Synthesis of bicyclic bis(γ-butyrolactone) derivatives bearing sulfide moieties and their alternating copolymers with epoxide

Article abstract of DOI:10.1002/pola.26278

A series of bicyclic bis(γ-butyrolactone)s (BBL) bearing sulfide moiety 2 were readily synthesized from a precursor BBL bearing isopropenyl group 1. This efficient and versatile synthesis of 2 was achieved by a highly reliable radical addition reaction of thiols to the C-C double bond in the isopropenyl group 2 underwent anionic copolymerization with glycidyl phenyl ether in a 1:1 alternating manner to give a series of the corresponding polyester 3, of which side chains inherited the sulfide group from 2. The glass transition temperatures (T_g) of 3 showed clear dependence on the flexibility of the sulfide side chains. The scope of this copolymerization system was further expanded by synthesizing a bifunctional BBL 4 from 1 with using hexanedithiol and performing its copolymerization with bisphenol A diglycidyl ether 5. The copolymerization gave the corresponding networked polymer in high yield. During the copolymerization, the volume expanding nature of the double ring-opening reaction of 4 contributed to the efficient compensation of the intrinsic volume shrinkage of the ring-opening of epoxide to achieve a shrinkage-free curing system. Copyright

Full text of DOI:10.1002/pola.26278

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
Synthesis of Bicyclic Bis(c-butyrolactone) Derivatives Bearing Sulfide
Moieties and Their Alternating Copolymers with Epoxide
Sousuke Ohsawa, Kazuhide Morino, Atsushi Sudo, Takeshi Endo
Molecular Engineering Institute, Kinki University, 11-6 Kayanomori, Iizuka, Fukuoka, 820-8555, Japan
Correspondence to: T. Endo (E-mail: tendo@moleng.fuk.kindai.ac.jp)
Received 28 March 2012; accepted 12 July 2012; published online
DOI: 10.1002/pola.26278
ABSTRACT: A series of bicyclic bis(c-butyrolactone)s (BBL) bear-
ing sulfide moiety 2 were readily synthesized from a precursor
BBL bearing isopropenyl group 1. This efficient and versatile
synthesis of 2 was achieved by a highly reliable radical addi-
tion reaction of thiols to the C-C double bond in the isoprope-
nyl group 2 underwent anionic copolymerization with glycidyl
phenyl ether in a 1:1 alternating manner to give a series of the
corresponding polyester 3, of which side chains inherited the
sulfide group from 2. The glass transition temperatures (Tg) of
3 showed clear dependence on the flexibility of the sulfide side
chains. The scope of this copolymerization system was further
expanded by synthesizing a bifunctional BBL 4 from 1 with
using hexanedithiol and performing its copolymerization with
bisphenol A diglycidyl ether 5. The copolymerization gave the
corresponding networked polymer in high yield. During the
copolymerization, the volume expanding nature of the double
ring-opening reaction of 4 contributed to the efficient compen-
sation of the intrinsic volume shrinkage of the ring-opening of
C
V
epoxide to achieve a shrinkage-free curing system.
2012
Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 000:
000–000, 2012
KEYWORDS: alternating; butyrolactone; copolymerization; poly-
ester; ring-opening polymerization; thiol-en
nating manner to give the corresponding polyester bearing
a,b-unsaturated ketone groups in the side chains, which were
efficiently used for side chain modifications of the polymer.
INTRODUCTION Epoxide-based compounds are important for
various products such as adhesive, sealant, and coating mate-
rials. One of the reasons for the wide range of applications is
based on the high reactivity of epoxides due to the distortion
energy of the three-membered ring, which permits the effi-
cient ring-opening polymerizations under both cationic and
anionic conditions. This high reactivity also enabled their
copolymerizations with various compounds including robust
compounds such as bicyclic bis(c-butyrolactone) (BBL).1–8
BBL exhibited no homopolymerizability at all; however, it
underwent the anionic alternating copolymerization with
epoxides by using anionic initiators such as potassium tert-
butoxide (t-BuOK)1–6 and phosphines.7,8 The copolymeriza-
tion proceeded in a 1:1 alternating manner together with an
isomerization process to give the corresponding polyester
bearing ketone groups. One of the features of this copolymer-
ization is the volume expanding nature due to the double
ring-opening reaction of a compactly folded structure of BBL.
