Recently there has been an increased focus on obtaining polymeric materials derived
from renewable resources including both the chemical modification of natural
polymers and the use of biomass-based monomers to synthesize new macromolecules.
This growing trend is part of a larger strategy aimed at finding replacements to
diminishing fossil resources. The concept and applications of the bio-refinery
illustrate these global trends. Biomass offers a promising alternative to fossil fuels as
a renewable resource, as it can be produced in a carbon-neutral way. To avoid
competition for land resources dedicated to food and animal feed production, it is
particularly desirable to utilize inedible biomass in the production of polymeric
materials. Wood-based biomass offers an abundant resource comprising cellulose
(35- 50%) hemicellulose (25-30%) and lignin (25-30%). Cellulose and
hemicellulose can be depolymerized into monosaccharides, including glucose,
fructose and xylose.
SUMMARY
[03] The use of sugars and/or polysaccharides as precursors to furan derivatives is perhaps
one of the most promising realms for the preparation of polymers which could
potentially replace current polymers derived from petroleum. Furfural (F) and
hydroxymethylfurfural (HMF) are second-generation chemicals obtained from
pentoses and hexoses, respectively. F is an abundant chemical commodity which can
be manufactured through a relatively simple technology and is used in a wide variety
of agricultural and forestry byproducts that are inexpensive and ubiquitous. The
natural structures involved in its synthesis are C sugars and polysaccharides, which
are present in biomass residues. The present world production of furfural is about
300,000 tons per year. HMF can be obtained from hexoses, and a so from F by
substituting the C5. HMF can also be oxidized or reduced to obtain 2,5-
furandicarboxylic acid (FDCA) and 2,5-bis(hydroxymemyi)furan (BUMF). FDCA
can be esterified by methanol to yield corresponding methyl ester derivative (FDE).
Isosorbide (IS) is also a dio available commercially and originating from vegetal
biomass.
Lignin is the second most abundant polymer from renewable resources. In some
aspects, lignin fragments may be used as a source of monomers to synthesize of
polymers, by mtroducmg them (lignin as a macro monomer) into formaidehyde-based
wood resins or polyurethane formulation. As lignin is produced in colossal amounts
in papermaking processes and consumed in situ as a source of energy (energy
recover}'), a small proportion may be isolated and used as a monomer source, without
affecting its primary use as a fuel. Certain papermaking technologies such as the
oraganosolv processes and biomass refinery approaches such as steam explosion,
provide lignin fragments with more regular structures. Therefore, lignin macro
monomers represent today a particularly promising source of novel materials based on
renewable resources. Vanillic acid may be derived from lignin.
n other aspects, vanillic acid (VA) may be used as an A-B-type monomer to prepare
novel polyesters originating from vegetal biomass.
In various aspects of the present invention, different polyesters incorporate furan
and/or other aromatic moieties in conjunction with complementary moieties. In one
aspect, a copolvester is formed from monomers of (i) 2,5-furandicarboxylic acid, or a
lower a ky! ester thereof (ii) at least one aliphatic or cyeloaliphatic C3-C 0 diol, and
(iii) terephthalic acid.
In another aspect, a polyester is formed from monomers of 2,5-furan dicarboxylic
acid, or a lower a ky ester thereof, and isosorbide.
In another aspect, a polyester is poly(2,5-furandimethylene adipate).
In another aspect, a polyester is polyvanillic ester.
In yet another aspect, a polyester is polyethylene isosorbide furandicarboxylate.
In some embodiments, a polyester or copolyester is prepared by direct
polycondensation. In other embodiments, the polyester or copolyester is prepared by
transesterification. Polyesters described herein may have physical and thermal
properties similar to or even better than those of poly(ethylene terephtha!ate), making
them useful in a wide variety of applications. In some aspects, polyesters are formed
into articles using suitable techniques, such as sheet or film extrusion, co-extrusion,
extrusion coating, injection molding, thermoforming, blow molding, spinning,
electrospirming, laminating, emulsion coating or the like. In one aspect, the article is
a food package. In another aspect, the article is a beverage container. Other
applications include, but not limited to, fibers for cushioning and insulating material,
oriented films, bi-axially oriented films, liquid crystal displays, holograms, coatings
on wood products, functional additives in a polymer blend system. The polyesters
described herein may be used either alone or in a blend or mixture containing one or
more other polymeric components.
[13] According to another aspect, a method of preparing a 2,5-furandicarboxyiic acid
based copolyester is disclosed. The method comprises combining 2,5-
furandicarboxylic acid or a lower alkyl ester thereof, at least one aliphatic or
cycloaliphatic C2-C 0 dio , terephthaiic acid, and a catalyst to form a reaction mixture,
and stirring the reaction mixture under a stream of nitrogen. The reaction mixture is
gradually heated to a first temperature of about 200-230°C and the first temperature is
maintained for about 8 to about 12 hours. The reaction mixture is then gradually
heated to a second temperature of about 240-260°C and the second temperature is
maintained for about 2 to about 18 hours. Water is removed from the reaction
mixture, and the resulting copolyester is collected. This protocol was found to yield
faster reaction times, providing a more efficient and cost effective route to
synthesizing the copolyesters.
[14] Polymers from furan-based monomers with different diols and diacids and also
polymer from ignin monomer were successfully prepared with the aim of replacing
polymers derived fro petrochemicals. Poly(butylene 2,5-furandicarboxylate) (PBF)
is of particular interest. As a homolog of poly(ethyiene 2,5-furandicarboxylate)
(PEF), it would be expected that the glass transition temperature (Tg) of PBF would
be lower than that of PEF. The opposite condition was unexpectedly found to occur,
such that the Tg of PBF is higher than that of PEF. PBF also has a dramatically lower
melting temperature (Tm) than that of PEF A lower Tm advantageously enables the
material to be processed at lower temperatures. Together these properties of PBF
make it highly desirable in food and beverage packaging applications, especially hotfilling
of beverages and the like. Also of interest is a copolyester of the PEF polymer
with isosorbide (IS) and PBTF. The copolyesters obtained are essentially amorphous
polymers. Use of isosorbide as a comonomer is expected to improve mechanical
properties of the straight polyester.
BRIEF DESCRIPTION OF THE DRAWINGS
[15] FIG. 1 shows the FTIR for 2,5-furandicarboxyiic acid (FDCA).
[16] FIG. 2 shows the NMR for FDCA in the solvent DMSO.
[17] FIG. 3 shows the DSC for FDCA.
[18] FIG. 4 shows the FTIR for FDE.
[19] FIG. 5 shows the NMR for 2,5-dirnethyl furandicarboxylate (FDE) in the solvent
[20] FIG. 6 shows the NMR for FDE in another solvent, CF3COOD.
