Science and Technology of Polymers(2nd Cycle)

Courses

Reactions of Polymers and Production of Polymers

and

https://fenix.ist.utl.pt/disciplinas/ctp364/2012-20 13/2-semestre

Coordination:Pedro Teixeira Gomes

Departamento de Engenharia Química

Instituto Superior Técnico

Reactions of Polymers and Production of Polymers(3rd Cycle)

https://fenix.ist.utl.pt/disciplinas/rppp-2/2012-20 13/2-semestre

STRUCTURE OF THE SUBJECT(2012-13)

Block 1 – Fundamentals of Macromolecular ChemistryDefinitions, nomenclature and classifications. Macr omolecular structures and their characterization. Solutions of polymers. Defin ition and determination of average molecular weights and molecular weight dist ributions.

12 hours13/02 – 28/02

Pedro T. Gomes

Block 2 – Polymerization Reactions and Reactions of PolymersNon-vinyl polymers (step polymerization). Vinyl poly mers (chain polymerization): radical polymerization ; copolymeriza tion; cationic polymerization; anionic polymerization; coordination polymerization; chemical reactions in vinyl polymers. Controlled/living poly merization .

16 hours06/03 – 04/04

Pedro T. Gomes

Block 3 – Polymer Melts and Polymers in the Solid St atePolymer melts: non-newtonian behaviour, visco-elast icity, rheological aspects of processing. Polymers in the solid state: amorpho us state and glass transition; crystalline state and melting. Techniqu es of characterization of thermal, structural and morphological properties. E lastomers. Mechanical properties and techniques of thermo-mechanical char acterization. Electrical and optical properties.

12 hours10/04 – 24/04

Jorge Morgado

Block 4 – Production of PolymersReactive polymers with industrial importance. Produ ction of composites. Main transformation processes (special emphasis on chemical aspects of processing). Chemical aspects in the main applicati ons of polymers. Polycondensation and polyaddition reactors. Dimensi oning of polymerization reactors. Thermoplastic formulation. Durability and degradation of polymers.

16 hours02/05 – 23/05

João C. Bordado

BIBLIOGRAPHY

- M. P. Stevens, "Polymer Chemistry - An Introduction", 3rd ed., Oxford Univ. Press, 1999 (DEQ library: 2 nd ed., 1990)

- G. Odian, “Principles of Polymerization”, 4th ed., Wiley-Interscience, N.Y., 2004(Pedro T. Gomes’ office)

- F. Rodriguez, “Principles of Polymer Systems”, Taylor & Francis, 4th ed., N.Y., 1996.(DEQ library: 2nd ed., McGraw-Hill, 1983)

- J. K. Fink, “Reactive Polymers Fundamentals and Applications - A Concise Guide to Industrial

Main Bibliography

Polymers”, William Andrew Publishing, 2005. (J. C. Bordado’s office)

- M Michalovic, K. Anderson, L. Mathias, “The Macrogalleria”, site of Polymer Site LearningCenter (da University of Southern Mississippi) (http://www.pslc.ws/macrog.htm)

- P. Munk, T.M. Aminabhavi, "Introduction to Macromolecular Science", 3rd ed., John Wiley &Sons, N.Y., 2002. (DEQ library : 1st ed., 1989)

- F. Billmeyer, "Textbook of Polymer Science", Wiley-Interscience, 3rd ed., N.Y., 1984.(DEQ library)

Other Bibliograhy

- “Encyclopedia of Polymer Science and Technology”, 3rd ed., Wiley-Interscience, 2004 (DEQ library )

- J. C. Salamone, Ed., “Polymeric Materials Encyclopedia”, John Wiley, 1996.(DEQ library )

- “Comprehensive Polymer Science”, Pergamon Press, Oxford, 1989(Complexo Interdisciplinar, CQE -Group II room )

- “Polymer Handbook”, Wiley-Interscience, 4th ed., John Wiley & Sons, 2003

Encyclopedias, Handbooks

- “Polymer Handbook”, Wiley-Interscience, 4 ed., John Wiley & Sons, 2003(DEQ library )

ASSESSMENT(2012-13)

CTP – Science and Technology of Polymers (2nd Cycle)

- Continuous assessment: 4 tests (at the end of eac h of the 4 blocks) and/or final exam(2 oportunities: 4 tests + 1 exam or 2 exams)

RPPP – Reactions of Polymers and Production of Polymers (3rd Cycle)

- Continuous assessment: 4 tests (at the end of eac h of the 4 blocks) and/or final exam(2 oportunities: 4 tests + 1 exam or 2 exams)(2 oportunities: 4 tests + 1 exam or 2 exams)

Alternatively:

- Writing up 1 monography (máx. 10-20 pages) in each of Blocks 2 and/or 3, to be delivered until the date of the corresponding test. Oral discussion.

Tests (provisional dates): Wednesady, 05/03 ( Block 1 Test ), 18 hTuesday, 09/04 ( Block 2 Test ), 18 hTuesday, 30/04 ( Block 3 Test ), 18 h

1st Exam: Wednesday, 05/06 (and also Block 4 Test ), 11:30 h 2nd Exam: Friday, 28/06, 11:30 h

Bloco 1

Fundamentals of Macromolecular Chemistry

Pedro Teixeira Gomes

MILESTONES IN THE USE OF STRUCTURAL MATERIALS BY MA NKIND

HISTORY

MODERNAGE

STONEAGE

PRE-HISTORY

METALSAGE

PROTO-HISTORY

ANCIENTAGE

MIDDLEAGE

CONTEMPORARYAGE

CEMENTCONCRETE

WOODCHIPPED STONEPOLISHED STONE

COPPER (4000 AC)TINBRONZEIRONCERAMICS

GLASS(1500 BC)

METALALLOYS

POLYMERS

1496 – Colombus (rubber balls brought in his 2nd expedition to America; the Mayans already used it for centuriesand the tree was called caoutchouc)

