Paper
Journal of Materials Chemistry A
0
condensed by rotovap and the residue was dissolved in toluene 4,4 -(6,6,20,20-Tetraethyl-2,9,13,17,24-pentaoxa-6,20-
and precipitated in hexane 3 times. Aerwards, the product was disilapentacosane-1,25-diyl)bis(1,3-dioxolan-2-one) (OP67)
ꢃ
dried in a vacuum oven at 80 C for 24 hours.
The same procedure as synthesis of OP73 was used with
di(ethylene glycol) divinyl ether as the linker. H NMR (in d6-
1
0
4
,4 -(6,6,21,21-Tetramethyl-2,7,10,13,16,19,25-heptaoxa-6,21-
acetone), 4.95 (m, 1H, CCH(C)O), 4.4–4.6 (m, 2H, CH
.8 (m, 10H, CCH OCH CH CH , OCH CH CH and OCH
CECA (10.86 g, 0.068 mol), anhydrous CH CN (20 mL) and CH O), 1.64 (m, 4H, OCH CH CH Si), 1 (m, 6H, OCH CH CH
), 0.67 (m, 6H, CH ) (Fig. S7†).
2
C), 3.45 to
disilahexacosane-1,26-diyl)bis(1,3-dioxolan-2-one) (OP62)
3
2
2
2
2
2
2
2
2
-
3
2
2
2
2
2
2
2
chlorodimethylsilane (7.67 g, 0.081 mol) were added into a pre- and SiCH
2
3
dried ask. The mixture was cooled by ice-bath before 0.3 mL Pt
catalyst was charged. The mixture was allowed to react over-
night to complete the reaction. The solvent was evaporated and
Results and discussion
the residue was vacuum distilled to obtain 4-((3-(chloro- Synthesis
dimethylsilyl)propoxy)methyl)-1,3-dioxolan-2-one as a colorless
Two types of plasticizers were synthesized. The rst type is
1
liquid (15.2 g, 89%). H NMR (in d6-acetone), d(ppm) 4.95 (m,
H, CCH(C)O), 4.4–4.6 (m, 2H, CH C), 3.75 (m, 2H, CCH -
referred to as copolymerized plasticizer (CPP), having (EO) side
3
1
2
2
chains and cyclic carbonate side chains, synthesized by hydro-
OCH CH H ), 3.55 (m, 2H, OCH CH CH ), 1.7 (m, 2H, OCH -
2
2
2
2
2
2
2
silylation using a method described in our previous work
2
9
CH CH ), 0.9 (m, 2H, OCH CH CH ), 0.35 (m. CH ); Si NMR
13
2
2
2
2
2
1
3
(
Scheme 1). The CPP samples are coded according to the
3
(
in d6-acetone) 33 (s); (Fig. S2†) C NMR (in d6-acetone),
d(ppm) 160, 75.1, 74.8, 74, 73.2, 23, 15, 0.2 (Fig. S3†).
-((3-(Chlorodimethylsilyl)propoxy)methyl)-1,3-dioxolan-2-
one (8.7 g, 0.034 mol) was added dropwise into the mixture of
NEt (7.5 g), tetraethylene glycol (6.67 g, 0.034 mol) and 20 mL
fraction f of carbonate-containing units, as determined by the
1
integrated areas of H NMR peaks (see Fig. S1 and Table S1† for
4
details). For example, CPP-19 means the copolymerized plasti-
cizer having molar fraction f ¼ 19% of carbonate containing
units.
To further improve the performance of the low-volatility
plasticizers, the second type of oligomeric plasticizers (OP) of
3
dry THF over 30 minutes. The reaction mixture was allowed to
stir overnight to complete the reaction. The mixture was ltered
to remove the solid. The liquid was condensed by rotavap and
4
50 < M < 700 were synthesized by condensation reactions
further dried by vacuum oven to yield OP62 as a brown liquid
0
(Scheme 2). To better compare with the CPP, an equivalent f is
1
(
(
13 g). H NMR (in d6-acetone), 4.95 (m, 1H, CCH(C)O), 4.4–4.6
calculated based on the carbonate : EO ratio. Since the CPPs
have carbonate side chains (with one cyclic carbonate group
and one EO) and EO side chains (with four EOs), the ratio of
carbonate : EO ¼ f/[f + 4(1 ꢁ f)]. For OP, by dening carbo-
m, 2H, CH
CH O) 3.55 (m, 2H, OCH
CH ), 0.9 (m, 2H, OCH CH
in d6-acetone) 17.57 (s) (Fig. S4†).
