Bridging from the Sequence to Architecture: Graft Copolymers Engineering via Successive Latent Monomer and Grafting-from Strategies?

Article abstract of DOI:10.1002/cjoc.202000643

The on-demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between polymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and distributions were achieved using successive latent monomer and grafting-from strategies. The hydroxyl group functionalized furan/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of L-lactide or ε-caprolactone, resulting in a library of multicomponent copolymers via grafting-from strategy. The initiating efficiency reached to ~100% with variable molecular weight (21300—58600 Da) and narrow distributions (D_M < 1.25), indicating that such graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal properties of the well-defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new method in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.

Full text of DOI:10.1002/cjoc.202000643

For submission: https://mc.manuscriptcentral.com/cjoc
Concise Report
CJC
中
国
化
学
-
An International Journal
For published articles: https://onlinelibrary.wiley.com/journal/16147065
Cite this paper: Chin. J. Chem. 2021, 39, 1273—1280. DOI: 10.1002/cjoc.202000643
Bridging from the Sequence to Architecture: Graft Copolymers
Engineering via Successive Latent Monomer and Grafting‐from
†
Strategies
a
a
a
a
,a
,a,b
a,c
Yajie Zhang, Xiaohuan Cao, Yang Gao, Yujie Xie, Zhihao Huang,* Zhengbiao Zhang,* and Xiulin Zhu
a
State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional
Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu
2
15123, China
b
State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, Jiangsu 215123, China
c
Global Institute of Software Technology, No. 5 Qingshan Road, Suzhou National Hi‐Tech District, Suzhou, Jiangsu 215163, China
Keywords
Sequence determination | Polymers | Latent Monomer | Polymerization | Maleimide
Main observation and conclusion
The on‐demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between pol‐
ymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for
complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and
distributions were achieved using successive latent monomer and grafting‐from strategies. The hydroxyl group functionalized fu‐
ran/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored
localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of
L‐lactide or ε‐caprolactone, resulting in a library of multicomponent copolymers via grafting‐from strategy. The initiating efficiency
M
reached to ~100% with variable molecular weight (21 300—58 600 Da) and narrow distributions (Ð < 1.25), indicating that such
graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal
properties of the well‐defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level
could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new meth‐
od in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.
Comprehensive Graphic Content
*
E‐mail: zhhuang@suda.edu.cn; zhangzhengbiao@suda.edu.cn
View HTML Article
Supporting Information
†
Dedicated to the special issue of Polymer Synthesis.
Chin. J. Chem. 2021, 39, 1273—1280
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
1273

Concise Report
Zhangꢀetꢀal.
adduct (FMOH) was selected as the latent monomer for generat‐
ing an array of sequence‐controlled polymers via RAFT polymeri‐
zation of styrene (St) and FMOH with programmable temperature
change. In the sequence‐controlled polymers, the N‐(2‐hydroxy‐
ehtyl) maleimide (MOH) was deposited along the polymer chain
with controlled distributions. The hydroxyl groups of MOH further
efficiently initiated the ring opening polymerization (ROP) of
L‐lactide (L‐LA) or ε‐caprolactone (ε‐CL) to extend the side chains
on the polymer. As a consequence, graft copolymers with con‐
trolled side chain density and distribution were synthesized
Background and Originality Content
Precise control over polymer sequence and architecture is es‐
sential for both understanding the structure‐property relationship
[
1‐3]
and designing optimal materials.
Graft copolymers, construct‐
ed by grafted polymeric side chains on the linear backbone, are
one of the important polymer topologies which benefited from
exquisite control over the structures, therefore exhibiting diverse
and variable self‐assembled morphologies, solution behaviors as
[
4‐5]
well as mechanical properties.
They have become an area of
[6]
(Scheme 1). This work endowed a general and adaptable platform
great interests especially in supersoft elastomers, rheology con‐
[
7‐8]
[9‐10]
[11]
for building well‐defined architectures, advancing the methodol‐
ogy research on precision polymer synthesis.
trol agents,
materials.
biosensors,
lubricants
and drug‐delivery
[
12‐14]
Meanwhile, regulation of the density and distribu‐
tion is decisive to the performance of graft copolymers, including
mechanical properties, physical behaviors, self‐assembly process
Scheme 1 Schematic illustration on the construction of well‐defined
polymeric architectures via successive control over latent monomer as
well as grafting‐from strategies
[
5,15‐21]
and stimuli‐responsive properties.
Various strategies and chemistries have been developed to‐
ward the graft copolymers with controlled density and distribu‐
[
22‐28]
tion.
For instance, Perrier and co‐workers have prepared a
library of poly(styrene‐co‐maleic anhydride) by RAFT polymeriza‐
tion with controlled sequence and architectures including alter‐
nating, diblock, multiblock, multisite, and alternating star. These
polymers were subsequently functionalized with long aliphatic
alcohols via grafting‐onto strategy, leading to well‐defined archi‐
[
26]
tectures with controlled side group density and distribution.
Taking advantage of the different reactivity of co‐monomer pairs,
Grubbs and co‐workers demonstrated an efficient grafting‐
through approach for simultaneously controlling the grafting den‐
sity and side chain distribution by ring opening metathesis poly‐
merization of norbornene‐functionalized macro‐monomer and Results and Discussion
[
29‐30]
norbonernenyl diester.
Kamigaito and co‐workers reported
the synthesis of ABB periodically graft copolymers by direct radical
copolymerization of functionalized limonene (A) and maleimide
derivatives (B) in fluorinated alcohol and subsequently allowed for
a grafting‐from installation of poly(methyl methacrylate) side
In this work, the latent monomer (FMOH) bearing initiating
moiety for grafting side chain was synthesized and characterized
[
57]
(Scheme S1 and Figures S1—S2). The temperature‐dependent
rDA reaction for releasing maleimide was identified through the
[
31]
1
chain. Based on grafting‐onto strategy for sequence regulation
via living anionic polymerization, three architectures with similar
number of SiH functional groups per chain but totally different
sequence, i.e., gradient, tandem and symmetrical structures, were
H NMR. Approximately 93% of FMOH was converted to malei‐
o
mide via rDA reaction within 10 h at 110 C, while no remarkable
rDA reaction was observed at 40 C within 60 h (Figure S3). This
o
result confirmed the strong temperature dependence of rDA reac‐
tion, guaranteeing the sequence controlled strategy and the de‐
sired placement of MOH along the polymer chain by programma‐
ble change of temperature (Figure 1A).
