supporting information wavenumber /cm › suppdata › py › c3 › c3py00679d ›...

1

Supporting Information

Alkoxyamine with reduced homolysis temperature and its application in

repeated autonomous self-healing of stiff polymer

Ze Ping Zhanga, Min Zhi Rong*

b, Ming Qiu Zhang*

b and Chan’e Yuan

a

aKey Laboratory for Polymeric Composite and Functional Materials of Ministry of

Education, DSAPM Lab, School of Chemistry and Chemical Engineering, Sun

Yat-sen University, Guangzhou 510275, P. R. China bMaterials Science Institute, Sun Yat-sen University, Guangzhou 510275, P. R. China

4000 3500 3000 2500 2000 1500 1000 500

Tra

nsm

itta

nce

Wavenumber /cm-1

3450

2976

2936

2228

1458

1373

12521169

1030

Figure S1. FTIR spectrum of CTPO with the following characteristic peaks

demonstrating its chemical structure: 3450 cm-1

(O-H bond), 2976 and 2936 cm-1

(-CH3 and -CH2 stretching), 2228 cm-1

(-C≡N stretching), 1458 cm-1

(-CH3 bending),

1373 and 1360 cm-1

(-CH3 anti-symmetric bending), 1252 cm-1

(C-N stretching), 1169

cm-1

(C-O-N anti-symmetric stretching), and 1033 cm-1

(C-OH stretching).

Electronic Supplementary Material (ESI) for Polymer ChemistryThis journal is © The Royal Society of Chemistry 2013

2

8 7 6 5 4 3 2 1 0

NHO O

CN

OH

/ ppm

Figure S2.1H NMR spectrum (300 MHz, CDCl3, 25 C) of CTPO with the following

characteristic peaks demonstrating its chemical structure: δ (ppm) = 7.283 (CDCl3),

1.188 (TEMPOL CH3), 1.193 (TEMPOL CH3), 1.235 (TEMPOL CH3), 1.386

(TEMPOL CH3), 1.708 (-CN-C-CH3), 1.386-1.999 (TEMPOL CH2), 1.999-2.206

(-CH2-CH2-), 3.763 (-OH-CH2-CH2-), and 3.991 (-OH-CH-(CH2)2-). The latter two

clearly prove the structure of this monomer.

150 120 90 60 30 0

NHO O

CN

OH

/ ppm

Figure S3. 13

C NMR spectrum (300 MHz, CDCl3, 25 C) of CTPO with the

following characteristic peaks: δ/ppm 22.29-24.18 (TEMPOL CH3), 34.71

(-CN-C-CH3), 38.62-49.54 (-CH2-CH2-, -CH2-CH2-), 60.74 (-CH2-C-NO-), 62.19

(CH2-CH2-OH), 63.01 (-OH-CH-(CH2)2-), 78.34 (-NO-C-CN, partially overlapped

with the triplet peaks of CDCl3), and 128.28 (C≡N).

78.5 78.0 77.5


3

4000 3500 3000 2500 2000 1500 1000 500

Tra

nsm

itta

nce

Wavenumber /cm-1

34503330

2874

1730

1531

1460

1360

1339

1230

1140

Figure S4. FTIR spectrum of ICPEG2000 with the following characteristic peaks:

3450 cm-1

(N-H hydrogen bonding), 3330 cm-1

(N-H free), 2874 cm-1

(-CH3 and CH2

stretching), 1730 cm-1

(C=O hydrogen bonding), 1664 cm-1

(C=O free), 1531 cm-1

(N-H bending and C-N stretching), 1460 cm-1

(-CH3 and –CH2 bending), 1360 cm-1


(N-O stretching), 1230 cm-1

(N-H bending

vibration and C-N stretching), and 1140 cm-1

(C-O-C anti-symmetric stretching).

Note: The peaks at 3450 and 3330 cm-1

are assigned to -NH in hydrogen bonding and

free -NH groups, respectively. The hydrogen bonding is constituted by -NH groups

(acting proton donors) and oxygen (in carbonyls of the hard segment and ethers of the

soft segment as proton acceptors). Analogously, the peak position at 1730 cm-1

is

ascribed to hydrogen bonded -C=O and the shoulder peak at 1664 cm-1

to free -C=O.

The FTIR spectrum also indicates completion of the reaction between diisocyanate

and polyol owing to the disappearance of the NCO absorption band at 2270 cm-1

.