1763– rubber dissolved in turpentine oil is sold as a glue in France

1748– Charles Marie de La Condamine, description of latex collected from “Hevea Brasiliensis”(native rubber tools)

ORIGINS OF RUBBER TECHNOLOGY

1763– rubber dissolved in turpentine oil is sold as a glue in France

1770– rubber is used as an eraser to delete pencil(Priestley)

1791-1823–Mackintosh clothing, made with natural rubber (McIntosh)

1844– Goodyear vulcanizesrubber with sulphur

1906– Harries polymerizes isoprene with sodium

1907– Hofman (Bayer) uses 2,3-dimethylbutadiene to make methyl rubber

1870– Hyatts, cellulose nitrate + camphor = CELLULOID (billiard balls (coating), table tennis balls)

1892– Cross e Bevan, cellulose acetate and xanthate →→→→ viscose rayon fibres

1907– Baekeland, first phenol-formaldheyde resin →→→→ BAKELITE

1846– Schonbein, first synthetic plastic →→→→ cellulose nitrate

ORIGINS OF PLASTIC TECHNOLOGY

- CELLULOSE NITRATE- CELLULOSE ACETATE

1918– Only 3 plastics industries : - CELLULOSE ACETATE- BAKELITE

OHO

HOOH

OH

OH

OO

HOOH

O

OH

O

HOOH

OH

O

HOOH

O

OH

- n H2O

CELLULOSEββββ-GLUCOSE

UNTIL 1918 – Polymers were thought to be aggregates of small molecules associated bysecondary forces (Van der Waals)

CONCEPT OF MACROMOLECULE (POLYMER)

1918 - 1920– Staudingerproposed that in many macromolecules the repeating units were covalently bonded→→→→ High molecular weight molecules.

• Synthesis of poly(ethyene oxide), poly(methylene oxide), polystyrene (1920-1930)

• Notion of molecular weight distribution. Viscometric method for the determinationof molecular weightsof molecular weights

1929– Meyer e Mark explained the vulcanization of rubber. Study of polymers by X-rays

1931– Carothers, first polycondensation reactions (polyesters, polyamides) leading to high molecular weight polymers

MACROMOLECULES

AGGREGATES – of small molecules, bonded by Van der Waals forces

POLYMERS – Long molecules containing an unit which is repeated throughout the chain. The repeating repeated throughout the chain. The repeating units are covalently bonded to each other

SYNONIMS: PLASTICS, RESINS, ETC. (according to their properties and/or physical appearance)

DEFINITIONS

POLYMER – Greek →→→→ Poly + mer(many) (parts)

MONOMER – Greeek →→→→ Mono + mer(one) (part )

OLIGOMER – Greek →→→→ Oligo + mer(few) (parts)

REPEATING UNIT – group of atoms (from the monomers) that

CH2 CH CH2

n

CH3CH2 CH2

REPEATING UNIT – group of atoms (from the monomers) that repeat throughout the polymer chain

part ≡≡≡≡ repeating unit≡≡≡≡ monomeric unit

END GROUPS – structural units situated at the polymer chain ends

End Groups

Repeating Unit

C C

H

H

H

H

n CH2 CH2n

Ethylene

Monomer

Poly(ethylene) ≡≡≡≡ Polyethylene

Polymer

NOMENCLATURE – According to IUPAC, the polymers are named by its monomer as:poly(monomer)

Example: The molecular weight of a polyethylene with DP=5000 is:

M = M RU ×××× DP= 28 ×××× 5000 = 140 000

MRU = repeating unit molecular weight =28

n = Degree of polymerization (DP) – total number of repeating units (RU), including terminal groups

it is related with:

CHAIN LENGTH MOLECULAR WEIGHT (M)

When DP is high, the importance of end groups is irrelevant and we should write:

or

When DP is low –oligomer - the importance of end groups is relevant. We should write :

MY Y'n

M Mn

The synthetic polymers (and oligomers) generally have chains of variable length (i.e. a molecular weight

distribution).

MONODISPERSE POLYMERS – a single chain length

POLYDISPERSE POLYMERS– several chain lengths ≡≡≡≡ molecular weight distribution

Then we should define an AVERAGE DEGREE OF POLYMERIZATION (DP)

TYPES OF POLYMERIZATION

•••• STEP POLYMERIZATION (Polycondensation)

HO OH + CCO

OH

O

HO

HO O CC

O

O

O

Hn

n n

+ (2n-1) H2O

Diol Diacid

•••• CHAIN POLYMERIZATION (Polyaddition)

n

Polyester

There can be elimination of small molecules: H2O, ROH, HCl, ...

CH

Xn CH

X

CH2n

CH2

There is no elimination of small molecules

The ultimate mechanical properties of any polymer result from a balance of:

• MOLECULAR WEIGHT / MOLECULAR WEIGHT DISTRIBUTION

• CHEMICAL STRUCTURE

A polymer must attain a certain value of molecular weightfor possessing

useful mechanical properties, but that molecular weight depends very much

on the molecular structure of the polymer.on the molecular structure of the polymer.

STRUCTURE and MOLECULAR WEIGHT condition the INTERMOLECULAR FORCES:

• Hydrogem Bonds

- permanent dipole - permanent dipole (Keesom)

• Van der Waals Forces: - permanent dipole-induced dipole (Debye)

- instantaneous dipole-induced dipole (London)

• Ion-dipole Forces

•••• PRIMARY STRUCTURE – resulting from the covalent bonds between repeating units

•••• SECONDARY STRUCTURE – resulting from the spatial arrangement of the main chain segmentsaccording to regular patterns, which are dictated by stereochemistry (most stable conformations) or hydrogen bonds (αααα-helix or ββββ-sheet)

•••• QUATERNARY STRUCTURE – resulting from the interaction between different chains

•••• TERTIARY STRUCTURE – resulting from the whole tridimensional structure of the chain, which is conditioned by intramolecular forces and hydrogen bonds between distant segments of the chain