This nature has permitted the use of BBL as a ‘‘volume
expandable monomer’’ that can suppress the intrinsic shrink-
age of epoxy curing systems.2,4,5 Recently, we have reported a
novel BBL bearing isopropenyl group 1, which was readily
synthesized by a reaction of propantricarboxylic acid with
methacrylic anhydride (Scheme 1).8 Anionic ring-opening
copolymerization of 1 with glycidyl phenyl ether (GPE) initi-
ated by triphenylphosphine (PPh3) proceeded in a 1:1 alter-
Herein, we demonstrate a new exploitation of 1 as a versa-
tile precursor for BBL-type monomers through thiol-ene
reaction of the isopropenyl group of 1 (Scheme 1). Anionic
alternating copolymerizations of the obtained sulfide-func-
tionalized BBLs involving a shrinkage-free curing system are
also reported.
RESULTS AND DISCUSSION
Radical Addition of Thiols to 1
Currently, thiol-ene reaction, i.e., radically mediated addition
of thiol to C-C double bond, is used as one of the so-called
‘‘click’’ reactions for combining two components into one mol-
ecule quickly and quantitatively.9–11 Its application field is
expanding to precise construction of macromolecular archi-
tectures,12–14 functionalization of polymer side chains,15–20
closslinking,21 and surface modification.22,23 In this work, a
new series of BBL-type monomers bearing sulfide moiety 2
were synthesized from BBL 1 bearing isopropenyl group by
thiol-ene reaction (Scheme 1, Table 1). The reaction of dode-
cane thiol and 1 proceeded quantitatively within 3 h to give
the corresponding adduct 2a in 89% yield (run 1 in Table 1).
1
Figure 1 shows the H NMR spectrum of 2a, where signals at
C
V
2012 Wiley Periodicals, Inc.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000
1

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
TABLE 1 Radical Addition of Thiols to 1a
Time
(h)
Conv.
(%)b
Yield
(%)c
Run
Thiol
Monomer
1
2
CH3(CH2)11SH
3
3
97
91
89
72
2a
2b
3
4
6
3
78
6
63
-
2c
2d
SCHEME 1 Synthesis of the bicyclic BBL bearing various sub-
stituents via radical addition of monothiols to 1.
2.26 ppm were assigned to the methine proton of the propyl
group. The doublet at 1.20 ppm was assignable to the methyl
group in the isopropyl moiety. Figure 2a shows the IR spec-
trum of 2a, where a strong absorption attributable to the lac-
tone moieties was observed at 1787 cmꢀ1. The reaction of 1
with cyclohexane thiol gave the corresponding adduct 2b (run
2 in Table 1). Analogously, a BBL 2c bearing benzylsulfide
was synthesized with using benzylmercaptane (run 3 in
Table 1). In contrast to these successful reactions of alkane
thiols that of thiophenol was not successful (run 4 in Table 1).
a
Conditions: [1]0 ¼ [thiol]0 ¼ 10[AIBN]0 ¼ 2.0 M; in chlorobenzene at
60ꢁC.
b
Determined by 1H NMR.
c
Isolated by silica-gel column chromatography.
of 3 were in good accordance with the 1:1 alternating
sequence (Figs. 2 and 3). For example, the IR spectrum of 3a
indicated absorption peaks at 1741 and 1716 cmꢀ1, which
were attributed to the ester linkage in the main chain and
the ketone groups in the side chain, respectively (Fig. 2). In
1
the H NMR spectrum of 3a, the signal b at 3.48 ppm for the
bislactone-derived structure and the signal d at 5.32 ppm for
the GPE-derived structure appeared with an integration ratio
in 49:51, to support that the copolymerization proceeded in
a 1:1 alternating manner. Thermal properties of the obtained
copolymers were investigated by differential scanning calo-
rimetry (DSC) and thermal gravimetric analysis (TGA). The
glass transition temperatures (Tg) and 10% weight loss tem-
peratures (Td10) thus measured are listed in Table 2. Tg of
Anionic Copolymerization of 2 and GPE
Copolymerizations of the obtained BBL-type monomers, 2a,
2b, and 2c with GPE were performed with using PPh3 as an
initiator (Scheme 2).7,8 In all the cases, conversions of both
2 and GPE were more than 90%, leading to the formation of
the resulting copolymers 3. The copolymers 3 were isolated
as methanol-insoluble fractions in good yield (Table 2). The
spectroscopic features clarified by IR and 1H NMR analyses
FIGURE 1 1H NMR spectra of 1 (a), 2a (b) and 4 (c) measured in CDCl3 at rt.
