 300סC Long construction lead time Mammoth space requirements Huge capital outlay High energy demands Limited to low density polyethylene Costly and complex maintenance Production rates vary with PE grade Meets environmental requirements with difficulty Rapidly inflating operating costs Limited catalyst system choice Catalyst removal required Acceptable resin properties Low Pressure Process (LLDPE) Pressures around 3 MPa Temp. 100סC Reduced const. lead time by 8-12 months Occupies 1/10 the space Capital outlay reduced by 50% Reduced energy demands by 75% Produces both HDPE and LLDPE Easy to Maintain Same production rate for all resin grades Environmental pollution minimal Operating costs reduced Catalyst removal not needed Superior resin properties Polyethylene processes
Polyethylene Copolymer • Types of Copolymers • Random • Regular • Segment • Graft
Polyethylene Copolymers • EVA • Glue, soft • EAA—Ionic bonds • Ionomer (Surlyn) • EPM (EPBM with butadiene) • Rubbery
Polypropylene (PP) • Mer unit • Polymer chain
Polypropylene • Analogy • I need 6 volunteers to come up front
Polypropylene • Atactic: no order • Syndiotactic: alternate • Isotactic: means “samehand”, stereoisomorphism, always on the same side (crystalline)
Polypropylene • Ziglar-Natta catalyst • Isotactic
Polypropylene • Properties • Stiff • Environmental Stress Crack Resistance • UV sensitive • Higher Tg than PE • Resistance to mechanical stress cracking • Carpets • Living hinges
Polyvinylchloride (PVC) • Mer unit • Polymer chain
PVC • Rigid • Amorphous • Heat Sensitive • Solvent Sensitive • Welding • Glueing
PVC • Plasticized PVC • Solvent effects • Processed w/o heat
PVC • Properties • UV sensitive • Non-flammable (except plasticized) • Self extinguishing
Polystyrene (PS) • Mer unit • Polymer chain
Properties • Brittle and Hard • Not good for extrusion • Fair scratch resistance
Properties • Modified for toughness • Compare to Buna –S (GR-S)
Properties • Clear but yellows
PS • Crystal • Amorphous • Clear • Brittle • UV sensitive • Flammable
PS • Foam • expanded
Alloys & Blends • NOT copolymers • HIPS (rubber added) • SAN • ABS • Not copolymers
ABS PolyButadiene Rubber B Alloys can acquire the properties of their component parts Properties of the ABS dependant on the mix ratio PolyAcrylonitrile PolyStyrene A S
Alloys vs Copolymers • Alloys • Created after • Copolymers