N-H bending and C-N stretching at 1531 cm-1

, N-H bending and C-N stretching at

1230 cm-1

, N-O stretching at 1339 cm-1

and C-O-C stretching at 1140 cm-1

are also

observed. The spectrum shows no absorption at 1650 cm-1

for urethane-urea

formation, implying that the polymer is a kind of thermoplastic material without

branched or crosslinking structure.


4

500 1000 1500 2000 2500 3000

Inte

nsit

y / a

.u.

Wavenumber / cm-1

2886

22301704

14801275

1060

845

923

1134859

Figure S5. Raman spectrum of ICPEG2000 with the following characteristic peaks:

2886 cm-1

(-CH3 and CH2 stretching), 2230 cm-1

(-CN stretching), 1704 cm-1

(C=O


(N-H bending), 1275 cm-1

(C-N stretching), 1134 cm-1

(C-O-C

anti-symmetric stretching), 1060 cm-1

(C-O anti-symmetric stretching), 923 cm-1

(O-N stretching), 859 cm-1

(C-O-C symmetric stretching and C-O-N

pseudo-symmetry stretching), and 845 cm-1

(C-O symmetric stretching). Note: It is

obvious that 2230 cm-1

peak belongs to –CN according to the Raman spectroscopy

result and the outcome of FTIR spectrum. The ether oxygen region between 1200 and

1000 cm-1

contains C-O-C anti-symmetric stretching of PEG soft segment (1134 cm-1

)

and C-O anti-symmetric stretching (~1060 cm-1

). The peak at 1704 cm-1

originates

from C=O symmetric stretching vibration (amide I band) of carbonate groups, while

those at 1480 and 1275 cm-1

are due to N-H bending (amide II band) and C-N (amide

III band) stretching. Additionally, O-N stretching at 923 cm-1

, C-O symmetric

stretching at 845 cm-1

, C-O-C anti-symmetric stretching and C-O-N pseudo-symmetry


are also observed.


5

The control material that excludes alkoxyamine moiety, IBPEG2000, was made

following similar procedures by using BDO instead of CTPO monomer (Scheme S1).

NCO

H2C NCO

OHHOn

+ +

IPDI PEG2000

HOOH

BDO

C

O

N

HN

H

CO

OO

n

OO

IPDI-BDO-PEG2000 (IBPEG2000)

DBTDL, argon, 80oC, 24h

= ···BDO-IDPI-BDO-IDPI-PEG2000···

Scheme S1. Synthesis of irreversible polyurethane IBPEG2000.

When PEG2000 diol was replaced by PCL2000 diol, ICPCL2000 can be prepared

by the similar process (Scheme S2). The chemical structure of the product was also

proved by FTIR spectrum (Figure S6).

IPDI-CTPO-PCL2000 (ICPCL2000)

NCO

H2C NCO

N OOH

HO

N

+ +

IPDI CTPO PCL2000

H2CO C

O

OO

C

O

H2C O

H

H 5 5n nk

N OO

O

N

C

O

N

HN

H

C

O

H2CO C

O

OO

C

O

H2C O

5 5n nk

DBTDL, argon, 80oC, 24h

= ···CTPO-IDPI-CTPO-IDPI-PCL2000···

Scheme S2. Synthesis of reversible polyurethane ICPCL2000.


6

4000 3500 3000 2500 2000 1500 1000 500

Tra

nsm

itta

nce

Wavenumber / cm-1

Figure S6. FTIR spectrum of ICPCL2000 with the following characteristic

peaks:3360 cm-1

(N-H bond), 2947, 2867 cm-1

(-CH3 and CH2 stretching), 1723 cm-1

(C=O stretching), 1528 cm-1

(N-H bending and C-N stretching), 1461 cm-1

(-CH3 and

–CH2 bending), 1367 cm-1


(N-O


(N-H bending vibration and C-N stretching), 1172 cm-1

(C-O

stretching), and 1104 cm-1

(C-O-C stretching). Note: The 3360 cm-1

peak is assigned

to -NH in hydrogen bonding, meaning that almost all the -NH groups act as proton

donor to constitute the hydrogen bonding. ICPCL2000 has seldom free -NH groups

because the PCL soft segments contain lots of ester groups to serve as proton

acceptors, which differ from ICPEG2000. The peak at 1760 cm-1

is ascribed to

hydrogen bonded -C=O of carbonate groups and ester groups. According to the

disappearance of the NCO absorption band at 2270 cm-1

, we can predicate the

reaction between diisocyanate and polyol is fully completed. In addition, N-H bending

and C-N stretching at 1528 cm-1

, N-H bending and C-N stretching at 1232 cm-1

, N-O


, C-O stretching at 1172 cm-1

and C-O-O stretching at 1104

cm-1

are also observed.