[21] FIG. 7 shows the DSC for FDE.
[22] FIG. 8 shows the FTIR for isosorbide (IS).
[23] FIGS. 9 and 10 show the DSC for IS.
[24] FIG. 1 shows the NMR for 2,5-bis(hydroxymethyl)furan (BHMF) in the solvent
DMSO.
[25] FIGS. 12 and 13 show the DSC for BHMF.
[26] FIG. 14 shows the FTIR for vanillic acid (VA).
[27] FIG. 1 shows the NMR for VA in the solvent CD3COCD3.
[28] FIG. 16 shows the DSC for VA.
[29] FIG. 17 shows the FTIR for polyethylene 2,5-furandicarboxylate) (PEF) synthesized
by polytransesten fiation
[30] FIG. 8 shows the NMR for PEF synthesized by polytransesterifiation in the solvent
CF3COGD.
[31] FIGS. 19 and 20 show the DSC for PEF synthesized by polytransesterifiation.
[32] FIG. 2 1 shows the FTIR for poly(butylene 2,5-furandicarboxylate) (PBF) synthesized
by polytransesterifi ation.
[33] FIG. 22 shows the NMR for PBF synthesized by polytransesterifiation.
[34] FIGS. 23 and 24 show the DSC for PBF synthesized by polytransesterifiation.
[35] FIG. 25 shows the FTIR for poiy(ethylene 2,5-furandicarboxylate) (PEF) obtained by
direct poiycondensation .
[36] FIG. 27 shows the DSC for PEF obtained by direct polycondensation.
[37] FIG. 28 shows the FTIR for poly(butylene 2 5-furandicarboxylate) (PBF) obtained by
direct polycondensation
[38] FIGS. 29 and 30 show the NMR for PBF, obtained by direct polycondensation, in the
solvent CF CGOD.
[39] FIGS. 3 and 32 show the DSC for PBF obtained by direct polycondensation.
[40] FIG. 33 shows the FTIR for a polyester synthesized from isosorbide (PIF).
[41] FIG. 34 shows the NMR for PIF in the solvent CF3COOD.
[42] FIGS. 35 and 36 show the DSC for PIF.
[43] FIG. 37 shows the FTIR for poiy(2,5-furandimethyiene adipate) (PFA).
[44] FIGS. 38 and 39 show the DSC for PFA.
[45] FIG. 40 shows the FTIR for polyvanillic ester (PVE) collected directly after synthesis.
[46] FIG. 4 1 shows the FTIR for PVE after purifi cation
[47] FIG. 42 shows the NMR for PVE collected directly after synthesis in the solvent
DMSO.
[48] FIG. 43 shows the NMR for PVE after purification in the solvent DMSO.
[49] FIGS. 44 and 45 show the DSC for PVE.
[50] FIG. 46 shows the FTIR for polyethylene isosorbide furandicarboxyiate (PEIF).
[51] FIGS. 47 and 48 show the DSC for PEIF; FIG. 48 shows a melting point at 84°C for
the copoiyester with 0% isosorbide.
[52] FIG. 49 shows the FT R for the copolyester PBTF.
[53] FIG. 50 shows the NMR for PBTF.
[54] FIG. 1 shows the DSC for PBTF.
[55] FIG. 52 shows the x-ray diffraction (XRD) for PEF.
[56] FIG. 53 shows the XRD for PBF.
[57] FIG. 54 shows the XRD for PEIF.
[58] FIG. 55 shows the XRD for PBTF.
[59] FIGS. 57 and 58 show the NMR and DSC, respectively, for PBF synthesized using
direct poiycondensation
DETAILED DESCRIPTION
[60] In various aspects described herein, polyesters may be prepared from biomass, either
directly or by synthesizing monomers which are obtained from biomass. The term
"polyester" as used herein is inclusive of polymers prepared from multiple monomers
that are sometimes referred to as copoiyesters. Terms such as "polymer" and
"polyester" are used herein in a broad sense to refer to materials characterized by
repeating moieties and are inclusive of molecules that may be characterized as
oligomers. Unless otherwise clear from context, percentages referred to herein are
expressed as percent by weight based on the total composition weight.
[61] Furfural (F) and hydroxymethyifurfural (HMF) may be obtained from pentoses and
hexoses, respectively. 2,5-furandicarboxylic acid (FDCA) can be esterified by
methanol to yield the corresponding methyl ester derivative (FDE). HMF also can be
oxidized or reduced to obtain 2,5-furandicarboxylic acid (FDCA) and 2,5-
bis(hydroxymethyl)furan (BHMF):
Lignin is the second most abundant polymer from renewable resources. Vanillic acid
(VA) may be used as an A-B-type monomer to prepare novel polyesters originating
from vegetal biomass.
In general, polyesters are prepared by reacting a dicarboxylic acid containing furan
and/or other aromatic functionality, an at least one diol. Suitable diols include
aliphatic or cycloaliphatic C3-C10 diols, non-limiting examples of which include 1,4-
butanediol, and isosorbide (IS) a commercially available dio which also can be
found in various vegetal biomasses.
In addition to these monomers, the polyesters may contain up to about 25 mol% of
other monomers such as ethylene glycol (EG or MEG), and/or other aliphatic
dicarboxylic acid groups having from about 4 to about 12 carbon atoms as well as
aromatic or cycloaliphatic dicarboxylic aci groups having from about 8 to about 14
carbon atoms. Non-limiting examples of these monomers include isophthalic acid
(IPA), phthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexane
diacetic acid, naphthalene-2,6-dicarboxylic acid, 4,4-diphenylene-dicarboxylic acid,
and mixtures thereof.
[65] The polymer also may contain up to about 25 mol% of other aliphatic C2-CJ O or
cycloaliphatic C -C2 diol components. Non-limiting examples include neopentyl
glycol, pentane- ,5-diol, cyclohexane- 1,6-diol, cyclohexane- 1,4-dimethanol, 3-methyl
pentane-2,4-diol, 2-methyl pentane-2,4-diol, propane- 1,3-diol, 2-ethyl propane- 1,2-
diol, 2,2,4-trimethyl pentane- 1,3-diol, 2,2,4-trimethyl pentane- 1,6-diol, 2,2-dimethyl
propane- 1,3-diol, 2-ethyl hexane- ,3-diol, hexane-2,5-diol, l,4-di(phydroxyethoxy)
benzene, 2,2-bis-(4-hydroxypropoxyphenyl)propane, and mixtures
thereof.
[66] Polyesters may be synthesized according to well-known polytransesterification or
direct polycondensation techniques. Catalysts conventionally used in
polycondensation reactions include oxides or salts of silicon, aluminium, zirconium,
titanium, cobalt, an combinations thereof. In some examples, antimony trioxide
(Sb?.0 ) is used as a polycondensation catalyst.
