Professional paper
The influence of ultraviolet stabilizers on high-impact polystyrene natural ageing
Vesna ŠKUNCA
; DIOKI - Organic Petrochemical Industry
Abstract
Natural ageing of plastics is caused by all weathering factors in the course of time, the most signifi cant ones being UV-radiation, temperature and humidity. Polystyrene is a widely used thermoplastics material that ages rapidly when exposed to ultraviolet radiation, particularly in direct, outdoor exposure. The main criteria for estimating ageing of high-impact polystyrene are changes in colour and mechanical properties. Polystyrene ageing is different under indoor and outdoor exposure conditions. By the addition of antioxidants and light stabilizers, polystyrene stability is increased, i.e. thermal and photooxidative degradation are slowed down or stopped. In this paper, natural ageing of unstabilised and stabilised PS–HI 485 and fl ame retardant polystyrene PSVM 40902 AF-N, to which two different masterbatches of light stabilizers were added, is investigated. Unstabilised PS–HI 485 yellowed signifi cantly under indoor and outdoor conditions. UV-stabilized PS–HI 485 did not yellow under indoor conditions in the period of 13 months, but it yellowed slightly and changed its mechanical properties under outdoor conditions in the same period of exposure. Flame retardant polystyrene PSVM 40902 AF-N is prepared by adding 26.6% halogen additive free of decabromo-diphenyl-ether in polystyrene based masterbatch. Non-stabilized PSVM 40902 AF-N yellowed under indoor and outdoor test conditions. Under indoor conditions, UV-stabilized PSVM 40902 AF-N yellowed very lightly but under outdoor conditions in direct exposure to weathering factors, it yellowed signifi cantly and changed its mechanical properties.
Keywords
ageing; high impact polystyrene; high impact polystyrene of low fl ammability; ultraviolet stabilisation; yellowness index
Hrčak ID:
97718
URI
Publication date:
27.2.2013.
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