[
32]
successfully achieved by Ma and coworkers.
Essentially, the control over the density and distribution of
side chains is the programmable placement of co‐monomer units
along the main chain, namely sequence control. Despite the for‐
midable task as next “Holy Grail” or one of the “ultimate goals” in
polymer synthesis, the sequence control over the polymer struc‐
0 0
The RAFT polymerization of St and FMOH ([St] /[FMOH] =
o
100 : 10) was firstly conducted at 110 C (Table 1, entry 1). The
1
conversion of St and FMOH was determined by H NMR (Figure
tures has received intense attention in recent years
,
largely on
S4). As conveyed in Figure 1B, the consumption of FMOH syn‐
[
1,33‐39]
o
account of their enticing properties.
Tremendous efforts
chronized with St conversion at 110 C, which resulted in the
have been devoted and many methodologies have been devel‐
oped for sequence‐controlled polymers, including controlled
polymer sequence with averagely distributed MOH units. The
cumulative (Fcum) and instaneous (Finst) contents of FMOH were
displayed in Figure 1C, which clearly confirmed the statistical
placements of MOH units with 14.2% incorporated into the poly‐
mer chain. The good livingness of the RAFT polymerization was
proved by size exclusion chromatography (SEC), which confirmed
the uniformity of the chain‐to‐chain sequence structure (Figure
[
40‐41]
[42‐47]
monomer addition,
bonding regulation.
template monomers
and hydrogen
In 2017, our group proposed a
latent monomer strategy to achieve the sequence controlled
[
31,36‐37,48‐53]
[
54‐58]
goal.
The furan/maleimide adduct was regarded as the latent
monomer, which was inhibited for radical polymerization at low
temperature. After elevating temperature, the polymerizable
S5). The final polymer (L1) was purified by precipitation and rig‐
1
maleimide can be released via the retro Diels‐Alder (rDA) reaction. orously characterized by SEC and H NMR (Figure 2 and Figure S6).
The in‐situ released maleimide was immediately involved in the
polymerization, thus creating the desired placements of malei‐
mide motifs along the growing chain. Such latent monomer strat‐
egy endowed a building platform for tailored sequence in a
non‐invasive and one‐shot feeding manner.
Herein, we bridged the polymeric architecture with program‐
mable sequence by successive control over the latent monomer
as well as grafting‐from strategies, leading to the constructions of
architectures with tailored side chain density and controlled dis‐
tribution (Scheme 1). The furan/N‐(2‐hydroxyehtyl) maleimide
As mentioned, the rDA reaction for releasing polymerizable MOH
monomer was temperature dependent, which provided the pos‐
sibility to manipulate the sequence of the structures by pro‐
grammable polymerization temperature. A temperature sequence
o
o
of 40 C (36.5 h)—110 C (7.0 h) was employed for synthesis of
the sequence‐controlled diblock polymer, i.e., L2 (Table 1, entry 2).
st
o
As depicted in Figure 1D, during the 1 slot (40 C, 36.5 h), RAFT
polymerization of St proceeded slowly and no MOH was released.
st
As a result, a homo‐polystyrene block was created in the 1 slot,
which was confirmed by the existence of St repeating units in
1274
www.cjc.wiley‐vch.de
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
Chin. J. Chem. 2021, 39, 1273—1280

Bridging from the Sequence to Architecture
Chin. J. Chem.
ymerized with St to form a hetero‐block. The polymerization
o
temperature was changed back to 40 C (32.5 h) at the final stage.
st
Similar to the 1 slot, the rDA reaction for releasing MOH was
ceased. Therefore, a second homo‐PS segment was fabricated as
the third block. This triblock sequence structure was also con‐
firmed by Finst, MOH and Fcum, MOH contents of MOH with normalized
chain lengths (Figure 1G). The polymer (L4) with similar sequence
to L1 but higher MOH content (23.6%) was successfully synthe‐
sized under the identical condition by only increasing the feed
0 0
ratio from [St] /[FMOH] = 100 : 10 to 100:20 (Figures 1H—1I and
S12—S13) (Table 1, entry 4). Meanwhile, another diblock copoly‐
mer (L5) with the similar MOH distribution but higher MOH con‐
tent (22.7%) (Table 1, entry 5) was also successfully synthesized by
0 0
increasing the feed ratio with [St] /[FMOH] = 100 : 20 (Table 1
and Figures S14—S16). These results established that the latent
monomer FMOH could be utilized for sequence regulation, and
the content of MOH can be readily manipulated by changing the
feed ratio of the co‐monomers.
In summary, by intentionally manipulating the temperature of
polymerization, five sequence‐controlled polymers, i.e., averagely
distributed (L1, L4), diblock (L2, L5) and triblock (L3), with differ‐
ent molecular weights (~10 400—15 400 Da), MOH contents
(~14.2%—23.6%) and distributions were created (Table 1). All the
sequence‐controlled polymers were purified by precipitation and
1
rigorously characterized by SEC and H NMR. The SEC elution pro‐
file showed narrow and unimodal traces (Figure 2A). Characteris‐
tic resonances from the terminal naphtyl group (a, δ 8.02—7.60),
hydroxyl groups in MOH units (b, δ 4.85—4.50) and phenyl groups
of PS (c, δ 7.43—6.10) were clearly identified (Figure 2B and Fig‐
ures S6, S9, S11, S13, S15).
Figure 1 Sequence‐controlled polymers through latent monomer strate‐
gy (A). Kinetic plots of the copolymers (B, D, F, H) with temperature se‐
o
o
o
o
o
o
quence: 110 C (B and H); 40 C—110 C (D); 40 C—110 C—40 C (F).
Cumulative (Fcum) and instantaneous (Finst) contents of MOH as a function
of normalized chain length) (C, E, G, I). [St]
00/10/1/0.2, St = 5.0 mL, in DMF, DMF/St (1/1, V/V) (B, D, F)
St] /[FMOH] /[CPDN] /[ACHN] = 100/20/1/0.2, St = 5.0 mL, in DMF,
0 0 0 0
/[FMOH] /[CPDN] /[ACHN] =
1
[
0
0
0
0
DMF/St (1/1, V/V) (H). The model diagram of polymer chains is not accu‐
rate but as the general illustration. The Finst profile has been smoothed.