[67] Other conditions suitable for polycondensation reactions will be apparent to those
skilled in the art, particularly in light of the examples described below.
EXAMPLES
[68] The following examples are provided to illustrate certain aspects of the invention and
should not be regarded as limiting the spirit or scope of the present invention.
Materials
[69] 2,5-furandicarboxylic acid (FDCA) of 97% purity is commercial!)' available from
Aldrich. Isosorbide (IS) (l,4:3,6-dianhydro-D-glucitol) of purity 99% is
commercially available from ADM Chemicals, USA. Bis-(hydroxymethyl)furan
(BHMF) is commercially available from Polysciences, Inc., Germany. Ethylene
glycol (>99.5%), 1, 4-butanediol (99%), adipic acid (> 99.5%), vanillic acid (VA) (>
97%), antimony oxide (99.999%), and other solvents described herein are
commercially available from Aldrich.
Techniques
FTIR-ATR spectra were taken with a Perkin Elmer spectrometer (Paragon 1000)
scanning infrared radiations with an acquisition interval of 125 n . The Ή NMR
spectra were recorded on a Bruker AC 300 spectrometer operating at 300.13 MHz for
1H spectra in CF3COOD, DMSO D , CD3COCD3 using 30° pulses, 2000/3000 Hz
spectral width, 2.048s acquisition time, 50s relaxation delay and 16 scans were
accumulated. Differential scanning calorimetry (DSC) experiments were carried out
with a DSC Q100 differentia] calorimeter (TA Instruments) fitted with a manual
liquid nitrogen cooling system. The samples were placed in hermetically closed DSC
capsules. The heating and cooling rates were 10 °C min and 5°C mm 1 in N
atmosphere. Sample weights were between 5 and 5 mg. Structures were confirmed
using conventional Size Exclusion Chromatography Multi-Angle Laser Light Scatter
(SEC-MALLS), Thermogravimetnc Analysis (TGA), and x-ray diffraction (XRD)
techniques.
Example 1
This example describes a process for the synthesis of the monomer 2,5-dimethyl furan
dicarboxylate (FDE) by esterification.
n a round bottom flask of 500 ml, 10 g of 2,5-furandicarboxylic acid, 5 ml of H
and 120 ml of methanol (excess) were added. The mixture was heated to 80°C for 9
hrs. under reflux and magnetic stirring. The reaction mixture was cooled at room
temperature (for total precipitation, the mixture was cooled in a refrigerator or in a
freezer for one day) and the off-white precipitate formed was isolated by filtering the
solution and washed (separately the precipitate in beaker repeatedly with methanol
and filtered the solution) before drying. The reaction yield was 97%.
0
[73] This 2,5-dimethyl furanic ester is soluble in methanol, ethanol, acetone, DMSO and
diisopropyl ether.
Example A
[74] This example describes preparing polyCethylene 2,5-furandicarboxylate) (PEF) by
po ytransesteri fi cation
[75] In a round bottom flask of 50 ml, 3.68 g (0.02 mo!) of 2,5-dimethyl furan
dicarboxylate and 1.1 1ml (0.02 mol) of ethylene glycol and 0.01 g (0.000034 mo ) of
Sb20 3 were added. This mixture was well stirred under a stream of nitrogen for 1 hr.
Then, the nitrogen flow was discontinued and the mixture was heated for 3 hrs. at
220°C (until it becomes viscous). When the solution became viscous, the released
methanol was removed by pumping the reactor under vacuum. The released methanol
was collected in a trap cooled with liquid N2 for 5-10 minutes. Then, the temperature
was reduced to 150°C and the viscous polymer was dissolved in DMSO ( 5 ml) under
heating. After dissolution in DMSO, the polymer was precipitated in methanol,
filtered and washed with methanol before being dried. The each trial yields were 66,
38 and 30%, respectively.
Example 2B
[76] This example describes preparing polyethylene 2,5-furandicarboxylate) (PEF) by
direct poiycondensation.
[77] A molar ratio of 1:1.5 of acid to glycols and 0.02g of Sb20 3 were used. As a direct
poiycondensation reaction, water molecules are released instead of methanol, and the
yield amount is high.
[78] In a round bottom flask of 100 ml, 3.12 g (0.02 mol) of 2,5 -furan dicarboxylic acid,
1.64 ml (0.03 mol) of ethylene glycol and 0.02 g (0.000068 mol) of Sb 0 were
added. This mixture was well stirred under a stream of nitrogen for 1 hr. Then the
1
nitrogen flow was stopped and the mixture was heated for slowly increasing the
temperature up to 220°C for 7hrs. Then the temperature was increased slowly to 240-
250°C and the mixture maintained under heating for 5 hrs. When the solution
becomes viscous, the released water was removed by pumping the reactor under
vacuum. The released water was collected in a trap cooled with liquid N2 for 2-3
minutes. Then, the temperature was reduced to 150°C and the viscous polymer was
dissolved in DM80 ( mi) under heating at !80°C for 4-5 hrs. After dissolution in
DMSO, the polymer was precipitated in methanol, filtered, washed with methanol and
dried. The yields were 52 and 97%.
Example 3A
This example illustrates preparing polyfbutylene 2,5-furandicarboxylate) (PBF) by
polytransesterification.
n a round bottom flask of 50 ml, 3.68 g (0.02 mol) of 2,5-dimethyl
furandicarboxylate and 1.76 m (0.02 mol) of ,4-butanediol and 0.01 g (0.000034
mol) of Sb20 were added. This mixture was stirred well in a nitrogen atmosphere for
1 hr. Then the nitrogen flow was stopped and the mixture was heated for 7 hrs. 220°C
(until it becomes viscous). When the solution became viscous, the methanol released
was collected in a trap under vacuum and cooled with liquid N for 5-10 minutes.
Then the temperature was reduced to 150°C and the viscous polymer dissolved in
DMSO ( 5 ml) under heating. After dissolving in DMSO, it was precipitated in
methanol, filtered and washed with methanol, before being dried. The yields were 1
an 9%.
2 e OH
Example 3B
This example describes preparing poly(butylene 2,5-furandicarboxylate) (PBF) by
direct poiycondensation
n a round bottom flask of 100 ml, 3.12 g (0 02 mol) of 2,5-furan dicarboxylic acid,
2.65 ml (0.03 mol) of 1,4-butanediol and 0.02 g (0 000068 mol) of Sb 0 3 were added.
