introduction to polymer chemistry

1Introduction to Polymer Chemistry

411317 Polymer Chemistry (2/2552)

by Dr. Walaiporn Prissanaroon-OuajaiDept. of Industrial Chemistry, KMUTNB

411317 by Dr. Walaiporn Prissanaroon-Ouajai (IC-KMUTNB)

2POLYMER CHEMISTRY - WHAT IS IT ?

Chemistry of large molecules

1980


3What are polymers ?

Why are polymers important ? Extraordinary range of

physical properties Many (not all) are cheap


4Polymer contains repeating units

Polymers vs. Macromolecules

A polymer is a macromolecule.but a macromolecule may not be a polymer

Polypropylene (PP)n

Macromolecules contain no repeating units

Ex. Protein, DNA


5 Packaging/films (PE, PP, PET) Everyday household stuff Paint (Polyacrylate, Epoxy) Adhesives (Epoxy resin, Acrylic resin) Auto's,aerospace,etc. Fibres (polyester, nylon) Electronic applications Elastomers (Rubber, Butadiene)

Applications

ABS


6Plastics and the Environment ?

From The Poison Plastic published byGreenpeace (www.greenpeace.org):

Most common plastics pose serious threats to human health and the environment.

extreme pollution from production toxic chemical exposure during use hazards from fires (CxHy + O2 CO2 + H2O) their contribution to the

worlds growing waste crisis.

http://www.pcd.go.th/info_serv/waste_rubbish.htm ()411317 by Dr. Walaiporn Prissanaroon-Ouajai (IC-KMUTNB)

7Ages ago Natural fibers Ex. wool, silk and cotton

1492 Columbus discovered South America and found the use of natural rubber (Hevea brasiliensis)

Historical background

Uses: Latex coatingPolyisoprene

Crying treesPara rubber


8Vulcanization transformation of hevea rubber to elastomer (valcanized rubber)

1839 Charles Goodyear

1st synthetic plastic made from natural polymer

1843 Nelson Goodyear

Ebonite High % vulcanization (rubber:S = 100:32)

S8


91848 - Menard Cellulose Nitrate

Synthetic polymers started!!

1st artificial thermoplastic

1846 Parkes and Hyatt CelluloidCellulose Nitrate + Camphor (as plasticizer)

use in photographic industry

highly flammable compound


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1905 - Baekeland Bakelite

1st truly synthetic plastic

not soften by heat

Phenol

Formaldehyde

Phenol-Formaldehyde resin


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1920s - Staudinger Macromolecule hypothesis

Nobel prize - Chemistry 1953

Demonstrations of Both natural & synthetic polymers

Polymer is Giant molecule not aggregate like colloid or cyclic compound long chain-like molecule formulated a polymeric structure for rubber,

based on a repeating isoprene unit

1927 PVC1931 PMMA & Neoprene1938 Nylon1941 LDPE

1943 Silicone1947 Epoxy resins1948 ABS1957 HDPE

Development of commercial polymers


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Classification of polymers1. By source1.1 Natural polymers (including macromolecules)

cis-polyisoprene (natural rubber)

glycosidic linkage

Polysaccharide Ex. starch, glycogen, cellulose, chitin, chitosan(C6H10O5)n-1 where n = 300 and 3000.

-NHCO-CH2 for chitin-NH2 for chitosan

Protein(Polyamide)

Ex. plastics, synthetic rubbers, synthetic fibers ect.1.2 Synthetic polymers


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2.1 Condensation polymerization (from bi/polyfunctional monomers)

2. By polymerization reaction (for synthetic polymers)

Dimer Monomer

Ester bond

[C-(CH2)n-C-O-(CH2)m-O]

O O polyester

Ex. Polyamide, polyurethane, polycarbonate, ect.

Step-growth polymerization


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2.2 Chain-growth polymerization (from unsaturated hydrocarbons or olefins )

Ex. poly(vinyl alcohol), PTFE, poly(vinyl acetate), PMMA ect.

