elastic modulus of petp: changes during fibre drawing
TRANSCRIPT
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