Week 2: Polymers Flashcards
Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule
polymer
smallest repeating molecule in polymer chain
monomer
reaction of monomers to synthesize/form
polymers
polymerization
elimination/release of a smaller molecule while forming covalent bonding between monomers (e.g., water, ethanol, etc)
condensation polymerization
polymerization in which free radicals (unpaired electron) form to react with vinyl compounds to form the polymer.
addition polymerization
hard rigid glass polymer
acrylic resin
forms an adhesive water-soluble polymer
acrylic acid
polymer aspects
- length
- temp
- alignment
- disentanglement
the number of repeating units in a polymer, the number of monomer units joined together
degree of polymerization
degree of polymerization multiplied by the molecular weight of the repeating units; “average mass of molecules”
molecular weight
the _____ the molecular weight, the ____ the strength and the rigidity because it is more difficult to _____/____
higher, higher, uncoil/disentangle
3 physical states of polymers
elastomers
hard amorphous polymers
hard semicrystalline
polymer with high Tg = ____ at mouth temp
polymer with low Tg = ____ at mouth temp
rigid at high Tg
flexible at high Tg
effects of cross-linking on properties
- more purely elastic, less viscous
- may have higher Tg
- hard and more brittle
two types of naturally occurring polymers
hydrocolloids, natural rubbers