Effect of crystal form and particle size of titanium dioxide on the photodegradation behaviour of ethylene-vinyl acetate copolymer/low density polyethylene composite

Processes influencing the toxicity of microplastics ingested through the diet

The present study assesses the effect of culinary treatment and gastrointestinal digestion upon the release of additives present in microplastics. Organic additives were determined by gas chromatography-mass spectrometry, and inorganic additives using inductively coupled plasma-mass spectrometry. The results revealed a large number of organic additives in the plastic samples, some being classified as possible carcinogens. Contents of Sb in PET (polyethylene terephthalate), Zn and Ba in LDPE (low-density polyethylene) and PVC (polyvinylchloride), and Ti and Pb in LDPE were also noteworthy. The culinary process promotes the release and solubilization of additives into the cooking liquid, with phthalates, benzophenone, N-butylbenzenesulfonamide (NBBS) and bisphenol A being of particular concern. The solubilization of phthalates and NBBS was also observed during gastrointestinal digestion. This study demonstrates that culinary treatment and gastrointestinal digestion promote release and solubilization of additives from plastics ingested with the diet. Such solubilization may facilitate their entry into the systemic circulation.

Comprehensive Investigation into the Impact of Degradation of Recycled Polyethylene and Recycled Polypropylene on the Thermo-Mechanical Characteristics and Thermal Stability of Blends

The impact of degradation on plastics is a critical factor influencing their properties and behavior, particularly evident in polyethylene (PE) and polypropylene (PP) and their blends. However, the effect of photoaging and thermal degradation, specifically within recycled polyethylene (rPE) and recycled polypropylene (rPP), on the thermo-mechanical and thermostability aspects of these blends remains unexplored. To address this gap, a range of materials, including virgin polyethylene (vPE), recycled polyethylene (rPE), virgin polypropylene (vPP), recycled polypropylene (rPP), and their blends with different ratios, were comprehensively investigated. Through a systematic assessment encompassing variables such as melting flow index (MFI), functional groups, mechanical traits, crystallization behavior, microscopic morphology, and thermostability, it was found that thermo-oxidative degradation generated hydroxyl and carboxyl functional groups in rPE and rPP. Optimal mechanical properties were achieved with a 6:4 mass ratio of rPE to rPP, as validated by FTIR spectroscopy and microscopic morphology. By establishing the chemical model, the changes in the system with an rPE-rPP ratio of 6:4 and 8:2 were monitored by the molecular simulation method. When the rPE-rPP ratio was 6:4, the system's energy was lower, and the number of hydrogen bonds was higher, which also confirmed the above experimental results. Differential scanning calorimetry revealed an increased crystallization temperature in rPE, a reduced crystallization peak area in rPP, and a diminished crystallization capacity in rPE/rPP blends, with rPP exerting a pronounced influence. This study plays a pivotal role in enhancing recycling efficiency and reducing production costs for waste plastics, especially rPE and rPP-the primary components of plastic waste. By uncovering insights into the degradation effects and material behaviors, our research offers practical pathways for more sustainable waste management. This approach facilitates the optimal utilization of the respective performance characteristics of rPE and rPP, enabling the development of highly cost-effective rPE/rPP blend materials and promoting the efficient reuse of waste materials.

Polyoxymethylene/silica/polylactic acid-grafted polyethylene glycol nanocomposites: structure, morphology, and mechanical properties and ozone and UV durability

Polyoxymethylene (POM) is a semicrystalline thermoplastic that displays high tensile strength, thermal stability, and chemical durability. However, its widespread application is limited by its low elongation at break and thermal durability. In the present study, nanosilica (NS) and polylactic acid-grafted polyethylene glycol (PELA) were used as enhancement additives to improve the performance of POM homopolymer. Specifically, the POM/PELA/NS nanocomposites with a fixed NS content and varying PELA contents were prepared by a melt mixing method. The influence of the additives on the processability, and dynamic thermo-mechanical and tensile properties of the nanocomposites was evaluated by comparing the torque, mixing energy at melt state, storage modulus, shear stress, loss modulus, tan δ, tensile strength, elongation at break and thermal degradation of the nanocomposites. The results showed that the combined addition of NS and PELA enhanced the thermal stability, tensile strength, elongation at break and chemical stability of the POM/PELA/NS nanocomposites owing to the good compatibility between PELA and the POM matrix. Furthermore, the morphology, and UV and ozone durability of POM and the nanocomposites were assessed and discussed.

The combined addition of nanosilica (NS) and polylactic acid-grafted polyethylene glycol (PELA) enhanced some properties of polyoxymethylene (POM).

Titanium dioxide-benzophenone hybrid as an effective catalyst for enhanced photochemical degradation of low density polyethylene

In this study, a hybrid of titanium dioxide, benzophenone and ethylene vinyl acetate (TiO2-BP-EVA) was used as a novel catalyst to accelerate photo-oxidization reaction of low-density polyethylene (LDPE) film under ambient conditions. The degradation of the LDPE films (thickness of ~25 μm) containing different catalyst concentrations were successfully investigated by different techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (SEM), differential scanning calorimetry (DSM), thermogravimetric analysis (TGA) and mechanical tests. The results showed that the use of catalyst in which TiO2-BP content (1/3 w/w) is 0.5 phr (parts per hundred resin) and EVA content is 4.5 phr in a LDPE film provided the best degradation rate. The carbonyl index of the polymer film achieved the highest value without an equilibrium stage. Besides, the carbon-carbon backbone of the polymer was completely broken down consistent with the deformation of the surface. In addition, the mechanical properties impressively dropped after 3 months’ exposure. The obtained results imply that the TiO2-BP-EVA compound can be considered as an efficient catalyst for the photodegradation of LDPE polymer.

Preparation and characterization of a red luminescent composite composed of an EVA copolymer and a Y3BO6:Eu3+ phosphor

This work describes the preparation of red luminescent composites based on an ethylene/vinyl acetate (EVA) copolymer filled with a Y₃BO₆:Eu³⁺ phosphor powder.

Near room-temperature thermocatalysis: a promising avenue for the degradation of polyethylene using NiCoMnO4 powders

Low-temperature thermocatalytic degradation of LDPE is successfully achieved by NiCoMnO₄ powders.