New poly(arylene ether sulfone)s based on 4,4′-[trans-1,4- cyclohexanediylbis(methylene)] bisphenol

Article abstract of DOI:10.1016/j.polymer.2013.06.018

Incorporation of 4,4′-dihydroxy-p-terphenyl (DHTP) and a new bisphenol comonomer, 4,4′-[trans-1,4-cyclohexanediylbis(methylene)] bisphenol (CMB), into a dichlorodiphenyl sulfone (DCDPS) based poly(ether sulfone) resulted in a synergistic effect with an or

Full text of DOI:10.1016/j.polymer.2013.06.018

Polymer 54 (2013) 4493e4500
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Polymer
journal homepage: www.elsevier.com/locate/polymer
New poly(arylene ether sulfone)s based on 4,40-[trans-1,
4-cyclohexanediylbis(methylene)] bisphenol
*
Bin Zhang, S. Richard Turner
Department of Chemistry, Macromolecules and Interfaces Institute (MII), Virginia Tech, Blacksburg, VA 24061-0344, USA
a r t i c l e i n f o
a b s t r a c t
Incorporation of 4,40-dihydroxy-p-terphenyl (DHTP) and a new bisphenol comonomer, 4,40-[trans-1,4-
cyclohexanediylbis(methylene)] bisphenol (CMB), into a dichlorodiphenyl sulfone (DCDPS) based pol-
y(ether sulfone) resulted in a synergistic effect with an order of magnitude increase observed in the
strain at break when compared to the structural analogs. Polysulfones with the CMB monomer and other
bisphenol comonomers such as 4,40-dihydroxy-p-biphenyl (DHBP) and bisphenol-A (BisA) were also
synthesized and characterized for comparison and this enhancement was not seen in these polymers.
The cyclohexylene containing monomer and polymers were analyzed by 1d 1H NMR and 2d HeH cor-
relation spectroscopy (COSY) confirming that the cyclohexylene units in all the polymers were in the
trans-configuration. DMA results suggested that the significant strain at failure enhancement was related
Article history:
Received 15 April 2013
Received in revised form
8 June 2013
Accepted 11 June 2013
Available online 19 June 2013
Keywords:
Poly(ether sulfone)s
sub-Tg relaxations
trans-1,4-cyclohexylene rings
to the strong intensity in both the
monomers.
b
and
g
-relaxations of the polysulfone containing CMB and DHTP
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
cyclohexylenedimethylene terephthalate) (PCT) is an important
commercial polyester. The cyclohexylene units in PCT impart a high
melting point and significant toughness [12]. Credico and co-
workers [10] did a systematic study on the dynamic mechanical
behavior of a group of cyclohexylene containing polyesters with
different cis/trans ratios. A series of relaxations were observed and
attributed to the flexible methylene groups and cyclohexylene
groups.
To the best of our knowledge, little research has been done on
cyclohexylene containing polysulfones. We have recently reported
a series of PAESs synthesized from trans-1,4-cyclohexylene ring-
containing acid chloride monomers [13]. In this paper we report
new PAESs that contain cyclohexylene ring units in the backbone
based on the CMB monomer. The configurations of the cyclo-
hexylene rings in the polymer backbones were carefully monitored
to ensure the all trans-configurations were obtained. This feature
provided a simplified polymer system to study the relaxation be-
haviors without the configuration complication in a cis/trans
mixture as a result of the starting materials or the isomerization
side reactions [4,5,10].
Poly(arylene ether sulfone)s (PAESs) are important commercial
polymers and have been extensively studied due to their excellent
thermal and mechanical properties [1,2]. PAESs are commonly
synthesized through aromatic nucleophilic substitution of
dichlorodiphenyl sulfone (DCDPS) and various bisphenols in pres-
ence of base. There has been a continuous interest in developing
new PAESs based on new monomers to obtain new properties or to
enhance existing properties.
In this paper, we describe new PAES polymer systems with
trans-1,4-cyclohexylene units incorporated into the backbone
based on a new bisphenol monomer 4,40-[trans-1,4-cyclohexane-
diylbis(methylene)] bisphenol (CMB) (Scheme 1). Polymers with
1,4-cyclohexylene ring units in the backbone are of great interest
from both a fundamental and a practical point of view. The most
explored areas of cyclohexylene containing polymers are poly-
esters, polycarbonates, and polyketones [3e11]. Yee and coworkers
comprehensively studied the properties of cyclohexylene contain-
ing polyketones, polycarbonates and polyester-polycarbonates [5e
9]. It was generally found that the incorporation of the cyclo-
hexylene units in the backbone enhanced the local chain
motion and showed enhanced craze resistance behavior. Poly(1,4-
2. Experimental
2.1. Materials
All chemicals were purchased from Aldrich with the exception
of trans-1,4-cyclohexane dicarboxylic acid (CHDA) which was
* Corresponding author. Tel.: þ1 540 231 4552; fax: þ1 540 231 3971.
E-mail address: srturner@vt.edu (S.R. Turner).