MALDI‐TOF mass spectra (104.09 Da, Figure S7). The reaction was
o
further moved to a pre‐stabilized oil bath at 110 C, for another
nd
o
7
.0 h (2 slot). Upon transferring to 110 C, the rDA reaction was
initiated and MOH was gradually released and immediately pol‐
ymerized with St. Therefore, the second block containing both St
and MOH units was formed. The sequence was also verified by
the changes in Finst, MOH and Fcum, MOH with the normalized chain
length (Figure 1E). The target polymer contained approximately
1
Figure 2 SEC traces of sequence‐controlled polymers (A). The H NMR
spectrum of L1 in DMSO‐d (300 MHz) (B).
6
1
4.5% of MOH content. SEC traces in Figure S8 indicated the good
livingness of this polymerization. Moreover, the triblock copoly‐
mer L3 was also pre‐designed and created with temperature se‐
quence of 40 C (36.0 h)—110 C (3.5 h)—40 C (32.5 h) (Table 1,
Aliphatic polyesters from lactones or lactides have long been
attractive in both industry and academia as a consequence of
their good biodegradability, biocompatibility as well as unique
o
o
o
[
59‐65]
entry 3 and Figures S10—S11). As shown in Figure 1F, during the
thermal properties.
In this work, poly(L‐LA) (PLLA) or
st
1
slot, a homo PS segment was formed and no releasing of MOH
poly(ε‐CL) (PCL) was designed as the side chains of the graft co‐
polymer. The hydroxyl groups with controlled locations on the
sequence‐controlled polymers were used as initiating sites for the
nd
was observed. In the 2 slot, the polymerization was exposed to
o
1
10 C (3.5 h), and FMOH gradually released MOH, which copol‐
Chin. J. Chem. 2021, 39, 1273—1280
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
www.cjc.wiley‐vch.de
1275

Concise Report
Zhangꢀetꢀal.
ring opening polymerization (ROP) of L‐LA or ε‐CL (Figure 3A). The
Meanwhile, the graft copolymer A4 resulted in the higher MW
and content of side chain than its analogue A1, owing to the
higher MOH content of its linear precursor. Similar graft copoly‐
mers with controlled grafting density and distribution were also
obtained using PCL as the side chains. These results confirmed
that the sequence‐controlled polymers could be used as the ideal
template for constructing well‐defined architectures via grafting‐
from strategy.
ROP was performed under the [OH]/[L‐LA] molar ratio of 1 :20 at
o
4
0 C for 48 h. For the ROP of ε‐CL, the [OH]/[ε‐CL] feed molar
2
ratio changed to 1 : 80 and polymerized by using Sn(Oct) as the
o
catalyst at 100 C (Supplemental Information Section A3.3). An
array of graft copolymers was readily obtained via grafting‐from
strategy.
Table 1 Summary of the sequence‐controlled polymers (SCPs) created
by latent monomer strategy
a
0
b
c
c
d
g
o
0
Entry SCPs [St] /[FMOH]
F
cum,MOH /%
M
n,SEC /Da
Ð
T
/ C
1
2
3
4
L1
L2
L3
L4
L5
100:10
100:10
100:10
100:20
100:20
14.24
14.48
13.71
23.55
22.68
10 700
11 000
10 400
14 800
15 400
1.18 118.0
1.28 117.8
1.35 111.8
1.18 133.6
5
1.36 133.8
a
b
[
CPDN]
0
/[ACHN]
0
= 1/0.2, St = 5.0 mL, in DMF, DMF/St (1/1, V/V). Calcu‐
1
c
lated by in situ H NMR. Determined by SEC with St standard calibration.
d
T
g
was characterized by DSC.
An array of graft copolymers with predetermined side chain
densities and distributions was demonstrated in this study
through the programmable latent monomer and grafting‐from
strategies, which could be ideal for precisely discovering the rela‐
tionship regarding the polymer structures and properties. Espe‐
cially, the study of the thermal properties of polymers with similar
MWs and compositions but different topologies necessitated the
applications of the different polymer architectures. In this work,
the thermal properties of the graft copolymers were evaluated by
differential scanning calorimetry (DSC) (Figures S20—S21). As
shown in Figure 4A and Table 1, the incorporation of MOH units
remarkably increased the glass transition temperature (T
g
) to
o
o
1
11.8—133.8 C, comparing with the T
g
of homo‐PS (95.7 C) for
the sequence‐controlled polymers, as the consequence of the
[
55]
incorporation of the heat–resistant maleimide units.
More
o
o
MOH units resulted in higher T
L4. For sequence‐controlled polymers with similar MOH contents
but different monomer distribution, L3 has a relatively lower T at
11.8 C as it contains two homo‐PS segments, which leads to a
g
, 118.0 C for L1 and 133.6 C for
g
Figure 3 ROP of L‐LA or ε‐CL for well‐defined architectures via grafting‐
o
1
1
from strategy (A). H NMR spectra of L1, A1 and C1 in DMSO‐d
6
(300 MHz)
more flexible chain than the other two linear polymers (L1 and
L2).
(B).
The structures of the graft copolymers were verified by SEC
Table 2 Summary of the graft copolymers created by successive latent
monomer and grafting‐from strategies
1
and H NMR (Figures S17—S19), and the results are listed in Table
1
2
. The H NMR spectra of typical graft copolymers (A1 and C1) as
Graft
copolymers
a
a
b
b
c
o
c
c
o
M
n,SEC /Da
Ð
DPLA/CL
f
PLLA/PCL /% Tg/m / C T
/ C
well as linear precursor (L1) are presented in Figure 3B. Compared
with the precursor, the resonance signals at δ 5.20 (b’), 1.45—
.24 (c’) are ascribed to PLLA in A1. Meanwhile, the δ 3.96 (e’’),
A1 21 300 1.16
A2 21 700 1.23
Grafted PLLA A3 22 000 1.24
A4 27 800 1.18
9
8
9
7
6
56
56
49
37
37
42.5
38.5
39.9
52.8
47.6
86.8
85.8
88.5
87.6
90.6
50.8
52.2
59.2
55.4
59.1
51.7
51.3
51.0
49.0
48.5
—
—
—
—
—
19.8
18.2
17.5
11.8
11.3
1
2
.25 (b’’), 1.50 (c’’) and 1.29 (d’’) are assigned to the characteristic
signals of the methylenes in PCL segments in C1. These results
confirmed the successful grafting of side chains to the L1. More
importantly, grafting efficiency reached to almost 100% according
to the disappearance of the proton resonance at δ 4.60, which
was assigned to the hydroxyl group in MOH moieties. These re‐
sults demonstrated that the graft copolymers possessed con‐
trolled density and distribution of side chains, inheriting from the
corresponding sequence‐controlled linear precursors. The degree
of polymerization (DP) and the composition ratio of side chain
A5 30 600 1.24
C1 49 800 1.24
C2 47 100 1.20
Grafted PCL C3 49 200 1.15
C4 50 700 1.22
C5 58 600 1.24
Determined by SEC with St standard calibration. Determined by H NMR.