PRIMARY STRUCTURE

PRIMARY

• LINEAR

• CYCLO-LINEAR

• BRANCHED

• COPOLYMERS

resulting from the covalent bonds between repeating units

PRIMARYSTRUCTURE

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

• LINEAR

• CYCLO-LINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

CARBON CHAIN POLYMERS

• Polymeric hydrocarbons (C=C chain polymerization)

- Nomenclature- some important polymers

•••• LINEAR POLYMERS- CARBON CHAIN POLYMERS- HETEROATOM CHAIN POLYMERS- INORGANIC CHAIN POLYMERS

PRIMARY STRUCTURE

• Polymeric hydrocarbons (C=C chain polymerization)

• POLYETHYLENE (Polyethene; Polymethylene (IUPAC))

CH2n CH2 CH2n

CH2

- Electrical insulating- Piping- Packing (films)- Bags- Agriculture (gree-houses)

•••• Low Density (branched- radical polymerization)•••• High Density (linear – coordination polymerization)

PE

• POLYPROPYLENE (Polypropene; Poly(1-methylethylene) (IUPAC))

- Fibres (ropes, carpets)- Packing (films and semirigids)- Piping

CH

H3Cn CH

CH3

CH2n

CH2

High density (coordination)PP

• POLY(ISOBUTYLENE) (Poly(isobutene); Poly(1,1-dimethylethylene) (IUPAC))

- Component of BR rubber- Inner tubes (bikes)- Motor gaskets- Electrical insulating

C

H3Cn C

CH3

CH2n

CH2

CH3H3C

• POLYBUTADIENE

n CH

HC

CH2n

CH2

HCH2C

CH CH2

1 2

3 4

HCH2C

CH CH2CH

H2C

CH

CH2

1,2-POLY(1,3-BUTADIENE)(Poly(1-vinylethylene) (IUPAC))

SYNTHETIC RUBBER

HCH2CH2C CH2 nn

TRANS-1,4-POLY(1,3-BUTADIENE)(trans-Poly(1-butenylene) (IUPAC))

CIS-1,4-POLY(1,3-BUTADIENE)(cis-Poly(1-butenylene) (IUPAC))

HCH2C CH CH2

n

CHHC CH2 CH2

n

≡

nCH CH2

CH2C1 2

3 4

CH2C

CH CH

C

H2C

CH

CH2n

CH3H3C

CH3

• POLY(ISOPRENE)

1,4-CIS

NATURALRUBBER

- Hevea Brasiliensis- Guayule

GUTTA-PERCHA

Hard material :low percentage

of 1,2 and 3,4 units CH CH2 n

1,4-TRANS

Hard material :- Insulator- Golf balls (old ones)

• POLYSTYRENE (Poly(1-phenylethylene) (IUPAC))

- General use plastic- Thermal insulator- Packing of fragile goods- Engineering plastic (syndiotactic)

CHn CH CH2n

CH2

of 1,2 and 3,4 units

• Polymers containing halogen substituents

• POLY(VINYL CHLORIDE) (PVC; Poly(1-chloroethylene) (IUPAC))

- Piping- Flooring- Packing (bottles, “tupperware”, etc. )

- Hoses, waterproof goods,seat covers

CH

Cln CH

Cl

CH2n

CH2

When additivated(esters, epoxides, etc.)

Radical polymerization (emulsion)

• POLY(TETRAFLUOROETHYLENE) (PTFE; TEFLON; Poly(difluoromethylene) (IUPAC))

- Insoluble- Thermally stable

- Frying pans coating (non-sticking material)-Kitchen tools - Waterproof material

CF2n CF2 CF2n

CF2

n

CH CH2

CH2C

Cl

CH2C

CH CH2 n

Cl

• POLY(CHLOROPRENE) (Poly(neoprene); Poly(1-chloro-1-butenylene) (IUPAC))

- Best hydrocarbon-proof rubber- High vacuum applications

1,4-TRANS

• Polymers with polar side groups

low percentageof 1,4-cisand 3,4 units

• POLY(METHYL ACRYLATE) (Poly(1-methylcarboxylatoethylene) (IUPAC))

- Rubber (without commercial application)

CH

C

n CH

C

CH2n

CH2

O

OCH3 O OCH3

• POLY(METHYL METHACRYLATE) (Plexiglas; Perspex; Poly(1-methyl-1-methylcarboxylatoethylene) (IUPAC))

- Highly transparent- Glasses for airplanes and shops- Good resistance to acids and bases

C

C

n C

C

CH2n

CH2

O

OCH3 O OCH3

H3C CH3

• POLY(HYDROXYE THYL M ETHA CRYLATE) (Poly-HEMA; Poly(1-methyl-1-hydroxyethylcarboxylatoethylene) (IUPAC))

- Swells with water → Gel (35% water)- Elastic and strong Cn C CH2CH2

H3C CH3

- Elastic and strong - Contact lenses andother biomedical

applications

C

C

n C

C

CH2n

CH2

O

OCH2CH2OH O OCH2CH2OH

• POLY(ACRYLIC ACID) • POLY(METHACRYLIC AC ID)

R= HR= CH3

- Polyelectrolyte- Soluble in basic medium

C

C

n C

C

CH2n

CH2

O

OH O OH

R R

• POLY(SODIUM ACRYLATE)

- Polyelectrolyte- Super-absorbent (babby nappies, etc.)- Agriculture

CH

C

n CH

C

CH2n

CH2

O

O- O O- Na+Na+

• POLYCYANOMETHYLACRYLATE) (Poly(1-cyano-1-methylcarboxylatoethylene) (IUPAC))

C C

N N

• POLY(ACRYLONITRILE) (PAN; Poly(1-cyanoethylene) (IUPAC))

- Acrylic Fibres (Orlon)- Insoluble in the majority of solvents- Precursor to carbon fibres

CH

Cn CH

C

CH2n

CH2

NN

- Super-gluesC

C

n C

C

CH2n

CH2

O

OCH3 O OCH3

• POLY(VINYL ALCOHOL) (Poly(1-hydroxyethylene) (IUPAC))

