part1

Polymer Colloids for Home and Personal Care ProductsDr ir Stefan BonUnilever Polymer Course 2003: 

Polymer Colloids for Home and Personal Care Products Dr ir Stefan Bon Unilever Polymer Course 2003

1.The Basic Concepts: 

1.The Basic Concepts History of Polymer Science Topology and Monomer Sequence Stereochemistry/Tacticity Molecular Weight Distributions

Polymers - poly = many, meros = partsPlastic - plasticos = to shape or form: 

Polymers - poly = many, meros = parts Plastic - plasticos = to shape or form Polymer science is relatively new: Macromolecules were not recognized as such until the 1920s (Staudinger) Exponential industrial growth since Worldwar II (1939-1945) In 1998 annual polymer consumption in Europe: 30,381,000 ton (On average each European citizen consumed 75.8 kg of polymer in 1998) From the mid 1980s recycling becomes big business (In 1996 in the USA 9.4 wt% of disposable waste was synthetic polymers)

Worldwide Polymer Production: 

Worldwide Polymer Production

Chemical IndustryUSA Employment: 

Chemical Industry USA Employment 1975 1985 1995 Inorganic Chemistry 9.5% 8.1% 6.7% Drugs 10.7% 11.6% 13.5% Soaps, detergents 9.1% 8.4% 7.9% Organic Chemistry 9.6% 9.0% 7.4% Agriculture 4.2% 3.4% 2.8% Synthetic Polymers 56.9% 59.5% 61.7% Total ( × 1000) 1561 1769 1924

Categories of Polymers: 

Categories of Polymers Natural Polymers Origin commodity Synthetic Polymers engineering specialty Thermoplastics Crosslinks Elastomers Thermosets

Historic Highlights in Polymer Chemistry: 

Historic Highlights in Polymer Chemistry 1600 BC - Meso-americans produce Rubber rubber balls rubber handles for tools (600-900 AD) medicinal chewing gum, rubber boots and clothes (1400 AD) 1830 AD - Re-invention of Rubber. New -vulcanisation with Sulphur - Charles Goodyear pneumatic tire (Real: 1845 Thomson, but ‘copy’1888 Dunlop) 1846 Gun Cotton by Christian Schönberg 1866 - Celluloid Wesley Hyatt & Alexander Parkes billiard balls

Meso-American Rubber: 

Meso-American Rubber Latex from Castilla Elastica Liquid extracted from Ipomoea Alba (morning glory vine) Mixing causes: Latex coagulation and purification Introduction of plasticizers Thermal curing: Crystalline entanglements Chemical crosslinking via sulfonyl chlorides and acids

Slide9: 

1907 - Bakelite Leo Baekeland electrical insulator light-weight war machinery 1924 Concept of Macromolecules H.Staudinger (Nobel Prize 1953) 1929 Concepts of Addition and Condensation polymers, Wallace H. Carothers neoprene polyesters nylons 1929 Plastisizing PVC by Waldo Semon 1938 TEFLON by Roy Plunkett 1943/1949 Silly Putty by James Wright/Peter Hodgson 1953/1954 Polyethylene/polypropylene Karl Ziegler & Giulio Natta (Nobel Prize 1963)

Concept of Macromolecules: 

Concept of Macromolecules “Es ist aber wichtig den Molekülbegriff hier anzuwenden, trotzdem er sehr stark von dem bei dem molekular-dispersen System gebrauchten abweicht; denn wenn wir die Kolloidteilchen als Moleküle des Kautshuks bezeichnen, so soll damit ausgedrückt werden, daß die einzelnen Isoprenreste, die das Kolloidteilchen aufbauen, durch normale chemische Bindungen zusammengehalten werden, und daß wir im strukturchemischen Sinn es mit sehr langen Kohlenstoffketten zu tun haben…..Für solche Kolloidteilchen….schlagen wir zum unterschied die Bezeichnung Makromolekül vor.” taken from: Berichte der Deutschen Chemische Gesellschaft, 1924, 57, 1208-1208.

