Table 5. Thermal and mechanical properties of poly(ester urethane)s (PEUs) prepared from triblock copolymers (PCL-b-B-b-PCL) and hexamethylene diisocyanate (HDI).
| Polyurethane | Precursor | Ether (%)a,b | HS (%)c | SS (%)d | T mPCL (°C)e | ΔHm (J g−1)e | x i (%)e,g | Stress at break (MPa) | Strain at break (%) | Modulus (MPa) |
|---|---|---|---|---|---|---|---|---|---|---|
| PEU-1PEG | PCL-b-PEG200-b-PCL10 | 14 | 13 | 87 | 31 | 38 (50)f | 28 (37)f | 2.7 ± 0.2 | 3 ± 0.3 | 133.5 ± 2.0 |
| PEU-2PTHF | PCL-b-PTHF250-b-PCL10 | 16 | 13 | 87 | 33 | 30 (63)f | 22 (46)f | 3.3 ± 0.1 | 14 ± 0.7 | 78.4 ± 2.9 |
| PEU-3PPG | PCL-b-PPG425-b-PCL10 | 27 | 12 | 88 | 30 | 28 (56)f | 20 (41)f | 2.7 ± 0.1 | 8 ± 0.8 | 85.6 ± 1.2 |
a
Obtained from the equation % ether = (MWinitiator/Mn(NMR)) × 100; where MWinitiator is the molecular weight of initiator (HOPEGOH, HOPTHFOH, or HOPPGOH).
b
Determined by 1H NMR in CDCl3.
c
Hard Segment.
d
Soft Segment.
e
Obtained by DSC analysis (second heating).
f
The values enthalpy (ΔHm) and crystallinity (xi)of the triblock copolymer utilized for the PEU are indicated within parentheses.
g
Using the value of 135.3 J g−1 for a PCL 100% crystalline,68 the crystallinity of PCL (xPCL) was calculated.