0032-3861/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.polymer.2013.06.018

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B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
Scheme 1. Synthesis scheme of 4,40-[trans-1,4-cyclohexanediylbis(methylene)] bisphenol (CMB).
provided by Eastman Chemical Company. RadelÒ R sample was
provided by Solvay Advanced Polymers L.L.C. All reagents were
used without further purification.
was charged with 16.00 g (93.02 mmol) of CHDA, 120 ml of thionyl
chloride and 0.1 ml of N,N-dimethylformamide (DMF). After heated
at 80 ꢀC under argon for 4 h, excess thionyl chloride was removed
under vacuum at 80 ꢀC. A white crystalline product was obtained
and dried in vacuum oven (ꢁ80 kPa, 80 kPa below atmospheric
pressure) at room temperature for 12 h. The product was used
directly in the next step without any further purification. Yield
97.6%. No melting point was observed due to the thermal instability
2.2. Instrumentation
Size Exclusion Chromatography (SEC) was used to determine
molecular weights and molecular weight distributions. With a flow
rate of 0.500 ml/min, data were obtained in N-methyl-2-
pyrrolidone (NMP) solvent at 30 ꢀC on a Waters Alliance model
2690 chromatograph equipped with a Waters HR 0.5þ HR 2þ HR
3þ HR 4 styragel column set. A Viscotek refractive index detector
and a viscometer were used for molecular weight determination.
Polystyrene standards were utilized to construct a universal mo-
lecular weight calibration curve.
FT-IR data were obtained on an M2004 FTIR spectrometer from
MIDAC Corporation from 4000 cmꢁ1 to 650 cmꢁ1 with a 4 cmꢁ1
resolution. 1H and 13C NMR spectra were obtained by a JEOL 500
(500 MHz) spectrometer at room temperature with chemical shifts
relative to tetramethylsilane (TMS). High Resolution Mass Spectra
(HRMS) were obtained from an Agilent liquid chromatography/
mass spectrometry (LC/MS) mass spectrometer with a time of flight
(TOF) analyzer. Elemental analysis was done by Atlantic Microlab,
Inc (Norcross, Georgia). Oxygen contents in the elemental analysis
were calculated by difference.
Tgs and Tms were determined by Differential Scanning Calo-
rimetry (DSC). Data were obtained by using a TA InstrumentsÔ
Q2000. Nitrogen was used as the carrying gas with a sample flow
rate of 20 ml/min and a heating rate of 10 ꢀC/min. Tgs were deter-
mined in the second heating cycle after the samples were quenched
at nominally 100 ꢀC/min in the cooling cycles. Thermogravimetric
analysis (TGA) was carried out by a TA InstrumentsÔ Q10 from
25 ꢀC to 600 ꢀC under nitrogen at a heating rate of 10 ꢀC/min. Dy-
of this compound. 1H NMR (CDCl3, ppm):
4H),
1.58 (m, 4H). 13C NMR (CDCl3, ppm):
d
2.73 (m, 2H),
d2.30 (m,
d
d188.4, 50.6, 30.0.
2.3.2. Synthesis of trans-1,4-cyclohexanediylbis[(4-methoxyphenyl)
methanone (compound 3 in Scheme 1)
A 250 ml one-necked round bottom flask was charged with
8.000 g (38.28 mmol) trans-1,4-cyclohexane dicarbonyl dichloride
and 100 ml anisole as the solvent and the reactant. The flask was
equipped with a Teflon coated magnetic stir bar and a condenser.
After a homogenous solution was obtained at room temperature,
the system was placed in an ice bath and cooled to 0 ꢀC. 12.76 g
(95.69 mmol) of aluminum chloride was then slowly added to the
solution with vigorous stirring. The reaction mixture was kept at
0
ꢀC for 2 h followed by another 8 h at room temperature. Then
400 ml deionized water was added to the reaction mixture which
was a light orange suspension. The mixture was vigorously stirred
at room temperature for 1 h then filtered. The white solid product
obtained by filtration was added to 200 ml methanol and stirred at
room temperature for another 3 h to remove residual anisole. The
suspension was filtered again to obtain the final product as a white
solid which was thoroughly dried in vacuum oven (ꢁ80 kPa) at
80 ꢀC for 12 h. Yield: 92.5%. m.p.: 157.1 ꢀC. Elemental analysis:
Found: C, 74.75; H, 6.90; O, 18.35. Calc. for C22H24O4: C, 74.98; H,
6.86; O, 18.16%. 1H NMR (CDCl3, ppm):
3.87 (s, 6H), 3.31 (m, 2H), 2.03 (m, 4H),
(CDCl3, ppm): 202.0, 163.5, 130.6, 129.1, 113.9, 55.6, 44.6, 28.9.
d
7.95 (d, 4H),
d6.95 (d, 4H),
d
d
d
d
1.69 (m, 4H). 13C NMR
namic mechanical analysis (DMA) was performed on
a
TA
d
InstrumentsÔ Q800 in nitrogen atmosphere from ꢁ150 ꢀC to
200 ꢀC with a rate of 2 ꢀC/min. The DMA parameters were Mode:
2.3.3. Synthesis of trans-1,4-bis(4-methoxybenzyl)cyclohexane
(compound 4 in Scheme 1)
Multi-Freq-Strain Tension Film; Amplitude: 10 mm; Preload force:
0.01 N. The tensile properties were obtained on an Instron Model
4400 Universal Testing System with a rate of 2 mm/min at room
temperature. The results were the average of at least five samples.