2
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
FIGURE 2 FTIR spectra of 2a (a) and 3a (b) measured at rt.
SCHEME 2 Copolymerization of 2 and GPE using PPh3 as an initiator in THF at 120ꢁC for 24 h.
TABLE 2 Copolymerization of 2 and GPEa
Conv. of
2 (%)b
Conv. of
GPE(%)b
Composition
Td10
(ꢁC)f
Run
2
Yield (%)c
Mn (Mw/Mn)d
2/GPE
Tg (ꢁC)e
1
2
3
a
2a
2b
2c
99
99
94
99
96
93
71
80
78
6100 (1.5)
5000 (1.5)
4400 (1.7)
49/51
51/49
50/50
ꢀ20
ꢀ1
2
265
281
265
Conditions: [2]0 ¼ [GPE]0 ¼ 25[PPh3]0 ¼ 2.0M; in THF at 120ꢁC for 24 h in a sealed tube.
b
c
d
e
f
Determined by 1H NMR.
Methanol-insoluble parts.
Estimated by SEC (eluent ¼ THF, polystyrene standards).
Determined by DSC.
Determined by TGA.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000
3

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
FIGURE 3 1H NMR spectra of 3a (a), 3b (b), and 3c (c) measured in CDCl3 at rt.
3a bearing flexible long alkyl chain was ꢀ20ꢁC, while those
of 3b and 3c bearing rigid cyclohexyl and phenyl moieties
were higher than that of 3a. These results demonstrated that
the thermal properties of the alternating copolymers can be
tuned by S-alkyl group of BBL monomers.
During a few hours from the initiation, the both mixture was
homogeneous. After that, these mixtures became heterogene-
ous gradually. The resulting insoluble networked polymer 6
and 7 were separated by filtration and washed with reflux-
ing chloroform (run 1and 2, Table 3). Figure 4b shows the
typical IR spectrum of 6, which indicated characteristic
absorptions that were observed commonly with the linear
Synthesis of a Bifunctional BBL Monomer and its
Copolymerization with Epoxide
The efficient synthesis of the sulfide-functionalized BBL-type
monomers 2 based on the thiol-ene reaction prompted us to
exploit this method for synthesizing a bifunctional BBL with
using dithiol (Scheme 3). The reaction of 1 and 1,6-hexane
dithiol proceeded smoothly to give the thioether-tethered
bifunctional BBL 4. The spectroscopic features of 4 were
quite similar to those of BBL 2a bearing dodecyl sulfide moi-
ety (Fig. 1c).
With using the obtained 4 as a BBL-type comonomer, its ani-
onic copolymerization with bisphenol A diglycidyl ether 5 in
a feed ratio of 1:1 and with GPE in a feed ratio of 1:2 were
investigated (Scheme 4). The conditions were same as those
for the copolymerization of monofunctional BBL 2 and GPE.
SCHEME 3 Synthesis of the bifunctional bicyclic BBL via radi-
cal addition of hexanedithiol to 1.
4
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
SCHEME 4 Copolymerization of 4 and epoxides and homopolymerization of 5.
polyesters 3: The absorptions due to the ester and ketone
groups appeared at 1741 cmꢀ1 and 1716 cmꢀ1, respectively,
implying that 6 was formed by the alternating copolymeriza-
tion of the bislactone moiety of 4 and the epoxy moiety of 5.
under the same conditions with those for the copolymeriza-
tions (run 3, Table 3). However, the polymerization scarcely
proceeded. On the other hand, the homopolymerization of 5
with using t-BuOK as an initiator proceeded successfully
(run 4, Table 3). The resulting insoluble product was isolated
by filtration and washed with refluxing chloroform to obtain
the corresponding networked polyether 8.