- Water solubleCH CH2

n

OH-CH CH2

n

CH

O

n CH

O

CH2n

CH2

C R

O

C

O

R

• POLY(VINYL ACETATE) • POLY(VINYL BUTYRAT E)

R= CH3R= CH2CH2CH3

- Flexible transparent films- Photographic films (old ones)

- Water soluble- PolyelectrolyteOH

nO

n

C

O

R

Poly(vinyl acetate)

• POLY(VINYL PYRROLIDONE) • POLY(VINYL CARBAZOLE)

- Biocompatible; contact lenses (with “cross-links”)

CH

Nn CH

N

CH2n

CH2

OO

CH

N

n CH

N

CH2n

CH2

- Used in Xeroradiography

HETEROATOM CHAIN POLYMERS

Normally prepared by: 1) Polycondensation;2) Ring Opening Polymerization of heterocyclic monomers

• Polyeters

• POLY(OXYMETHYLENE) (POM; poly(methylene oxide); poly(oxymethylene) (IUPAC))

- Hard and strong material- Good thermal stability- Engineering plastic(it replaces metals in light and medium dutyapplications)

C

H

n CH2 On

O

HH+

applications)

• POLY(ETHYLENE OXIDE) (Poly(ethyleneglycol); PEG; PEO; Poly(oxyethylene) (IUPAC))

- Water soluble- Ionic conductor

H2Cn CH2 CH2 On

CH2

OH+ (B-)

• Polyesters

• POLY(ETHYLENE TEREPHTHALATE) (PET; Poly(oxyethylenoxyterephthaloyl) (IUPAC))

- Main polymer of polyester textiles (textile fibres)- Beverage bottles

CH2

HOn CH2

OH+ C C

O

OH

O

HO

-2n H2OO CH2 CH2 On C

O

C

O

n

ethyleneglycol terephthalic acid(Cyclolinear polymer)

PET

- Beverage bottles- Engineering plastic (mould construction)

CH2C C

O

OH

O

HO

nx

H3C C O

O

C CH3

O

n +- 2n CH3COOH

CH2C Cx

O

O O

n

CC

O

O

O

n

- Resistant fibres

acetic anhydride diacid

• Polyanhydrides

- Manufacture of organic lenses- Safety glass- Beverage bottles containers

diolphosgene

O C O C

CH3

CH3

O

n

• Polycarbonates

• Polyamides

CO On

O

HO OHn n+ C

O

Cl Cl

-2n HCl

+C C

O

OH

O

HO

-2n H2On C

O

C

O

NH

n

NHH2N NH2

terephthalic acid p-phenylenediamine KEVLAR

- Impact resistant fibres (bullet-proof vests, tire inner lining, sport objects, etc.)

- Texteis

εεεε-caprolactam Poly(εεεε-caprolactam) ≡ NYLON 6 ≡ Poly(imino(1-oxahexamethylene)) (IUPAC)

NH

O

CH2NH C5

O

n

H+

CH2N Nn3

+ CH2NH NH3

C C O

n

OOn

CNH NHC

O

CO C O

O

O

O

HO OH

O

- Elastic fibres (aliphatic)- Varnishes (aromatic)- Elastomers- Thermal insulating- Packing- Pillows, mattresses, etc.

diol Polyurethane

• Polyurethanes

diisocianate

- Pillows, mattresses, etc.

• Polyureas

- Properties similar to polyurethanes

diamine

CNH NHn

O

H2N NH2n n+ C

O

Cl Cl

-2n HCl

phosgenePolyurea

• Poly(isocyanates)

B-

Nn C OR N C

O

R n

• Polymers containing sulphur in the main chain

RubbersCH2 Sbx n

Poly(alkylene poly(sulphide))

- Rubbers

O C O

CH3

CH3 n

S

O

O n

- High temperatures resistance- Electrical insulator- Materials for high precision moulding

Poly(sulfone)

INORGANIC CHAIN POLYMERS

• Polymeric sulphur

- Elastic material1) ∆∆∆∆ (170ºC)

n S82) quenching

S S S S2n

Reversible Reaction !

• Poly(siloxanes) (Silicones)

Si ClCl

R

n + n H2O-2n HCl

Si O

R R= - alkyl- cyanoalkyl- perfluoroalkyl

R

2

Rn

- Rubbers (-30 to 200ºC) (high molecular weight)- Oils (low molecular weight)

- perfluoroalkyl- phenyl

Si ClCl

R

R'

nNa, ∆∆∆∆

Si

R

R' ntolueno

- 2n NaCl

• Poly(silanes)

- Used as photoresists(Si-Si bond sensitive light)

The -Cl atoms can be substituted by -OR, -CF3, -NR2 groups

• Polyphosphazenes

- Good chemical resistance- Good thermal resistance- Specialty rubbers, films

P N

Cl 3n

N

PN

P

NP

Cl Cl

Cl

Cl

Cl

Cl

Cl∆∆∆∆

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

•••• CYCLOLINEAR POLYMERS- WITH ALTERNATING CYCLIC-LINEAR FRAGMENTS- WITH BONDED RINGS- WITH FUSED RINGS

• Polymers with alternating cyclic-linear fragments

• POLY(p-PHENYLENE OXIDE) (PPO; poly(oxy-2,6-dimethyl-1,4-phenylene) (IUPAC))

CH3

OH

CH3

O

n

n + n/2 O2 + n H2Oamina

Cu2+

- Hard polymer- Engineering plastic (easy to be machined → article parts)

CH3 CH3

• POLY(VINYLACETAL) AND • POLY(V INYLBUTYRAL)

- Used In the manufacture of safety laminated glasses (car windscreens, etc.)