To a 250 ml two-necked round bottom flask equipped with an
argon inlet, a Teflon coated magnetic stir bar, and a condenser,
15.00 g (42.61 mmol) of compound 3, 19.18 g (38.35 mmol) of hy-
drazine monohydrate, 21.48 g (38.35 mmol) of potassium hydrox-
ide and 100 ml of diethylene glycol were added. Under argon
atmosphere, the mixture was heated to 250 ꢀC in a high tempera-
ture silicon oil bath with stirring. The reaction mixture was held at
this temperature for 24 h then the system was cooled to room
temperature and 300 ml deionized water was added. The aqueous
solution was extracted with 100 ml chloroform three times. The
2.3. Monomer synthesis
2.3.1. Synthesis of trans-1,4-cyclohexane dicarbonyl dichloride
(compound 2 in Scheme 1)
With a Teflon coated magnetic stir bar, a condenser, and an
argon inlet, a pre-dried 250 ml three-necked round bottom flask

B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
4495
chloroform solutions were combined and chloroform was removed
by rotary evaporation to obtain a light yellow solid. The solid was
extracted in a Soxhlet extractor for 8 h with 400 ml methanol to
remove soluble side products followed by drying at 80 ꢀC in vac-
uum oven (ꢁ80 kPa) for 12 h. Yield: 97.7%. m.p.: 134.6 ꢀC. Elemental
analysis: Found: C, 81.39; H, 8.81; O, 9.80. Calc. for C22H28O2: C,
different starting materials. We defined a homopolymer as a
polymer from DCDPS with a single bisphenol and a copolymer as
the one with two bisphenols. The synthesis of the random PAES
copolymer based on 0.5 molar equivalent of CMB, 0.5 molar
equivalent of DHBP, and 1 molar equivalent of DCDPS is described
here as an example. All the other homopolymer and copolymers
were synthesized via a similar technique. To a 100 ml round bottom
flask equipped with a mechanical stirrer, an argon inlet and a
81.44; H, 8.70; O, 9.86%. 1H NMR (CDCl3, ppm):
(d, 4H), 3.77 (s, 6H), 2.39 (d, 4H), 1.67 (m, 4H),
0.89 (m, 4H). 13C NMR (CDCl3, ppm):
157.7, 133.5, 130.0, 113.5,
55.3, 43.1, 40.1, 33.0.
d7.02 (d, 4H),
d6.80
d
d
d
d1.40 (m, 2H),
d
d
DeaneStark trap, 3.875 g (13.50 mmol) of DCDPS, 2.000 g
(6.75 mmol) of CMB, 1.256 g (6.75 mmol) of DHBP, 4.842 g
(35.09 mol) of K2CO3, 60 ml of N,N-dimethylacetamide (DMAc), and
30 ml of toluene were added. Under the protection of argon, the
reaction was allowed to dehydrate at 140 ꢀC for 3 h by azeotropic
distillation. Then the temperature was slowly increased to 160 ꢀC
over 2 h to remove toluene. After 20 h at 160 ꢀC the reaction
mixture was cooled to room temperature. The solution was
precipitated in a 5 weight percent HCl aqueous solution. The
polymer product was obtained after filtration and subsequently
washed three times with 200 ml deionized water and three times
with 200 ml methanol. The polymer sample was obtained as a
white solid and was dried thoroughly at 120 ꢀC for 12 h in vacuum
2.3.4. Synthesis of 4,40-[trans-1,4-cyclohexanediylbis(methylene)]
bisphenol (CMB, compound 5 in Scheme 1)
15.00 g (46.30 mmol) of compound 4 and 53.47 g (46.30 mmol)
of pyridine hydrochloric acid were added to a 250 ml two-necked
round bottom flask equipped with an argon inlet, a Teflon coated
magnetic stir bar, and a condenser. Under argon atmosphere, the
system was heated in a high temperature silicon oil bath to 225 ꢀC
and allowed to react at this temperature for 12 h with stirring. Then
the reaction mixture was cooled to room temperature and 200 ml
water was added. The suspension was vigorously stirred at room
temperature for 12 h then filtered to obtain the crude product with
a beige color. Crystals with a light beige color were obtained after
recrystallization with methanol with a yield of 85.4%. m.p.:
232.0 ꢀC. Elemental analysis: Found: C, 80.35; H, 8.24; O,10.66. Calc.
for C20H24O2: C, 81.04; H, 8.16; O, 10.80%. 1H NMR (DMSO-d6, ppm):
oven (ꢁ80 kPa). Yield: 92.4%. 1H NMR (CDCl3, ppm):
d
7.86 (m),
d7.58 (m, 3.90),
d
7.11 (m),
1.46 (m),
integration area ratio between the protons with chemical shift of
7.58 and 2.47 was used to determine the actual monomer per-
d7.06 (m), d7.98 (m), d6.92 (m), d2.47 (d,
4.00),
d1.70 (m),
d
d0.93 (m). In the proton NMR, the
d
d
d
9.08 (s, 2H),
d
6.89 (d, 4H),
d
6.63 (d, 4H),
d
2.30 (d, 4H),
d
1.58 (m,
155.7,
centage in the polymer sample.
