polymers Flashcards
(43 cards)
the extent to which all (entire) monomer is polymerized
degree of conversion
Two molecules react to form a larger molecules with
elimination of a small molecule
condensation polymerization
free radicals react with double bond of a monomer for
crosslinking
– is activated with light
camphoroquinone (CQ)
added to polymer to modify the physical properties
plasticizer
Minimize or prevent spontaneous or accidental
polymerization of monomers
inhibitors
Polymers containing two or more chemically different
types of monomer units to create different polymer
properties
copolymer
low MW monomer =
diluent
condensation polymerization –> like water and alcohols
byproducts
condensation polymerization –> – dimensional stability
low (shrinkage)
Two molecules react to form a larger molecule without
the elimination of a small molecule
additional polymerization (no byproduct)
additional polymerization –> – in composition
no change
additional polymerization –> – dimensional stability
better
examples of additional polymerization
free-radical and ring opening
most dental resins are formed from –
additional polymerization
silicone impression material
condensation polymerization
most common type of additional polymerization
free radical
CQ absorbs light and –
releases free radicals
activator of CQ
blue light
accelerator of CQ
DMAM
Do plasticizers participate in the polymerization rxn?
no
do plasticizers become part of polymer chain?
no
plasticizers – attraction between polymer chains
reduce
plasticizers – the polymer
softens (more flexible)
