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33 Cards in this Set
- Front
- Back
3 types of polymers:
Heat active Chemically Light Which is for dentures, acrylic teeth, crown bridge? |
Heat
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3 types of polymers:
Heat active Chemically Light which is for denture repair, relines, ortho appliance, pouring resin |
chemical
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3 types of polymers:
Heat active Chemically Light Whch is composite, adhesive, Glass ionomer cements? |
Light
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3 TOPOLOGICAL classifications of polymers?
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linear, cross linked, or branched
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2 monomer distrubtion classifcations:
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homo or co - polymers
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The supramolecular structure of a polymer is either Amorphous or semicrystalline. describe each
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amorphous - coiled, irregular shape opf chains
semicryst - domains w/ regular structure |
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Describe thermoplastic polymers ( cross links, properties)
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NOT cross linked - linear/branched.
Flow when heated |
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Desscribe thermosetting polymers (cross links, properties)
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Cross linked, Do not melt/reshape - decompose in ehat
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what type of polymer exhibits recovery under low strains?
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elastomer
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Describe degree of saturation of a compound that is an elastomer.
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UNSATURATED
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What is a thermoplastic elastomer? 2 examples
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behaves like rubber at RT, but w/ heat loosens, behaves thermoplastic. Latex, synthetic rubbers
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Polysaccs like alginate and polyisoprenes are examples o fwhat?
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natural polymers
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What are alginates used for? what type of polymer are they?
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impressions - natural polymer
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2 types of synthetic reactions for polymers
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addition and step growth
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What types of synethic polymers have higher MW?
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addition reaction products
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what types of synthetic polymers have lower MW?
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stepgrowth polymer
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A free radical product's active center (for reaction) is what?
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the free radical
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a cationic reaction for synthetic polymer's active center is what? it's propagation site?
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ACID, w/ a positive propgation site
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an anionic reaction for synthetic polymer's active center is what? it's propagation site?
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Nucleophile, w/ negative prop site
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what is the difference between a retarder and an inhibitor
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retarder slows, to make less reactive products
inhibitor STOPS - makes no future reactions |
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4 advantages of MMA?
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able to be manipiulated
Good mech properties (strong/wear resist) Biocompatible (taste/odorless, non-toxic Good esthetic properties |
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2 negatives of MMA?
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exothermic reaction
Flammable (also may be irritant? |
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3 reasons to add a polymer inhibitoir
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prolong setting time
decrease light sensitivity extend shelf life (prevent spontaneuos polymerzation) |
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For PMMA, cross linking is
Positive (3) Negative (1) |
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1 - hard/stiff 2 - crazing resistance 3 - increase thermal resistance (-) brittle |
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what is the use of plasticizing?
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reline dentures?
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3 classifications of polymerss based on initiation reactions?
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heat, chemical, light
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3 classifications of polymerss based on initiation reactions: heat/light/chemical. each has how many comoonents?
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heat - 2
chem - 2 light - 1 |
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What are the 2 components of a heat-activated polymer?
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powder - PMMA prepolymer
Liquid - MMA/cross link/additive/regulatro in a 3:1 ratio |
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why is a regulator needed for a heat activated reaction?
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if it heats too fast, it will be porous
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what are the 2 components of a chemcially activated initatior
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powder - PMMA pre/copolymer DIBENZOYL PEROXIDE
liquid - MMA, cross link, inhiitor, accelerator, UV absorbers |
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What is a disadvantage of a chemically activated polymer (vs heat)
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LESS color stability
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what is camphorquinone?
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light initiating system
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What is BIS-GMA
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dimethacylate light iactivated resin
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