The spectrum also involved the absorption at 1794 cmꢀ1
,
which implied that the consumption of the lactone moiety of
4 was not quantitative. IR spectrum of 7 was quite similar
with that of 6 indicating similar main chain structures with
the difference in crosslinking density.
With three networked polymers 6, 7 and 8 at hand, their Tg
and temperatures for 10% weight loss (Td10) were measured
(Table 3). Tg and Td10 values of networked polymer 6 were
27 and 276 ꢁC, respectively, which were lower than that of
networked polymer 7, because of the high crosslinking den-
sity. Although the difference in initiation system for the syn-
thesis of these two polymers may have influenced on their
properties slightly, the Tg and Td10 values were compared to
discuss the correlation between structure of main chain and
thermal properties: The Tg values of 6 and 7 were 68 and
53 ꢁC, respectively, implying that the main chain of 6 was
more rigid than that of 7 due to the incorporation of the
ester linkages. On the other hand, the Td10 values of 6 and 7
Besides the copolymerizations, the homopolymerization of
epoxide 5 was performed with using PPh3 as an initiator
TABLE 3 Copolymerization of Bifunctional BBL 4 and Epoxides
and Homopolymerization of 5a
Run [4]0:[5]0:[GPE]0 initiator yield (%)b Tg (ꢁC)c Td10 (ꢁC)d
1
2
3
4
a
50:50:0
50:0:100
0:100:0
0:100:0
PPh3
PPh3
PPh3
98
93
0
68
27
–
301
276
–
ꢁ
t-BuOK 99
53
370
were 301 and 370 C, respectively. The lower thermal stabil-
ity of 6 than 7 was attributable to the intrinsic higher ther-
mal degradability of ester bond than ether one.
Polymerization conditions: [4]0 ¼ [epoxide moieties]0 ¼ 25[initiator]0
¼
1.0M; in THF at 120ꢁC for 24 h in a sealed tube.
b
Chloroform-insoluble parts.
c
The last topic of this article is the use of 4 as a volume
expandable monomer. As described in Introduction, we have
Determined by DSC under N2 atmosphere.
d
Determined by TGA under N2 atmosphere.
FIGURE 4 FTIR spectra of 4 (a) and 6 (b) measured at rt.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000
5

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
TABLE 4 Volume Changes upon the Copolymerization of 4 and
taken on a Thermo Scientific Nicolet iS10 spectrometer.
Number average molecular weight (Mn) and polydispersity
index (Mw/Mn) were estimated by size exclusion chromatog-
raphy, performed on a Tosoh chromatograph model HLC-
8120 system equipped with Tosoh TSKgel SuperHM-H styro-
gel columns (6.0 mm / ꢂ 15 cm) using THF as the eluent at
a flow rate of 0.6 mL/min. The molecular weight calibration
curve was obtained with polystyrene standards. DSC was
carried out with a Seiko Instrument DSC-6200 using an alu-
minum pan under a 20 mL/min N2 flow at the heating rate
of 5 ꢁC/min. TGA was performed with a Seiko Instrument
TG-DTA 6200 using an alumina pan under a 50 mL/min N2
5 and the Homopolymerization of 5
Volume
[4]0:[5]0:
[GPE]0
Density before
polymerizationa
Density of
polymera
change
(%)b
Run
1c
2d
a
50:50:0
0:100:0
1.2846
1.1741
1.2719
1.2487
þ1.0
ꢀ6.4
Measured by gas pycnometer at 25ꢁC.
b
Volume change ¼ [density before polymerization–density of polymer]/
density before polymerization ꢂ 100.
c
The copolymerization was initiated by PPh3.
d
ꢁ
The homopolymerization was initiated by t-BuOK.
flow at a heating rate of 10 C/min.