Slide11: 

1974 Paul J. Flory Nobel Prize Flory temperature Chain Transfer Universal constant 1991 Pierre-Gilles de Gennes Nobel Prize Reptation model 2000 Heeger, Macdiarmid, Shirakawa Nobel Prize conductive polymers 2002 - John B. Fenn, Koichi Tanaka, Kurt Wüthrich Nobel Prize Structural determination biomacromolecules

Conductive Polyacetylene: 

Conductive Polyacetylene Trans polyacetylene Doping. Conductivity similar to copper/silver. LED: principle of electroluminescence

Polymer Chain Topology: 

Polymer Chain Topology Linear in case of copolymers: random alternating, gradient or tapered, blocks Cyclic Branched irregular comb (e.g. graft copolymer) star

Slide14: 

hyper-branched

Slide15: 

dendritic

Slide16: 

Crosslinked structures hydrogel

How to Classify Polymerisations?: 

How to Classify Polymerisations? According to kinetics and mechanism Addition versus Condensation polymerisation Step-growth or Chain-growth …and where does living fit in? According to polymerisation process Mode of operation Batch or Ab initio Semi-batch Continuous How many phases? homogeneous heterogeneous bulk solution emulsion dispersion precipitation suspension surface solid state

Addition versus Condensation polymerisation: 

Addition versus Condensation polymerisation Condensation polymers (C): fewer atoms in the backbone because of formation of by-products Addition polymers (A): the repeating unit contains the same atoms as the monomer

A or C??…aaaaaargggh!!!: 

A or C??…aaaaaargggh!!!

Step-growth or Chain-growth?: 

Step-growth or Chain-growth? Step-growth: polymer molecules are build step by step Chain-growth: fast growth of a polymer chain from active site

Steps versus Alice in Chains: 

Steps versus Alice in Chains Low average degree of polymerisation (DP) monomer consumed rapidly but average molar masses increase slowly No initiation No termination steady decrease of overall rate of polymerisation as functional groups are consumed Degree of polymerisation can be very high monomer consumed “slowly” but average molar masses increase fast Initiation needed termination steady-state conditions with relatively a constant rate of polymerisation Replace: polymerisation=intelligence, monomer=music, molar masses=heartbeat, initiation=alcohol, termination=permanent hearing damage, functional groups=creative thoughts

Is step-growth = Condensation?: 

Is step-growth = Condensation? …it seems so ….although…. + 2HCl

Is Chain-growth = Addition?: 

Is Chain-growth = Addition? The brightest idea ever…. Oh well I can always go and work at

And what about living polymerisations?: 

And what about living polymerisations? This term is only used for chain-growth polymerisations Dormant chain-end can be reactivated to make e.g. blocks Characterised by narrow MWD with PD~ 1-1.3 Definition: termination is not one of the essential mechanistic events Chain-growth occurs “stepwise”

Chain Growth: Regioselectivity: 

Chain Growth: Regioselectivity Asymmetric substitution pattern of most monomers Addition may not be completely regiospecific; not 100% head-to-tail

Chain-growth: Tacticity: 

Chain-growth: Tacticity Isotactic: all side groups in one direction Syndiotactic: side groups alternating Atactic: side groups in random order

Stereochemical structural units: 

Stereochemical structural units Smallest structural unit is the dyad: this is a bit confusing since…. What about triads? Three possibilities mm, rr, rm (mr) Tetrats? rrr, rrm, (mrr), rmr, mrm, mmr (or rmm), mmm meso (m) racemic (r) racemic (r) meso (m)

Molecular Weight Distributions (MWDs): 

Molecular Weight Distributions (MWDs) Polymer material consists of polymer chains with a variable number of monomer units fingerprint of polymerisation process physical properties e.g. Tg, viscosity, tensile strength

Average Molecular Weights: 

Average Molecular Weights Number weight z-average (z+1)-average polydispersity

Viscosity average molecular weight: 

Viscosity average molecular weight

Determination of <Mn>: 

Determination of <Mn> End-group analysis: titration, NMR, UV, FTIR, etc. Membrane Osmometry: Vapor Pressure Osmometry Cryoscopy and Ebulliometry GPC or SEC

Determination of <Mw>: 

Determination of <Mw> Light scattering GPC or SEC Ultracentrifugation (also for <Mz> and <Mz+1>) Determination of <Mv>, or K and a viscometry using: