Structural engineering of polyurethane coatings for high performance applications

Three types of amine-containing polyurethanes and poly(urethane−ureas), N-methyldiethanolamine (MDEA) and/or tetraethylenepentamine (TEPA) as the chain extender and poly(ethylene glycol) of MW 400 as the soft-segment component, have been studied by FTIR. The hydrogen bonding in hard and soft segments was examined for the extent of phase separation, and the microstructure was evidenced by differential scanning calorimetry (DSC). The temperature effects on the hydrogen bonding were also investigated. They show a significant amount of hydrogen bonding between the hard and soft segments. It indicates that there exists a large amount of partial phase mixing of hard and soft segments compared to the conventional polyurethanes. The bulky CH3 groups of MDEA in hard segments restrict the hydrogen bonding within the hard segments, while the TEPA-containing urethane−urea polymers have more distinct phase separation. However, all of the polymers studied are amorphous materials such that the dissolved soft segments in...

Fourier Transform Infrared Spectroscopy Study on Effects of Temperature on Hydrogen Bonding in Amine-Containing Polyurethanes and Poly(urethane−urea)s

Green synthesis of flexible polyurethane foams from liquefied lignin

A series of degradable polyurethanes of variable soft segment chemistry and content were synthesized and characterized. An amino acid-based diester chain extender was used to confer degradability and both polycaprolactone diol (PCL) and polyethylene oxide (PEO) were used as soft segments. In addition, the diisocyanate component was a potentially nontoxic diisocyanate (2,6-diisocyanato methyl caproate, LDI). The physicochemical properties of these unique series of polyurethanes were investigated. It was found that the PEO containing polyurethanes were generally weak, tacky amorphous materials. In contrast, the PCL polyurethanes were relatively strong, elastomeric materials which ranged from completely amorphous to semicrystalline as noted by differential scanning calorimetry. The PCL containing polyurethanes exhibited increasing tensile strength, modulus, and ultimate strain with increasing PCL molecular weight because of increasing phase separation and increasing soft segment crystallinity. Fourier transform infrared analysis showed significant hard segment urea and urethane hydrogen bonding which increased with hard segment content, although interphase bonding is believed to be significant for the PCL polyurethanes. Surface characterization carried out by contact angle analysis and X-ray photoelectron spectroscopy indicated soft segment surface enrichment for all of the polyurethanes. The PEO-based polymers were very hydrophilic whereas the PCL-based polymers displayed significantly higher contact angles, indicating greater surface hydrophobicity. The observed diversity in material properties suggests that these polyurethanes may be useful for a wide range of applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1522–1534, 2000

Structure‐property relationships of degradable polyurethane elastomers containing an amino acid‐based chain extender

Published literature on biomedical polyurethanes is reviewed. Selected topics concerning chemistry, structure-property relations, tissue-material interactions, surface properties, applications, processing, and sterilization, etc., are discussed.

N. S. Schneider

Papers

Infrared Studies of Hydrogen Bonding in Toluene Diisocyanate Based Polyurethanes