Ultra-violet Radiation Effect on the Mechanical Properties of Polyuria

This study shows that the mechanical properties of polyurea's low strain rate are a function of the duration of ultraviolet irradiation. The polyurea sample was cast and continuously exposed to UV radiation for 15 weeks to simulate direct sunlight exposure of about 9,200 hours. Each sample (unexposed and exposed) was uniaxially tested according to ASTM D 638-8 with semi-static tension. Stress-strain data were used to calculate the elastic modulus of polyurea, 0.2% offset yield stress, shear modulus and stress at 250% strain. In addition, the optical properties and surface topology change of polyurea were investigated using ultraviolet - visible spectroscopy (UV - Vis) and scanning electron spectroscopy (SEM), respectively. Finally, we apply stress-strain data to Ogden's superelastic model. The change in fitting parameter of Ogden is due to the duration of UV exposure. The elastic modulus increased by 23.89% (90.15 MPa to 11.68 MPa) and the 0.2% offset yield stress decreased by 15.78% (2.46 MPa to 07 MPa).

Epoxy resin is susceptible to ultraviolet (UV) damage, outdoor, although it has some excellent properties such as low shrinkage, excellent chemical resistance, curing at low temperature, no by-products or volatile substances, It is exposed to the environment. Its durability deteriorates markedly. In order to overcome this disadvantage, ultraviolet absorbers are generally used to lower the ultraviolet decomposition rate. In this study we investigated the effect of ultraviolet radiation on the chemical, mechanical and physical properties of the cured epoxy resin structure and the influence of the organic UV absorber Tinuvin 1130 on the properties of the epoxy resin. Using Fourier Transform Infrared Spectroscopy (FT - IR) analysis, chemical changes of cured epoxy system with and without Tinuvin 1130 were measured. The effect of Tinuvin 1130 on epoxy surface morphology was also examined by scanning electron microscopy (SEM).

Influence of ultraviolet light on chemical and mechanical properties of organic UV absorber transparent epoxy diamine system

This study shows that the mechanical properties of polyurea's low strain rate are a function of the duration of ultraviolet irradiation. The polyurea sample was cast and continuously exposed to UV radiation for 15 weeks to simulate direct sunlight exposure of about 9,200 hours. Each sample (unexposed and exposed) was uniaxially tested according to ASTM D 638-8 with semi-static tension. Stress-strain data were used to calculate the elastic modulus of polyurea, 0.2% offset yield stress, shear modulus and stress at 250% strain. In addition, the optical properties and surface topology change of polyurea were investigated using ultraviolet - visible spectroscopy (UV - Vis) and scanning electron spectroscopy (SEM), respectively. Finally, we apply stress-strain data to Ogden's superelastic model. The change in Ogden's fitting parameter is due to the duration of UV exposure