Abstract:

Spiro [2H-indole-2,3’–[3H]naphth[2,1-b][1,4]oxazine],1,3-dihydro-1,3,3-trimethyl-6’–(1-piperidinyl) was incorporated onto polypropylene and photochromic polypropylene multifilaments produced through the mass coloration technique. Subsequently the polypropylene (PP) filaments were doped with a different concentration of photochromic pigment, and after producing the filaments different drawing ratios were applied. The photochromic colour build was found to be maximum with the highest concentration of dyes as well as with the lowest drawing ratio. Also the colour differences for L*, a*, b* and ΔE* were analysed with respect to the different concentrations and drawing ratios of the filament. The filaments generally showed good stability of photocoloration during the colour measurement till five cycles. The results for the optical density were reduced by increasing the fineness of the filament. In this experimental work, the impact of the drawing ratio on the optical and mechanical properties of these multifilaments were investigated.