elastic modulus of petp: changes during fibre drawing

Elastic modulus of PETP:changes during fibre drawing

Hall: Polymer Materials, 2nd edn

Polymer viscoelasticity

Maxwell element

D

Hookean elastic spring

Viscous elementdashpot

Polymer viscoelasticity

Maxwell element

D

At constant applied stress

Polymer viscoelasticity

Maxwell element

D

At constant applied strain

Polymer viscoelasticity

Kelvin-Voigt element

D

Polymer viscoelasticity

Standard linear solid

D1

D2

ADHESIVES

Many commercial adhesives

Four examples

Polymer cement: polystyrene Latex or emulsion type: EvoStik PVAEpoxy: thermoset AralditeCyanoacrylate: Loctite, Glasbond

ADHESIVES

Polystyrene cement

Solid PS polymer + solventLiquid adhesiveBonds by solvent evaporation

Yes, it’s that simple.

Latex or emulsion type adhesiveEvoStik

Spherical polymer particles dispersed in water

Ma, Davis and Scriven Prog Org Coatings 2005, v52, 46-62

Latex coalescenceFilm formation

As water is lost, particles come into contact and merge

Ma, Davis and Scriven Prog Org Coatings 2005, v52, 46-62

Super-glue

Cyanoacrylate adhesives

The uncured adhesive consists of a monomercommonly

CH2=C-COOCH3

The polymerisation reaction is triggered by traces of water, generally present on the surface to be bonded

CN

Melting temperatures of common polymers

•Polyethylene PE 100 °C •Polypropylene PP 130 °C

Hall: Polymer Materials, 2nd edn

Polymer forming:

extrusion

Hall: Polymer Materials, 2nd edn

Polymer forming:

extrusioninjection moulding

Hall: Polymer Materials, 2nd edn

Polymer forming:

extrusioninjection mouldingrotational moulding

Hall: Polymer Materials, 2nd edn

Polymer forming:

extrusioninjection mouldingrotational mouldingblow moulding

Hall: Polymer Materials, 2nd edn

Polymer forming: simple extrusion

Granules of raw thermoplastic IN

Increasing temperature along the extruder barrel

Extruded product OUT

Hall: Polymer Materials, 2nd edn

Polymer forming: simple extrusion

Granules of raw thermoplastic IN

Increasing temperature along the extruder

Die swell

Extruded product OUT

Polymer forming: injection moulding

Polymer forming: rotational moulding

Polymer forming: blow moulding

Netlon process for mesh

Hall: Polymers, in Civil Engineering Materials, 5nd edn

Netlon process:1992 patent

(one of many)

Netlon process for mesh

Hall: “Polymers”, in Civil Engineering Materials, 5nd edn, Pt VI

Netlon process for mesh

Hall: “Polymers”, in Civil Engineering Materials, 5nd edn, Pt VI