Influence of varying hard segments on the properties of chemically crosslinked moisture‐cured polyurethane‐urea
Влияние различных жестких сегментов на свойства химически сшитого влагоотверждаемого полиуретан-мочевинного полимера
2005-11-11
SCID: 54.1/xad4usft
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X-ray photoelectron spectroscopychemical crosslinkingdynamic mechanical thermal analysishard segmentsmoisture-cured polyurethane-urea
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Abstract (AI)
Abstract Polyurethane prepolymers are widely used in the reactive hot melt adhesives and moisture‐cured coatings. The chemically crosslinked moisture‐cured formulation based on PEG‐1000 and isophorone diisocyanate was prepared with NCO/OH ratio of 1.6:1.0. Trimethylol propane was used as a crosslinking agent. The excess isocyanate of the prepolymer was chain extended in the ratio of 2:1 (NCO/OH) with different aliphatic diols, and 4:1 with different aromatic diamines. The polymer network maturation during moisture cure was followed by dynamic mechanical thermal analyzer (DMTA) instrument. The thermal and dynamic mechanical properties of the crosslinked polymers were evaluated using thermogravimetric analysis, differential scanning calorimetric analysis and DMTA. Surface properties were evaluated through angle‐resolved X‐ray photoelectron spectroscopy. The present article discusses the physical properties of moisture‐cured polyurethane‐urea (MCPU) containing chemical crosslinks in the hard segment. The complete moisture‐cured polymers showed amorous results toward room temperature modulus, tensile strength, hardness, thermal stability, and transparency. The surface properties showed the enrichment of soft segments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 102–118, 2006
Key Findings
1
Angle-resolved XPS indicated enrichment of soft segments at the polymer surface.
2
Chemically crosslinked moisture-cured polyurethane-ureas were prepared from PEG-1000 and isophorone diisocyanate using trimethylol propane as the crosslinking agent.
3
DMTA monitoring showed maturation of the polymer network during moisture curing, while TGA, DSC, and DMTA characterized the resulting thermal and dynamic mechanical properties.
4
Different aliphatic diols and aromatic diamines were used to vary the hard-segment structure through chain extension at NCO/OH ratios of 2:1 and 4:1, respectively.
5
Fully moisture-cured polymers exhibited amorphous behavior near room temperature in modulus, tensile strength, hardness, thermal stability, and transparency.
Research Object
Chemically crosslinked moisture-cured polyurethane-urea polymers based on PEG-1000 and isophorone diisocyanate, containing varied hard segments
Research Subject
The influence of hard-segment composition and chemical crosslinking on the thermal, dynamic mechanical, tensile, hardness, transparency, and surface properties of the moisture-cured polymers
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2005-11-11
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