4H), 1.32 (m, 2H),
d
d
0.83 (m, 4H). 13C NMR (DMSO-d6, ppm):
d
131.3, 130.3, 115.4, 42.9, 40.1, 32.9. HRMS (m/z): Found: 296.1776.
Calcd for C20H24O2: 296.1785. Diff: 2.80 ppm.
2.4.2. Synthesis of high molecular weight 4,40-dihydroxy-p-
biphenyl (DHBP) based polysulfone as a property control
The DHBP based PAES was synthesized with comparable high
molecular weight to the commercial RadelÒ R sample. Both the
RadelÒ R sample and the lab-synthesized high molecular weight
DHBP based PAES sample were used as controls in the thermal and
mechanical property evaluations. The high molecular weight DHBP
based PAES sample was synthesized in the same way as described
in the polymer synthesis paragraph above but with a stoichiometry
imbalance to control the molecular weight based on the Carothers
equation.
2.3.5. Synthesis of 4,40-dihydroxy-p-terphenyl (DHTP)
4,40-Dihydroxy-p-terphenyl (DHTP) was synthesized according
to a previously published procedure [14]. 1H NMR (DMSO-d6 ppm):
d
d
7.56 (s, 4H),
157.1, 138.1, 130.5, 127.5, 126.3, 115.8.
d7.46 (d, 4H), d
6.80 (d, 4H). 13C NMR (DMSO-d6 ppm):
2.4. Polymer synthesis
2.4.1. Synthesis of 4,40-[trans-1,4-cyclohexanediylbis(methylene)]
bisphenol based polysulfone homopolymer and random copolymers
trans-1,4-Cyclohexylene ring-containing poly(arylene ether
sulfone)s based on CMB, 4,40-dihydroxy-p-biphenyl (DHBP), and
DHTP were synthesized by nucleophilic aromatic substitution with
DCDPS as shown in Scheme 2. The polymers based on bisphenol-A
(BisA), DHTP, and DCDPS were synthesized in a similar fashion with
2.5. Polymer film preparation
Film samples were obtained by solution casting. The solid
polymer sample was dissolved at room temperature in chloroform,
DMAc, or NMP to offer a homogeneous solution with a concen-
tration of 10% wt. The polymer solution was filtered through a
45 mm micro glass fiber filter and then was cast on a leveled glass
substrate with a syringe, dried at 80 ꢀC for 12 h, and subsequently
dried at 120 ꢀC under vacuum (ꢁ80 kPa) for 12 h. After drying, the
tough film was separated from the glass substrate. Dog bone
samples for the mechanical property evaluation were prepared
from the polymer films by a dog bone puncher on a Teflon sub-
strate. The dimensions on the tested area were 4.0 mm in width and
about 20 mm in length. The thickness of the samples was in the
range of 60e100 mm. All the soluble polymers formed transparent
tough films with no color or a light yellow color.
3. Results and discussion
3.1. Synthesis of 4,40-[trans-1,4-cyclohexanediylbis(methylene)]
bisphenol (CMB) monomer
The CMB monomer was successfully synthesized in four steps
with an overall yield of 77%. The key reaction step was the Wolff-
Scheme 2. Synthesis of 4,40-[trans-1,4-cyclohexanediylbis(methylene)] bisphenol
based homopolymer (x ¼ 1, R1 ¼ CMB) and random copolymers.
Kishner-Huang reduction reaction [15] where
a strong base

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B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
3.2. Polysulfone homopolymer and random copolymers based on
4,40-[trans-1,4-cyclohexanediylbis(methylene)] bisphenol (CMB),
4,40-dihydroxy-p-biphenyl (DHBP) and 4,40-dihydroxy-p-terphenyl
(DHTP)
3.2.1. Characterization of the cyclohexylene ring-containing
polysulfones
The PAES homopolymer based on CMB as the only bisphenol and
the random copolymers based on different ratios of CMB and DHBP
(or DHTP) were all synthesized with high yield. In the random
copolymer names, the numbers after the acronyms indicate the
molar percentages of the phenol monomers. For example,
CMB75DHBP25 is the random copolymer made with 75 M percent of
CMB, 25 M percent of DHBP, and 100 M percent of DCDPS. The con-
figurations of the cyclohexylene ring units in the polymers were
monitored by 1H NMR. The 1H NMR of the homopolymer based on
CMB isshowninFig. 4 asanexample. Thealiphaticringprotonareain
all thesolublepolymersamplesdisplayed thesame patternas shown
in the CMB monomer in Fig. 2. Only one signal was observed for F
(broadened by multiple splitting) and D protons which indicated the
cyclohexylene ring units retained the trans-configuration and no
isomerization reactions occurred during the polymerizations.
Fig. 1. FT-IR spectra monitoring the Wolff-Kishner-Huang reduction reaction.
(potassium hydroxide), a reducing agent (hydrazine monohydrate),
and a high boiling point solvent (diethylene glycol) were used
(shown in Scheme 1). The FT-IR spectra in Fig. 1 clearly showed the
characteristic adsorption of the carbonyl group at 1667 cmꢁ1 was
eliminated which was indicative of the successful reduction of the
carbonyl. The structures of compound 3 and 4 were confirmed by
1H NMR and 13C NMR. They also exhibited sharp melting points.
