Biomedical Engineering Reference
In-Depth Information
R
O
O
O
O
O
*
O
O
N
H
U
*
n
1.23
Tyrosine-derived arylates.
R
O
O
O
O
O
PEG
*
O
O
O
O
N
H
*
f
1-
f
1.24
Tyrosine-containing poly(DTR-PEG carbonates).
R
O
O
O
O
O
O
N
H
*
*
m
n
1.25
Tyrosine-containing poly(DTR-PEG ethers).
diacids (such as succinic, adipic, suberic and sebacic acids) in order to
modify backbone structure and thus polymer properties.
∑
Tyrosine-containing poly(DTr-PeG carbonates) (Fig. 1.24): these
polymers are obtained with a copolymerization of tyrosine-derived
diphenolic monomers with blocks of poly(ethylene glycol) (PeG).
There are three main degrees of freedom that allow to modulate material
properties: mole fraction of PeG, molecular weight of PeG, and the
pendent alkyl group. PeG increases material hydrophilicity and thus
water uptake; when the amount of PeG is 15% (mol) the material has a
hydrogel-like behavior, whilst with a PeG content of about 70% (mol)
the material becomes water soluble. Moreover, as PeG fraction increases,
polymer becomes less stiff and more flexible, and degradation is more
rapid.
∑
Tyrosine-containing poly(DTr-PeG ethers) (Fig. 1.25): these polymers
are synthesized by copolymerization of tyrosine-derived monomers and
methylsulfone-activated PeG.
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