Monomer is a small molecule

Polymer is a long chain of monomers

The process by which monomers combine is called polymerization

Repeating units are a simplified method of drawing a polymer

Polymers consist of repeating molecular units which usually are joined by covalent bonds

A pendant group on a polymer is a small group of atoms (even a small chain sometimes) that hangs off of the main chain (that is, the backbone of the polymer).

Here are some examples of pendant groups circled in red:

                                                                                 

polypropylene polyvinylalcohol polystyrene

Here are some examples of pendant groups circled in red:

Polymers can be classified into several ways:

• Based on Structure of Polymersi) Linear polymers    (ii) Branched chain polymers        (iii) Cross linked polymers

• Based on the Origin of the Polymeri) Natural polymers    (ii) Semi-synthetic polymers        (iii) Synthetic polymers

• Based on Types of Monomersi) Homopolymer     (ii) Copolymer

 • Based on Tacticity (Configuration)

i) Isotactic polymer    (ii) Syndiotactic polymer        (iii) Atactic polymer

• Based on Synthesis i) Addition polymers     (ii) Condensation polymers

• Based on Thermal Processing Behaviour i) Thermoplastic Polymers    (ii) Thermosetting Polymer

Appearance of real linear polymer chains as recorded using an atomic force microscope on surface under liquid medium. Chain contour length for this polymer is ~204 nm; thickness is ~0.4 nm. (The contour length of a polymer chain is its length at maximum

physically possible extension).

Linear Polymers:

Branched Polymer:

Linear Polymer:

Cross-linked Polymer:Linear Polymer:

Star Polymer:

Dendrimers:

Cellulose

Cellulose, a linear polymer of D-glucose units (two are shown) linked by

β(1→4)-glycosidic bonds.

Natural Polymers: Polymers in Plants

Starch

Natural Rubber

Natural rubber is a polymer of isoprene

Charles GOODYEAR discovered

vulcanization in 1839

Protein

Natural Polymers: Polymers in Animals

Functions of Proteins

• All enzymes are proteins.• Structural: e.g. collagen in teehth and bone; keratin in skin, hair

and nails.• Contractile proteins: actin and myosin in muscles allow

contraction and therefore movement.• Hormones: many hormones have a protein structure (e.g. insulin,

glucagon, growth hormone).• Transport: for example, haemoglobin facilitates the transport of

oxygen around the body• Defence: immunoglobulins (antibodies) protect the body against

foreign invaders; fibrinogen in the blood is vital for the clotting process.

(polymer of the N-Acetylglucosamine units)

Chitin

the exoskeletons of crabs, lobsters and shrimps

Cellulose nitrate

Semi-synthetic Polymers: Cellulose nitrate and cellulose acetate

Cellulose triacetate

obtained from natural polymers by subjecting them to some chemical processes

Bakelite (1909)

1950s Black Bakelite Telephone

Blue Bakelite Handle

Synthetic Polymers

Bakelite Sockets & Switches

Poly(methyl methacrylate) (PMMA) (1935)

PMMA sheet (organic glass) Plexiglass aquarium

Polystyrene (1937)

rigid polystyrene case, weight 2.6 Kg

Styrofoam - a brand of polystyrene foam

Nylon 6,6 (1938)

A 1949 advertisement in Life Magazine sings the praises of

nylon products.

Natural animal bristles were replaced by synthetic fibers, usually nylon, by DuPont

in 1938.

Polyesters (1950)

Poly(ethylene terephthalate)-PET bottles

Recycled PET Fabric

Polycarbonates (1957)

Lexan MR-10 windshields

GE Lexan® face shield