Polymeric Materials Sunan Tiptipakorn, D.Eng. Department of Chemistry, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaen Saen Campus, Nakorn Phathom, 73140 Thailand.
Introduction Material Science Relationship Structure Processing Properties Performance
Materials Metals Polymers - organic polymers - inorganic polymers Composites Ceramics Semiconductors
Polymers
Thermoplastics - can be recycled Example:- PE, PP, PVC Ref.: http://cltad.arts.ac.uk Ref.:http://www.resinsystems.com/products/highvoltageinsulators.html Thermosetting -can not be recycled Example:- polyurethane, epoxy - no melting temp. Ref.: http://www.emeraldinsight.com
Organic Polymers
Main Organic Polymers 6 types of well known thermoplastics
Extruder http://commons.wikimedia.org/wiki/file:extruder_section.jpg http://www.synaflex.com/products/extrudedrubberproducts
Polyethylene (PE) Ethylene monomer (Ethene) or polyethylene (polyethene) or Ref.:http://www.yurak.com PE granules: (1)Natural form, (2) and (3) are colored with dyes
HDPE (High Density Polyethylene) Ref.:www.hdpe-containers.com/pipette-droppers.htm Ref.: www.thaigoodview.com high crystallinity (Linear PE) LDPE (Low Density Polyethylene) Low crystalinity (Branched PE) Ref.: http://www.waterwiseliners.co.za/pondimages/ldpe%20pond.jpg
Branched Chains and Linear Chains Ref.:http://www.makingthemodernworld.org.uk/learning_modules/chemistry/03.TU.02/?section=7
Free Radical Polymerization High Temp. High Pressure Examples:- LDPE PVC PS Ref.: http://pslc.ws/mactest/radical.htm
Coordination Polymerization Low Temperature Low Pressure Ziegler and Natta Catalyst icl 4 + Aluminium co-catalyst Examples: HDPE, PP Ref.: http://chem.chem.rochester.edu/~chem421/zn.htm
Polypropylene (PP) Ref.: www.vcharkarn.com/varticle/38233/2 Ref.:http://www.chemicals-technology.com/projects/hmcpolymers-thailand/
Three Types of Polypropylene Ref.:http://www.steinwall.com/ART-polypropylene.html
Polystyrene (PS)
Types of Polystyrenes
Polyvinyl chloride Polymerization: Morphology: Glass transition temperature: free radical chain polymerization highly amorphous, ~11% crystallinity ~84 o C Ref.:http://www.vcharkarn.com/varticle/38233/2
Polyethylene terephthalate (PET) Ref.:http://www.vcharkarn.com/varticle/38233/2
Organic Polymers Benefits Low Cost / Affordability Electrical Insulation Abrasive Resistance Easiness to Process Light-weight Drawbacks - Low performance @ high Temp. - Swelling organic solvent - Flexibility @ low range of Temp. - Low flame resistance - Not suitable for artificial organs
Inorganic Polymers
Methodology 1) Addition of Side Groups Addition polymerization of vinyl monomer H H Vinyl monomer H C C X Examples X = SiCH 3 ; OSiCH 3 ; C 6 H 5 PO Steric effect Free Radical Polymerization Coordination Polymerization
1) Addition of Side Groups (cont.) Vinyl monomer Copolymer with Styrene Methyl Methacrylate Acrylonitrile
2) Coordination polymerization of organometallic reagent with organic polymer (e - donor) Example M M = inorganic Coordination bonding
3) Synthesis via polymers with inorganic substance in main chain 3.1 Non-metallic inorganic substances (Si, P, S, O, N) 3.2 Transition metals Main chain Examples Poly(organosiloxane) or Silicone Phosphazene polymer Metallo-backbone polymer
Polyorganosiloxane (Silicone) Most commonly used : poly(dimethylsiloxane) CH 3 H 2 O (CH 3 ) 2 SiCl 2 -HCl hydrolysis dimethyldichlorosilane H 3 C H 3 C Si O O CH 3 Si CH 3 O Si O Si CH 3 CH 3 CH 3 octamethylcyclotetrasiloxane acid or base CH 3 O Si CH 3 n poly(dimethylsiloxane) (MW > 25,000) O 2 penetration: artificial organs
Phosphazene Polymer Conductive Polymer Raw Materials: PCl 5 + NH 4 Cl R N P R n n> 15000 Ring-opening polymerization Macromoleular substitution reaction Direct condensation
Phosphazene Polymer (cont.) R changes R N P R n n> 15000 Properties changes Cl - Inorganic rubber - Organic solvent swelling - Reacted with water OCH 2 CF 3 - water resistant Applications: Dyes, gasket, O-ring, and etc.