Synthesis of 2,8-Dioxa-1-(2-dodecylmercaptoisopropyl)
bicyclo[3.3.0]octane-3,7-dione (2a)
demonstrated a shrinkage-free polymerization system based
on the copolymerization of BBLs and epoxides. With expect-
ing the potential of newly developed bifunctional BBL 4 as a
volume expandable monomer, the volume change upon the
copolymerization of 4 and 5 was investigated. In Table 4,
the density of the mixture of 4, 5, and PPh3 and that of the
resulting copolymer 6 measured by gas pychnometer are
shown. From these values, the volume change upon the
copolymerization was calculated. Similarly, the volume
change upon the homopolymerization of bisepoxide 5 initi-
ated by t-BuOK was calculated from the corresponding den-
sities. As can be seen from the volume change upon the
homopolymerization of bisepoxide 5, it is generally known
that large volume shrinkage often occurs during ring-open-
ing polymerization of epoxides. When using monofunctional
epoxide, GPE, the polymerization seems to involve larger vol-
ume shrinkage than bisepoxide 5. However, the volume
change that accompanied the copolymerization was þ1.0%,
which means a small volume ‘‘expansion’’ was achieved by
using 4 as a comonomer. This achievement was highly con-
trastive to the serious volume shrinkage in 6.4% during the
homopolymerization of 5, confirming the remarkable compe-
tence of 4 as a volume expandable monomer.
A mixture of 1 (0.15 g, 0.84 mmol), dodecanethiol (0.17 g,
0.84 mmol), AIBN (6.9 mg, 0.042 mmol), and chlorobenzene
(0.4 mL) was stirred in the sealed tube at 60 ꢁC. After 3 h,
chlorobenzene was removed by evaporation. The residue
was purified by silica-gel chromatography (eluent: hexane/
ethyl acetate ¼ 1/1) to afforded 0.29 g (89%) of 2a as color-
less powder. Spectroscopic data of 2a: IR (neat): 2921, 2851,
1787, 1467, 1239, 1171, 1135, 970, 865 cmꢀ1 1H NMR
.
(CDCl3, 400 MHz): d 0.88 (t, 3H, CH3), 1.20 (d, 3H, CH3),
1.25–1.57 (m, 20H, alkyl), 2.26 (m, 1H, CH), 2.40–2.65 and
2.85 (m, 2H, OCOCH2 and 4H SCH2), 3.03 (q, 2H, OCOCH2),
3.32 (m, 1H, CCH).
Synthesis of 2,8-Dioxa-1 -(2-(cyclohexylmercapto)
isopropyl)bicyclo[3.3.0]octane-3,7-dione (2b)
A mixture of 1 (0.30 g, 1.6 mmol), cyclohexanethiol (0.19 g,
1.6 mmol), AIBN (0.030 g, 0.16 mmol), and chlorobenzene
(0.8 mL) was stirred in the sealed tube at 60 ꢁC. After 3 h,
chlorobenzene was removed by evaporation. The residue
was purified by silica-gel chromatography (eluent: hexane/
ethyl acetate ¼ 1/1) to afforded 0.27 g (72%) of 2b as col-
orless powder. Spectroscopic data of 2b: IR (neat): 2928,
1784, 1238, 1173, 1137, 1120, 1015, 969, 946, 889, 863,
EXPERIMENTAL
794 cmꢀ1 1H NMR (CDCl3, 400 MHz): d 1.17 (d, 3H, CH3),
.
1.23–2.03 (m, 10H, cyclohexyl), 2.26 (m, 1H, CH), 2.42–2.51
(m, 1H, SCH2), 2.54 and 2.59 (m, 2H, OCOCH2), 2.57–2.67 (b,
1H, SCH), 2.88 and 2.90 (m, 1H, SCH2) 3.01 and 3.08 (m, 2H,
OCOCH2), 3.34 (m, 1H, CCH). 13C NMR (CDCl3, 100 MHz): d
14.5, 26.8, 27.0, 27.1, 31.9, 34.6, 34.7, 36.7, 37.0, 37.1, 42.1,
45.6, 117.2, 172.4, 172.5.
