Degradation and fragmentation behavior of polypropylene and polystyrene in water.

Abstract

A polystyrene (PS) retrieved from the beach exhibited no change in surface texture. In contrast to it, a retrieved polypropylene (PP) had a rumpled surface texture. Highly reactive sulfate radical generated by K2S2O8 was employed as degradation initiator of PP and PS, and their degradation behavior was studied in water. The PS carbonyl index value gradually went up down, and its molecular weight (MW) curve discontinuously shifted to a lower MW with the increase of the degradation time unlike the PP. It was found that PP microplastic production rate was approximately three time higher than PS from weight ratio dependence on degradation time. The higher microplastic production rate of PP arose from its crystallizability. The voids were produced by change in specific volume occurring by chemi-crystallization and then provoked the cracks leading to quick fragmentation. The SEM photographs suggested that the PP microplastic size facilely reached nm order by the cracking around lamella.

Solar-Driven Interfacial Evaporator with a Self-Powered Detector Based on the Gr@Ti4O7:Eu3+,Yb3+ Fibrous Membrane

“…Photothermal materials (PTMs) with smaller bandgap and wide solar absorption spectrum are suitable for fabricating efficient solar-driven evaporators. The types of PTMs are mainly divided into plasmonic metals, , carbon-based materials, semiconductors, , and polymers. , However, plasmonic noble metals can only absorb light within a partial spectral range and have insufficient raw materials. , Although carbon-based materials are currently widely used in interface evaporation processes driven by solar energy, they have almost no catalytic degradation effect on organic pollutants in seawater. , Most of the organic materials for photothermal conversion are limited by photobleaching and aging. , Therefore, semiconductor materials are most likely to achieve large-scale application of photothermal conversion.…”