VNU. JOURNAL OF SCIENCE, Nat.. S cL & Tech., T .xx, N03, 2004

S Y N T H E S I S A N D CHARACTERIZATION OF S E G M E N T E D
P O L Y U R E T H A N E S B A S E D ON P O L Y E T H Y L E N E A N D
PO L Y T E T R A M E T H Y L E N E GLYCOLS
PART 2: THERMO-MECHANICAL AND SWELING PROPERTIES
Ph am N goc Lan
Polymer Research Cen ter, Hanoi University o f Technology
N gu yen Thu Hang
College o f Science, Vietnam N ational University, Hanoi

1. In trod u ction
In the previous paper [1] we presented our study on the synthesis and
characterization of some SPUs based on polyethylene and polytetramethylene glycols.
Segmented polyurethanes (SPUs) are multiblock copolymers. Due to their specific phase
separation characteristics caused by incompatibility between the hard and soft segments,
they have quite good biocompatibility [2].
In this paper we present the second part of our study on the thermo-mechanicahand
swelling properties of the SPUs based on polyethylene and polytetram ethylene glycols. The
effects of the macrodiols on the properties of the SPUs obtained were discussed.
2. E xp erim en tal
2.1. M a teria ls
Polyethylene

and

polyteramethylene

glycols

selected

1100
2070
4109
1950

40
55
62
25

-70 (very weak)
-70 (very weak)
-

-30

(a): Determined via GPC; (b): Determined via chemical titration
The hydroxyl num ber of the polyetherdiols for calculation of the molecular weights
was determined bv esterification of the polyetherdiols with acetic anhydride and
subsequent titrim etric analysis of the carboxylic acid groups according to the standard
procedure [3].

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Pham N u o c Lan, N m iy cn T ill! Hang

The molecular weights of the polydiols were also verified by m eans of gel permeation
chromatography (PL columns, 103A°, 7mm i. d., 60 cm length, Polymer Laboratories Ltd,
Shropshire, UK. Eluent: chloroform, Differential reflectometric detection (Model Waters

copolymer product was dried under vacuum a t 60°c a t least for 2 days.

V N U . Jo u rn al o f Science, N a t.. Sci.. & Tech.. I XX, N J . 2004


Synthesis and ch aracterizatio n o f

3. R esults and d is c u s s io n
3.1. NMR spectra a n d IR analysis
The stru ctu re of the SPUs obtained was confirmed by proton NMR and IR spectra.
The NMR and IR absorption bands of the SPUs were shown in the previous paper [1].
3.2. DSC analysis o f SPUs
The soft segm ent glass transition tem p eratu re (Tg) and the melting tem p eratu re
(Tin) of the SPUs obtained from the DSC d ata are summarized in the table 2.
Table 2: DSC data of SPUs
Polyol ratio
P E G -1000 + PTMO-2000
PEG-2000 + PTMO-2000
PEG-4000 + PTMO-2000
PEG-2000 + PTMO-2000
PEG-2000 + PTMO-2000
PEG-2000 + PTMO-2000

Code
PƯ-1
PƯ-2
PU-3
PU-4
PƯ-2
PU-Õ

+

PTMO-2000
PTMO-2000
PTMO-2000
PTMO-2000
PTMO-2000
PTMO-2000

(1/1)
(1/1)
(1/1)
(1/2)
(1/1)
(2/1)

V N U . Journal o f Science. N a t.. Sci.. & Tech., T XX, N lt3. 2004

Tensile
at break,
MPa
7.0
12.1
15.2
9.0
12.1
13.8

Ultimate
Tensile,

The swelling study was carried out in distilled water at different tem pertures, the
results are shown in figure 1:
For the all SPUs samples, the swelling decreases with rising tem peratures. When
comparing PU-1 with PU-2 we see the swelling of PU-2 is much higher th an th a t of PU-1.
This is due to lareger crystalline domain of the soft segments in PƯ-2 compared to th at in
PU-1.
If we compare PU-4 with PU-2 and PU-5, we can see also the increase in swelling
from PU-4 to PU-2 and to PU-5. Here again, the reason would be the same: the increase in
swelling is due to enhancem ent of the crystallinities from PU-4 to PU-2 and to PU-5.

Figure 1: The swelling curves of the SPƯS in water at different temperatures

V N U . Journal o f Science. N a t., Sci..

ổi Tech..

ỉ '.XX. N J . 2004


23

Synthesis and charactcrization of.

The same swelling behaviour of the SPUs in buffer solution can be observed in Figure 2.
Comparing PU l with PU2 and PƯ3 we can see th a t when molecaular weight of the
soft segments of SPUs is increasing from P U l to PU2 and PU3, the swelling is also
increasing from P U l to PU2 and PU3. The swelling is increasing from PU4 to PU2 and PU5
when the ratio PEO-2000: PTMO 2000 in the soft segments is increasing. It can be
therefore concluded th a t the swelling behavior of the selected SPUs for study is strongly
dependent on the PEO am ount and PEO molecular weight.

25

30 37.5

Temperature, °c
4. C onclusion
The data obtained show th a t the increase in PEO am ount as well in PEO molecular
weight of the macroether diols in the SPUs soft segments results in enhancem ent of their
crystalline domain making the SPUs more phase separated. The mechanical and swelling
properties of the SPUs are increasing upon increasing the crystalline domain of the soft
segments in the SPUs as well.

REFERENCE
1.

Pham Ngoe Lan, Schacht E., J. o f Science, Natural Sciences and Technology, T. 19, No 6
(2003), 21-28.

2.

P.N. Lân, Corneillie s., Schacht E., Davies M. and Shard A., Biomaterials, 17 (1996), 22732280.

3.

Sorenson WR., Campbell TW., Preparative Methods o f Polymer Chemistry. New York:
Interscience, (1961).

V N U . Journal o f Science. N a t.. Sci.. á Tech.. T. XX. A y . 2004




V N U . Journal o f Science, N at., S ri.. & Tech., T. XX. N J . 2004