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Extended AbstractPlastic waste is generated by a variety of sources including packaging, automotive, consumer goods, electrical and electronics industries, leading to a significant growth in the volume of waste and the impetuous need to reduce it [1]. Recycling of used products is considered one of the best ways to save money and protect the environment, although technologies must be designed and managed so as to avoid environmental pollution [2]. Global warming and diminishing oil reserves have prompted scientists to focus more on the use of natural fibers from renewable resources such as jute, hemp, cotton, flax, coconut fiber, fibers from pineapple and banana leaves [3][4], etc., for the reinforcement of composite materials [5]. Due to the high hydrophilicity of all natural fibers, adhesion to polymers most frequently used as matrix (hydrophobic) is rather problematic [6]. This problem can be solved by fiber surface modification through, physical, chemical, and mechanical methods or by changing the chemical composition of the polymer matrix.The paper aims at developing new layered composite materials based on recycled thermoplastic polymer (PETpolyethylene terephthalate) from the food industry reinforced with woven flax fiber functionalized with nano (micro) particles of titanium or alumina and testing the composite in terms of physico-mechanical (tensile strength, bending, shock, etc.), morphological (SEM), structural (FTIR), and thermal (Vicat) properties. Based on this technology, the new composite will exhibit improved physical, mechanical and thermal properties, as well as resistance to mold attack. In this regard, in the first stage, the surface of flax fibers were chemically modified using aluminum (AlCl3), and titanium (titanium butoxide) precursors followed by precipitation. The woven flax whose surface was functionalized with nano (micro) alumina or TiO2 particles were subsequently used to obtain layered composite materials. Layered composite materials were obtained by alternating functionalized / not functionalized woven flax fiber with sheets made from recycled PET. The recycled PET sheets and layered composites based on recycled PET and functionalized / not functionalized woven flax fiber were obtained by press molding using an electrical press at the following optimum parameters: plate temperature -254ºC, preheating time -8 min; pressing time -2 min; cooling time -15 min; pressing force -100 kN. Special attention must be paid to the pre-drying process (at 100-110ºC) to remove adsorbed water. In the absence of the pre-drying operation, the resulting sheets exhibit holes, porosity and discontinuities, making them unusable for the development of layered composite materials.Physical, mechanical and thermal analyses results for specimens of layered composite materials based on recycled PET / functionalised woven flax fiber show significantly improved values compared with the control samples obtained from recycled PET / not functionalized flax fiber. Improved mechanical and thermal properties are due ...

The high increase in post-consumption waste, especially from the packaging industry, has prompted scientists to find effective ways to recycle and reuse it. One of the most common polymers used as raw material in the production of disposable bottles is polyethylene terephthalate (PET). PET is a semi-crystalline thermoplastic polyester with optimal physical and mechanical properties-tensile strength, stiffness, hardness, resistance to crack formation, low moisture absorption and thermal expansion [1, 2]. The physical processing of PET using melt extrusion s considered to be the most advantageous method of recycling compared to the chemical way/incineration because it is simple, it uses common equipment, it is flexible in terms of raw material volume and has a much lower impact on the environment. However, during the reprocessing of PET there are problems related to the level and nature of the contaminants present in the flakes, which negatively affect the physical and chemical properties (acidsact as catalysts for the chain cleavage reactions, waterreduces the molecular weight through the hydrolysis reaction, dyespresent in bottles, and ink-printed labels lead to yellowing of the polymer due to intra-molecular crosslinking and oxidation reactions) [1, 3]. Numerous studies in the literature have focused on improving PETr properties by adding: PC in varying proportions (20-50%) [4], chain extender containing epoxy groups-JONCRYL and impact modifier-LOTADER which is a glycidyl methacrylate terpolymer [5], sawdust wood [6], graphene [7], montmorillonite [8], CaCO3 [9], SEBS-g-AM [10]. The purpose of this paper is to improve the mechanical, thermal and processability properties of the PETr/PE mixture (70 wt/30 wt%) by adding various percentages (1, 3 and 5%) of CaO nanoparticles. To improve the compatibility of PETr / PE, ethylene vinyl acetate copolymer (EVA) was used as compatibilizer at 5wt% based on the total amount of polymers. Prior to processing, PETr granules were subjected to a pre-drying process in a hot air oven at 140-150°C for about 4-7 hours to remove the physically adsorbed water. Nanocomposites were obtained on a Brabender mixer at a temperature of 245-254°C and a mixing time of 5-7 minutes. From the mixtures obtained, test specimens (for physico-mechanical, morphostructural and thermal determinations) were made by the compression molding method, using an electric press at 190-254°C, preheating-5 minutes , pressing time-5-7 minutes, cooling-15 minutes, pressure-150 kN. The thermal results obtained by DSC demonstrate that the PETr/PE mixture shows a more pronounced thermal stability compared to the results obtained for plain polyethylene. Moreover, in the case of adding EVA compatibility agent, the thermal stability decreases significantly but this is subsequently compensated by the addition of various percentages of CaO nanoparticles. The hardness of the mixtures also increases progressively with the increase in CaO. Izod shock resistance increases both for EVA mixtures and for mixtures containing 1 wt%...

Protecting the environment by reducing PET waste has become a global priority. Recycling is considered one of the simplest and most environmentally friendly ways to reduce PET waste. However, during recycling, PET undergoes thermal / hydrolytic degradation, which leads to reduced molecular weights and low physical, mechanical, chemical, etc. properties. Thus, in order to prevent the degradation processes and to improve the mechanical and processing properties, various blends based on PETr / HDPE (60: 40 mass ratio) will be processed on a Brabender mixer in the presence / absence of the compatibilizers, EVA and PEg AM. The diagrams of torque versus time, recorded during processing demonstrate that PETr suffers degradation processes, which leads to a decrease in torque due to reduced viscosity /molecular weight and reduced physical-mechanical and processing properties. Instead, with the addition of EVA or PEg AM , in varying amounts, degradation processes are largely avoided. These observations are also supported by the values obtained from the Izod impact resistance tests, namely the higher the amount of compatibilizer, the higher the shock resistance due to the higher phase adhesion. The hardness of the blends progressively decreases, relative to the PETr control sample value, from 83 to at least 61°Sh D for the compatibilized blends. FTIR microscopy, performed on the obtained samples, shows higher homogeneity between PETr / HDPE if the addition of EVA or PEg AM is higher (20%). Melt flow index is improved for compatibilized blends compared to PETr and PETr / HDPE.