What’s
a polyolefin?
According to Whittington’s Dictionary of Plastics,
polyolefins are “polymers of relatively simple olefins
such as ethylene, propylene, butenes, isoprenes, and pentenes;
and copolymers and modifications thereof.” So
what’s an olefin?
Again, from Whittington’s: “The group
of unsaturated hydrocarbons of the general formula CnH2n.”
Finally, from Rosato’s Plastics
Encyclopedia and Dictionary: “The family of polyolefins
includes polyethylene, polypropylene, ethylene-vinyl acetate,
ionomers, polybutylene, polyisobutylene, and polymethylpentene.”
|
| An
important concept in polymer rheology is that of viscosity.
The definition of viscosity is the resistance of a material
to flow. (J.F. Carley, Whittington’s Dictionary
of Plastics, Technomic Publishing, Lancaster, Pa., 1993).
The easiest way to understand this is the form of examples:
| Common
materials and their relative viscosities |
| Relative
Viscosity |
Materials |
| Low |
Gasoline |
| Medium-Low |
Cooking
Oil |
| Medium-High |
Maple
Syrup |
| High |
"Silly
Putty" |
|
