pps proceeding - Abstract Preview
pps proceeding
Symposium: G06 - Polymer composites
Oral Presentation
 
 

Synergistic effect of organic and inorganic nano-UV additives for improving weather resistant property of thermoplastic polyurethane nanocomposite films

Adak Bapan (1)*, Joshi Mangala (1), Butola Bhupendra Singh (1)

(1) Indian Institute of Technology Delhi - DELHI - India

In this study, the synergistic effect of different organic UV additives such as UV-absorber, HALS, antioxidant and antiozonant as well as the effect of inorganic UV-Shielding nanopowder (nano-TiO2 and ZnO) on weather resistance property of thermoplastic polyurethane (TPU) films were studied. Polyurethane nanocomposite films were produced using these UV-additives in different combinations. The mixing of TPU and UV additives were done in a micro twin screw extruder, followed by preparation of film in compression molding. The accelerated weathering was carried out by exposing these films in a weather-o-meter up to 300h under UV-light plus raining cycle as per ISO 4892 method. The weather resistance performance was analyzed in term of change of UPF, tensile properties and yellowness index of the films after exposure. The chemical change after exposure were analyzed by FTIR. The surface morphology of the films (before and after exposure) was studied by SEM. Incorporation of UV-shielding nanopower in TPU matrix resulted in improved tensile properties of the films. However, in presence of organic UV-additive with nanopowder, almost no improvement was observed in tensile properties, due to plasticizing effect of organic UV additives. The organic UV absorber was quite efficient to increase UPF value initially and a good synergistic effect was found with HALS and antioxidant. However, there was an issue of their sustainability. UPF value increased significantly with addition of UV-shielding nanopowder due to their UV absorbance plus UV reflectance property. However, only UV shielding nanopowder was not effective to increase UPF value at lower concentration. Incorporation of organic UV additives with UV-shielding nanopowder resulted in good weather resistance properties even at very low concentration about 1 wt% and also provided sustained effect. Similarly, the antiozonant showed good synergistic weather resistant effect with UV-shielding nanopowder.