Materials
Gycidyl phenyl ether (GPE), cyclohexane thiol, and benzyl
mercaptane were purchased from Tokyo Kasei (TCI, Tokyo
Japan). PPh3, 2,2-azobis(isobutironitrile) (AIBN), 1-dodecane-
thiol, and 1,6-hexanedithiol were obtained from Wako Pure
Chemical Industries (Osaka, Japan). Bisphenol A diglycidyl
ether was obtained from Nippon Steel Chemical (Tokyo Ja-
pan). PPh3 was recrystallized from ethanol. AIBN was recrys-
tallized from diethylether. GPE was dried over calcium
hydride and distilled under nitrogen. Tetrahydrofuran (THF)
was dried over sodium benzophenone ketyl and distilled
under nitrogen just before use. 2,8-Dioxa-1-isopropenylbicy-
clo[3.3.0]octane-3,7-dione (1) was prepared according to
previously reported method.1–7
Synthesis of 2,8-Dioxa-1 -(2-(benzylmercapto)
isopropyl)bicyclo[3.3.0]octane-3,7-dione (2c)
A mixture of 1 (0.23 g, 1.3 mmol), benzylmercaptane (0.17 g,
1.3 mmol), AIBN (0.020 mg, 0.12 mmol), and chlorobenzene
(0.6 mL) was stirred in the sealed tube at 60 ꢁC. After 6 h,
chlorobenzene was removed by evaporation. The residue was
purified by silica-gel chromatography (eluent: hexane/ethyl
acetate ¼ 1/1) to afforded 0.18 g (63%) of 2c as colorless
powder. Spectroscopic data of 2c: IR (neat): 2981, 2937,
1782, 1495, 1453, 1422, 1317, 1052, 943, 863, 718, 692
cmꢀ1. 1H NMR (CDCl3, 400 MHz): d 1.13 (d, 3H, CH3), 2.04 (m,
1H, CH), 2.33–2.39 (m, 1H, SCH2), 2.46–2.50 (m, 2H, OCOCH2),
Measurements
1H and 13C NMR spectra were recorded on a Varian NMR
Unity Inova 400 (400 and 100 MHz for H and 13C with tet-
1
ramethylsilane as the internal standard). IR spectra were
6
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
2.74 (m, 1H, SCH2), 2.84–2.95 (m, 2H, OCOH2), 3.13 (m, 1H,
CCH), 3.71 (s, 2H, SCH2Ph), 7.23–7.35 (m, 5H, Ph). 13C NMR
(CDCl3, 100 MHz): d 13.5, 32.4, 35.3, 35.7, 35.9, 36.0, 37.2,
40.5, 116.1, 127.4, 128.8, 129.0, 138.0, 172.3, 172.4.
Copolymerization of 4 and Bisphenol
A Diglycidyl Ether 5
PPh3 (7.8 mg, 30 mmol), 4 (0.38 g, 0.74 mmol), 5 (0.25 g,
0.74 mmol), and 0.74 mL of THF were placed in a glass
ampule under nitrogen atmosphere. The tube was cooled,
evacuated, sealed off, and heated at 120 ꢁC for 24 h. The
resulting solid was grinded and washed with chloroform in a
Copolymerization of 2 and GPE
A
typical copolymerization procedure 2 and GPE is
ꢁ
described below. PPh3 (2.5 mg, 0.090 mmol), 2a (93 mg,
0.24 mmol), GPE (33 mg, 0.24 mmol), and 0.1 mL of THF
were placed in a glass ampule under nitrogen atmosphere.
The tube was cooled, evacuated, sealed off, and heated at
120 ꢁC for 24 h. After the reaction mixture was cooled to
room temperature, a chloroform solution of acetic acid (1.0
vol %, 1.0 mL) was added. The resulting mixture was
poured into 50 mL of methanol. The resulting copolymer
was collected by centrifugation, washed with methanol dried
in vacuo to afford 85 mg (71%) of alternating copolymer 3a
as viscous oil. The Mn and Mw/Mn were 6.1 ꢂ 103 and 1.5,
respectively.
Soxhlet’s extractor and then dried in a vacuum oven at 80 C
to afford networked polymer 6 (0.62 g, 98%). Spectroscopic
data: IR (neat): 2928, 1796, 1733, 1712, 1607, 1507, 1456,
1410, 1362, 1227, 1179, 1040, 981, 829, 750 cmꢀ1
.