X XXXX

[CH2-CH2]

[CH-CH2]n

n

[CH-CH2]Cl

n


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3. By composition

3.1 Homopolymers (contain one type of repeat unit)

[CH2-CH2] [CH-CH2]OH

n n

3.2 Copolymers (contain at least 2 repeat units)Ex. Styrene-Butadiene-Styrene block copolymer (SBS)

Thermoplastic Elastomer

Ex. Acrylonitrile-butadiene-styrene copolymer (ABS)


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4.1 Linear chain with 2 ends

4.2 Cyclic - chain with no end

4.3 Branched polymers have side chains

4.4 Dendritic (or dendrimer) - tree-like molecule

4.5 Network (or crosslinked) 3D structures which each chain is

connected to others

4. By skeletal structure


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Strain (e) = DLL0

Deformation Stress Strain

5. By application

In case solid See mechanical properties-

Strain

Stress Flexible plastics

FiberRigid plastics

Elastomer

Emulsion


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6.1 Thermoplastics - Soft (and melt) and formable when heated- Rigid when cooled - Can be re-heated and re-formed into different shapes

6. By thermal behavior

Recycled plastics

6.2 Thermosetting plastics - Initially form a X-linked solid with by heating- Soft (not melt) when 2nd heated but cannot re-shaped

Melamine-formaldehyde resins

Epoxy resins


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Biodegradable polymers

Conducting polymers

Specific classes of polymers

PLA

PHBPCL


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Nomenclature of PolymersSource-based name: base on name of monomer

Structure-based name: base on structure of repeat unit

Poly + name of monomer Note: use ( ) if monomer has a multi-worded name

Poly(name of structure of repeat unit)

CH2=CH2

CH=CH2OH

CH=CH2CH3

Monomer Polymer Source-based nameStructure-based name

In UK called polythene


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IUPAC recommendation for source-based names of polymers1. Homopolymer Poly+name of monomer

For multi-worded monomer namePoly(name of monomer)or

Polyethylene(PE)

Polypropylene(PP)

Polystyrene(PS)

Poly(vinyl chloride)(PVC)

Polytetrafluoroethylene(Teflon)

1.1) Addition polymers

Most common polymer. Used in bags,wire insulation, and squeeze bottles

Fibers, indoor-outdoor carpets, bottles

Styrofoam, molded objects such as tableware (forks, knives and spoons),trays, videocassette cases.

Clear food wrap, bottles, floor covering,synthetic leather, water and drain pipe

Nonstick surfaces, plumbing tape,chemical resistant containers and films

(or ethylene)

(or propylene)


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1.1) Addition polymers (continued)

Polyacrylonitrile(Acrilan, Orlon, Creslan)

Polychlorprene(neoprene rubber)

Poly(vinyl acetate) (PVA)

PolyisopreneNatural rubber

Styrene butadiene rubber (SBR)

Poly(methyl methacrylate)(Lucite, Plexiglas) Glass replacement, paints, and

household products

Fibers used in knit shirts,sweaters,blankets, and carpets

Adhesives (Elmers glue), paints,textile coatings, and chewing gum

Rubber bands, gloves, tires, conveyor belts, and household materials

Oil and gasoline resistant rubber

Non-bounce rubber used in tires

(or isoprene)

(or chloroprene)(2-chloro-1,3-butadiene)

(copolymer)411317 by Dr. Walaiporn Prissanaroon-Ouajai (IC-KMUTNB)

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1.2) Condensation polymers

Polyamides(nylon)

Polyesters(Dacron, Mylar, Fortrel)

Polyesters(Glyptal resin)

Polyesters(Casting resin)

Fibers, molded objects

Linear polyesters, fibers,recording tape

Cross-linked polyester, paints

Cross-linked with styrene and benzoyl peroxide, fiberglass boat resin, casting resin

(from condensation polymerization)

(Thermoset)

(Thermoset)

(Thermoplastic)


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Phenol-formaldehyde (Bakelite)

Cellulose acetate

Silicones

Polyurethanes

Mixed with fillers, molded electrical cases, adhesives, laminates,varnishes

Photographic film

Water-repellent coatings,temperature-resistant fluids and rubber

Foams, rigid and flexible, fibers

Note : Same repeat units and names can exhibit different chemical and physical characteristics, e.g. MW or MWD.


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2. Copolymer

Poly(name of monomer A-co-name of monomer B)

Poly(propene-co-methacrylonitrile) Polyacrylonitrile-block-polybutadiene-block-polystyrene Poly[(acrylic acid)-ran-(ethyl acrylate)]Polyisoprene-graft-poly(methacrylic acid)

Ex.

Copoly(propene/methacrylonitrile) Block-copoly (acrylonitrile/butadiene/styrene) Ran-copoly (acrylic acid/ethyl acrylate) Graft-copoly (isoprene/methacrylic acid)

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introduction to polymer chemistry

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