a
b
1
1
c
were calculated from H NMR (Figures S17—S18). Moreover, the
Tg, Tm and T (T was for sequence‐controlled polymers and grafted PLLA
c
g
SEC curves of the graft copolymers derived from L1 were pre‐
sented in Figure S19a. Unimodal, symmetrical, and narrow dis‐
tributed SEC traces (Ð < 1.25) as well as an apparent molecular
weight shift were obtained. The graft copolymers with similar
molecular weights, dispersity and side chain compositions
copolymers, while Tm and T were for grafted PCL copolymers) were char‐
acterized by DSC.
c
For graft copolymers (Figure 4A and Table 2), taking grafted
g
PLLA series as an example, a significant drop in T was observed
(fPCL/PLLA), but with different precursors are listed in Table 2.
for grafted PLLA copolymers compared with their corresponding
1276
www.cjc.wiley‐vch.de
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
Chin. J. Chem. 2021, 39, 1273—1280

Bridging from the Sequence to Architecture
Chin. J. Chem.
linear precursors due to the homo PLLA side chain (T
g
: 50—80
reached to approximately 100%, guaranteeing the controlled
distribution of the side chains from the linear precursor. The
on‐demand architectures resulted in the different thermal prop‐
erties such as the crystallization or glass transition, which provid‐
ed the insight in exploring the structure‐property relationship.
This work offered a general and adaptable platform for graft
polymers engineering with tailored side chain density and distri‐
butions, endowing an example for building variable polymers
architecture with well‐defined properties.
o
[66‐67]
C).
linear‐brush‐linear) with similar grafting density but different
distribution displayed different T . A3 possessing a linear‐brush‐
linear type topology displayed the highest T
Furthermore, A1 (brush‐like), A2 (tadpole‐like) and A3
(
g
o
g
(59.2 C), while
(50.8 C) (Table 2 and Figure 4A). It
has been reported that entanglements in amorphous polymers
o
brush‐like A1 had the lowest T
g
[
68]
could affect the relative chain motion in the glassy state. Here,
the two homo‐PS segments of A3 might cause more entangle‐
ments than A2, which decreased the flexibility of the graft co‐
polymers and reflected a higher T
C3 with linear‐brush‐linear type topology demonstrated the lowe‐
st T than other analogues (C1 and C2). Such decrease could be
attributed to the entanglements, which induced crystalline imper‐
fections during the crystallization (fPCL > 80%) (Figure 4B).
The results indicated that the thermal properties could be tuned
by regulating the grafting density and distribution.
g
value. In grafted PCL system,
Experimental
c
General procedure for the synthesis of FM
[
22,61,69‐70]
Furan (64.0 g, 0.94 mol) was added to a solution of maleic
anhydride (40.0 g, 0.41 mol) in diethyl ether (300 mL), and the
mixture was stirred at room temperature for 41 h. After the reac‐
tion was completed, the solid was filtered through the suction
filtration and washed with dry ether (3×20 mL). Compound FM
1
was dried and obtained as a white solid (57.20 g, 84.4% yield). H
3
NMR (300 MHz, CDCl ) δ: 6.58 (t, 2H), 5.46 (t, 2H), 3.18 (s, 2H).
General procedure for the synthesis of FMOH
Compound FM (30.0 g) was added to 300 mL of anhydrous
o
methanol. The suspension was cooled to 0 C. A mixed solution of
ethanolamine and anhydrous methanol (volume ratio of 1:1) was
slowly added dropwise to the suspension. The reaction mixture
was then returned to room temperature and stirred for 0.5 h. The
o
reaction solution was further refluxed at 70 C for 14 h. After the
completion of the reaction, the resulted solution was cooled to
room temperature and placed in an ice bath for crystallization.
The solid was filtered through suction filtration, washed with cold
methanol and dried. The resulting white solid was the monomer
1
FMOH (25.80 g, 68.3% yield). H NMR (300 MHz, DMSO‐d
6
) δ:
6
2
.55 (s, 2H), 5.12 (s, 2H), 4.77 (t, 1H), 3.50—3.36 (d, 4H), 2.92 (s,
H).
Typical procedures for RAFT polymerization of St and FMOH
with programmable fluctuations of temperature
The polymerization was carried out in an oven‐dried Schlenk
tube under argon protection. A general procedure for a St/FMOH
di‐blocky copolymer was provided. All polymerizations were per‐
formed in the glass tube with FMOH (0.914 g, 4.37 mmol), CPDN
(
0
0.118 g, 0.437 mmol), St (5.0 mL, 43.7 mmol), ABVN (0.022 g,
.087 mmol), and DMF (5.0 mL). The mixture was then degassed
by three freeze‐pump‐thaw cycles. The reaction tube was placed
o
in a water bath kept at 40 C. After a predetermined time, the
o
tube was moved to another pre‐stabilized oil bath at 110 C. To
prevent the polymer chain from loss of livingness during the
temperature change, we normally add a certain amount of initia‐
tor azobis(cyclohexanecarbonitrile) (ACHN). At predetermined
intervals, an aliquot was taken out with a syringe under argon,
Figure 4 DSC results of graft copolymers and their corresponding se‐
quence‐controlled polymers, in the second heating run (A). Proposed
explanation of the different thermal behaviors within the different topolo‐
gies of graft copolymers (B).
o
and the reaction was terminated by cooling to ‒20 C. The mon‐
1
omer conversion was determined by H NMR spectroscopy. The
crude copolymer was diluted with THF and precipitated in cold
anhydrous MeOH to obtain the pure product, which was further
1
analyzed by SEC and H NMR spectroscopy.