CH

OH

CH2n

R C

O

H

+- n H2O

CH CH2 CH CH2

O OCH

R

n/2n/2

R= HR= CH2CH2CH3

• CYCLIZATION OF POLY(METHYLVINYLKETONE)

- n H2OCH CH2 CH CH2

n

O CH3 O CH3

CHCH2

CH CH2n

H3C CH O

Poly(methylvinylketone) Aldol condensation

• Polymers with bonded rings

• POLY(p-PHENYLENE) (poly(1,4-phenylene) (IUPAC))

C

O

C C

O

C

O

O

O

O

H2N NH2+- 2n H2O

C

N

C C

N

C

O

O

O

O

n

n n

• POLY(IMIDES)

Pyromelytic dianhydridep-phenylenediamine

- Very hard polymer; - High melting point; - Thermally stable; - Insulating varnishes; - Parts of airplane motors

nAlCl 3

nCuCl2

- Good electrical conductor (when doped)

• Polymers with fused rings - (Ladder Polymers)

• POLY(PHENYLSILSESQUIOXANE)

- Soluble in the majority of organic solvents

Si ClPh

Cl

Cl

n + n H2O- n HCl

Si O

Ph

O

Sin

O

Ph

O

Si SiO O

Ph Phn

OH-

- Soluble in the majority of organic solvents

C

O

C C

O

C

O

O

O

O

+ - 2n H2On n

NH2

NH2H2N

H2N

N

C

N N

C

N

CC

C

N

C

N

OOO

n

• POLY(IMIDAZO PYRROLONE)

• CYCLIZATION OF POLYACRYLONITRILE

- Very hard polymers- Intermediates in the synthesis of carbon fibres

(by pyrolisis at very high temperatures)

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

•••• BRANCHED POLYMERS

LINEAR

• • •

•

• •• • • •

• ••

COMB TYPE

•••• ••••

STATISCALLY BRANCHED

•

•

••

•

• •

••

•

NETWORK

••

•

•

••

••

• •

•

•

•

• • ••

•

••

•

•

DENDRIMERS

STAR TYPE

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

HOMOPOLYMER – Polymer synthesized from the same monomer (A)

COPOLYMER – When 2 monomers A and B (or more) are incorporated in the samemacromolecule

-A-A-A-A-A-A-A-A-

•••• COPOLYMERS

Considering there are n polymers, there will be n(n-1) copolymers

We can also vary the composition of monomers within the macromolecule

“Exponential” growth of materials available

TYPES OF COPOLYMERS

-A-A-B-A-B-B-A-B- RANDOM (OR STATISTIC) COPOLYMER

-A-A-A-A- B-B-B-B- BLOCK COPOLYMER OF THE AB (diblock) TYPE

-A-B-A-B-A-B-A-B- ALTERNATING COPOLYMER

-A-A-A-A-B-B-B-B-A-A-A-A--A-A-A-A-B-B-B-B-A-A-A-A-

-A-A-A-A-A-A-A-A-

-B-B

-B-B

- GRAFT COPOLYMER

BLOCK COPOLYMER OF THE ABA (triblock) TYPE

NOMENCLATURE OF COPOLYMERS

Ex: •••• Styrene-methyl methacrylate copolymer

Poly(styrene-alt-(methyl methacrylate))

Polystyrene-block-poly(methyl methacrylate)

Poly(styrene-ran-(methyl methacrylate))

ORPoly(styrene-a-(methyl methacrylate))

Poly(styrene-b-poly(methyl methacrylate))

Poly(styrene-r-(methyl methacrylate))

Polystyrene-graft-poly(methyl methacrylate)

-copoly(styrene/methyl methacrylate)

altblockgraftran

Poly(styrene-g-poly(methyl methacrylate))

OR

Ex: •••• Polybutadiene-block-(polystyrene-graft-polyacrylonitrile)

B = butadieneS = styreneA = acrylonitrile

-B-B-B-B-B-B-S-S-S-S-S-S-

-A-A

-A-A

-A-A

-

block-copoly(butadiene/graft-copoly(styrene/acrylonitrile))

Ex: •••• Poly(styrene-alt-acrylonitrile)- block-polybutadiene-block-(poly(methyl methacrylate)-graft-polystyrene)

B = butadieneS = styreneA = acrylonitrileM = methyl methacrylate

-S-A-S-A-S-A-S-A-B-B-B-B-B-B-B-B-B-M-M-M-M-M-

-S-S

-S-S

-S-S

-

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

R R H R R H HH H R H H R R

•••• ISOMERISM IN POLYMERIC CHAINS - TACTICITY

CONFORMATIONS – Resulting from the rotation around a chain bond or side group

P H H

0 120 240 θθθθ

Epot

P

HR

H H

P

HR

H PP

HR

P H

θθθθ

CONFIGURATIONS – Resulting from the existence of pro-chiral atoms

ISOTACTIC

RRRRRRR r r r r r rSYNDIOTACTIC

n

RRRRRRR

n

m mr r r rATACTIC

= r (racemic) diad = syndiotactic diad

= m (meso) diad = isotactic diadm

r

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

•••• MACROMOLECULAR NETWORKS

• Loose Networks

••••••••

•••• ••••

••••

••••

••••

••••

ELEMENTARY CHAIN

Portion of chain in between 2 branching points

••••••••

••••

ELEMENTARY CHAIN > 5 MONOMERIC UNITS

Exs: •••• VULCANIZED RUBBER

Sx

Sx~ x=3

~ 1 crosslink/ 300 RU

•••• crosslinked POLY-HEMA (Poly(hydroxyethyl methacrylate))

This polymers forms loose networks when crosslinked.The solvent penetrates the interstitial voids forming a gel (it swells)

• Dense Networks(Thermosets)

ELEMENTARY CHAIN < 5 MONOMERIC UNITS

The linear polymers are thermoplastics

THERMOSETS:

- ARE INSOLUBLE

- DO NOT SWELL WITH ANY SOLVENT

- ARE RIGID

- ARE INFLEXIBLE

- ARE BREAKABLE

The linear polymers are thermoplastics

Exs: •••• EPOXY RESINS

HO OH(n+1) CH CH2

O+ (n+2) CH2Cl

- (n+2) NaCl

NaOH

HCH2C

O

CH2 O O CH2 CH CH2

OH

O O CH CH2

O

CH2

n

bisphenolepichlorohydrin (excess)

“prepolymer” (DP n = ~3 – 10)

Pre-polymer reacts with epoxyfunctonal groups

∆∆∆∆

DENSE NETWORKS

- Strong glues (ARALDITE© type)

- “Fibreglass” for leisure boats, laminates, etc.

