Degradation behavior of an ultraviolet and hygrothermally aged polyurethane elastomer: Fourier transform infrared and differential scanning calorimetry studies

Abstract

ABSTRACT:The degradation behavior of an elastomeric polyurethane (PU) was investigated with accelerated ultraviolet (UV) and hygrothermal (HT) techniques. Samples were subjected to UV exposure and HT conditions for 3 or 5 months and were removed in 1-month intervals from the test chambers. Their chemical structure was evaluated with Fourier transform infrared (FTIR) spectroscopy. The thermal transitions of the aged samples were evaluated with differential scanning calorimetry (DSC). Both FTIR and DSC results showed no evidence of significant structural damage to the HT-aged PU throughout exposure. FTIR analysis of the UV-aged samples showed a noticeable change in the chemical structure of the polymer after 1 month of UV exposure. The results from DSC correlated with the FTIR analysis of the UV-aged samples. Spectroscopic and thermal analysis of the aging of the PU samples was correlated to mechanical analysis.

Data on Specific Polymers

“…935 Degradation behavior of an ultraviolet and hygrothermally aged polyurethane elastomer was studied by FTIR and DSC. 936 No evidence of significant structural damage to PU throughout exposure of up to 5 month was found, but a noticeable change in the chemical structure of the polymer after 1 month of UV exposure was observed. 936 …”

“…936 No evidence of significant structural damage to PU throughout exposure of up to 5 month was found, but a noticeable change in the chemical structure of the polymer after 1 month of UV exposure was observed. 936 …”

Testing Methods of Weathered Specimen

“…At aging temperatures of up to 70 o C a decrease of glass transition temperature was caused by hydrolytic chain scission alone. 405 Thermal methods results are affected by so many factors that they can never, by themselves, provide quantitative information about the degradation process. 376 Hygrothermal aging of polyurethane elastomer did not cause substantial changes in glass transition temperature.…”

“…494 Hardness 80,127,487,488 is easy to measure. 405 The impact strength of ABS and PC was used to monitor the effect of exposure to solar radiation. The Vicker hardness number correlates very well with the carbonyl index of exposed polyethylene sheets ( Figure 13.58).…”

Improving the Acid and Base Resistance of Polyurethane Using Carbon Nanotubes

“…However, PU gradually deteriorates owing to hydrolysis, which occurs immediately after its synthesis and causes various problems . It is known that the rate of hydrolysis accelerates under high temperature and humidity and also in acidic or basic environments . Inhibiting the hydrolysis of PU is indispensable for improving the reliability of PU‐basedproducts.…”