Conclusions
Synthesis of graft copolymers
In this study, we demonstrated the construction of well‐de‐
fined polymeric architectures with controlled density and distri‐
bution of side chains by successive control over latent monomer
as well as grafting‐from strategies. The latent monomer allowed
to produce a series of linear polymers with predetermined loca‐
tions of the pendent hydroxyl groups, which could further initiate
the ROP of L‐LA or ε‐CL for the PLLA or PCL side chains via graft‐
ing‐from strategy. The initiating efficiency of hydroxyl group
Method for grafting PLLA. The sequence‐controlled polymer,
L‐LA and DMAP were added into DCM with the ratio 1 :20:4 (se‐
quence‐controlled polymer : L‐LA : DMAP). The polymerization was
o
carried out in a Schlenk flask at 40 C for 48 h under argon and
terminated after several minutes by removal of heat and exposure
to oxygen. The polymer was then precipitated in cold MeOH and
dried under vacuum.
Method for grafting PCL. The sequence‐controlled polymer,
Chin. J. Chem. 2021, 39, 1273—1280
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
www.cjc.wiley‐vch.de
1277

Concise Report
Zhangꢀetꢀal.
ε‐CL and Sn(Oct)
2
were added into toluene with the ratio 1:80:4
). The polymeriza‐
[14] Que, Y. R.; Liu, Y. J.; Tan, W.; Feng, C.; Shi, P.; Li, Y. J.; Huang, X. Y.
Enhancing Photodynamic Therapy Efficacy by Using Fluorinated Na‐
noplatform. ACS Macro Lett. 2016, 5, 168‒173.
[15] Noel, A.; Borguet, Y. P.; Wooley, K. L. Self‐Reporting Degradable Flu‐
orescent Grafted Copolymer Micelles Derived from Biorenewable
Resources. ACS Macro Lett. 2015, 4, 645‒650.
(
sequence‐controlled polymer : ε‐CL : Sn(Oct)
2
o
tion was carried out in a Schlenk flask at 100 C for 4 h under ar‐
gon and terminated after several minutes by removal of heat and
exposure to oxygen. The polymer was then precipitated in cold
MeOH and dried under vacuum.
[
16] Zhang, Q.; Ran, Q. P.; Zhao, H. X.; Shu, X.; Yang, Y.; Zhou, H. X.; Liu, J.
P. pH‐induced conformational changes of comb‐like polycarboxylate
investigated by experiment and simulation. Colloid Polym. Sci. 2016,
Supporting Information
2
94, 1705‒1715.
The supporting information for this article is available on the
WWW under https://doi.org/10.1002/cjoc.202000643.
[
17] Paturej, J.; Sheiko, S. S.; Panyukov, S.; Rubinstein, M. Molecular
structure of bottlebrush polymers in melts. Sci. Adv. 2016, 2,
e1601478.
18] Kikuchi, M.; Nakano, R.; Jinbo, Y.; Saito, Y.; Ohno, S.; Togashi, D.;
Enomoto, K.; Narumi, A.; Haba, O.; Kawaguchi, S. Graft Density De‐
pendence of Main Chain Stiffness in Molecular Rod Brushes. Mac‐
romolecules 2015, 48, 5878‒5886.
19] Li, Y. J.; Jian, Z. K.; Lang, M. D.; Zhang, C. M.; Huang, X. Y. Covalently
Functionalized Graphene by Radical Polymers for Graphene‐Based
High‐Performance Cathode Materials. ACS Appl. Mater. Interfaces
Acknowledgement
[
This work was supported by the National Natural Science
Foundation of China (21925107 and 21674072), the Collaborative
Innovation Center of Suzhou Nano Science and Technology, the
China Post‐doctoral Science Foundation (2020M671571), the
Priority Academic Program Development of Jiangsu Higher Edu‐
caction Institutions (PAPD) and the Program of Innovative Re‐
search Team of Soochow University.
[
2016, 8, 17352‒17359.
[
20] Xu, B. B.; Liu, Y. J.; Sun, X. W.; Hu, J. H.; Shi, P.; Huang, X. Y. Semi‐
fluorinated Synergistic Nonfouling/Fouling‐Release Surface. ACS Appl.
Mater. Interfaces 2017, 9, 16517‒16523.
21] Tao, D. L.; Feng, C.; Cui, Y. A.; Yang, X.; Manners, I.; Winnik, M. A.;
Huang, X. Y. Monodisperse Fiber‐like Micelles of Controlled Length
and Composition with an Oligo(p‐phenylenevinylene) Core via "Liv‐
ing" Crystallization‐Driven Self‐Assembly. J. Am. Chem. Soc. 2017,
139, 7136‒7139.
References
[
[1] Lutz, J. F.; Ouchi, M.; Liu, D. R.; Sawamoto, M. Sequence‐controlled
polymers. Science 2013, 341, 1238149.
[2] Lutz, J. F.; Lehn, J. M.; Meijer, E. W.; Matyjaszewski, K. From preci‐
sion polymers to complex materials and systems. Nat. Rev. Mater.
2
016, 1, 16024.
[22] Zhang, W.; Li, Y.; Liu, L.; Sun, Q.; Shuai, X.; Zhu, W.; Chen, Y. Am‐
phiphilic Toothbrushlike Copolymers Based on Poly(ethylene glycol)
and Poly(ε‐caprolactone) as Drug Carriers with Enhanced Properties.
Biomacromolecules 2010, 11, 1331‒1338.
[23] Ding, N.; Shentu, B.; Pan, P.; Shan, G.; Bao, Y.; Weng, Z. Synthesis and
Crystallization of Poly(vinyl acetate)‑g‑Poly(L‑lactide) Graft Copol‐
ymer with Controllable Graft Density. Ind. Eng. Chem. Res. 2013, 52,
12897−12905.
[
3] Feng, C.; Huang, X. Y. Polymer Brushes: Efficient Synthesis and Ap‐
plications. Acc. Chem. Res. 2018, 51, 2314‒2323.
4] Huang, Y. J.; Mai, Y. Y.; Yang, X. W.; Beser, U.; Liu, J. Z.; Zhang, F.; Yan,
D. Y.; Mullen, K.; Feng, X. L. Temperature‐Dependent Multidimen‐
sional Self‐Assembly of Polyphenylene‐Based "Rod‐Coil" Graft Poly‐
mers. J. Am. Chem. Soc. 2015, 137, 11602‒11605.
