4.2.3 - macromolecules: proteins, polymers and carbohydrates Flashcards
what are synthetic polymers?
plastics formed through addition reactions
what are 3 types of synthetic polymers?
- LDPE/HDPE
- PP
- PTFE
what factor will effect the strength of the dispersion forces?
- density
How do weak IMF affect LDPE/HDPE?
they make the plastic:
- soft
- flexible
- transparent
- low MP
- low tensile strength
How do strong IMF affect LDPE/HDPE?
they make the plastic:
- rigid
- tougher
- opaque
- higher MP
- higher tensile strength
what conditions cause LDPE/HDPE to become weaker?
- high temperatures
- high pressures
- causing randomness in structure (branching) making the structure more amorphous
what conditions cause LDPE/HDPE to become stronger?
- low temperatures
- low pressures
- causes order in structure (no branching) making the structure more crystalline?
why is the methyl group positioning important on polypropene (PP)?
because changing the packaging will effect the strength of the dispersion forces
define isotactic
strongest IMF being the most rigid and less flexible
what are the properties of polytetrafluoroethene (PTFE)?
- biodegradability
- biodegradability: formed via an addition reaction that is not able to be broken down naturally
define atactic
weakest IMF being the least rigid (lowest strength) and highest flexibililty
define syntactic
not as strong as isotactic but stronger than atactic
define tensile strength
- Depends on the positioning of the methyl side group (tacticity).
- Higher tensile strength is more rigid, stronger and less flexible
order the dispersion forces; isotactic, syntactic and atactic in terms of strength
- isotactic > syntactic > atactic
- due to the small side group
define biodegradability
formed via an addition reaction that is not able to be naturally broken down
define density
depends on the positioning of the methyl side group (tacticity)
what are the properties of polytetrafluoroethene (PTFE)?
- tensile strength
what are the properties of polytetrafluoroethene (PTFE)?
- density
density: high density due to size of fluorine allowing for polymer chain to pack tightly
what are the properties of polytetrafluoroethene (PTFE)?
- reactivity
- high unreactive and chemically inert - good for nonstick as it doesn’t interact with other chemicals