This mixture was well stirred under a stream of nitrogen for 1 hr. Then, the nitrogen
flow was stopped and the mixture was heated for slowly increasing the temperature
up to 220-230°C The reaction mixture was then maintained at this temperature for 10
hrs. Then, the temperature is increased slowly to 250-260°C and the mixture
maintained under heating for another 10 hrs. When the solution became viscous, the
released water was removed by pumping the reactor under vacuum. The released
water was collected in a trap cooled with liquid 2 for 4-5 minutes. Then, the
temperature was reduced to 180°C and the viscous polymer was dissolved in DMSO
(25 mi) under heating at 80°C for 3-4 hrs. After dissolution in DMSO, the polymer
was precipitated in methanol, filtered, washed with methanol and dried. The yields
were 32 and 40
O 220-240-C ° J + ' ° o
PBF
Example 4
[83] This example illustrates preparing a polyester from isosorbide (PIF).
[84] In a round bottom flask of 100 ml, 3.12 g (0.02 mol) of 2,5-furan dicarboxylic acid,
4.38 g (0.03 mol) of l,4:3,6-dianhydro-D-glucitoi and 0.02 g (0 000068 mol) of Sb20 3
were added. This mixture was stirred under a stream of nitrogen for 1 hr. Then the
nitrogen flow was stopped and the mixture was heated for slowly increasing the
temperature up to 220-230°C When reaching this temperature value, the mixture was
kept to react for 10 hrs. Then, the temperature was again increased slowly to 250-
260°C and the mixture again maintained under heating for another 1 hrs. When the
solution became viscous, the released water was removed by pumping the reactor
under vacuum. The released water was collected in a trap cooled with liquid N2 for 4 ~
5 minutes. Then the temperature was reduced to 180°C and the viscous polymer was
dissolved in DMSO (20ml) under heating at 180°C for 3-4 hrs. After dissolution in
DMSO, the polymer was precipitated in methanol, filtered, washed with methanol and
dried. The reaction yield was around 57%.
Example 5
This example illustrates preparing poly(2,5-furandimethylene adipate) (PFA).
In a round bottom flask of 100 ml, 2.923 g (0.02 mol) of adipic acid, 3.843 g (0.03
mol) of B MF and 0 02 g (0.000068 mol) of Sb20 3 were added. This mixture was
well stirred under a stream of nitrogen for 1 hr. Then, the nitrogen flow was stopped
an the mixture was heated for slowly increasing the temperature up to 190-220°C.
The reaction mixture was then maintained at this temperature for 10 hrs. Then the
temperature was increased slowly to 230-240°C and the mixture maintained under
heating for another 10 hrs. When the solution became viscous, the released water was
removed by pumping the reactor under vacuum. The released water was collected in a
trap cooled with liquid 2 for 4-5 minutes. The temperature was then reduced to
ambient temperature and the polymer was recovered without using any solvent
(neither DMSO nor methanol). The reaction yield was 62%.
Example 6
[87] This example illustrates preparing polyvaniili
4
In a round bottom flask of 100 ml, 5.0445 g (0.03 mol) of vanillic acid, 0.02 g
(0.000068 mol) of Sb20 3 were added. This mixture was well stirred under a stream of
nitrogen for 1 hr. The nitrogen flow was then stopped and the mixture was heated for
slowly increasing the temperature up to 220-230°C. At this plateau, the mixture was
left to react for 7 hrs. Then the temperature was increased slowly to 25G~260°C and
the mixture maintained under heating for another 6½ hrs. When the solution became
viscous, the released water was removed by pumping the reactor under vacuum. The
released water was collected in a trap cooled with liquid N for 4-5 minutes. Then the
temperature was reduced to 180°C and the viscous polymer was dissolved in DM80
(20ml) under heating at 180°C for 3-4 hrs. After dissolution in DMSO, ha f of the
polymer solution was precipitated in methanol, filtered, washed with methanol and
dried. The other half was recovered and characterised as such. The reaction yield
was around 60%.
Example 7
[89] This example illustrates preparing polyethylene isosorbide furandicarboxylate (PEIF).
[9] In a round bottom flask of 00 ml, 3.12 g (0.02 mol) of 2,5-furandicarboxylic acid, (n
mol) of ethylene glycol and 0.2192 g (m mol) of isosorbide and 0.02g (0.000068 mol)
of Sb 0 were added. This mixture was well stirred under a stream of nitrogen for 1
hr. Then, the nitrogen flow was stopped and the mixture was heated for slowly
increasing the temperature up to 200-230°C. The reaction mixture was then
maintained at this temperature for hrs. Thereafter, the temperature was increased
slowly to 245-255°C and the mixture maintained under heating for another 4 hrs.
Vacuum was applied to remove the water released in the reaction medium by
pumping the reactor under vacuum. The released water was collected in a trap cooled
with liquid N for 4-5 minutes. This was heated again for 5 hr. Then, the temperature
was reduced to ambient temperature and the polymer was collected.
1
[9 ] Copolyesters with four different mole ratios of ethylene glycol and isosorbide were
synthesized. Yields obtained were from 70-90%
Example 8
[92] This example illustrates preparing the eopolyester PBTF.
[93] In a round bottom flask of 100 ml, 1.56 g (0.01 mol) of 2,5-furandicarboxylic acid,
(0.03 mol) of ethylene glycol and 1.66 g (0.01 mol) of terephthalic acid and 0.02g
(0.000068 mol) of Sb. ( ) : were added. This mixture was well stirred under a stream of
nitrogen for 1 hr. Then, the nitrogen flow was stopped and the mixture was heated for
slowly increasing the temperature up to 200-230°C. The reaction mixture was then
maintained a this temperature for 2 hrs. Then, the temperature was increased slowly
to 245-255°C and the mixture maintained under heating for another 18 hrs. Vacuum
was applied to remove the water released in the reaction medium by pumping the
reactor under vacuum. The released water was collected in a trap cooled with liquid
N2 for 4-5 minutes. This was heated again for 1 hr. Then, the temperature was
reduced to ambient temperature and the polymer was collected. The reaction yield
was around 40%.
Results and Discussion
[94] Al the monomers including the purchased one were studied using DSC, NMR, FTIR,
SEC-MALLS, XRD, and TGA.
Monomers
[95] F G. 1 shows the FTIR for 2,5-furandicarboxylic acid (FDCA). The main peaks and
their assignements are:
(Carboxylic acid) C=0 -1678 cm4
Elongation of O-H (acid) -2700-3400 cm 1
Furan ring ( C) - 70 cm-
Acid (C-O-H bending) - 400 cm4
Furan ring (Bending of C-H and furan ring) -960,840,762 cm
6
[96] FIG. 2 shows the NMR for FDCA in the solvent DMSO. In the 1H-NMR, the signal
at the chemical shift (8) of 7.26 ppm corresponds to the protons 3 and H4 of the
fttran ring, whereas that appearing at 3.46 ppm is assigned to the OH of the acid and
that observed at 2.50 ppm is due to DMSO.
