Thermoplastic polyurethane elastomers based on polycarbonate diols with different soft segment molecular weight and chemical structure: Mechanical and thermal properties

Abstract

A series of thermoplastic polyurethane elastomers based on polycarbonate diol, 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol was synthesized in bulk by two‐step polymerization varying polycarbonate diol soft segment molecular weight and chemical structure, and also hard segment content, and their effects on the thermal and mechanical properties were investigated. Dynamic mechanical analysis termogravimetric analysis, differential scanning calorimetry, Fourier transform infrared‐attenuated total reflection spectroscopy and mechanical tests were employed to characterize the polyurethanes. Thermal and mechanical properties are discussed from the viewpoint of microphase domain separation of hard and soft segments. On one hand, an increase in soft segment length, and on the other hand an increase in the hard segment content, i.e., hard segment molecular weight, was accompanied by an increase in the microphase separation degree, hard domain order and crystallinity, and stiffness. In phase separated systems more developed reinforcing hard domain structure is observed. These hard segment structures, in addition to the elastic nature of soft segment, provide enough physical crosslink sites to have elastomeric behavior. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers

Exploitation of Arundo donax L. Hydrolysis Residue for the Green Synthesis of Flexible Polyurethane Foams

“…These imperfections are due to the irregular structure of the A. donax hydrolysis residue that affected the properties of the final foams. The plateau is due to the breakage in the physical cross-links inside the polyurethane network that caused the plateau to end and repercussions on the storage modulus to decrease (Eceiza et al 2008). The end of the plateau corresponds to the maximum temperature for the material application; this temperature was higher for the foams produced using EJ 300 as polyolic reagent (ARF and ARJ), further confirming the promising results obtained for the ARF formulation.…”

Aliphatic polycarbonate-based thermoplastic polyurethane elastomers containing diphenyl sulfide units

“…Polyurethanes require an analysis of the carbonyl stretching region, which gives some information about their order of hard domains or degree of microphase separation. The spectrum of the RPUR H showed a sharp band at 1684 cm -1 , while that of the RPUR HM exhibited a broader one at 1701 cm -1 , characteristic of the H-bonded urethane carbonyl groups [22,23], in well-ordered ''crystalline'' structures and disordered ''amorphous'' ones, respectively. This was in agreement with the results of DSC and XRD analyses.…”

Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

“…The PCUs showed tensile moduli in the range of 9.4-18.3 MPa and elongation at break in the range of 380%-530%. The mechanical behavior of the polyurethanes were dependent on several factors, such as the degree of crystallinity and microphase separation [40,41], concentration, and the interconnectivity of hard segments. Here, all samples containing hard segments with the same composition presented an amorphous structure, as already indicated by AFM.…”