Andrew R. McLauchlin

Solid-state ¹³ C nuclear magnetic resonance spectroscopy reveals contrasting differences in the concentration of the various domains in formulated high-density poly(ethylene).

The increasing use of bio‐sourced and biodegradable polymers such as poly(lactic acid) (PLA) in bottle packaging presents an increasing challenge to the polyethylene terephthalate (PET) recycling process. Despite advanced separation technologies to remove PLA from PET recyclate, PLA may still be found in rPET process streams. This study explores the effects of PLA on the mechanical properties and crystallization behavior of blends of PET containing 0.5–20% PLA produced by injection molding. SEM indicates an immiscible blend of the two polymers and TGA confirms the independent behavior of the two polymers under thermal degradation conditions. Temperature‐modulated DSC studies indicate that adding PLA to PET increases the rigid amorphous fraction of the PET moiety. Critical amounts of PLA induce stress oscillation behavior during mechanical testing. The mechanical behavior of the samples is explained by antagonistic interaction between increased rigid amorphous fraction and decreased fracture strength arising from an increased population of PLA microparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44147.

This paper summarises the results of a study to assess the environmental impact of oxo-degradable plastics. These plastics are mainly based on polyethylene and contain additives that cause the plastic to undergo oxidative degradation by a process accelerated by light and/or heat. The approach used in the study has been to review the published research on oxo-degradable plastics, assess other literature available in the public domain, and also to engage with stakeholders throughout the life cycle of the product. The main purpose of the study was to assess what happens at the end of life of the plastics and whether this has a beneficial effect. The study concluded that incorporating additives into petroleum-based plastics to accelerate their degradation does not improve their environmental impact and potentially gives rise to certain negative effects. In particular there is concern that these plastics are neither suitable for conventional recycling methods, due to the presence of degradation accelerators, nor suitable for composting, due to the lack of biodegradability. There is also concern about the fate of oxo-degradable plastic fragments in the environment.