[97] FIG. 3 shows the DSC for FDCA. The DSC protocol is as follows:
(1) Ramp 50°C to 350°C at 10°C/min
(2) Isothermal for 5 min
(3) Ramp 350°C to 50°C at 10°C/min.
[98] From the DSC tracings, the melting temperature at T = 334°C and the crystallization
exotherm at T = 232 °C are observed.
2,5-dimethyl furandicarboxylate (FDE)
[99] FIG. 4 shows the FTXR for FDE. The main peaks and their assignements are:
C=H (furan ring) -3142 cm 1
C-H (methyl) -2965 cm
C=0 -1712 cm 1
C-0 (ester) -1298 cm 1
[100] FIG. 5 shows the NMR for FDE in the solvent CD3COCD 3 . In the spectrum, the
signal at 7.33 ppm corresponds to the H3 and H4 protons of furanic ring whereas
that appearing at 8 3.86 ppm could be assigned to the CH3 of the formed ester group.
[101] FIG. 6 shows the NMR for FDE in another solvent, CF3COOD. When using the
solvent (CF 3COOD), we obtain similar spectrum with peaks at = 7.33 ppm and =
4.02 ppm which correspond to one proton of furan ring and the CH3 of the ester,
respectively. The = 1.5 ppm corresponds to the solvent.
[102] FIG. 7 shows the DSC for FDE. The DSC protocol used is given below.
(1) Heating step from 50° to 150°C at 5°C/min
(2) Isothermal for 5 min
(3) Cooling step from 150° to 50° at 5°C/min
(4) Isothermal for 5 min
(5) Second heating step 50° to 150°C at 5°C/mm.
)3] First heating was to remove the thermal histor of the monomer. From the DSC
thermogram, it could be observed that the Tm of the dimethyl ester monomer of
FDCA is at about 0 °C. The high value (334°C) of FDCA may be due to strong
cohesive energy due to intermolecuiar hydrogen bonds. But in the case of diester
there are no such interactions ( 10°C), because the hydrogen bonds arising from
carboxyiic functions were broken when the COOH groups were converted to COOMe
counterpart.
sosorbide (IS)
)4] FIG. 8 shows the FT R for isosorbide (IS) ( Br). The I spectra displayed the
presence of the peaks at 3374 (OH elongation), 2943, 2873 cm , corresponding to
methyl elongation (asymmetric and symmetric) and those at 1120, 1091, 1076, 1046
cm , attributed to the vibration of C-O-C.
5 ] FIGS. 9 and 0 sho the DSC for IS. The DSC protocol used is given below.
(1) Heating step from 50° to 300°C at 10°C/mm
(2) Isothermal for 5 min
(3) Cooling step 300° to 50° at 10°C/min
(4) Isothermal for 5 min
(5) Second heating step 50° to 300°C at 10°C/mm (FIG. 9)
(6) 1s Ramp (50°C-300°C at l Q C/rmn) (FIG. 10).
)6] It is observed that isosorbide gives a melting point at 62°C and that its thermal
degradation starts around ~205°C.
2,5-Bis(hydroxymethyl)Furan (BHMF)
[107] FIG. 11 shows the NMR for BHMF in the solvent DMSO. The NMR spectrum
shows several shifts, namely: at 6.18 ppm which corresponds to 2H of furan ring,
= 5.18 ppm assigned to the OH, = 4.35 ppm attributed to the 4H of the CH OH, 
= 3.36 and 2 25 ppm associated with the solvent and OH of the water present in it.
[18] FIGS. 12 and 13 show the DSC for BHMF. FIG. 12 shows the full thermodiagram of
BHMF; and FIG. 3 shows the second heating step. The protocol is as follows.
(1) Heating step 10°C/min to 260°C
(2) Isothermal for 5 min
(3) Cooling step 10°C/min to 45°C
(4) Isothermal for 5 min
(5) Second heating step 0°C/min to 260°C
(6) Ramp 10°C/min to 260°C (3rd step).
[19] From the DSC thermogram, a melting point Tra of ~ 77°C is observed for BHMF.
The degradation of the monomer starts at a temperature of around 230°C. In the 2nd
and 3rd steps, i.e., the cooling and heating steps, there is a small peak observed at ~
100°C. This can be due to the crystallization (cooling step) and evaporation (heating
step) of water. No other peaks (T , Tc) were detected.
Vanillic Acid (VA)
[110] FIG. 14 shows the FTIR for VA. From the FT R spectrum, one could draw the
following assignments: the peak at 3483 cm 1 corresponds to the OH elongation
(phenolic); 2963 cm 1 is attributed to in phase OH (COOH) stretching and CH
asymmetrical stretching; and 2628 cm is assigned to CH symmetrical stretching.
The band at 1673 cm 1 corresponds to C=0 stretching and that appearing at 585 cm '
corresponds to OH (phenol) in plane deformation.
9
[111] FIG. 15 shows the NMR for VA in the solvent CD3CQCD 3 . The NMR spectrum
gives chemical shifts at = 7.6 ppm, which corresponds to the 2Ha , = 6.9 ppm to the
1Kb, = 3.9 ppm to the 3H of CH and = 2.05 ppm of the solvent.
[112] FIG. 16 shows the DSC for VA. The DSC protocol is:
(1) Ramp 50°C to 250°C at 0 °C/min
(2) sotherma for 5 min
(3) Ramp 250 °C-50 °C at 10 °C/min
(4) isothermal for 5 min
(5) Ramp 50°C-250 °C at °C/min.
[113] I is observed that the melting point of vanil lic acid at 2 0 °C and the crystallization
temperature at 190 °C, which agrees with the literature data.
Polymers
[114] From the experimental section it can be observed that the yield of the polymers
obtained are high in direct polycondensation method compared to the
polytransesterification method.
a) Polytransesterification
Po1y(ethylene 2,5-furan dicarboxylate) (PEF)
[115] FIG. 17 shows the FT R for PEF. The FTIR spectrum shows peaks (cm 1) at 1715
and 1264 corresponding to the ester carbonyi and C-0 moieties and the characteristic
bands of disubstitttted furanic rings (3120, 1575, 1013, 953, 836 and 764). It is
observed that the band characteristic of OH (3400) disappeared. So it can be
confirmed that no acid monomer is left.
[116] FIG. 18 shows the NMR for PEF in the solvent CF3COOD. In the solvent ViSO. the
resonance peaks corresponding to furanic H3 and H4 at 7.4 ppm and that of ester
C¾ at 4.6 ppm are observed with an approximate ratio of integration 1:2. It seems
that there is an excess of furanic protons. In the solvent CF3COOD, it was found that
the chemical shift (8) value of H3 and H4 protons of furanic ring is shifted to 8 75
ppm instead of ~ 7.33 ppm, and also the integration value was not in agreement with
the expected structure.
