Stručni rad
Optical properties of polystyrene
Vesna ŠKUNCA
; Tvornica polistirena DIOKI, DIOKI d.d., Zagreb
Želimir JELČIĆ
; PLIVA-Istraživanje i razvoj d.o.o., Zagreb
Sažetak
Transparency and translucency of general purpose polystyrene are usually determined visually. Since eyes as perceivers are subjective observers, errors are possible in assessment of clearness, haze and shade of uncoloured polystyrene. However, clearness and haze can be exactly determined by spectrophotometric measurements made in the visible part of the spectrum from 400 to 700 nm on the samples of polystyrene moulded parts. Thus, clearness as the optical property of both uncoloured and coloured polystyrene is determined by spectrophotometric measurements performed in two possible ways. One way is to measure the transmission of clear specimens, and the other is to measure their remission (reflexion) using black and white standard specimens as the base. The basic characteristic of transparent specimens is that they are pervious to light. Specimens can be either clean - which means that they do not disperse light at all or that they do so only to a very limited extent – or hazy (translucent), i.e. they disperse light. Using spectrophotometer Macbeth 2020+, with diffusion measuring geometry 8, UV filter and specular component included, the transmission and remission measurements were performed. The specimens were plates of 2,5±5 % mm in thickness having different clearness and haze properties. In the case of PS-GP of the 678E type measurements were made on: (1) transparent specimens, (2) specimens at the bottom limit of specification range and (3) translucent, slightly yellow samples. In polystyrene of the 680L type measurements were performed on: (1) transparent, (2) translucent, and (3) very translucent specimens. The identification of clearness and haze of specimens was determined by transmission measurements with percentage of transmitted light and percentage of K/S values. It was confirmed by remission values, specifically by quantified absorption values (absorption constant K) and quantified dispersion values (scatter constant S), percentage of opacity and finally visually.
Ključne riječi
polystyrene; translucency; transparency
Hrčak ID:
10083
URI
Datum izdavanja:
12.3.2007.
Posjeta: 2.756 *