Supporting Information
In Situ Ester-amide Exchange Reaction between Polyamide 6
and Ethylene-Vinyl Acetate Rubber during Melt Blending
Wenjing Wu1, Chaoying Wan2, Hongmei Zhang1, Yong Zhang1
1
State Key Laboratory of Metal Matrix Composites, School of Chemistry and
Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
WMG, University of Warwick, UK, CV4 7AL.
100
95
90
Weight, %
2
85
80
EVM heat treated in N2 for 60 min
75
240 °C (W: 0.8%)
260 °C (W: 2.7%)
280 °C (W: 9.3%)
300 °C (W: 22.0%)
70
65
60
0
10
20
30
40
50
60
Time, min
Figure S1. TGA thermal curves of EVM at different temperatures in nitrogen.
1
Figure S2. Morphology of PA6/EVM blends at different weight ratios: (a) 60/40; (b)
50/50; (c) 40/60.
Table S1. Assignments of chemical shifts due to the protons belonging to sequences
adjacent to the heteroatoms, as observed in their NMR spectra
Structure
Proton chemical
shift (ppm)
a0
3.06
b0
2.40
a
3.45
b
2.65
c
2.18
d
4.98
a
3.45
c′
2.40
b
2.65
a
3.45
b
2.65
c
2.18
d
4.98
NMA
PA6
EVM
Acetamide-ter
minated PA6
(in Fraction I)
EVM-g-PA6
(Fraction III)
Table S2. The weight fraction of extracted fractions from PA6/EVM blends
Blends
Fraction I, %
Fraction II, %
2
Fraction III, %
PA6/EVM (10
min)
PA6/EVM (20
min)
PA6/EVM/DBTO
(10 min)
PA6/EVM/DBTO
(20 min)
PA6/EVM/DBTO
(40 min)
PA6/EVM/DBTO
(60 min)
60.1
39.9
-
61.3
37.5
1.2
58.5
39.5
2.0
58.8
37.2
4.1
60.8
33.4
5.7
58.9
34.3
6.8
Table S3. PA6 content
PA6/EVM/DBTO blends
in
the
EVM-g-PA6
copolymer
extracted
from
EVM-g-PA6
PA6/EVM/DBTO (20
min)
PA6/EVM/DBTO (40
min)
PA6/EVM/DBTO (60
min)
PA6 content, wt%
4.4
5.9
5.2
3
Figure S3. SEM images of cryogenically fractured surface of PA6/EVM blends
(etched by formic acid). (a) PA6/EVM (40/60), 10 min; PA6/EVM/DBTO (40/60/1):
(b) 10 min; (c) 30 min; (d) 60 min.
Derivation of the exchange reaction kinetic expression
The ester-amide exchange reaction between PA6 and EVM follows:
A B  A1B1
F AB, 0  x F A1 B1 , 0  x
k
k
A1B AB1
x
x
where the structures of AB, A1B1, A1B and AB1 are shown in Scheme 4, k and k- stand
for the forward and reverse reaction rate constants, F AB, 0 and F A1 B1 , 0 are the
initial molar fractions of AB and A1B1, respectively, and x is the molar fraction of
reacted acetate group. Then, Equation 1 is obtained:
dx
 k ( F AB, 0  x)( F A1 B1 , 0  x)  k x 2
dt
4
(1)
As this ester-amide exchange reaction is reversible and the chemical equilibrium
constant of exchange reaction is close to unity, i.e.,
k  k  K . Put
F AB, 0  F A1 B1 , 0  1 into Equation 1, then,
dx
 K ( F AB, 0 F A1 B1 , 0  x)
dt
(2)
For the ester-amide exchange reaction, the reaction ratio of acetate groups is
expressed by y  x F A1 B1 , 0 . By linking to the integral form of Equation 2,
F
F AB, 0 F A1 B1 , 0
dx
  Kdt  ln(
)  Kt
AB, 0 F A1 B1 , 0  x
F AB, 0 F A1 B1 , 0  x
ln(
F AB, 0
F AB, 0  y
)  Kt
(3)
In order to eliminate the influence of the side reactions of EVM at elevated
temperatures, it can be defined as z  x F AB, 0  yF A1 B1 , 0 F AB, 0 . Then the integral
form of Equation 3 is derived as,
ln(
F A1 B1 , 0
)  Kt
F A1 B1 , 0  z
5
(4)