] FIGS. 19 and 20 show the DSC for PEF. The DSC protocol used is given below.
(1) Ramp 50-250 °C at 10 °C/min
(2) Isothermal for 5 mm
(3) Ramp 250-50 °C at 10 °C/min
(4) Isothermal for 5 min
(5) Ramp 50-250 °C at 10 °C/min (FIG. 19)
(6) 3rd Step (Ramp 50°C -250°C at 10°C/min) (FIG. 20).
] First heating removes the thermal history of the polymer. From the second curve,
they showed a high melting temperature at 212 °C and a Tg at around ~74°C (similar
to PET) and also a crystallization exotherm at 150 °C.
Polyfbutylene 2,5-furandicarboxylate) (PBF)
] FIG. 2 1 shows the FTIR for PBF. The spectrum shows peaks at 3 3, 1573, 1030,
964, 829, 767 cm , corresponding to 2,5-disubtituted furanic rings. The C=0 ester
corresponding band and the C-0 stretching bands are found at 1715 and 1272 cm .
This spectrum shows that there is no diacid left. In fact, the diacid is fully converted
to the polymer. The 2959 cm ' peak is due to the asymmetric stretching of the
methylene groups, while the symmetric stretching of the methylene groups causes the
weaker 2889 cm 1 peak. Also, the peak at 29 cm 1, which is the characteristic of the
asymmetric vibration of COC ether, which according to the literature is attributed to
the formation of an ether link between terminal OH groups and/or could be assigned
to C-O-C of the furan ring.
F G. 22 shows the N R for PBF. From the NMR spectra of PBF (both two trials),
the synthesis of PBF is confirmed from the corresponding peak 8 = 7.3 ppm for the
H3 and H4 protons of the furanic ring and 8 - 4.5 ppm for the a CFI2 and
= 1.98 ppn for the CH2 protons. Here also, the integration of these protons is not
quantitatively correlated with the structure.
FIGS. 23 and 24 show the DSC for PBF. The DSC protocol used is given below.
(1) Ramp 50-250°C at 10 C min
(2) Isothermal for 5 min.
(3) Ramp 250-50 C at 10 °C/min
(4) Isothermal for 5 min.
(5) Ramp 50-250°C at 10°C/min (FIG. 23)
(6) 3rd step (Ramp 50°C-250°C at 10°C/min) (FIG. 24).
From the above curves, the)' showed a melting temperature at 5 °C and 239 °C, and
a Tg at temperature ~104°C and a so a crystallization exotherm at 2 °C and 22 °C,
respectively. This DSC tracing suggests that there are two different polymers. The
large portion of the polymer has a T of around 55 °C, whereas the remainder is
composed of macromolecules with higher molecular weights having a T of 239 °C.
Such a result may indicate that the synthesis of PBF was not left to occur with the
highest conversion possible and/or that the 1,4-butanediol has much lower reactivity
to compare with ethylene glycol.
b) Direct Polycondensation
Polyiethylene 2,5-furandicarboxylate) (PEF)
FIG. 25 shows the FT R for PEF. The obtained I spectrum of the polymer (PEF) by
direct polycondensation with the FDCA (2,5-furandicarboxylic acid) is in agreement
with the previous PEF polymer obtained with d ester monomer. The spectrum shows
peaks at 3 119, 1574, 1013, 955, 831, and 779 cm 1 , corresponding to 2,5-disubtituted
furanic rings. The C 0 ester corresponding peak and the C-0 stretching bands are
found at 1714 and 1264 cm 1. It therefore can be confirmed that there the acid was
fully converted to the polymer, since there was no more acid detected. Also the peak
at 29 cm ' , which is the characteristic of the asymmetric vibration of C-O-C (ether),
according to the literature, is attributed to the formation of an ether link between
terminal OH groups and/or coul be assigned to C-O-C of the furan ring
[124] FIG. 26 shows the NMR for PEF in the solvent CF3COOD. The wider peaks give
indication about the formation of high molecular weight of the polymer, as compared
to the previous ones. Here from the spectrum, the peaks corresponding to furanic H3
and H4 at ~ 7.6 ppm and that of the ester C 2 at 5 pp are observed with a ratio
of integration of 1:2.
[125] FIG. 27 shows the DSC for PEF. The DSC protocol is the following:
(1) Heating step from 50° to 260°C at 10°C/min
(2) Isothermal for 5 min
(3) Cooling step 260° to 50° at i0°C/min
(4) isothermal for 5 min
(5) Second heating step 50° to 260°C at 10°C/min.
[126] From the DSC curves, it is found that the T ( 204°C) and Tg (~ 79°C), which is
very close value to the PEF polymer (Tm 212°C) synthesized by
po!ytransesterification using the diester monomer and ethylene glycol, thus
confirming the similar characteristics between the two polymers. Thus, this indicates
that these polymers have very similar structures.
P ly(butylene 2,5-furandicarboxy 1ate) (PBF)
[127] FIG. 28 shows the FTIR for PBF. It agrees with the previous result obtained (i.e., the
PBF synthesized from polytransesterifiation). The spectrum shows peaks at 3 15,
1574, 10 8, 965, 821, and 769 cm 1 , corresponding to 2,5-disubtituted furanic rings.
The C=0 ester corresponding band and the C-0 stretching bands are found at 1710
and 1269 cm 1 . Thus, the diacid was fully converted to the polymer. The 2959 cm 1
peak is due to the asymmetric stretching of the methylene groups, while the
symmetric stretching of the methylene groups causes the appearance of a weaker peak
at 2892 cm peak. Also, the peak at 27 cm 1, which is the characteristic of the
asymmetric vibration of COC ether, is observed. It is worth to mention that in all the
polyesters containing furan ring, the corresponding FTIR spectra displayed the
presence of a band at around 1020-1050 cm 1, which corresponds to ring breathing
and witnesses about the preservation of this heterocycle. Thus, during the synthesis at
high temperature furanic ring does not suffer any degradation (ring opening and/or C
or C substitution).
FIGS. 29 and 30 show the NMR for PBF in the solvent CF3COOD. From the NMR
spectra of PBF, the synthesis of PBF is confirmed from the corresponding peaks at
- 7.67 ppm for the H3 and H4 protons of the furanic ring; - 4.85 ppm for the
a CH2; and - 2.5 ppm for the CH2 protons. Here, the integral values are in good
ratio as compared to PBF synthesized by polytransesterification.
FIGS. 3 and 32 show the DSC for PBF. F G. 3 shows the full thermodiagram of
PBF; and FIG. 32 shows the second heating step. The DSC protocol used is given
below.
