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Acidic liquids such as verjuice, lemon juice and vinegar are frequently consumed in Iran. Different kinds of acidic liquids are packaged in polyethylene terephthalate (PET) and high-density polyethylene (HDPE) bottles. There is evidence indicating that phthalates can leach from PET and HDPE bottles into their contents. In this work the effect of storage time, temperature and bottle type on the migration of phthalates from packaging materials into acidic liquids is studied by analyzing the samples stored under different conditions, before storage and after 2, 4 and 6 months of storage. The determined mean phthalate concentrations in µg/L were: <0.04 to 0.501 in verjuice, <0.04 to 0.231 in lemon juice and <0.04 to 0.586 in vinegar. The highest concentrations of diethyl phthalate (DEP) and diethyl hexyl phthalate (DEHP) were found in PET and HDPE bottles, respectively. Results of analyses before and after storage indicate that under some storage conditions, the concentrations of DEP, DEHP and dibutyl phthalate (DBP) increased in acidic liquids. The possible migration of phthalic acid esters from plastic packaging materials into the contents was indicated by the results of the present study.

In this work, two types of solid paraffins (i.e., linear and branched) were added to high-density polyethylene (HDPE) to investigate their effects on the dynamic viscoelasticity and tensile properties of HDPE. The linear and branched paraffins exhibited high and low crystallizability, respectively. The spherulitic structure and crystalline lattice of HDPE are almost independent of the addition of these solid paraffins. The linear paraffin in the HDPE blends exhibited a melting point at 70 °C in addition to the melting point of HDPE, whereas the branched paraffins showed no melting point in the HDPE blend. Furthermore, the dynamic mechanical spectra of the HDPE/paraffin blends exhibited a novel relaxation between −50 °C and 0 °C, which was absent in HDPE. Adding linear paraffin toughened the stress–strain behavior of HDPE by forming crystallized domains in the HDPE matrix. In contrast, branched paraffins with lower crystallizability compared to linear paraffin softened the stress–strain behavior of HDPE by incorporating them into its amorphous layer. The mechanical properties of polyethylene-based polymeric materials were found to be controlled by selectively adding solid paraffins with different structural architectures and crystallinities.

The good interaction between the ceramic powder and the binder system is vital for ceramic injection molding and prevents the phase separation during processing. Due to the non-polar structure of polyolefins such as high-density polyethylene (HDPE) and the polar surface of ceramics such as zirconia, there is not appropriate adhesion between them. In this study, the effect of adding high-density polyethylene grafted with acrylic acid (AAHDPE), with high polarity and strong adhesion to the powder, on the rheological, thermal and chemical properties of polymer composites highly filled with zirconia and feedstocks was evaluated. To gain a deeper understanding of the effect of each component, formulations containing different amounts of HDPE and or AAHDPE, zirconia and paraffin wax (PW) were prepared. Attenuated total reflection spectroscopy (ATR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rotational and capillary rheology were used for the characterization of the different formulations. The ATR analysis revealed the formation of hydrogen bonds between the hydroxyl groups on the zirconia surface and AAHDPE. The improved powder-binder adhesion in the formulations with more AAHDPE resulted in a better powder dispersion and homogeneous mixtures, as observed by SEM. DSC results revealed that the addition of AAHDPE, PW and zirconia effect the melting and crystallization temperature and crystallinity of the binder, the polymer-filled system and feedstocks. The better powder--binder adhesion and powder dispersion effectively decreased the viscosity of the highly filled polymer composites and feedstocks with AAHDPE; this showed the potential of grafted polymers as binders for ceramic injection molding.

The excessive amount of global plastic produced over the past century, together with poor waste management, has raised concerns about environmental sustainability. Plastic recycling has become a practical approach for diminishing plastic waste and maintaining sustainability among plastic waste management methods. Chemical and mechanical recycling are the typical approaches to recycling plastic waste, with a simple process, low cost, environmentally friendly process, and potential profitability. Several plastic materials, such as polypropylene, polystyrene, polyvinyl chloride, high-density polyethylene, low-density polyethylene, and polyurethanes, can be recycled with chemical and mechanical recycling approaches. Nevertheless, due to plastic waste’s varying physical and chemical properties, plastic waste separation becomes a challenge. Hence, a reliable and effective plastic waste separation technology is critical for increasing plastic waste’s value and recycling rate. Integrating recycling and plastic waste separation technologies would be an efficient method for reducing the accumulation of environmental contaminants produced by plastic waste, especially in industrial uses. This review addresses recent advances in plastic waste recycling technology, mainly with chemical recycling. The article also discusses the current recycling technology for various plastic materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Cajas y Palets en una Economia Circular (CAPEC) (EU register number RECYC242). The input consists of crates made of high‐density polyethylene (HDPE) or polypropylene (PP) originating from closed and controlled product loops for the packaging of whole fruits and vegetables. Flakes or pellets are produced that will be used by manufacturers of new crates for food contact. The Panel considered that the management system put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability from input to final product is the critical process step. It concluded that the input of the process CAPEC originates from product loops which are in closed and controlled chains designed to ensure that only materials and articles that have been intended for food contact are used and that contamination can be ruled out when run under the conditions described by the applicant. The recycling process CAPEC is therefore suitable to produce recycled HDPE and PP crates intended to be used in contact with fruits and vegetables.