5] Daniel, W. F. M.; Burdynska, J.; Vatankhah‐Varnoosfaderani, M.;
Matyjaszewski, K.; Paturej, J.; Rubinstein, M.; Dobrynin, A. V.; Sheiko,
S. S. Solvent‐free, supersoft and superelastic bottlebrush melts and
networks. Nat. Mater. 2016, 15, 183‒189.
[
[
[24] Liu, N.; Liu, B.; Yao, C.; Cui, D. Immortal Ring‐Opening Polymerization
of rac‐Lactide Using Polymeric Alcohol as Initiator to Prepare Graft
Copolymer. Polymers 2016, 8, 17.
[
6] Pakula, T.; Zhang, Y.; Matyjaszewski, K.; Lee, H.; Boerner, H.; Qin, S.;
Berry, G. C. Molecular brushes as super‐soft elastomers. Polymer
[25] Moriceau, G.; Gody, G.; Hartlieb, M.; Kim, H.; Mastrangelo, A.;
Smithb, T.; Perrier, S. Functional multisite copolymer by one‐pot se‐
quential RAFT copolymerization of styrene and maleic anhydride.
Polym. Chem. 2017, 8, 4152–4161.
[26] Moriceau, G.; Tanaka, J.; Lester, D.; Pappas, G. S.; Cook, A. B.; O’Hora,
P.; Winn, J.; Smith, T.; Perrier, S. Influence of Grafting Density and
Distribution on Material Properties Using Well‐Defined Alkyl Func‐
tional Poly(Styrene‐co‐Maleic Anhydride) Architectures Synthesized
by RAFT. Macromolecules 2019, 52, 1469−1478.
[27] Ogura, Y.; Terashima, T.; Sawamoto, M. Amphiphilic PEG‐Function‐
alized Gradient Copolymers via Tandem Catalysis of Living Radical
Polymerization and Transesterification. Macromolecules 2017, 50,
822‒831.
2006, 47, 7198‒7206.
[
7] Kobayashi, M.; Terayama, Y.; Hosaka, N.; Kaido, M.; Suzuki, A.;
Yamada, N. L.; Torikai, N.; Ishihara, K.; Takahara, A. Friction behavior
of high‐density poly(2‐methacryloyloxyethyl phosphorylcholine)
brush in aqueous media. Soft Matter 2007, 3, 740‒746.
[
8] Yuan, J.; Xu, Y.; Walther, A.; Bolisetty, S.; Schumacher, M.; Schmalz,
H.; Ballauff, M.; Muller, A. H. E. Water‐soluble organo‐silica hybrid
nanowires. Nat. Mater. 2008, 7, 718‒722.
[9] Huang, K.; Rzayev, J. Well‐Defined Organic Nanotubes from Multi‐
component Bottlebrush Copolymers. J. Am. Chem. Soc. 2009, 131,
6880‒6885.
[
10] Liu, M.; Wen, Y. T.; Song, X.; Zhu, J. L.; Li, J. A smart thermorespon‐
sive adsorption system for efficient copper ion removal based on al‐
ginate‐g‐poly(N‐isopropylacrylamide) graft copolymer. Carbohydr.
Polym. 2019, 219, 280‒289.
[28] Xu, B. B.; Feng, C.; Huang, X. Y. A versatile platform for precise syn‐
thesis of asymmetric molecular brush in one shot. Nat. Commun.
2017, 8, 333.
[29] Chang, A. B.; Lin, T. P.; Thompson, N. B.; Luo, S. X.; Liberman‐Martin,
A. L.; Chen, H. Y.; Lee, B.; Grubbs, R. H. Design, Synthesis, and
Self‐Assembly of Polymers with Tailored Graft Distributions. J. Am.
Chem. Soc. 2017, 139, 17683‒17693.
[
11] Watson, S.; Nie, M. Y.; Wang, L.; Stokes, K. Challenges and develop‐
ments of self‐assembled monolayers and polymer brushes as a green
lubrication solution for tribological applications. RSC Adv. 2015, 5,
8
9698‒89730.
[30] Lin, T. P.; Chang, A. B.; Chen, H. Y.; Liberman‐Martin, A. L.; Bates, C.
M.; Voegtle, M. J.; Bauer, C. A.; Grubbs, R. H. Control of Grafting
Density and Distribution in Graft Polymers by Living Ring‐Opening
Metathesis Copolymerization. J. Am. Chem. Soc. 2017, 139, 3896‒
3903.
[
12] Johnson, J. A.; Lu, Y. Y.; Burts, A. O.; Xia, Y.; Durrell, A. C.; Tirrell, D. A.;
Grubbs, R. H. Drug‐Loaded, Bivalent‐Bottle‐Brush Polymers by
Graft‐through ROMP. Macromolecules 2010, 43, 10326‒10335.
13] Heinrich, C. D.; Thelakkat, M. Poly‐(3‐hexylthiophene) bottlebrush
copolymers with tailored side‐chain lengths and high charge carrier
mobilities. J. Mater. Chem. C 2016, 4, 5370‒5378.
[
[31] Matsuda, M.; Satoh, K.; Kamigaito, M. Periodically Functionalized
and Grafted Copolymers via 1:2‐Sequence‐Regulated Radical Co‐
1278
www.cjc.wiley‐vch.de
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
Chin. J. Chem. 2021, 39, 1273—1280

Bridging from the Sequence to Architecture
Chin. J. Chem.
polymerization of Naturally Occurring Functional Limonene and Ma‐
leimide Derivatives. Macromolecules 2013, 46, 5473‒5482.
ical Additions and 1:1 or 2:1 Alternating Radical Copolymerization. J.
Am. Chem. Soc. 2016, 138, 944‒954.
[
32] Huang, W.; Ma, H. W.; Han, L.; Liu, P. B.; Yang, L. C.; Shen, H. Y.; Hao,
X. Y.; Li, Y. Synchronous Regulation of Periodicity and Monomer Se‐
quence during Living Anionic Copolymerization of Styrene and Di‐
methyl‐[4‐(1‐phenylvinyl)phenyl]silane (DPE‐SiH). Macromolecules
[50] Ojika, M.; Satoh, K.; Kamigaito, M. BAB‐random‐C Monomer Se‐
quence via Radical Terpolymerization of Limonene (A), Maleimide (B),
and Methacrylate (C): Terpene Polymers with Randomly Distributed
Periodic Sequences. Angew. Chem. Int. Ed. 2017, 129, 1815‒1819.