(1) Heating step from 50° to 260°C at 10°C/min
(2) Isothermal for 5 mm
(3) Cooling step from 260° to 50°C at 10°C/min
(4) Isothermal for 5 mm
(5) Second heating step from 50° to 260°C at 10°C/mm
(6) 3rd step (Heating step from 50° to 250°C at 10°C/min).
From the DSC curve, better peaks are observed as compared to PBF synthesized by
polytransesterification. A melting temperature Tm at 163 °C, and a T at -104 °C.
Also, a crystallization exotherm at 1 °C was observed.
Polyester from Isosorbide (PIF)
FIG. 33 shows the FTIR for PIF. The IR spectra give a peak at -3400 cm 1, which
corresponds to the OH elongation. This spectrum shows also that may be some by
products have been formed during the synthesis at higher temperature or some
residual water is still present in the medium.
[132] FIG. 34 shows the NMR for P F in the solvent CF3COOD. From the NMR spectra,
the synthesis of PIF is confirmed by the presence of several peaks: 8 - 7.67 ppm for
the H3 an 4 protons of the furanic ring; - 5.75 ppm for the 1IT (H5); - 5.44 ppm
for the 1 (H2); = 5. 2 ppm for thelH (H3); 4.8 ppm for she ! ! (H4); = 4.47
ppm; and 4.33 ppm corresponding to the two protons at H6 and H . The integral
values are not in good ratios.
[133] FIGS. 35 and 36 show the DSC for PIF. FIG. 35 shows the full thermodiagram of
PIF; and FIG. 36 shows the second heating step. The DSC protocol used is given
below.
(1) Heatmg step from 50° to 260°C at 10°C/min isothermal for 5 min
(2) Cooling step 260° to 50° at 10°C/min
(3) Isothermal for 5 min
(4) Heating step from 50° to 260°C at 10°C/min
(5) 3rd step: Ramp 50°C -260°C at 10°C/min.
[134] The PIF obtained by direct polycondensation gives a T at -~137°C, which
approximately agrees with the literature values, in which another synthesis method is
used.
Poly(2,5-furandimethyiene adipate) (PFA)
[135] FIG. 37 shows the FT for PFA. The spectrum shows peaks at 920, 733 cm 1,
correspondmg to 2,5-disubtituted furanic rings. The C=0 ester corresponding band
and the C-0 stretching signal are detected at 1687 and 274 cm 1, respectively.
The 2946 cm ' peak is due to the asymmetric stretching of the methylene groups,
whil e the symmetric stretching of the methylene functions causes the appearance of a
weaker signal at 2648 cm 3 . The peak at 1190 cm ' is attributed to the asymmetric
vibration of COC ether.
[136] The polymer obtained was char-like and not soluble in any solvents.
[137] FIGS. 38 and 39 show the DSC for PFA. The protocol was as follows.
(1) Heating step from 45 to 250 °C with a rate of 5 °C/min
(2) Isothermal for 5 min
(3) Cooling step from 250 to 45 C with a rate of 5°C/min
(4) Isothermal for 5 min
(5) Heating step from 50 to 250 C wit a rate of 5 °C/min
(6) 3rd step (Ramp 45-25 at 5 °C/mm) (FIG. 39).
8 ] From the DSC thermogram, in the first heating step, a broad peak at around 0 °C is
observed, which is due to the evaporation of water. In the 3rd step, only a small peak
in the same temperature region (100°C) is observed. This peak is exothermic. It
could be assigned to the crystallisation of some polymer fraction, although the amount
of this fraction seems to be very low.
Polyvanillic ester (PVE)
9] FIG. 40 shows the FTIR for PVE collected directly after synthesis. FIG. 4 1 shows
the FTIR for PVE after purification. Comparing the two spectra, that of the polymer
that directly recovered after the synthesis gives a better resolution compared to the
"precipitated" second one. The first spectrum shows a broad peak at 3280 cm 1,
corresponding to the OH elongation, two small peaks at 2929 and 2832 cm 1 which is
attributed to CH asymmetrical and symmetrical stretching, respectively. The peak at
693 and 1248 cm 1 are assigned to C-0 stretching bands characteristics of C=0 ester.
The peak 0 cm 1 is related to the C-O-C asymmetric vibration. But, in both
spectra, the peaks are not wel defined, especially in the second one.
] FIG. 42 shows the NMR for PVE collected directly after synthesis in the solvent
DMSO. F G. 43 shows the NMR for PVE after purification in the solvent DMSO.
The NMR spectra of PVE before purification shows some peaks at = 7.4 ppr and
6.87 pprn. But these peaks are very weak and also no integrals correspond to these
peaks. PVE after purification shows peaks corresponds only to the soivents. Thus no
corresponding peaks of PVE were observed from the NMR spectra, probably because
of the very lo solubility of the tested polymer.
] FIGS. 44 and 45 show the DSC for PVE. FIG. 44 shows the full thermodiagram of
PVE; and FIG. 45 shows the second heating step. The following protocol was used.
(1) Ramp 5°C/min - 25 to 240°C
(2) Isothermal for 5 min
(3) Ramp 5°C/min 240 to - 25°C
(4) Isothermal for 5 min
(5) Ramp 5°C/min - 25 to 240°C
(6) 3rd step (Ramp - 25°C to 250°C at 5°C/min).
] From the DSC curves, in the first heating step a peak at ~ 100°C is observed, this can
be due to water evaporation.
Copolyesters
] FIG. 46 shows the FTIR for PEIF. The FTIR spectra obtained shows peaks at 3400,
3 115, 2936, 1710, 1575, 1261, 1128, 957, 820, and 759 The peaks at 3 115,
1575 1010, 957, 820 759 cm correspond to 2,5-disubtiruted furanic rings. The
C O ester is attributed band and the C-0 stretching bands are found at 1710 and 6 1
cm . The 2936 cm 1 peak is due to the asymmetric stretching of the methylene
groups, while the symmetric stretching of the methylene functions causes the weaker
2868 cm peak. The peak at 128 cm is attributed to the asymmetric vibration of
COC ether. As from the resulting peaks, it shows the diacids are converted (peaks at
1710 and 1261 cm 1), while the peak at 3400 cm could be due to the presence of
water in the polymer.
] FIGS. 47 show the DSC for PEIF. The following protocol was used:
(1) Ramp 5°C/min 45 to 260°C
(2) Isothermal for 5 min
(3) Ramp 5°C/min 260 to 45°C
(4) Isothermal for 5 min
(5) Ramp 5°C/min 45 to 260°C
5 ] The DSC thermogram obtained for the copolyesters is shown in FIG. 47. The
thermogram shows that as isosorbide is increased, there is an increase in Tg, followed
by a decrease. Also observed was a melting point at 84°C for the copolyester with
10% isosorbide, as shown in FIG. 48.
