Chemistry Reference
In-Depth Information
1st Heating
2nd Heating
1st Heating
2nd Heating
150
100
(a)
(b)
145
80
145,8
145,0
144,8
144,4
77
74
69
140
60
69
1
36,3
51
137,7
135
40
46
42
39
130
20
129,6
128,7
125
0
170
190
210
227
170
190
210
227
T isothermal (ºC)
T isothermal (ºC)
Figure 4.
Effect of isothermal temperature on melting temperature (a) and crystallinity (b).
isothermal treatment was increased. How-
ever, in the second heating, the melting
temperature evidenced a significant drop
(around 7
8
C) when the nascent powder was
heated over 190
that the tie molecules were completely
destroyed during the melting process.
These experimental results indicated
that the best DSC conditions for this kind
of polyethylenes were: sample mass
C. This behaviour might
indicate that all crystalline entities initially
present in the polyethylene were destroyed
above 190
8
C. Regarding the crystallinity,
both 1
st
and 2
nd
heatings showed that the
crystallinity increases with the temperature
of
8
7 mg,
heating rate
¼
10
8
C/min and isothermal
temperature treatment
¼
170 C, which were
used to evaluate the polymers obtained by
the other systems.
For the TpTiCl
2
(OR)/MAO/ethylene/1-
hexene system, the copolymers were char-
acterized by
13
C NMR, GPC and DSC. The
¼
isothermal
treatment.
In agreement
with the literature,
[23,26]
this tend suggest
Figure 5.
NMR
13
C of copolymer made with TpTiCl
2
OEt complex ([1-Hex]
¼
0.5)
