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Synthesis of Polyurethane Elastomers by One-shot Technique and Study of Different Polyol Types and Hard Segment Content After Exposure to g -Irradiation |
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PP: 705-715 |
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doi:10.18576/amis/120405
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Author(s) |
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H. M. Abd El-Raheem,
Y. K. Abdel-Monem,
I. M. El-Sherbiny,
K. Lotfy,
M. M. Basuni,
H. A. Youssef,
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Abstract |
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| In the present study, a series of polyurethane elastomers (PUEs) are developed via a one-shot technique, with the aid of
an internal mixer, followed by the compression molding of the samples. Bis(4-isocyanatophenyl)methane (MDI) is used with various
ratios; of 1,4-butanediol (BG) as a hard domain, whereas the soft domain is based on two classes of polyols of different number of
-OH groups; castor oil (CO) as a polyester and poly(tetramethylene ether) glycol (PTMO) as a polyether. The obtained PUEs films are
irradiated with gamma radiation from a 60Co source in air at doses that ranged from 100 kGy to 600 kGy at room temperature and a
dose rate of 5kGy/h. The samples are characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), differential scanning
calorimetry (DSC) and mechanical testing. The formation of the PUEs is confirmed via disappearance of the NCO peak in the FT-IR
spectrum and which demonstrates that MDI has reacted completely. TGA and DSC results have shown that the thermal resistance,
glass transition temperature (Tg) and the melting point (Tm) have increased with increasing BG content and irradiation dose. It has been
found also that the PUEs samples based on polyester polyol are more superior than the ones based on polyether polyol. The mechanical
tests of the polyester-based PUE’s shown that their tensile strength, hardness modules rise and the elongation at break decrease with
increasing both BG and crosslinking density contrariwise of polyether-based PUEs. Moreover, the crosslinking density that formed
upon increasing irradiation dose has shown the same results. |
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