HO C OHCH3

CH3

bis-phenol A

•••• PHENOL-FORMALDEHYDE RESINS

Reaction with an excess of phenol

Prepolymer (n ~ 3 - 10) (Novolac)

In moulding, further formadehyde is added(or paraformaldehyde or hexamethylenetetramine)

OH

+ C O

H

H

OH OHOH

excess

pH ~ 4.5 - 6

SnR4 ou M(OR)n

- H2O

- Parts of electrical equipment- Electrical switches- Telephones (old ones)- Heaters, etc.- Furniture coatings

DENSE NETWORK

CH2 CH2

CH2

OH

CH2

CH2

OH

CH2

CH2

OH OH

CH2

CH2

CH2OH

H2C

H2C

Resite- Insoluble- Infusible

Reticulated polymer

∆∆∆∆(>230ºC)

CH2O

OH

CH2

OHOH

CH2

n

Novolac(linear prepolymer with n ~ 3-10)

C O

H

H

+ C

O

H2N NH2∆∆∆∆

C

O

H2N NH CH2 OH +

H

O

H

C

O

NH NH CH2 OHCH2HO

C

O

NH NCH2

CH2

N

CH2CH2N

CH2 NH CH2

C NH CH2O

∆∆∆∆ ∆∆∆∆

+ H2O

H

O

H

H

O

H

+ ++

urea

•••• UREA-FORMALDEHYDE RESINS

C NH CH2O

- Furniture coatings- Electrical equipment

∆∆∆∆

DENSE NETWORK

etc.

CH2N N CH2 NCH2N

C

CC

C

CH2 N

CO

O O

O O

CH2N N CH2 NCH2N

C C

CH2 N

OO

Reticulated polymer

C O

H

H

+∆∆∆∆N

N

N

H2N NH2

NH2

N

N

N

N NH

NH2C CH2

CH

HOH2C

CH2melamine

•••• MELAMINE-FORMALDEHYDE RESINS

- Furniture coatings (Formica©)

CH2CH2melamine

∆∆∆∆

DENSE NETWORK

etc.

• LINEAR

• CYCLOLINEAR

• BRANCHED

• COPOLYMERS

PRIMARY STRUCTURE

PRIMARY

resulting from the covalent bonds between repeating units

• COPOLYMERS

• POLYMER CHAIN ISOMERISM AND TACTICITY

• MACROMOLECULAR NETWORKS

• NATURAL MACROMOLECULES

PRIMARYSTRUCTURE

•••• NATURAL MACROMOLECULES

- POLYSACCHARIDES- PROTEINS AND POLYPEPTIDES- NUCLEIC ACIDS- NATURAL RUBBER

• Polysaccharides

DP=15000 (in cotton)

DP=10000 (in wood)

Native cellulose

DP=2600

Cellulose separation from lignin

(there is some degradation)

(DP=150-7000)

(DP>7000)

cellulose xanthate(water soluble)

• Cellulose (Modifications)

spinningfibres H+

Cellulose

fibresviscose rayon

slit

H+

Cellophane sheet

Textile fibres

Rayon acetate

spinning

Regenerated Cellulose

cellulose nitrate

Plastics, lacquers, explosives

cellulose hydroxyacetate

emulsifier, shampoo

additives (thickeners)

cellulose acetate Rayon acetate

10 - 11% N 13.5% N

aminoacid

• Polypeptides (Proteins)

They are polymers (or copolymers) of aminoacids

- H2O

PEPTIDE BOND

Peptides → 2 – 10 units

Polypeptides → > 10 units

Exs: - Wool, hair, etc. → αααα-keratin

- Silk → ββββ-keratin (fibroin)

• Nucleic Acids

Polyesters obtained from the condensation reaction between phosphoric acid and a sugar (D-ribose, D-2-deoxyribose)

DNARNA

O

H

HH

H

CH2

HO

PO

O

OH

base

Ex: DNA

SECONDARY STRUCTURE

resulting from the spatial arrangement of the main chain segments according to regular patterns, which are dictated by stereochemistry (most stable conformations) or hydrogen bonds (αααα-helix or ββββ-sheet)

Ex: Isotactic vinyl polymers tend to acquire a minimum energy conformation by curling up on itself,

adopting an αααα-helix conformation, that enables the minimization of the repulsion between side groups

R R R R R R R

n

Hydrogenbond

•••• αααα-Helix

Ex: Some proteins acquire αααα-helix- or ββββ-sheet structures owing to the establishment of intramolecular hydrogen bonds

Hydrogenbond

αααα-Helix(top view)

Hydrogenbond

bond

Hydrogenbond

•••• ββββ-Sheet(folded)

Protein foldsin ββββ-sheets

TERTIARY STRUCTURE

resulting from the whole tridimensional structure of the chain, which is conditioned by intramolecular forces and hydrogen bonds between distant segments of the chain

Intramolecular arragement RIBONUCLEASE

•••• Tertiary structures composed only by αααα-helices secondary structures

•••• Tertiary structures composed only by ββββ-sheets secondary structures

•••• Tertiary structures composed by αααα-helices and ββββ-sheets secondary structures

QUATERNARY STRUCTURE

resulting from the interaction between different chains

DNA(resulting from the association of 2

polynucleotide chains, through H-bonds between the bases)

HEMOGLOBINE(resulting from the association of 4 proteins: 2 αααα-globines and 2 ββββ-globines. Each globine has a hemecontaining a Fe atom)

AGREGGATES

• COLLOIDS

• MICELLES

•••• Colloids

Basically insoluble materials, which are kept in solution, as molecular aggregates(very tiny and invisible), owing to stabilizing factors, for example, electrostatic repulsion.