In the CMB monomer synthesis, trans-CHDA was used as the
starting material. In Scheme 1, the configurations of the cyclo-
hexylene rings were carefully monitored by NMR. For example, the
1d 1H NMR of CMB is shown in Fig. 2 with the 2d HeH Correlation
Spectroscopy (COSY) NMR shown in Fig. 3. The enlarged area in
Fig. 2 showed the aliphatic ring protons where F protons were the
cyclohexyl protons and D protons were the methylene protons
between the phenyl rings and the cyclohexylene rings. Based on the
HeH COSY NMR spectra, the only HeH correlation of D protons was
with the F protons, which confirmed that the F protons were the
cyclohexyl protons. Due to the fact that only one signal (broadened
by multiple splitting) was observed for both D and F protons, the
cyclohexylene ring in the CMB monomer remained in the trans-
configuration. The cyclohexyl proton single peak (broadened by
multiple splitting) was consistent with the raw material (trans-
CHDA) NMR spectrum and agreed with the reference observation
[4,16]. All the cyclohexylene ring-containing compounds and
polymers showed the same proton NMR pattern which confirmed
the trans-configurations. The CMB monomer structure and purity
were further confirmed by 13C NMR, HRMS and elemental analysis.
3.2.2. Homopolymer and random copolymers based on 4,40-[trans-
1,4-cyclohexanediylbis(methylene)] bisphenol (CMB) and 4,40-
dihydroxy-p-terphenyl (DHTP)
The compositions, molecular weights, thermal properties of
CMB/DHTP polysulfone random copolymers are summarized in
Table 1. The CMB50DHTP50 and CMB25DHTP75 polymer samples
exhibited limited solubility in all common organic solvents
including chloroform, dichloromethane, DMF, DMAc, and NMP, etc.
even at 80 ꢀC for the high boiling point solvents. Therefore mo-
lecular weight and monomer composition results were not ob-
tained for these two samples. CMB75DHTP25 was soluble in DMAc
and NMP.
Glass transition temperatures were observed to increase from
172 ꢀC to 222 ꢀC as the DHTP content increased from 0 to 75 M
percent. These results are expected due to the rigidity of the DHTP
units and the trends were similar to our previous work on DHTP
containing polysulfones [14]. No melting points were observed in
the CMB homopolymer and CMB/DHTP random copolymers. The
polymers all showed excellent resistance to thermal decomposi-
tion. The decomposition temperatures (defined as 5% weight loss
temperatures in nitrogen) were observed higher than 460 ꢀC. The
decomposition temperatures increased from 466 ꢀC to 510 ꢀC when
DHTP content increased from 0 to 75 M percent. Similar high
Fig. 2. 1d 1H NMR spectrum of the CMB monomer.

B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
4497
Fig. 3. 2d HeH COSY spectrum of the CMB monomer.
decomposition temperatures also have been reported in polymers
with DHTP moiety [17].
with decomposition temperatures all higher than 470 ꢀC. Compa-
rable molecular weights were obtained with Mn higher than 35 kg/
mol. Reasonable polycondensation Polydispersity Indexes (PDIs)
were also obtained. They were slightly lower than the theoretical
PDI value of 2.0 because of fractionation in the precipitation pro-
cess. The SEC traces of the samples were all monomodal with no
indication of branching. The comparable high molecular weights
and comparable PDIs of these polymers ensured that the me-
chanical properties were not molecular weight dependent.
The polymers shown in Fig. 5 shared structural similarity
exhibiting similar glass transition temperatures and comparable
high molecular weights. However mechanically, they showed
significantly different behaviors which are shown in Table 3. When
DHTP was copolymerized with BisA, the polymer exhibited brittle
behavior where the polymer failed immediately after the yield
point. When CMB was copolymerized with DHBP, slight improve-
ment was observed over the BisA/DHTP polymer. A significant
strain at failure enhancement, about 10-folds over the latter, was
observed in CMB/DHTP copolymer. The moduli results of the ma-
terials shown in Table 3 indicated that the elongation enhancement
was not obtained due to the loss of stiffness.
Due to the solubility issues and the unknown molecular weights
of the CMB50DHTP50 and CMB25DHTP75 samples, the structure
analogs of CMB75DHTP25 were prepared to perform a mechanical
property comparison. The structures are shown in Fig. 5. These
polymers were all soluble in DMAc which allowed us to cast films
from homogeneous 10 weight percent solutions. Transparent tough
films with no color or a light yellow color were obtained. Me-
chanical properties were obtained from the dog bone samples
made from the film samples. The compositions, molecular weights,
and thermal properties of these random copolymers were sum-
marized in Table 2. As shown in the table, the actual monomer
compositions determined by 1H NMR exhibited an excellent
agreement with the monomer feed compositions. The cyclo-
hexylene ring-containing polymers (CMB75DHBP25 and
CMB75DHTP25) showed lower glass transition temperatures in the
vicinity of 190 ꢀC due to the flexibility provided by the trans-1,4-
cyclohexylene ring units incorporated in the CMB monomer via
low energy conformational changes. This result agreed very well
with our recent results on a series of PAESs based on the trans-1,4-
cyclohexylene ring-containing acid chloride monomers [13].
