Thermoplastic Polymers with Nanosilver Addition-Microstructural, Surface and Mechanical Evaluation during a 36-Month Deionized Water Incubation Period

Exploring the Surface Potential of Recycled Polyethylene Terephthalate Composite Supports on the Collagen Contamination Level

With a significant number of features (namely being multipurpose, inexpensive and durable), thermoplastic polymers, most often named plastics, are part of our daily routine, with an increasing production over the last decade. Among them, polyethylene terephthalate (PET), high-density polyethylene (HDPE) and polypropylene (PP) are distinguished as the five most commonly used plastics in various fields, mainly in the packaging industry. Even if it is difficult to imagine the world without plastics, the boosted plastic assembly comes with huge plastic waste, creating a number of challenges, as the most important threat for our environment, but also opportunities for recycling. Currently, a special attention is dedicated on how to improve the current recycling methods or to find new ones, since the quality of recycled plastics and potential chemical or biological contaminations are two problematic aspects. Understanding the properties of each thermoplastic polymer and the interaction with possible contaminants may be the key for an efficient recycling process. The aim of this paper was to evaluate the surface behaviour of different composite supports based on recycled PET before and after interaction with collagen (used as a biological contaminant). The surface contamination bias of PET supports was studied through different techniques: scanning electron microscopy (SEM), water uptake through swelling studies, contact angle measurements and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR).

Use of Fourier-Transform Infrared Spectroscopy for DNA Identification on Recycled PET Composite Substrate

Fourier-transform infrared (FTIR) spectroscopy has been extensively used in plastic pollution research, since it has the advantages of great simplicity, rapidity, and low cost, being widely employed in the fingerprint identification of molecular composition and structure. The present study evaluates attenuated total reflection (ATR)–FTIR spectroscopy as a sensitive and effective assay for the identification of deoxyribonucleic acid (DNA) isolated from experimental animals. Various composite materials based on recycled polyethylene terephthalate (PET) as the main component, along with high-density polyethylene (HDPE), polypropylene (PP), and aluminum nanopowder obtained using an injection-molding machine, were used as substrate contaminants. The contamination was performed using quantified nucleic acid solution added in droplets to the clean, decontaminated samples, which were then dried and kept in a protective environment until the analysis. ATR–FTIR (with an FTIR spectrometer equipped with an ATR accessory) spectroscopy was used to analyze the bare composite materials’ substrates and the DNA-contaminated samples. To the best of our knowledge, the evaluation of PET packaging contamination with DNA species by FTIR has not been reported previously. This study demonstrated that FTIR spectroscopy could provide a rapid, sensitive, and reliable approach for screening of biochemical contaminants on composite materials based on recycled PET.