These factors prevent particle growth and precipitation

SOL – When the colloids move without kinematic restrictions

GEL – When the colloids touch each other forming semi-permanent bonds, restrictingtheir thermal motion (physic gel) → analogy with polymeric networks

COLLOIDSHydrophobic

Hydrophilic

•••• Micelles

Agreggates of small molecules, generally thermodynamically stable (opposite to colloids)

Observed in molecules containing a:

- Hydrophilic part (polar group)

- Hydrophobic part (nonpolar group)

Detergentsor

Surfactants

Increase of thesurfactant concentration

Increase of thesurfactant concentration

LAYERS(formation in bulk

solution)MICELLES(formation in bulk

solution)

INDUSTRIAL POLYMERSmost important

Gross annual consumption of polymers: 150 Mton/Year

- PE (LDPE + HDPE)- PP- PVC- PS- Styrene-Butadiene- Acrylonitrile-Butadiene-Styrene (ABS)- Polyamides (Nylon-6) - Polyesters (PET and PBT)

TH

ER

MO

PLA

ST

ICS

(85

%)

COMMODITY(90%)

- Polyamides (Nylon-6,6)- Polycarbonates- Polyesters- Poly(oxymethylene) (POM)

99%

- Phenol-formaldehyde- Urea-formaldehyde- Unsaturated Polyesters- Epoxy Resins- Melamine-Formaldehyde

90%

TH

ER

MO

SE

TS

(15

%)

PLASTICS(56%)

TH

ER

MO

PLA

ST

ICS

ENGINEERING- Poly(oxymethylene) (POM)- Poly(phenylene oxide) (PPO)- Poly(imides)- Polysulfones- etc.

- Polyester (PET, etc.)- Polyamides (Nylon 6 and 6,6, etc.) - Olefinic (PP, etc.)- Acrylic (AN 80-90% + VA or VC)

70%

- Cellulose acetate (rayon acetate)- Cellulose xanthate (viscose rayon)CELLULOSIC

NON-CELLULOSIC

FIBRES(18%)

SYNTHETIC

(18%)

NATURAL(50%)

- Cotton (polysaccharide)(~80%)- Wool (polypeptide) (20%)-Silk (polypeptide) (less important)

RUBBERS(11%)

SYNTHETIC(Elastomers)

- Styrene – butadiene (SBR)- Polybutadiene (“synthetic rubber”)- Ethylene-propylene-diene (EPDM rubber)- Polychloroprene (“neoprene rubber”)- Poly(isoprene) ( “natural synthetic rubber”)- Acrylonitrile-butadiene (“nitrile rubber”)- Isobutylene-isoprene (“butyl rubber”)- Polysiloxane (“silicone rubber”)- Polyurethane (“urethane rubber”)- ABA copolymers (“thermoplastic elastomers”)

70%

(11%)

NATURAL(Trees)

- Hevea Brasiliensis (obtained from the latex, which contains 32-35% ofpoly(isoprene) 97% 1,4-cis)

- Guayule (Parthenium argentatum) (obtained from the tree pulp,which is boiled and refined)

- Chicle (obtained from the latex, which contains 32-35% of a mixture oflow molecular weight poly(isoprene) 1,4-cisand 1,4-trans)

- Styrene-butadiene latex- Poly(vinyl acetate)- Poly(acrylate esters)

PAINTS

With very complicated formulations:including solvents, filling agents,

- Phenol-formaldehyde- Urea-formaldehyde- Epoxy Resins- Cyanoacrylates

ADHESIVES

including solvents, filling agents,stabilizers, pigments, etc.

Polymers

Fibres Termoplastics Thermosets Elastomers

CrystallineCrystalline Amorphous

Amorphous Amorphous

PROPERTIES AND STRUCTURE

Cristalitos

Matriznão cristalina

crystallites (crystalline zones)

Amorphous zones

Crystalline or Semicrystalline Polymers

When the percentage of crystallites is largely the majority with respect to amorphous zones.In other words, when there are:

Syndiotactic

- Strong intermolecular forces(hydrogen bonds and Keesom forces)

- Highly stereoregular structures(isotactic or syndiotactic polymers)

Isotactic Nylon 6,6- Hydrogen bonds

- permanently aligned dipoles

It is characterized by a melting temperature – Tm

Amorphous Polymer

When the morphology is mainly amorphous, lacking or having few crystallites.

It is characterized by a glass transition temperature–Tg

Tg - temperature at which long range (20 to 50 atoms) chain rotations and translations are observed, the polymer

acquiring elastomeric properties. Further increasing the temperature the polymer will lose these properties

and will melt to give a liquid.

There is:- an increase of specific volume- a change in the specific heat

Amorphous and semicrystalline polymeershave aTg and aTm

Amorphous and semicrystalline polymers:Elastomers: Tg < Tambient

Thermoplastics: Tg > Tambient

- a change in the specific heat - alteration of the refractive index and thermal conductivity

T T Tv f

Volu

me

espe

cífi

co

Sólido

não cristalino

Líquido

Cristal

g

TYPES OF AVERAGE MOLECULAR WEIGHTS OF POLYMERS

Molecular Weight ≡≡≡≡ Molecular Mass≡≡≡≡ Molar Mass(Units: g/mol)

It depends basically on the determination method used:

- Colligative methods(freezing-point depression, boiling point elevation,changes in vapour pressure, osmometry)

•••• NUMBER-AVERAGE MOLECULAR WEIGHT,

Resulting from measurements depending on the number(concentration) of macromolecules:

nM

i i ii 1 i 1

w w N M∞ ∞∞ ∞∞ ∞∞ ∞

= == == == == == == == =∑ ∑∑ ∑∑ ∑∑ ∑

w = total mass of polymer samplewi = mass of a chain with a degree of polymerization of iNi = number of moles of a chain with a molecular weight of M i

changes in vapour pressure, osmometry)

