Environmental Engineering Reference
In-Depth Information
O
O
Sb 2 O 3
O
O
OH
*
O
O
HO
O
O
O
O
O
OH
HO
O
O
Fischer esterification
O
OH
HO
FDCA
O
HO
Sb 2 O 3
OH
O
O
O
O
O
*
O
O
O
O
O
OH
HO
Scheme 5.3
Pathway to polyester from FDCA, using ethylene glycol and propylene glycol [91].
temperature T m = 215°C, and an onset thermal decomposition T di = 300°C, sug-
gesting that PEF could successfully replace PET [91].
Knoop et al. followed up the work by Gomes et al. investigating PEF synthe-
sized using a solid-state postcondensation technique [92]. The work examined
PEF, poly(1,3-propylenefuranoate) (PPF), poly(1,4-butylenefuranoate) (PBF),
and their terephthalic counterparts. It was shown that the furan-based polymers
had similar T g but lower T m , suggesting similar material behavior in specific appli-
cations but lower processing temperatures [92]. The mechanical properties of
both amorphous and annealed PEF were studied using tensile testing and dynamic
mechanical thermal analysis (DMTA). PEF had a Young's modulus of 2450 MPa,
comparable to that of PET (2000 MPa) [92, 98], which is another indication that
PEF may be a viable alternative to PET.
Polyesters from furans can also be used to produce cross-linked thermosets.
The first-generation furan derivative, 5-HMF, can be substituted to give a conju-
gated double bond next to the furan [99]. This double bond is photoreactive at
308 nm and can be used to cross-link with similar moieties [99]. This can be
exploited using low T g aliphatic hydroxyesters as comonomers to produce
cross-linked elastomers, with T g below room temperature [67, 99].
5.3.6
Polyamides
Polycondensation reactions can be used to produce polyamides based on furan moi-
eties, an approach primarily explored by Gandini's research group [100-104].
Aliphatic and aromatic diamines can be used to react with 2,5-FDCA and 3,4-
FDCA to produce polymers ranging from amorphous to semi-crystalline materials
[67]. Gharbi et al. studied a series of polyamides based on a diacid chloride
(2,2′- bis [2-(5-chloroformylfuryl)]propane), which can be obtained by coupling of
FDCA as seen in Scheme 5.4 [103-105]. Diacid chloride was reacted with various
aliphatic and aromatic diamines, and the thermal properties of the resulting poly-
mers were examined using DSC and TGA. The polyamides with aliphatic amide
Search WWH ::




Custom Search