The widespread use of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics has resulted in a large amount of waste plastic that requires appropriate disposal or reuse. One potential solution is to use them in the modification of asphalt concrete (AC) mixtures for more sustainable highways. To study this possibility, permanent deformation and dynamic modulus (DM) of the LDPE and HDPE modified AC mixtures was investigated by conducting flow number (FN), flow time (FT) and DM tests on Superpave gyratory compacted specimens. Machine learning models; multi-layer perceptron (MLP), radial basis function neural network (RBFNN), generalized regression neural network (GRNN) and support vector machine (SVM) were used to predict the DM on the basis of frequency and temperature parameters. The model’s performance was gauged by analyzing the root mean square error, mean relative error, and coefficient of determination. The study findings revealed that the LDPE and HDPE modified AC mixtures provide 2.07 times and 1.27 times better resistance to permanent deformation, respectively, than their counterpart. It was also found that the LDPE and HDPE modified AC mixtures have 2.1 times and 1.4 times higher DM values, respectively, than the Control AC mixtures. Among the machine learning models, MLP (R 2  = 0.98) showed best accuracy in predicting DM and thus is recommended to be used in similar studies due to its robustness. Additionally, the feature importance analysis revealed that frequency has the highest impact on DM predictions, followed by temperature and the inclusion of the LDPE.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Kunststof Recycling Nederland (KRN) (EU register number RECYC251). The input consists of box pallets made of high‐density polyethylene (HDPE) originating from a closed and controlled product loop for packaging of meat. Flakes are used to produce new box pallets for food contact. The Panel considered that the management system put in place to provide full traceability from the input to the final product and to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 is critical. According to the applicant, the input of the process KRN originates from a product loop which is in closed and controlled chain, designed to ensure that only materials and articles that have been intended for food contact are used and that contamination can be ruled out when run under the conditions described by the applicant. The Panel concluded that the recycling process KRN is suitable to produce recycled HDPE box pallets intended to be used in contact with refrigerated or frozen, packed or unpacked meat.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process LOGIFRUIT (EU register number RECYC260). The input consists of pre‐washed high‐density polyethylene (HDPE) or polypropylene (PP) crates from closed and controlled food distribution loops. The process separates crates by material type. Crates are ground to flakes, possibly extruded to pellets and used by companies approved to be in the loop to manufacture new crates. The Panel considered that the quality management system (QAS) put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability is critical. The Panel concluded that, when run under the conditions described, the input of the process LOGIFRUIT exclusively originates from product loops which are in closed and controlled chains. The process is designed to ensure that only crates intended for food contact are used and that contamination other than by food can be ruled out. Therefore, the recycling process LOGIFRUIT to produce HDPE and PP crates to be used in contact with fruits and vegetables, and packed meat and fish, dairy, bakery and pastry products is not of safety concern.

Abstract Polyethylene (PE) is high molecular weight synthetic polymer, very hydrofobic and hardly biodegradable. To increase polyethylene bio-degradability it is very important to find microorganisms that improve the PE hydrophilic level and/or reduce the length of its polymeric chain by oxidation. In this study, we isolated Cladosporium halotolerans, a fungal species, from the gastric system of Galleria mellonella larvae. Here, we show that C. halotolerans grows in the presence of PE polymer, it is able to interact with plastic material through its hyphae and secretes enzymes involved in PE degradation. In this article, a fungus is isolated from the gastrointestinal tract of the G. mellonella larva, which infests hives by feeding on wax. The similarity of structure between the wax and the polyethylene makes the microorganism suitable for the degradation of plastic materials that are difficult to eliminate.

Plastics recycling remains a challenge due to the relatively low quality of the recycled material, since most of the developed recycling processes cannot deal with the additives present in the plastic matrix, so the recycled products end up in lower-grade applications. The application of volatile organic solvents for additives removal is the preferred choice. In this study, pretreatment of plastic packaging waste to remove additives using biosolvents was investigated. The plastic waste used was high-density polyethylene (HDPE) with blue and orange colorants (pigment and/or dye). The first step was to identify the type of colorants present in the HDPE, and we found that both plastics presented only one colorant that was actually a pigment. Then, limonene, a renewable solvent, was used to solubilize HDPE. After HDPE dissolution, a wide range of alcohols (mono-, di-, and tri-alcohols) was evaluated as antisolvents in order to selectively precipitate the polymer and maximize its purity. The use of limonene as solvent for plastic dissolution, in combination with poly-alcohols with an intermediate alkyl chain length and a large number of hydroxyl (OH) groups, was found to work best as an antisolvent (1,2,3-propanetriol and 1,2,4-butanetriol), leading to a removal of up to 94% and 100% of the blue and orange pigments, respectively. Finally, three cycles of extraction were carried out, proving the capability of the solvent and antisolvent to be recovered and reused, ensuring the economic viability and sustainability of the process. This pretreatment provides a secondary source of raw materials and revenue for the recycling process, which may lead to an increase in the quality of recycled polymers, contributing to the development of an economical and sustainable recycling process.