The CMB75DHTP25 sample showed slighter higher Tg than
CMB75DHBP25 sample due to the backbone rigidity increase by
replacing the biphenyl units with the terphenyl units. All three
polymers showed excellent resistance to thermal decomposition
Tan
copolymers had very different relaxation behaviors.
Two relaxations, -relaxation and -relaxation, were observed
in the low temperature DMA range of these polymers as shown in
Fig. 6. The -relaxation in DMA at 1 Hz has been widely reported in
d curves obtained from DMA (Fig. 6) showed that the three
b
g
g
cyclohexylene ring-containing polymers and non-cyclohexylene
containing polysulfones at around ꢁ100 ꢀC. Similar
g-relaxations
were also observed in a series of PAESs based on trans-1,4-
cyclohexylene ring-containing acid chlorides which we recently
reported [13]. In a paper by McGrath and coworkers [18], the dy-
namic mechanical behavior of non-cyclohexylene containing pol-
ysulfones was reviewed. The origin of the
g-relaxation was
concluded to be a combination of motions of aryl ether bonds and
sulfone-water complexes. In the work reported by Yee and co-
workers [6,8], Tomomi and coworkers [19], and Credico and co-
workers [10],
g-relaxations were observed in DMA studies of
cyclohexane ring-containing polycarbonates, polyesters, and
poly(1,4-cyclohexylene dimethylene phthalate)-reinforced epoxy
resins, respectively. The relaxation peak values were reported in the
vicinity of ꢁ60 ꢀC for these polymers. All the results listed above
were reported for polymer samples containing cis/trans-mixed
cyclohexylene rings. In relaxation studies on the all trans-configu-
ration cyclohexylene ring incorporated into poly(butylene 1,4-
Fig. 4. 1d 1H NMR of the CMB DCDPS homopolymer (CMB100).

4498
B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
Table 1
Compositions, molecular weights, and thermal properties of the CMB/DHTP polysulfone random copolymers.
c
Polymer
CMB
DHTP
CMB
DHTP
Tg
Td
Molar mass
(kg/mol)
Mn
PDI
molb (%)
molb (%)
molb (%)
molb (%)
(ꢀC)
(ꢀC)
Mw
CMB100a
CMB75DHTP25
CMB50DHTP50
CMB25DHTP75
100
0
100
74.8
NAd
NA
0
172
189
207
222
466
472
490
510
28.9
35.1
NAd
NA
64.2
68.5
NA
2.2
1.9
NA
NA
75.0
50.0
25.0
25.0
50.0
75.0
25.2
NA
NA
NA
a
The numbers indicate the percentage contents of the bisphenol monomers.
b
c
The first two columns are the feed compositions of the monomers; the second two columns are the actual monomer percentages determined by 1H NMR.
The decomposition temperature is the 5% weight loss temperature in nitrogen.
d
The polymers with 50 and 75 M percent of DHTP monomer were not soluble in SEC solvents.
supported by the correlation of the g-relaxation intensities and the
cyclohexylene ring contents in the CMB/DHBP copolymer series
shown later in this paper (Fig. 8).
The b-relaxation observed in the low temperature DMA Tan d
curve at around 50 ꢀC has been reported in non-cyclohexylene
containing polysulfones in the temperature range of 0 ꢀCe60 ꢀC
with no clear conclusion on the origin [18]. Since it showed strong
intensity in the BisA75DHTP25 sample, this b-relaxation was likely
related to the sulfone units or the aromatic units in the polymers
and not the cyclohexylene groups. This hypothesis was also sug-
gested by the CMB/DHBP copolymers DMA study shown later in
this paper (Fig. 8).
As shown in Fig. 6, the CMB containing copolymers
(CMB75DHTP25 (squares) and CMB75DHBP25 (triangles)) exhibi-
ted strong
cyclohexylene units. In contrast, only
with aromatic sulfone units was observed in the BisA75DHTP25
polymer (circles). The -relaxation was absent due to the absence of
the cyclohexylene ring. The CMB75DHTP25 copolymer (squares)
exhibited a strong intensity in both -relaxation and -relaxation
which is possibly contributive to the significant ultimate elongation
enhancement. In the cases of BisA75DHTP25 copolymer (circles)
and CMB75DHBP25 copolymer (triangles), significantly lowered
g
-relaxation due to the incorporation of the trans-
b-relaxation which related
Fig. 5. Structures of CMB or DHTP containing random copolymers.
g
b
g
cyclohexanedicarboxylate) (PBCHD), enhanced
g-relaxations
around ꢁ100 ꢀC were observed which were attributed to the local
motion of the methylene units enhanced by the less polar trans-
enchained cyclohexylene units when compared to the cis-
enchained units [10]
intensities in
respectively.