CONCLUSIONS
A novel bicyclic BBLs bearing various substituents such as
dodecyl, cyclohexyl, and benzyl group (2) was synthesized
through ‘‘thiol-en’’ radical addition of thiols to C¼¼C double
bond of bicyclic BBL bearing isopropenyl group (1). The sev-
eral thiols such as dodecanethiol, cyclohexanethiol, and ben-
zyl mercaptan were successfully reacted with 1 to give the
corresponding BBL derivatives 2 in high yield, whereas thio-
phenol was scarcely reacted. We demonstrated that the ani-
onic ring-opening copolymerization of 2 and glycidyl phenyl
ether (GPE) smoothly proceeded and corresponding alternat-
ing copolymers were obtained in high yield. The obtained
copolymers showed different thermal properties depend on
the structure of the polymer side chains. Analogously, the
reaction of 1 with 1,6-hexandithiol gave the corresponding
bifunctional BBL 4, which underwent the anionic ring-open-
ing copolymerization with GPE and bisphenol A diglycidyl
ether to form chloroform-insoluble networked polymers with
low volume shrinkage during crosslinking.
Spectroscopic data of 3a: IR (neat): 2924, 2853, 1741, 1716,
1599, 1497, 1457, 1374, 1243, 1173, 1050, 754, 691 cmꢀ1
.
1H NMR (CDCl3, 400 MHz): d 0.88 (t, 3H, CH3 (dodecyl)),
1.10–1.73 (br, 23H, CH3 (isopropyl), and CH2 (alkyl)), 2.46
(br, 5H, CH2COO, SCH2, and CH (isopropyl)), 2.72–3.03 (br,
4H, CH2COO and SCH2), 3.48 (br, 1H, CH), 4.06 (br, 2H,
COOCH2), 4.29–4.40 (br, 2H, CH2OPh), 5.32 (br, 1H, COOCH),
6.87–7.26 (m, 5H, Ph).
Spectroscopic data of 3b: IR (neat): 2927, 2851, 1737, 1713,
1599, 1588, 1496, 1449, 1372, 1216, 1152, 1047, 997, 690
cmꢀ1 1H NMR (CDCl3, 400 MHz): d 1.10–2.99 (m, 13H, CH3
.
(isopropyl) and CH2 (cyclohexyl)), 2.46–3.01 (m, 9H,
CH2COO, SCH2, and CH (isopropyl)), 3.49 (br, 1H, CH), 4.06
(br, 2H, COOCH2), 4.19–4.45 (br, 2H, CH2OPh), 5.31 (br, 1H,
COOCH), 6.87–7.26 (m, 5H, Ph).
ACKNOWLEDGMENT
This work was financially supported by JSR Corporation.
Spectroscopic data of 3c: IR (neat): 3063, 3027, 2969, 2928,
1736, 1713, 1599, 1588, 1494, 1454, 1407, 1372, 1237,
REFERENCES AND NOTES
1152, 1047, 982, 691 cmꢀ1 1H NMR (CDCl3, 400 MHz): d
.
1 Takata, T.; Tadokoro, A.; Endo, T. Macromolecules 1992, 25,
2782–2783.
1.10 (br, 3H, CH3), 2.21–2.89 (m, 5H, CH2COO, SCH2, and CH
(isopropyl)), 3.40 (br, 1H, CH), 3.64 (br, 2H, SCH2Ph), 4.05
(br, 2H, COOCH2), 4.15–4.48 (br, 2H, CH2OPh), 5.31 (br, 1H,
COOCH), 6.87–7.26 (m, 5H, Ph).
2 Tadokoro, A.; Takata, T.; Endo, T. Macromolecules 1993, 26,
4400–4406.
3 Takata, T.; Tadokoro, A.; Chung, K.; Endo, T. Macromolecules
1995, 28, 1340–1345.
Synthesis of 1,6-Bis[2-(2,8-Dioxabicyclo[3.3.0]
octane-3,7-dionyl)propylsulfanyl]hexane (4)
A mixture of 1 (2.26 g, 12.4 mmol), hexanedithiol (0.93 g,
6.2 mmol), AIBN (0.10 g, 0.62 mmol), and chlorobenzene
4 Takata, T.; Chung, K.; Tadokoro, A.; Endo, T. Macromolecules
1993, 26, 6686–6687.