Natural Inorganic Polymers
Characteristics Natural Inorganic Polymers Three dimensional structure Rigid and Brittle Silica glass Ref.: http://minerals.caltech.edu/silica_polymorphs/index.html Asbestos Silicate Ref.:http://beachcomberonsaipan.blogspot.com Ref.: http://www.treehugger.com/2009/06/14-week/
Silicic acid HO Condensation O- Si OH -4H 2 O Na+ OH Polysilicate Tetrahedral structure Ref.: http://commons.wikimedia.org/wiki/file:silicic_acid.jpg http://minerals.caltech.edu/silica_polymorphs/index.html
Most well known polysilicate : Silica (SiO 2 ) Crystalline: Quatz Tridymite Cristobalite Amorphous
Molecular Alignments of Tetrahedral Molecules in Various Patterns of (SiO 4 ) 4-
(SiO 4 ) 4- and (AlO 4 ) 5- Polysilicate aliminate Zeolite Tetrahedral Crystalline aluminosilicate http://img.alibaba.com/photo/10872242/zeolite_from_indonesia.jpg To Soften water; act as catalyst in petrochemical plants
Basic Zeolite Structure Ref.: http://www.cheresources.com/zeolitezz.shtml Legend: Circle = Oxygen, Square = Silicon, aluminium Tetrahedral Ref.:http://www.moutere.com/stories/storyReader$39
Ionomer Main chain: Hydrocarbon or Fluorocarbon Side chain: Carboxylic or sulfonic group Na + http://www.jsce.co.kr/polymer_lecture/ionomer.html Ref.: http://www.jsce.co.kr/polymer_lecture/ionomer.html
Ref.: http://www.jsce.co.kr/polymer_lecture/ionomer.html
Applications of Ionomers Golf ball Primer Coating http://www.wemixallup.com/car-center-f35/car-paint-detailing-research-t180.htm http://www.honeypixel.com/clients/inglewood/index.php?page=news-item-1
Ceramics
Ceramics Compounds of Silicates Oxides Carbides Nitrides Aluminates Ref.:http://www.ceramickitchenware.com/ Strong covalent bond with network structure High strength and modulus High thermal Resistance Brittle Ref.:http://www.selectcon.com/ Ref.:http://www.ttc.most.go.th/
Manufacturing Steps Milling to micron scale Sintering @ High Temperature and High Pressure Ref.: http://sandblastingabrasives.com/ Ref.: http://www.thaiceramicsociety.com/pc_burn_oxygen.php
Sol-gel Process 1. Mixing metal with alcohol to form metal alkoxide Ti + C 2 H 5 OH Ti(OCH 2 CH 3 ) (s) + 2H 2 2. Dissolving metal alkoxide and mixing with water Ti(OCH 2 CH 3 ) (solution) + 4H 2 O Ti(OH) 4(s) +4C 2 H 5 OH Ti + H 2 O Complex of Titanium Oxide and hydroxide 3. Dehydrating Ti(OH) 4 with acid or base Three dimensional network..gel 4. Burning gel @ 200-500 o C
Ceramic Composites Ceramics + Additives Increase Toughness Cutting machine, Grinding wheel Ceramic Fiber of SiC or carborundum Polydimthyl silane 400 o C Ceramic Fiber Sintering @1200 o C to remove H 2 and C atom
Ceramics Alumina: Circuit Board SiC: Abrasive resistant materials Ref.:http://dea.brunel.ac.uk/cleaner/Electronics_Projects/Handbook_2.htm http://www.gravescompany.com/cabmate.htm Quartz: piezoelectric Ref.: http://www.britannica.com/ebchecked/topic-art/636716/108321/typical-components-of-a-quartz-watch La-Ba-Cu:Superconducting Ceramic
Piezoelectricity is the ability of some materials to generate an electric field or electrical potential in response to applied mechanical stress. Ref.:http://wever.wordpress.com/2008/07/
Reinforcing Elements Pure Resin Glass Fiber Cellulose Fiber Carbon Fiber Aramid Fiber or Kevlar
Carbon Fiber Most commonly used Acrylic Fiber: Polyacrylonitrile Step 1 300 o C http://www.psrc.usm.edu/macrog/carfsyn.htm
Step 2 http://www.psrc.usm.edu/macrog/carfsyn.htm
Step 3 http://www.psrc.usm.edu/macrog/carfsyn.htm
Step 4 http://www.psrc.usm.edu/macrog/carfsyn.htm
Thermoplastic Elastomer
Thermoplastic Elastomer Copolymer Behaviors: Melt when heating (Thermoplastics) Elastic (Elastomer) Example Butadiene + High Impact Polystyrene PS Butadiene PS Ref.: http://pslc.ws/macrog/kidsmac/rubber.htm
SBS Rubber http://pslc.ws/macrog/kidsmac/rubber.htm Polystyrene = tough hard plastic durability. Polybutadiene = rubbery material rubber-like properties.
References: 1. Schaffer J.P. et al., The Science and Design of Engineering Materials, R.D. Irwin Inc., Chicago, 1995. 2. Allen S.M. and Thomas e.l., The structure of materails, The MIT Series in Materials Science and Engineering, John Wiley and Sons. Inc., New York, 1999. 3. Allcock H.R. and Lampe F.W., Contemperary Polymer Chemistry, 2 nd Ed., Prentice Hall, New York, Jersey, 1990.
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