2
C), 3.75 (m, 2H, CCH
CH
CH ), 0.35 (m. CH
2
OCH
2
CH
2 2
H ), 3.63 (s, 16H,
OCH
CH
(
2
2
2
2
CH
2
), 1.7 (m, 2H, OCH -
2
2
9
2
2
2
2
2
3
); Si NMR
0
0
0
0
nate : EO ¼ f /[f + 4(1 ꢁ f )] enables an estimation of f anal-
0
ogous to f of CPP. OPs are coded according to f , for example
0
4
,4 -(6,6,22,22-Tetraethyl-2,9,12,15,19,26-hexaoxa-6,22-
0
OP73 means f ¼ 73%.
disilaheptacosane-1,27-diyl)bis(1,3-dioxolan-2-one) (OP73)
OP62 was synthesized by condensation reaction with triethyl
Diethyldihydrosilane (7.2 g, 0.082 mol), CECA (8.4 g, 0.053 mol) amine as an acid scavenger (Scheme 2(a)). The resulting product
and 10 mL benzene were added into a ask followed by 0.1 g with Si–O–C linkages is moisture sensitive. The rst attempt to
RhCl(PPh ) catalyst. The mixture was stirred at room temper- synthesize OP67 and OP73 (Scheme 2(b)) failed because the
3
3
ature overnight to complete the reaction. The solvent was platinum catalyst that works for most hydrosilylation reactions
evaporated and the residue was vacuum distilled to afford 4-((3- gave nearly no desired product. The well-known Wilkinson Rh
(
diethylsilyl)propoxy)methyl)-1,3-dioxolan-2-one as a colorless
1
liquid (20 g, 100%). H NMR (in d6-acetone), 4.95 (m, 1H,
CCH(C)O), 4.4–4.6 (m, 2H, CH
OCH CH CH , OCH CH CH and SiH), 1.64 (m, 4H, OCH
CH2CH Si), 1 (m, 6H, OCH CH CH and SiCH
CH3); Si NMR (in d6-acetone) ꢁ1.38 (s) (Fig. S5†).
-((3-(Diethylsilyl)propoxy)methyl)-1,3-dioxolan-2-one (5 g,
.02 mol) and tri(ethylene glycol) divinyl ether (2 g, 0.01 mol)
were mixed followed by 0.1 g RhCl(PPh catalyst. The mixture
2
C), 3.45 to 3.8 (m, 5H, CCH
2
-
2
2
2
2
2
2
2
-
2
9
2
2
2
2
), 0.67 (m, 6H,
2
4
0
3 3
)
was stirred at room temperature overnight to complete the
reaction. The mixture was washed with cyclohexane to afford
1
the product as a brown liquid (7 g). H NMR (in d6-acetone),
4
.95 (m, 1H, CCH(C)O), 4.4–4.6 (m, 2H, CH
2
C), 3.45 to 3.8 (m,
1
2H, CCH OCH CH CH , OCH CH CH and OCH CH O),
2
2
2
2
2
2
2
2
2
1
.64 (m, 4H, OCH CH CH Si), 1 (m, 6H, OCH CH CH and
2 2 2 2 2 2
Scheme 1 Synthesis of siloxane random copolymer plasticizers CPP-
0, 19, 31, 57, 80, 100), where the number is the mol% of cyclic
carbonate containing units, i.e., 100f.
2
9
2 3
SiCH ), 0.67 (m, 6H, CH ); Si NMR (in d6-acetone) 5.25 (s)
(
(
Fig. S6†).
This journal is © The Royal Society of Chemistry 2015
J. Mater. Chem. A