Effects of a soft segment component on the physical properties of synthesized waterborne polyurethanes by using triblock ester-ether copolydiol as the soft segment

This paper examines the effect of an ester-ether soft segment structure on the physical properties of synthesized WBPUs. The CET series, CPT series, and CMT series anionic waterborne polyurethane (WBPU) were prepared with PCL-PEG-PCL, PCL-PPG-PCL, and PCL-PTMG-PCL triblock copolydiol as the soft segment. These copolydiols were synthesized from polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene glycol (PTMG), respectively, by end capping with caprolactone (CL). Particle size and its distribution, solvent absorption, thermal properties, and the mechanical properties of the WBPUs were studied. The particle size of WBPU dispersion was in the sequence of CET > CPT > CMT series. The CET series WBPU had better phase mixing between the soft and hard segment, whereas the CMT series WBPU had good phase separation and better mechanical properties. In addition, both the phase mixing and mechanical properties increased with PCL content, except for the CMT series WBPU.