Week 2: Polymers Flashcards

1
Q

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

A

polymer

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2
Q

smallest repeating molecule in polymer chain

A

monomer

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3
Q

reaction of monomers to synthesize/form

polymers

A

polymerization

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4
Q

elimination/release of a smaller molecule while forming covalent bonding between monomers (e.g., water, ethanol, etc)

A

condensation polymerization

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5
Q

polymerization in which free radicals (unpaired electron) form to react with vinyl compounds to form the polymer.

A

addition polymerization

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6
Q

hard rigid glass polymer

A

acrylic resin

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7
Q

forms an adhesive water-soluble polymer

A

acrylic acid

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8
Q

polymer aspects

A
  • length
  • temp
  • alignment
  • disentanglement
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9
Q

the number of repeating units in a polymer, the number of monomer units joined together

A

degree of polymerization

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10
Q

degree of polymerization multiplied by the molecular weight of the repeating units; “average mass of molecules”

A

molecular weight

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11
Q

the _____ the molecular weight, the ____ the strength and the rigidity because it is more difficult to _____/____

A

higher, higher, uncoil/disentangle

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12
Q

3 physical states of polymers

A

elastomers
hard amorphous polymers
hard semicrystalline

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13
Q

polymer with high Tg = ____ at mouth temp

polymer with low Tg = ____ at mouth temp

A

rigid at high Tg

flexible at high Tg

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14
Q

effects of cross-linking on properties

A
  • more purely elastic, less viscous
  • may have higher Tg
  • hard and more brittle
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15
Q

two types of naturally occurring polymers

A

hydrocolloids, natural rubbers

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16
Q

hydrocolloids (2 to know)

A

agar, alginate

17
Q

types of natural rubber

A

gutta percha

18
Q

types of hard synthetic polymers

A
  • condensation polymers
  • free radical addition polymers (mostly linear)
  • free radicals addition polymers (cross-linked)
19
Q

flexible synthetic polymers

A
  • elastomers

- plasticized methacrylates

20
Q

a polymeric material is made out of polymeric _____

A

molecules

21
Q

polymeric molecules are composed of ____

A

monomers

22
Q

acrylic ___ is supplied as a _________ and the final polymer is synthesized in office/lab

A

resin, liquid monomer

23
Q

acrylic ___ is supplied as a ________ and is ready to be used by the dentist

A

acid, liquid polymer

24
Q

three steps needed for addition polymerization

A
  • generation of radicals
  • propagation of reaction
  • termination of reaction
25
Q

generation of radicals is accomplished when ______/(____) works on the ______(___) of reaction

A

activator (energy), initiator (molecule)

26
Q

examples of activators; which is most important in dentistry?

A

heat, light, chemical; light is most important

27
Q

intramolecular forces in polymeric molecules are ___ because covalent bonds are formed while polymer ____

A

strong, polymerizes

28
Q

intermolecular forces between polymeric molecules to form a polymeric material can be _________ due to…

A

less to more strong; entanglement/friction, van der Waals forces, covalent bonds

29
Q

small molecules that act reducing friction between polymeric molecules and thus soften the polymer to make it more flexible/visoelastic

A

plasticizers

30
Q

example of a typical plasticizer

A

water

31
Q

cross-linker polymers are usually more ____________ because mobility of molecules is limited

A

more rigid/harder/stronger, less viscoelastic (more purely elastic)

32
Q

____ can be obtained by combining different monomers with different sequential arrangments

A

co-polymers

33
Q

viscous material refers to…

A
  • breaking of intermolecular bonds

- disentanglement of molecules

34
Q

example of cross-linked polymer in dentistry

A

dimethacrylate resins (resin composites)

35
Q

examples of condensation polymerization in dentistry

A

formation of nylon, polysulfides, silicones

36
Q

examples of free addition polymerization in dentistry

A

acrylics

37
Q

addition polymerization reaction

A
  1. generation of free radicals
  2. propagation of reaction
  3. termination of propagation