Photoaging phenomena of biodegradable polybutylene succinate and conventional low density polyethylene by artificial weathering - A comparative surface study

Polybutylene succinate (PBS) is a promising eco-friendly alternative to many conventional plastics. It is not intended for outdoor use when a longer shelf life is desired. Research about the weatherability of PBS is important to expand its applicability. In the present study, the degree of aging on injection-molded sheets of biobased PBS and additive-free LDPE was investigated. These were subjected to accelerated photo-aging by 14-, 28-, and 56-days daylight exposure and 7-days UV irradiation. The comparison with LDPE confirmed that photo initiated degradation processes occurred. The aging phenomena were monitored by atomic force microscopy, contact angle goniometry, Fourier-transform infrared spectroscopy, and synchrotron-assisted X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure. The results demonstrated effects in early stages of aging for PBS on surface morphology, roughness and wetting behavior. No significant chemical changes were detected on the surface of exposed PBS samples. For LDPE chemical changes in sp2/sp3 ratio, atomic oxidation state, and wetting behavior were observed for UV-and daylight weathered LDPE. However, no effects were apparent on the LDPE surface morphology. The biobased PBS is thus chemically more stable, but more surface sensitive to accelerated photoaging than the LDPE used here.