Thermal and crystalline properties of water-borne polyurethanes based on IPDI, DMPA, and PEBA/HNA

摘要

A series of water-borne polyurethanes (WPUs) with different soft segments, various COOH contents, and various hard segment contents were prepared through a pre-polymerization process. Thermal and crystalline properties of their films were studied by the measurement of differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermogravimetry (TG), respectively. Two T-g areas in DSC of WPUs with polyethylene-butylene adipate glycol (PEBA) as the soft segment were found; an endothermic peak at similar to 33 degrees C was also found with polyhexane neopentyl adipate glycol (HNA) as the soft segment. The DSC of WPUs with the mixture of PEBA/HNA as soft segment was investigated to show similarity to those from HNA, but with a relatively smaller endothermic peak at similar to 34 C. Three sharp diffraction peaks at 2 theta = 20.50 degrees, 21.72 degrees, and 24.54 degrees in XRD of water-bourne PUs from HNA were found to indicate the crystallization of soft segments, which was disrupted by the addition of polyacrylate (PA), as evidenced by the amorphous shoulder at similar to 2 theta = 20 degrees. TG analysis and differential thermogravimetric (DTG) analysis were measured to indicate that the films lost weight in two stages, and the decomposition temperatures of the films depended on the COOH content. (c) 2006 Wiley Periodicals, Inc.