[51] Satoh, K.; Hashimoto, H.; Kumagai, S.; Aoshima, H.; Uchiyama, M.;
Ishibashi, R.; Fujiki, Y.; Kamigaito, M. One‐shot controlled/living co‐
polymerization for various comonomer sequence distributions via
dual radical and cationic active species from RAFT terminals. Polym.
Chem. 2017, 8, 5002‒5011.
[52] Hashimoto, H.; Takeshima, H.; Nagai, T.; Uchiyama, M.; Satoh, K.;
Kamigaito, M. Valencene as a naturally occurring sesquiterpene
monomer for radical copolymerization with maleimide to induce
concurrent 1:1 and 1:2 propagation. Polym. Degrad. Stabil. 2019, 161,
183‒190.
2018, 51, 3746‒3757.
[
[
[
33] Pfeifer, S.; Lutz, J. F. A facile procedure for controlling monomer se‐
quence distribution in radical chain polymerizations. J. Am. Chem.
Soc. 2007, 129, 9542‒9543.
34] Kleiner, R. E.; Brudno, Y.; Birnbaum, M. E.; Liu, D. R. DNA‐templated
polymerization of side‐chain‐functionalized peptide nucleic acid al‐
dehydes. J. Am. Chem. Soc. 2008, 130, 4646‒4659.
35] Ida, S.; Terashima, T.; Ouchi, M.; Sawamoto, M. Selective radical ad‐
dition with a designed heterobifunctional halide: a primary study
toward sequence‐controlled polymerization upon template effect. J.
Am. Chem. Soc. 2009, 131, 10808‒10809.
[53] Satoh, K.; Ishizuka, K.; Hamada, T.; Handa, M.; Abe, T.; Ozawa, S.;
Miyajima, M.; Kamigaito, M. Construction of Sequence‐Regulated
Vinyl Copolymers via Iterative Single Vinyl Monomer Additions and
Subsequent Metal‐Catalyzed Step‐Growth Radical Polymerization.
Macromolecules 2019, 52, 3327‒3341.
[
36] Satoh, K.; Matsuda, M.; Nagai, K.; Kamigaito, M. AAB‐sequence living
radical chain copolymerization of naturally occurring limonene with
maleimide: an end‐to‐end sequence‐regulated copolymer. J. Am.
Chem. Soc. 2010, 132, 10003‒10005.
[
37] Satoh, K.; Ozawa, S.; Mizutani, M.; Nagai, K.; Kamigaito, M. Se‐
quence‐regulated vinyl copolymers by metal‐catalysed step‐growth
radical polymerization. Nat. Commun. 2010, 1, 6.
[54] Ji, Y.; Zhang, L.; Gu, X.; Zhang, W.; Zhou, N.; Zhang, Z.; Zhu, X. Se‐
quence‐Controlled Polymers with Furan‐Protected Maleimide as a
Latent Monomer. Angew. Chem. Int. Ed. 2017, 56, 2328‒2333.
[55] Meng, F.; Zhang, Y.; Ding, K.; Liu, B.; Han, F.; He, Y.; Zhou, N.; Zhang,
Z.; Zhu, X. One‐shot synthesis of sequence‐controlled polymers with
versatile succimide motifs for post‐modifications. React. Funct.
Polym. 2019, 134, 67‒73.
[
38] Hibi, Y.; Ouchi, M.; Sawamoto, M. Sequence‐regulated radical
polymerization with a metal‐templated monomer: repetitive ABA
sequence by double cyclopolymerization. Angew. Chem. Int. Ed. 2011,
50, 7434‒7437.
[
39] Nakatani, K.; Ogura, Y.; Koda, Y.; Terashima, T.; Sawamoto, M. Se‐
quence‐regulated copolymers via tandem catalysis of living radical
polymerization and in situ transesterification. J. Am. Chem. Soc. 2012,
[56] Zhang, L.; Ji, Y.; Gu, X.; Zhang, W.; Zhou, N.; Zhang, Z.; Zhu, X. Synthe‐
sis of sequence‐controlled polymers with pendent “clickable” or hy‐
drophilic groups via latent monomer strategy. React. Funct. Polym.
2019, 138, 96‒103.
134, 4373‒4383.
[
40] Zamfir, M.; Lutz, J. F. Ultra‐precise insertion of functional monomers
in chain‐growth polymerizations. Nat. Commun. 2012, 3, 1138.
[57] Han, F.; Shi, Q.; Zhang, L.; Liu, B.; Zhang, Y.; Gao, Y.; Jia, R.; Zhang, Z.;
Zhu, X. Stereoisomeric furan/maleimide adducts as latent monomers
for one‐shot sequence‐controlled polymerization. Polym. Chem.
2020, 11, 1614‒1620.
[41] Zamfir, M.; Theato, P.; Lutz, J. F. Controlled folding of polystyrene
single chains: design of asymmetric covalent bridges. Polym. Chem.
2
012, 3, 1796‒1802.
[58] Zhang, L. Q.; Gao, Y.; Huang, Z. H.; Zhang, W.; Zhou, N. C.; Zhang, Z.
B.; Zhu, X. L. Controllably Growing Topologies in One‐shot RAFT
Polymerization via Macro‐latent Monomer Strategy. Chinese J. Polym.
Sci. 2021, 39, 60‒69.
[59] Zhou, S.; Deng, X.; Yang, H. Biodegradable poly(ε‐caprolactone)‐
poly(ethylene glycol) block copolymers: characterization and their
use as drug carriers for a controlled delivery system. Biomaterials
2003, 24, 3563‒3570.
[
42] Ogura, Y.; Terashima, T.; Sawamoto, M. Synchronized Tandem Catal‐
ysis of Living Radical Polymerization and Transesterification: Meth‐
acrylate Gradient Copolymers with Extremely Broad Glass Transition
Temperature. ACS Macro Lett. 2013, 2, 985‒989.
43] Hibi, Y.; Ouchi, M.; Sawamoto, M. A strategy for sequence control in
vinyl polymers via iterative controlled radical cyclization. Nat. Com‐
mun. 2016, 7, 11064.
