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In the transition to renewably sourced, biodegradable polymers, the preparation of low viscosity polyester‐polyols has posed a challenge for renewable polyurethane (PU) development. Low viscosity polyols not only reduce the requirement for high process temperatures but also decrease manufacturing time. In our efforts to incorporate increasing ratios of bio‐based monomers into renewable PUs, we mixed diacids such as even carbon sebacic acid and odd carbon azelaic acid along with a renewable diol. This provided library of 2000 g/mol molecular weight polyester‐polyols, and structures were established by 1H and 13C NMR analysis. The prepared polyester‐polyols offered lower viscosity and enable lower fabrication temperatures to make TPUs, and their structure and material metrics were evaluated. The formation of TPUs is ascertained from FTIR and NMR analysis. The final TPUs displayed good physical and mechanical properties. These TPUs exhibited Tg in the range of −56.5 to −39.7°C, corresponding to TPU soft block structure, and Tm between 98.3 and 105.1°C originating from the hard segment. Prepared TPUs exhibit excellent biodegradation under compost environmental conditions. These TPUs showed up to 57% decrease in molecular weight by GPC analysis after 9 weeks of biodegradation, and respirometer analysis displayed up to 97% biodegradation over 120 days.

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The Phased Array Ultrasonic Technique (PAUT) offers great advantages over the conventional ultrasound technique (UT), particularly because of beam focusing, beam steering and electronic scanning capabilities. However, the 2D images obtained have usually low resolution in the direction perpendicular to the array elements, which limits the inspection quality of large components by mechanical scanning. This paper describes a novel approach to improve image quality in these situations, by combining three ultrasonic techniques: Phased Array with dynamic depth focusing in reception, Synthetic Aperture Focusing Technique (SAFT) and Phase Coherence Imaging (PCI). To be applied with conventional NDT arrays (1D and non-focused in elevation) a special mask to produce a wide beam in the movement direction was designed and analyzed by simulation and experimentally. Then, the imaging algorithm is presented and validated by the inspection of test samples. The obtained images quality is comparable to that obtained with an equivalent matrix array, but using conventional NDT arrays and equipments, and implemented in real time.