The oxidative degradation of styrenic copolymers: A comparison of photoproducts formation under natural and accelerated conditions

Abstract

Natural and accelerated weathering of polystyrene and high-impact polystyrene were carried out in the present investigation. The structural changes in the polymer samples were characterized by using FTIR spectroscopy, tensile strength testing, and SEM spectroscopy. The natural exposure was conducted throughout the year. Rates of photooxidation were determined by measuring the evaluation in hydroxyl and carbonyl regions. The surface deterioration was revealed from SEM micrographs. The drop in tensile strength was also monitored. A correlation between natural and artificial weathering was considered for lifetime prediction in a short exposure time.

The effect of natural weathering on the mechanical, morphological and thermal properties of high impact polystyrene (HIPS)

“…Qayyum and White [18], Bedia et al [12], Sing et al [19], Baum et al [20], Van Krevelen and Hoftyzer [21], Ragab et al [22], Uzomah and Onuoha [23], Schoolenberg [24], Sharbel et al [25], Kalfoglou [26], Sınmazçelik [27] investigated the effects of natural weathering on the polymers. The objective of this study is investigating the effect of natural weathering and cold drawing on HIPS.…”

Thermal and photochemical degradation of PPO/HIPS blends

“…The mechanical results show that HIPS is more sensitive to thermal and thermooxidative degradation. A pronounced drop of the mechanical performance of HIPS was also described by Singh et al 21 who studied the oxidative degradation of HIPS with different polybutadiene contents and found a slight increase in tensile strength during the early stages of exposure; thereafter, a continuous drop was observed. The increase was attributed to the dominance of crosslinking reactions over chain scission during the early stages.…”

Data on Specific Polymers

“…On exposure to solar radiation the benzene ring does not absorb energy therefore initiation is caused either by photoexcited impurities or charge transfer complexes. The following radical was confirmed by ESR and it is commonly believed to be a starting point for further conversions: In the next step, the polystyryl radicals react with oxygen: 796,814 Again, this product was identified by ESR. 796 The next step involves hydrogen abstraction from an additive or from a neighboring chain (in both cases a new radical is formed):…”