6] FIG. 49 shows the FTIR for PBTF, and FIG. 50 shows the NMR for PBTF. NMR
spectrum gives peaks at = 8.2ppm which corresponds to the aromatic ring of
terephthalic acid, 7.38 ppm which corresponds to furanic ring, 4.5 ppm for the a CH2,
and 2 1 ppm for the C 2 group with the corresponding integration of 1:1:3:3. From
this it can be seen that the ratio of the monomer block in the copolyester is 2 furan
rings for one terephthalate group.
7] FIG. 5 1 shows the DSC for PBTF. The DSC thermogram shows no peaks
corresponding to the thermal properties of the polymer.
8] The other characteristics of the polymers and copolymers like thermal degradation
properties, molar mass and also the crystallinity of the polymers are discussed below.
9 ] Table 1 shows decomposition temperature and onset temperature for the polymers:
Table 1
0] The above values show that a ll the polymers obtained have good thermal properties.
Values for PEF and PBF agree with the values obtained for the synthetic polymers.
Molecular weight calculations were performed on the three polymers PEF, PBF, and
PE F The results obtained from the 8EC-MALL8 analysis is shown in Table 2
below.
Table 2
[152] FIGS. 52-55 show the results of x-ray diffraction (XRD) for the polymers. The
degree of crystallmity of each polymer was calculated using the equation:
Xc= [Ac/ (Ac+Aa)] l 00
[153] FIG. 52 shows the results of x-ray diffraction (XRD) for PEF. The degree of
crystallmity obtained was 40-50%.
[154] FIG. 53 shows the results of XRD for PBF. The degree of crystallmity obtained was
30-40%.
[155] FIG. 54 shows the results of XRD for PEIF. The degree of crystallinity obtained was
20-25%.
[156] FIG . 55 shows the results of XRD for PBTF. The degree of crystallmity obtained was
17-20%.
[157] From the above results, it was found that the copolyesters are essentially amorphous
polymers. The value obtained for PEF and PBF are close to the values of PET and
PBT.
Density
5 ] Densities of the polymers were measured using a glass pycnometer. The method used
is as described below:
[159] The weight of the empty pycnometer was measured. Then 1/3 of the pycnometer was
filled with the polymer and the weight measured. Then water was added so that the
capillary hole in the stopper is filled with water and measured weight. Then the
pycnometer was emptied and then weighed by adding water. Based on the known
density of water, its volume can be calculated. Then, the mass and volume of the
object was calculated to determine the density. Table 3 below gives the density of the
polymers and their degrees of crystallinity.
Table 3
The following table summarizes Tg, Tc, and T for the polyesters PEF, PBF-a, PBF-b,
and PEIF.
Table 4
Catalyst effect
161] The effect of catalyst in the polymerization is also studied by using imidazole as the
catalyst instead of antimony trioxide. The polymer synthesized is PBF using the direct
polycondensation method. FIG. 56 shows the FT of the resulting polymer. The R
spectrum obtained agrees with that of the PBF synthesized using antimony trioxide as
the catalyst.
[162] FIG. 57 shows the NMR for the polymer (Solvent: CF3COOD). From the NMR
spectra, the synthesis of PBF is confirmed from the corresponding peak at:
- 7.47 ppm for the H3 and H4 protons of the furanic ring; 4.51 ppm for the
a CI¾ and - 2. 5 ppm for the C 2 protons. Here the integral values are in good
ratio as compared to PBF.
[163] FIG. 58 shows the DSC for the polymer. Observed from the DSC thermogram were a
Tg at 101°C, Tm at 150°C and Tc of 113°C. As compared with the PBF using
antimony as the catalyst, there was ~10°C less in Tc and Tm. Thus it is possible to
obtain a polymer with different Tm values by the use of a different catalyst.
Scaling-up trials
164] The scaling-up trials concerning the polymer syntheses were successful for PET and
PEF and PBF. These polymers were prepared and characterized. The FTIR spectra
and the DSC tracings show that these polymers are similar to those prepared
previously. It is worth to note that in these trials, the reaction time is shorter. This
could provide more efficient and cost effective methods for synthesizing the
polymers.
The foregoing description should be considered illustrative rather than limiting. It
should be recognized that various modifications can be made without departing from
the spirit or scope of the invention as described and claimed herein.
WHAT IS CLAIMED IS:
1. A copolyester formed from monomers of (i) 2,5-furandicarboxylic acid, or a lower
alkyl ester thereof, (ii) at least one aliphatic or cycloaliphatic C3-C10 diol, an (iii)
terephthalic acid.
2. The copolyester of claim 1 wherein the at least one diol is selected from the group
consisting of ,4-butanedioi, isosorbide, and combinations thereof.
3. The copolyester of claim 1 wherein the monomers further comprise (iv) ethylene
glycol.
4. The copolyester of claim 1 wherein the at least one diol is 1,4-butanediol.
5. The copolyester of claim 1 wherem the at least one diol is isosorbide.
6. An article comprising the copolyester of claim .
7. The article of claim 6 which is a food package.
8. The article of claim 6 which is a beverage container.
9. A polyester formed from monomers of 2,5-furan dicarboxylic acid, or a lower alkyl
ester thereof, and isosorbide.
10. A polyester selected from the group consisting of poly(2,5-furandimethylene adipate),
polyvaniilic ester, and polyethylene isosorbide furandicarboxylate.
. An article comprising the polyester of claim 10.
12. The article of claim which is a food package.
13. The article of claim which is a beverage container.
14. A method of preparing a 2,5-furandicarboxylic acid based copolyester, the method
comprising:
combining 2,5-furandicarboxylic acid or a lower alkyl ester thereof at least one
aliphatic or cycloaliphatic C2-C 0 diol, terephthalic acid, and a catalyst to form a reaction
mixture;
stirring the reaction mixture under a stream of nitrogen;
gradually heating the reaction mixture to a first temperature of about 200-230°C and
maintaining the first temperature for about 8 to about hours;
gradually heating the reaction mixture to a second temperature of about 240-260°C
and maintaining the second temperature for about 2 to about 18 hours;
removing water from the reaction mixture; and
collecting the resulting copolyester.
. The method of claim 14 wherein the at least one dio is selected from the group
consisting of ethylene glycol, ,4-butanediol, isosorbide, and combinations thereof.
16. The method of claim 14 wherein the at least one diol is ethylene glycol.
17. The method of claim 14 wherein the at least one diol is 1,4-butanediol.
18. The method of claim 14 wherein the at least one diol is isosorbide.
19. The method of claim 14 wherem the catalyst is an oxide or salt of a metal selected
from the group consisting of silicon, aluminium, zirconium, titanium, cobalt, and
combinations thereof.
20. The method of claim 14 wherem the catalyst is antimony trioxide.