g-relaxation and b-relaxation were observed
In the system shown in Figs. 5 and 6, all the DMA samples were
dried at elevated temperature in vacuum which eliminated the
formation of the sulfone-water complex suggested by McGrath. The
-relaxation also only appeared in cyclohexylene ring-containing
polymers (CMB75DHTP25 and CMB75DHBP25). Based on these
3.2.3. Polysulfone homopolymer and random copolymers based on
4,40-[trans-1,4-cyclohexanediylbis(methylene)] bisphenol (CMB)
and 4,40-dihydroxy-p-biphenyl (DHBP)
g
To further evaluate the DMA and mechanical behavior of trans-
cyclohexylene ring-containing PAESs, copolymers based on CMB
and DHBP were studied. The CMB/DHBP copolymers were prepared
by the same synthetic method as used for the CMB/DHTP co-
polymers. However, unlike the CMB/DHTP system, the character-
ization of the CMB/DHBP system was not limited by solubility. The
facts and the trans-configuration of the cyclohexylene rings, we
assigned the g-relaxation to the motion of the methylene groups
and the trans-cyclohexylene ring units, probably chair boat
conformational transitions under DMA conditions. This assignment
agreed with the g-relaxation observation in PBCHD with all trans-
configuration cyclohexylene rings. This assignment was also
Table 2
Compositions, molecular weights, and thermal properties of CMB or DHTP containing polysulfone random copolymers.
c
Polymer
M1
M2
M1
M2
Tg
Td
Molar mass
(kg/mol)
Mn
PDI
molb (%)
molb (%)
molb (%)
molb (%)
(ꢀC)
(ꢀC)
Mw
BisA75DHTP25a
CMB75DHBP25
CMB75DHTP25
75.0
75.0
75.0
25.0
25.0
25.0
75.2
74.4
74.8
24.8
25.6
25.2
207
186
189
515
474
472
38.2
39.9
35.1
66.2
72.7
68.5
1.7
1.8
1.9
a
The numbers indicate the percentage contents of the bisphenol monomers.
The first two columns are the feed compositions of the monomer 1 (M1) and monomer 2 (M2); the second two columns are the actual monomer percentages determined
b
by 1H NMR.
c
The decomposition temperature is the 5% weight loss temperature in nitrogen.

B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
4499
Table 3
Table 5
Mechanical properties of CMB or DHTP containing polysulfone random copolymers.
Mechanical properties of the CMB homopolymer and CMB/DHBP polysulfone
random copolymers.
Polymers
Modulus
(MPa)
Yield stress
(MPa)
Strain at
yield (%)
Strain at
failure (%)
Polymers
Modulus
(MPa)
Yield stress
(MPa)
Strain at
yield (%)
Strain at
failure (%)
BisA75DHTP25a
CMB75DHBP25
CMB75DHTP25
972 ꢂ 161
1132 ꢂ 110
1055 ꢂ 67
40.8 ꢂ 9.0
55.6 ꢂ 5.7
52.4 ꢂ 4.2
5.8 ꢂ 0.7
6.6 ꢂ 0.8
7.2 ꢂ 0.5
6.4 ꢂ 1.5
9.9 ꢂ 3.8
118 ꢂ 19
RadelÒ Ra
1353 ꢂ 92
1498 ꢂ 140
1157 ꢂ 31
1132 ꢂ 110
1130 ꢂ 302
1063 ꢂ 51
62.3 ꢂ 6.0
82.3 ꢂ 5.7
64.8 ꢂ 3.5
55.6 ꢂ 5.7
58.8 ꢂ 4.8
50.2 ꢂ 5.0
7.0 ꢂ 1.0
7.8 ꢂ 0.7
8.2 ꢂ 0.9
6.6 ꢂ 0.8
10.4 ꢂ 3.4
9.4 ꢂ 5.7
8.1 ꢂ 1.3
7.9 ꢂ 0.8
14.3 ꢂ 6.0
9.9 ꢂ 3.8
18.2 ꢂ 4.0
21.1 ꢂ 4.0
DHBP PAESb
CMB100c
a
The numbers indicate the percentage contents of the bisphenol monomers.
CMB75DHBP25
CMB50DHBP50
CMB25DHBP75
a
Provided by Solvay Advanced Polymers L.L.C.
Lab synthesized DHBP based PAES.
The numbers indicate the percentage content of the bisphenol monomers.
b
c
the data in Table 2 and the previously published results [13]. No
melting points were observed in the CMB homopolymer and CMB/
DHBP random copolymers. All the polymer samples exhibited high
resistance to thermal decomposition. In nitrogen, the thermal
degradation temperatures at 5% weight loss were all observed
around 450 ꢀC.
The excellent solubility of the homopolymer and CMB/DHBP
copolymer system allowed us to cast films from homogeneous 10
weight percent DMAc solution. Transparent tough films with no
color or a light yellow color were obtained. Mechanical properties
were obtained from dog bone samples made from the films. The
film samples of RadelÒ R provided by Solvay Advanced Polymers
L.L.C. and the lab synthesized DHBP based PAES with comparable
high molecular weight were used as the mechanical property
controls with the same solvent casting technique. As the tensile
results show in Table 5, the CMB containing polymers exhibited
slightly reduced moduli when compared to the controls, however,
independent of the monomer percentages in the copolymer, all
CMB containing polymers showed similar moduli values. Moderate
strain at failure enhancement was observed for the CMB homo-
polymer and CMB/DHBP copolymers. The largest strain at failure
value about 20% was observed in the CMB25DHBP75 sample.
