New thermoplastic segmented polyurethanes with hard segments derived from 4,4′‐diphenylmethane diisocyanate and methylenebis(1,4‐phenylenemethylenethio)dialcanols

Abstract

New thermoplastic poly(ether-urethane)s and poly(carbonate-urethane)s were synthesized by a onestep melt polymerization from poly(oxytetramethylene) diol (PTMO) and poly(hexane-1,6-diyl carbonate) diol (PHCD) as soft segments, 4,4 0 -diphenylmethane diisocyanate, and 2,20 -[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as unconventional chain extenders. The effects of the kind and amount of the polymer diol and chain extender used on the structure and properties of the polymers were studied. The polymers were examined by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), TGA coupled with FTIR spectroscopy, and Shore hardness and tensile testing. The obtained highmolecular-weight polymers showed elastomeric or plastic properties. Generally, the PTMO-based polymers exhibited significantly lower glass-transition temperatures (up to À48.1 vs À1.4 C), a higher degree of microphase separation, and ordering in hard-segment domains in comparison with the corresponding PHCD-based ones. Moreover, it was observed that the polymers with the PTMO soft segments showed poorer tensile strengths (up to 36.5 vs 59.6 MPa) but higher elongations at break. All of the polymers exhibited a relatively good thermal stability. Their temperatures of 1% mass loss were in the range 270-320 C.

Aliphatic polycarbonate-based thermoplastic polyurethane elastomers containing diphenyl sulfide units

“…This study is a part of an ongoing investigation concerning new TPUs obtained from aliphatic-aromatic sulfur-containing chain extenders, derivatives of, among others, diphenylmethane, diphenylethane, benzophenone, diphenyl ether and diphenyl sulfide [6][7][8][9][10][11][12][13]. On the basis of the studies conducted for selected polymers, it was stated that the introduction of sulfur atoms to the polymer chain improved their adhesive strength [12,[14][15][16] and refractive index [15,16].…”

New thermoplastic polyurethane elastomers based on aliphatic diisocyanate

“…In contrast, the aliphatic diisocyanate-based TPUs show no change of colour in the same condition [3]. This paper is a continuation of research on the new TPUs derived from aliphatic-aromatic sulphur-containing chain extenders as well as derivatives of diphenylmethane [5][6][7][8][9][10][11][12][13], diphenylethane [14][15][16], benzophenone [17][18][19], diphenyl ether [20] and diphenyl sulphide [21,22]. Based on the test results, it can be concluded that the introduction of sulphur atoms into the structure of a polymer has increased their adhesive strength [21] and refractive index [11,12].…”

“…There appeared also a small peak at approx. 2170 cm -1 , connected with stretching vibrations C-O in carbon monoxide [5]. It indicated that at that temperature the decay of the polyether soft segment took place and its products were aldehydes and aliphatic ethers.…”

“…R-PUR decomposition took place based on the mechanisms 1 (formation of isocyanates and alcohols), 2 (formation of primary amines) and 4 generating COS [5].…”

“…In the case of carboxylated SPURs, the increase in DMPA content in a polymer resulted in a decrease of T g . When the type of a soft segment is a criterion for comparison, it is evident that a lower T g as well as a lower difference between T g value for a pure soft segment (PTMO-1000: -77°C, PHCD: -68°C) [5] and an appropriate polymer, and at the same time better microphase separation, was revealed by polymers derived from PTMO.…”