5 Chung, K.; Takata, T.; Endo, T. Macromolecules 1995, 28,
3048–3054.
ꢁ
(12.4 mL) was stirred in the sealed tube at 60 C. After 3 h,
precipitated crude products were filtered and the residue
was purified by silica-gel chromatography (eluent: hexane/
ethyl acetate ¼ 1/1) to afforded 2.29 g (72%) of 4 as color-
less powder. Spectroscopic data of 4: IR (neat): 2928, 2853,
6 Zhang, C.; Ochiai, B.; Endo, T. Nettowaku Porima 2004, 25,
66–73.
7 Ohsawa, S.; Morino, K.; Sudo, A.; Endo, T. Macromolecules
2010, 43, 3585–3588.
1785, 1459, 1237, 1168, 1035, 968, 864 cmꢀ1 1H NMR
.
8 Ohsawa, S.; Morino, K.; Sudo, A.; Endo, T. Macromolecules
2011, 44, 1814–1820.
(CDCl3, 400 MHz): d 1.18 (d, 6H, CH3), 1.40 (m, 4H, alkyl),
1.597 (m, 4H, alkyl), 2.27 (m, 2H, CH), 2.40–2.65 and 2.85
(m, 4H, OCOCH2 and 8H SCH2), 3.05 (q, 4H, OCOCH2), 3.32
(m, 2 H, CCH). 13C NMR (CDCl3, 100 MHz): d 13.5, 28.3,
29.4, 32.9, 33.1, 35.8, 36.1, 40.9, 116.2, 172.6.
9 Hoyle, C. E.; Lowe, A. B.; Bowman, C. N. Chem. Soc. Rev.
2010 39, 1355–1387.
10 Kade, M. J.; Burke, D. J.; Hawker. C. J. J. Polym. Sci. Part A:
Polym. Chem. 2010, 48, 743–750.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000
7

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
11 Hoyle, C. E.; Lee, T. Y.; Roper, T. J. Polym. Sci. Part A:
Polym. Chem. 2004, 42, 5301–5338.
18 David, R. L. A.; Kornfield, J. A. Macromolecules 2008, 41,
1151–1161.
ꢀ
ꢁ
12 Lluch, C.; Ronda, J. C.; Galia, M.; Lligadas, G.; Cadiz, V. Bio-
19 Campos, L. M.; Killops, K. L.; Sakai, R.; Paulusse, J. M. J.;
Damiron, D.; Drockenmuller, E.; Messmore, B. W.; Hawker, C.
J. Macromolecules 2008, 41, 7063–7070.
macromolecules 2010, 11, 1646–1653.
13 Killops, K. L.; Campos, L. M.; Hawker, C. J. J. Am. Chem.
Soc. 2008, 130, 5062–5064.
20 Chen, G.; Amajjahe, S.; Stenzel, M. H. Chem. Commun.
2009, 1198–1200.
14 Dondoni, A. Angew. Chem. Int. Ed. 2008, 47, 8995–8997.
21 Carioscia, J. A.; Stansbury, J. W.; Bowman, C. N. Polymer
2007, 48, 1526–1532.
15 Geng, Y.; Discher, D. E.; Justynska, J.; Schlaad, H. Angew.
Chem. Int. Ed. 2006, 45, 7578–7581.
22 Campos, M. A. C.; Paulusse, J. M. J.; Zuilhof, H. Chem.
Commun. 2010, 46, 5512–5514.
16 Hordyjewicz-Baran, Z.; You, L.; Smarsly, B.; Sigel, R.;
Schlaad, H. Macromolecules 2007, 40, 3901–3903.
€
17 Gress, A.; Volkel, A.; Schlaad, H. Macromolecules 2007, 40,
7928–7933.
23 Gu, W.; Chen, G.; Stenzel, M. H. J. Polym. Sci. Part A:
Polym. Chem. 2009, 47, 5550–5556.
8
JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2012, 000, 000–000