[
[
44] Oh, D. Y.; Ouchi, M.; Nakanishi, T.; Ono, H.; Sawamoto, M. Iterative
Radical Addition with a Special Monomer Carrying Bulky and Con‐
vertible Pendant: A New Concept toward Controlling the Sequence
for Vinyl Polymers. ACS Macro Lett. 2016, 5, 745‒749.
[60] Ghoroghchian, P. P.; Li, G.; Levine, D. H.; Davis, K. P.; Bates, F. S.;
Hammer, D. A.; Therien, M. J. Bioresorbable vesicles formed through
spontaneous self‐assembly of amphiphilic poly(ethylene oxide)‐
block‐polycaprolactone. Macromolecules 2006, 39, 1673‒1675.
[61] Yuan, W.; Yuan, J.; Zhang, F.; Xie, X. Syntheses, Characterization, and
in vitro Degradation of Ethyl Cellulose‐graft‐poly(ε‐caprolactone)‐
block‐poly(l‐lactide) Copolymers by Sequential Ring‐Opening Poly‐
merization. Biomacromolecules 2007, 8, 1101‒1108.
[
45] Ouchi, M.; Nakano, M.; Nakanishi, T.; Sawamoto, M. Alternating Se‐
quence Control for Carboxylic Acid and Hydroxy Pendant Groups by
Controlled Radical Cyclopolymerization of a Divinyl Monomer Carry‐
ing a Cleavable Spacer. Angew. Chem. Int. Ed. 2016, 128, 14804‒
1
4809.
[62] Castillo, R. V.; Muller, A. J.; Raquez, J.; Dubois, P. Crystallization Ki‐
netics and Morphology of Biodegradable Double Crystalline
PLLA‐b‐PCL Diblock Copolymers. Macromolecules 2010, 43, 4149‒
4160.
[63] Yang, C.; Wu, H.; Sun, J.; Hsiao, H.; Wang, T. Thermo‐induced
shape‐memory PEG‐PCL copolymer as a dual‐drug‐eluting biode‐
gradable stent. ACS Appl. Mater. Interfaces 2013, 5, 10985‒10994.
[64] Gu, J.; Xiao, P.; Chen, P.; Zhang, L.; Wang, H.; Dai, L.; Song, L.; Huang,
Y.; Zhang, J.; Chen, T. Functionalization of Biodegradable PLA
Nonwoven Fabric as Superoleophilic and Superhydrophobic Material
for Efficient Oil Absorption and Oil/Water Separation. ACS Appl. Ma‐
ter. Interfaces 2017, 9, 5968‒5973.
[
[
[
[
46] Hattori, G.; Hirai, Y.; Sawamoto, M.; Terashima, T. Self‐assembly of
PEG/dodecyl‐graft amphiphilic copolymers in water: consequences
of the monomer sequence and chain flexibility on uniform micelles.
Polym. Chem. 2017, 8, 7248‒7259.
47] Kametani, Y.; Nakano, M.; Yamamoto, T.; Ouchi, M.; Sawamoto, M.
Cyclopolymerization of Cleavable Acrylate‐Vinyl Ether Divinyl Mon‐
omer via Nitroxide‐Mediated Radical Polymerization: Copolymer
beyond Reactivity Ratio. ACS Macro Lett. 2017, 6, 754‒757.
48] Matsuda, M.; Satoh, K.; Kamigaito, M. 1: 2‐sequence‐regulated radi‐
cal copolymerization of naturally occurring terpenes with maleimide
derivatives in fluorinated alcohol. J .Polym. Sci. A Polym. Chem. 2013,
5
1, 1774‒1785.
[65] Shi, J.; Zhang, L.; Xiao, P.; Huang, Y.; Chen, P.; Wang, X.; Gu, J.; Zhang,
J.; Chen, T. Biodegradable PLA Nonwoven Fabric with Controllable
Wettability for Efficient Water Purification and Photocatalysis Deg‐
49] Soejima, T.; Satoh, K.; Kamigaito, M. Main‐Chain and Side‐Chain Se‐
quence‐Regulated Vinyl Copolymers by Iterative Atom Transfer Rad‐
Chin. J. Chem. 2021, 39, 1273—1280
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
www.cjc.wiley‐vch.de
1279

Concise Report
Zhangꢀetꢀal.
radation. ACS Sustainable Chem. Eng. 2018, 6, 2445‒2452.
Graft Copolymers by the Combination of ATRP and Enzymatic ROP in
[66] Lee, S. H.; Kim, S. H.; Han, Y. K.; Kim, Y. H. Synthesis and degradation
2
scCO . Macromolecules 2006, 39, 9080‒9086.
of end‐group‐functionalized polylactide. J. Polym. Sci. A Polym. Chem.
[70] Zhang, J.; Ren, W.; Sun, X.; Meng, Y.; Du, B.; Zhang, X. Fully Degrada‐
ble and Well‐Defined Brush Copolymers from Combination of Living
2001, 39, 973‒985.
[
67] Nakayama, Y.; Matsubara, N.; Cai, Z.; Shiono, T.; Inumaru, K.; Shira‐
hama, H. Effect of end‐group modification of poly(lactide)s by cin‐
namoyl chloride on their thermal stability. Polym. Degrad. Stabil.
2
CO /Epoxide Copolymerization, Thiol–Ene Click Reaction and ROP of
ε‐caprolactone. Macromolecules 2011, 44, 9882‒9886.
2017, 141, 97‒103.
[
68] Litvinov, V.; Deblieck, R.; Clair, C.; Van den fonteyne, W.; Lallam, A.;
Kleppinger, R.; Ivanov, D. A.; Ries, M. E.; Boerakker, M. Molecular
Structure, Phase Composition, Melting Behavior, and Chain Entan‐
glements in the Amorphous Phase of High‐Density Polyethylenes.
Macromolecules 2020, 53, 5418‒5433.
Manuscript received: November 23, 2020
Manuscript revised: January 6, 2021
Manuscript accepted: January 8, 2021
Accepted manuscript online: January 11, 2021
[69] Villarroya, S.; Zhou, J.; Thurecht, K. J.; Howdle, S. M. Synthesis of
1280
www.cjc.wiley‐vch.de
© 2021 SIOC, CAS, Shanghai, & WILEY‐VCH GmbH
Chin. J. Chem. 2021, 39, 1273—1280