Figs. 7 and 8 show the dynamic mechanical analysis data of the
Fig. 6. The dynamic mechanical analysis results of BisA75DHTP25 (circles),
CMB75DHBP25 (triangles), and CMB75DHTP25 (squares) copolymer.
good solubility of the polymers allowed the property comparisons
to be performed with different phenol monomer contents. The
compositions, molecular weights, and thermal properties are
shown in Table 4. As shown in the table, the actual monomer
percentages determined by 1H NMR were very close to the mono-
mer feed percentages. The SEC traces of the samples were all
monomodal with no indication of branching. The homopolymer
and random copolymers exhibited high molecular weights with
number average molecular weights around 30 kg/mol and PDIs
close to 2.0. The comparable high molecular weights of the new
PAESs ensured that thermal properties and mechanical properties
results were from structural and/or composition differences not
molecular weight based effects. These polymer samples were
readily soluble in chloroform, DMF, DMAc, NMP at room temper-
ature but not in THF and methanol.
tan
sequence of
perature region (Fig. 7) are the
the relaxations at the glass transition. With increasing CMB con-
tent, a shift of the -relaxation peak value to the lower tempera-
d
curves with relaxations in the decreasing temperature
peaks. The relaxations shown in the high tem-
-relaxations which correspond to
a, b, g
a
a
As expected, decreasing glass transition temperatures were
observed in DSC with increasing CMB incorporation as shown in
Table 4. The decreasing glass transition temperature was due to the
enhanced flexibility in backbone from the incorporated cyclo-
hexylene rings. This agreed with the previous conclusion based on
tures was observed. These results agreed well with the glass
transition values obtained from the DSC measurements shown in
Table 4. In the low temperature region, two series of relaxations,
the
b and g-relaxations, were observed and are shown in Fig. 8.
Table 4
Compositions, molecular weights, and thermal properties of CMB homopolymer and CMB/DHBP polysulfone random copolymers.
e
Polymer
CMB
DHBP
CMB
DHBP
Tg
Td
Molar mass
(kg/mol)
Mn
PDI
mold (%)
mold (%)
mold (%)
mold (%)
(ꢀC)
(ꢀC)
Mw
RadelÒ Ra
e
e
e
e
220
227
172
186
199
214
526
565
466
474
453
442
14.2
21.6
28.9
39.9
40.3
34.7
28.8
37.4
64.2
72.7
84.6
68.2
2.0
1.7
2.2
1.8
2.1
2.0
DHBP PAESb
e
e
e
e
CMB100c
CMB75DHBP25
CMB50DHBP50
CMB25DHBP75
100
75.0
50.0
25.0
0
100
74.4
49.7
24.1
0
25.0
50.0
75.0
25.6
50.3
75.9
a
Provided by Solvay Advanced Polymers L.L.C.
Lab synthesized DHBP based PAES.
b
c
The numbers indicate the percentage content of the bisphenol monomers.
d
e
The first two columns are the feed compositions of the monomers; the second two columns are the actual monomer percentages determined by 1H NMR.
The decomposition temperature is the 5% weight loss temperature in nitrogen.

4500
B. Zhang, S.R. Turner / Polymer 54 (2013) 4493e4500
bisphenol monomer with 4,40-trans-1,4-cyclohexanediylbis(-
methylene) unit. The monomer and the polymers were carefully
characterized. The mechanical properties and relaxation character-
istics were studied. A ten-fold elongation to break enhancement was
observed in the CMB75DHTP25 polymer, which may be a result of
the strong sub-Tg b-relaxation and g-relaxation. In the CMB/DHBP
copolymers, moderate strain at failure improvements with reduced
moduli were observed. The sub-Tg relaxations were assigned based
on the previous studies and the DMA study of the CMB/DHBP and
CMB/DHTP systems. The
b-relaxation was assigned to the sulfone
units or the aromatic units in the polymers. The
g-relaxation was
assigned to the combination motion of the cyclohexylene ring and
the methylene groups.
Acknowledgments
Fig. 7. Dynamic mechanical analysis results of the CMB/DHBP copolymers in the high
temperature region.
This research was sponsored by the Army Research Laboratory
and was accomplished under Cooperative Agreement Number
W911NF-06-2-0014. The views and conclusions contained in this
document are those of the authors and should not be interpreted as
representing official policies, either expressed or implied, of the
Army Research Laboratory or the U.S. Government. The U.S. Gov-
ernment is authorized to reproduce and distribute reprints for
Government purposes notwithstanding any copyright notation
hereon. We acknowledge the assistance of the Department of
Chemistry and the Macromolecules and Interfaces Institute at Vir-
ginia Tech. We are grateful to Solvay Advanced Polymers L.L.C. and
Eastman Chemical Company for supplying chemicals. We appre-
ciate the assistance of Professor Long’s, Professor Riffle’s, and Pro-
fessor McGrath’s groups at Virginia Tech.
Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.polymer.2013.06.018.
Fig. 8. Dynamic mechanical analysis results of the CMB/DHBP copolymers in the low
temperature region.
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