Weathering of Lignocellulosic Polymer Composites

Environmental Degradation of Plastic Composites with Natural Fillers—A Review

“…In 2015, Shahzad and Isaac [113] published a comprehensive report on weathering studies found in literature at that time on lignocellulosic polymer composites, with detailed discussions on the UV and moisture effects on composites components (fiber and polymer matrix), methods to improve their resistance, and testing methods to evaluate weathering properties. Therefore, the focus here is mainly on studies reported after the year 2015.…”

“…UV radiation (100-400 nm) represents only about 6.8% of the spectral range of solar radiation (100-3000 nm) but it has sufficiently high energy to break chemical bonds (Table 2), thus damaging the outdoor exposed materials. The UV-B radiation (315-280 nm) is the shortest wavelength solar radiation reaching the Earth's surface (UV-C radiation below 280 nm is totally absorbed by the ozone layer) and is the most aggressive to polymeric materials [113]. Photodegradation of polyolefins involves Norrish reactions of ketones and aldehydes, the type I ones leading to free radicals generating cross-linkings or chain scissions, and the type II ones leading to carbonyl and vinyl groups (Figure 3).…”

“…Dissociation energy of several bonds and the corresponding radiation wavelengths. Reprinted with permission from [113]. Photodegradation of polyolefins involves Norrish reactions of ketones and aldehydes, the type I ones leading to free radicals generating cross-linkings or chain scissions, and the type II ones leading to carbonyl and vinyl groups (Figure 3).…”

“…Norrish I (a) and Norrish II (b) reactions occurring in photodegradation of polyethylene Reprinted with permission from[113].…”

Nanoridge patterns on polymeric film by a photodegradation copying method for metallic nanowire networks

“…22,[26][27][28] Actually, the polymer breakdown caused by photodegradation also has been reported. [29][30][31] The schematic of ridge patterning process on PET lm is shown in Fig. 2.…”