Chemistry Reference
In-Depth Information
Table 1.
Design of a olefin block copolymer.
Targeted
wt% Octene
Hard Segment
or polymer
in blend
Targeted
wt% Soft
Segment
or polymer
in blend
Targeted
wt % Octene
in Soft
Segment
or polymer
in blend
Example
Density
(g/cc)
I2
(g/min)
wt% Hard
Segment or
polymer
in blend
Chain
Shuttling
Agent Present
OBC
0.8786
1.5
29
0.4
71
15
Yes
In Reactor Blend
0.8895
0.9
39
0.4
61
15
No
As controlled by the polymerization conditions via predictive reactor modelling.
Analytical Temperature Rising Elution
Fractionation (ATREF)
In ATREF analysis, the composition to be
analyzed was dissolved in 1,2,4 trichloro-
benzene (2 mg/ml) at 160
comonomer incorporation was determined
using the method reported by Zhou et al.
[4]
Polymer Fractionation by TREF
Large-scale TREF fractionation was car-
ried out by dissolving 15-20 g of polymer in
2 liters of 1,2,4-trichlorobenzene (TCB) by
stirring for 4 hours at 160
8
C. The polymer
solution is forced by 15 psig (100 kPa)
nitrogen onto a 3 inch by 4 foot (7.6 cm
121.9 cm) steel column packed with a 60:40
(v:v) mix of 30-40 mesh (600-425
C and allowed to
crystallize in a column containing an inert
support (stainless steel shots) by slowly
reducing the temperature to 20
8
C, at a rate
of
8
C/min, where the temperature was
held for one hour. The instrumentation was
equipped with an IR4 infra-red detector
(PolymerChar, Valencia, Spain). An ATREF
chromatogram curve was then generated by
eluting the crystallized polymer sample (at a
flow rate of 1 cc/min) from the column while
slowly increasing the temperature of the
column and eluting solvent (trichlorobenzene)
from 20 to 120
0.1
8
m)
spherical, technical quality glass beads
(available from Potters Industries, HC
30 Box 20, Brownwood, TX, 76801) and
stainless steel, 0.028
00
(0.7mm) diameter cut
wire shot (available from Pellets, Inc.
63 Industrial Drive, North Tonawanda,
NY, 14120). The column is immersed in a
thermally controlled oil jacket, set initially
to 160
8
C. The column is first cooled
ballistically to 125
m
8
C(atarateof1.0
8
C/min).
13
C Nuclear Magnetic Resonance (NMR) Analysis
The samples were prepared by adding
approximately 3 g of a 50/50 mixture of
tetrachloroethane-d
2
/orthodichlorobenzene
to 0.4 g sample in a 10 mm NMR tube. The
samples were then dissolved and homo-
genized by heating the tube and its contents
to 150
8
C. The data was collected using a
JEOL Eclipse
TM
400 MHz spectrometer or
a Varian Unity Plus
TM
400 MHz spectro-
meter, corresponding to a
13
C resonance
frequency of 100.5 MHz. The data was
acquired using 4000 transients per data file
with a 6 second pulse repetition delay. To
achieve maximum signal-to-noise for quan-
titative analysis, multiple data files were
added together. The spectral width was
25,000 Hz with a minimum file size of 32K
data points. The samples were analyzed at
130
C, then slow cooled to
8
20
C per minute and held for
one hour. Fresh TCB is introduced at about
65 ml/min while the temperature is increased at
0.167
8
C per minute. Approximately 2000 ml
portions of eluant fromthe preparative TREF
column are collected in a 16-station, heated
fraction collector. The polymer is concen-
trated in each fraction using a rotary
evaporator until about 50 to 100 ml of
the polymer solution remains. The concen-
trated solutions are allowed to stand over-
night before adding excess methanol,
filtering, and rinsing (approx. 300-500 ml
of methanol including the final rinse). The
filtration step is performed on a 3 position
vacuum assisted filtering station using
5.0
C at 0.04
8
8
8
C in a 10 mm broad band probe. The
m
m polytetrafluoroethylene coated