7

-60 -40 -20 0 20 40 60 80 100 120

En

do

Temperature / C

ICPEG2000

IBPEG2000

Figure S7. DSC heating scans of ICPEG2000 and IBPEG2000.

-120 -100 -80 -60 -40 -20 0 20 400.0

0.1

0.2

0.3

0.4

0.5

Tan

TemperatureoC

Figure S8. Tan versus temperature of ICPEG2000.


8

Table S1. Radical concentrations in TEMPO and CTPO determined by titration

Sample and test temperature W0[a] (g) V1

[b] (ml) V2[c] (ml) C1

[d] (mN g-1) C2[e] (mN g-1)

TEMPO

-30 C 0.1752 11.44 21.68

2.922 2.918

-30 C 0.1733 11.58 2.914

30 C 0.1755 10.75 21.28

3.000 2.999

30 C 0.1717 10.98 2.999

CTPO

-30 C 0.5201 20.19 21.12

0.089 0.0895

-30 C 0.4765 20.26 0.090

30 C 0.5197 17.26 20.45

0.307 0.3035

30 C 0.4198 17.93 0.300

[a]W0 = sample weigh;

[b]V1 = volume of iodine solution used for titration of the

sample; [c]

V2 = volume of iodine solution used for titration of the blank experiment; [d]

C1 = radical concentration; [e]

C2 = average radical concentration. Note: Free radical

concentrations of TEMPO and CTPO at different temperatures (-30 ~ 30 C) are

determined by titration, which quantifies fission behavior of CTPO. During the

measurements, nitroxide and carbon radicals are reduced by ascorbic acid, while

ascorbic acid is oxidized. For stable nitroxide radicals of TEMPO, the measured

radical concentration keeps constant at both -30 and 30 C. In contrast, the amount

of free radicals of CTPO at -30 C is only about 30 % of that measured at 30 C,

demonstrating that fission of C-ON bonds indeed happens at ambient temperature.


9

in air

in argon

20G

-50oC

-30oC

-10oC

10oC

30oC

20G

(a) (b)

-50oC

-30oC

-10oC

10oC

30oC

20G

(c)

Figure S9. (a) Typical ESR spectra of ICPEG2000 measured at 30 C in argon and

air, respectively. Typical ESR spectra measured at various temperatures of (b) CTPO

and (c) ICPEG2000, which had been stored at ambient temperature in air for a week

and 6 months, respectively.


10

10 20 30 40 50

0

2000

4000

6000

8000

10000

12000

BC

DE

FG

HI

JK

LM

N

2degree

Inte

nsit

y /

a.u

.

-100C

25C

23.5019.20

(a)

10 20 30 40 50

0

2000

4000

6000

8000

10000

12000

14000

BC

DE

FG

HI

JK

L

30C

-70C

2degree

Inte

nsit

y /

a.u

.

23.50

19.20

(b)

Figure S10. Temperature dependences of wide angle X-Ray diffraction patterns of (a)

ICPEG2000 and (b) IBPEG2000.


11

210.95

[nm]

0.001.00 um 2.00 x 2.00 um

con

(a)

- 3 . 8 1

[ V]

- 5 . 5 31 . 0 0 um 2 . 0 0 x 2 . 0 0 um

c o n

(b)

Figure S11. AFM high-contrast (a) and phase-contrast (b) image of ICPEG2000.


12

Figure S12. SEM image of ICPEG2000.

-100 -80 -60 -40 -20 0 20 40 60 80 100 120

En

do

>

Temperature / oC

ICPCL2000

Tg = -42

oC

Figure S13. DSC heating scan of ICPCL2000.


13

0.00

0.05

0.10

0.15

0.20

0.25

0.30

1st healed (healing efficiency= 98.1 3.1%)

2nd

healed (healing efficiency= 97.1 2.7%)

3rd healed (healing efficiency= 95.7 3.1%)

Imp

ac

t s

tre

ng

th /

kJ

m-2

virgin 1st healed 2

nd healed 3

rd healed

Figure S14. Impact strengths of virgin ICPCL2000 specimens and the repeatedly

healed versions. Temperature of impact test and crack healing: 15 C. Healing time

and atmosphere: 48 h, air.


supporting information wavenumber /cm › suppdata › py › c3 › c3py00679d ›...

Documents