- End group analysis

i ii 1

n i ii 1

i ii 1 i 1

N Mw

M x M

N N

∞∞∞∞

∞∞∞∞====

∞ ∞∞ ∞∞ ∞∞ ∞====

= == == == =

= = == = == = == = =∑∑∑∑

∑∑∑∑∑ ∑∑ ∑∑ ∑∑ ∑

xi = molar fraction of a chain of the i type = i i

TOTALi

i 1

N NN

N∞∞∞∞

====

====

∑∑∑∑

i i ii 1 i 1

ni

iii 1 i 1

N M w

Mw

NM

∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =

= == == == =∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

- Light Scattering

•••• WEIGHT-AVERAGE MOLECULAR WEIGHT,

Resulting from measuremnts depending on the massof macromolecules:

wM

- Equilibrium Sedimentation

2i i i i

i 1 i 1w i i

i 1i i i

i 1 i 1

w M N MM m M

w N M

∞ ∞∞ ∞∞ ∞∞ ∞

∞∞∞∞= == == == =

∞ ∞∞ ∞∞ ∞∞ ∞====

= == == == =

= = == = == = == = =∑ ∑∑ ∑∑ ∑∑ ∑

∑∑∑∑∑ ∑∑ ∑∑ ∑∑ ∑

mi = mass fraction of a chain of the i type = i i

TOTALi

i 1

w ww

w∞∞∞∞

====

====

∑∑∑∑

2i i i i

i 1 i 1w

i i ii 1 i 1

N M w M

M

N M w

∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =

= == == == =∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

Resulting from measurements of ultracentrifugation sedimentation of polymer solutions

3 2i i i i

i 1 i 1z

2i i i i

i 1 i 1

N M w M

M

N M w M

∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =

= == == == =∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

•••• Z-AVERAGE MOLECULAR WEIGHT, zM

a 1 ai i i i

i 1 i 1

a a 1i i i i

i 1 i 1

N M w M

M

N M w M

∞ ∞∞ ∞∞ ∞∞ ∞++++

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

−−−−

= == == == =

= == == == =∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

•••• GENERAL EQUATION OF MOLECULAR WEIGHTS

n

w

z

M a 0

M a 1

M a 2

⇒⇒⇒⇒ ====

⇒⇒⇒⇒ ====

⇒⇒⇒⇒ ====

z w nM M M≥ ≥≥ ≥≥ ≥≥ ≥Thus:

z w nM M M= == == == =• When:

w

n

M1

M====

M i

Ni

ALL THE CHAINS HAVE THE SAME LENGTH

MONODISPERSE POLYMER

•••• POLYDISPERSITY INDEX (POLYDISPERSITY), w nM / M

z w nM M M> >> >> >> >• When:

w

n

M1

M>>>>

M i

Ni

THE CHAIN HAVE A MOLECULAR WEIGHT DISTRIBUTION

POLYDISPERSE POLYMER

M i

Ni

σσσσ

22

i i i iN M N MM

∞ ∞∞ ∞∞ ∞∞ ∞

∑ ∑∑ ∑∑ ∑∑ ∑

σσσσ – distribution standard deviation:

i i i iwi 1 i 1

nn

i ii 1 i 1

N M N MM

M 1M

N N

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =

σ = − = −σ = − = −σ = − = −σ = − = −

∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

2nd moment ofthe distribution

1st moment of the distribution

The larger , the broader the distributionw

n

MM

Resulting from viscometry measurements in polymer solutions

1 1

1i i i i

i 1 i 1v

i i ii 1 i 1

a aa aN M w M

M

N M w

∞ ∞∞ ∞∞ ∞∞ ∞++++

= == == == =∞ ∞∞ ∞∞ ∞∞ ∞

= == == == =

= == == == =

∑ ∑∑ ∑∑ ∑∑ ∑

∑ ∑∑ ∑∑ ∑∑ ∑

•••• VISCOSITY-AVERAGE MOLECULAR WEIGHT, vM

[[[[ ]]]] avKMη =η =η =η =

[ηηηη] = intrinsic viscosityK = constanta = constant (normally, 0,8 > to > 0,5)

tabulated or measuredexperimentally

w v nM M M≥ ≥≥ ≥≥ ≥≥ ≥

normally closer to wM

Problem 2: After mixing 9 g of a polymer sample with a molecular weight of 30000 to 5 gof a polymer with a molecular weight of 50000, what are the Mn, Mw, Mz and Mw/M n of the resulting sample?

Problem 1: After mixing 9 mol of a polymer sample with a molecular weight of 30000 to 5 molof a polymer with a molecular weight of 50000, what are the Mn, Mw, Mz and Mw/M n of the resulting sample?

Problem 3: Calculate the Mn, Mw, Mw/M n and σσσσ for the following molecular weight distribution(the coordinates of 9 particular points of the distribution are shown):

70

10, 16000

25, 26000

50, 3600055, 46000

65, 56000

40, 66000

20, 7600015, 86000

5, 960000

10

20

30

40

50

60

70

0 50 100 150

M x 10 -3

Uni

dade

s ar

bitr

ária

sA

rbitr

ary

Uni

ts

- M. P. Stevens, "Polymer Chemistry - An Introduction", 3rd ed., Oxford Univ. Press, 1999 (DEQ library: 2 nd ed., 1990)

- P. Munk, T.M. Aminabhavi, "Introduction to Macromolecular Science", 3rd ed., John Wiley &Sons, N.Y., 2002. (DEQ library: 1 st ed., 1989)

Bibliography (Block 1)

- G. Odian, “Principles of Polymerization”, 4th ed., Wiley-Interscience, N.Y., 2004(Pedro T. Gomes office )

- M Michalovic, K. Anderson, L. Mathias, “The Macrogalleria”, site do Polymer Site LearningCenter (da University of Southern Mississippi) (http://www.pslc.ws/macrog.htm)