Because of the effort to preserve petroleum resources and promote the development of eco-friendly materials, bio-based polymers produced from sustainable resources have attracted great attention. Among them, polylactide (PLA) and natural rubber (NR) present prominent polymers with unique barrier and mechanical features. A series of samples with improved phase compatibility were obtained by blending PLA and NR using a double-rotor mixer. A plasticizing and enhancing effect on the polymers’ compatibility was achieved by using epoxidized soybean oil (ESO) as a natural plasticizer and compatibilizer. ESO compounding in the PLA-NR blends increased the mobility of the biopolymer’s molecular chains and improved the thermal stability of the novel material. The size of the NR domains embedded in the continuous PLA matrix decreased with the ESO content increment. The combination of thermal analysis and scanning electron microscopy enabled the authors to determine the features of potential packaging material and the optimal content of PLA-NR-ESO for the best mechanical properties.
The purpose of this study is to conduct and study the process of chemical recycling of solid household waste of polyethylene terephthalate (PET) with a mixture of amino alcohols (monoethanolamine and triethanolamine) under relatively mild conditions and without the use of catalysts. It was revealed that during the reaction of PET with a mixture of amino alcohols of a low molecular weight white product is formed, containing in its structure an aromatic core, two amide and two hydroxyl groups - N, N'-bis (2-hydroxyethyl) terephthalamide. The most effective purification and isolation of the target low molecular weight compound from the reaction mixtures is achieved by recrystallization from water. The structure of the obtained compound was studied using IR Fourier spectrometry, gas chromatography-mass spectrometry and differential scanning calorimetry, as well as some physicochemical properties of the obtained compound (solubility, melting point). A technological scheme for obtaining this low molecular weight substance in relatively large volumes by a periodic method with the regeneration of the initial amino alcohols for their reuse is proposed. The process is carried out in a heated batch reactor, which receives crushed PET waste, as well as a mixture of amino alcohols. The reaction mass is maintained at a temperature of 160 °C and periodic stirring for 3-4 h. After completion of the reaction and cooling the mixture is fed into the apparatus-crystallizer for further selection of the target product by crystallization from water. In addition, on the basis of the available experimental data and theoretical assumptions, the possibility in principle of using the obtained low-molecular compound as a monomer in the polycondensation reaction to obtain polyamidoesters is considered, similar to the principles of obtaining polyethylene terephthalate from diglycolterephthalate. It was shown that the depolymerization product enters into a polycondensation reaction with the formation of an oligomeric product - a viscous, resinous mass having a color from yellow to caramel.
A large number of scarce, often toxic, ingredients are currently being used in the tyre industry, and therefore it is urgent to create new, effective, readily available, and non-toxic rubber mix ingredients. N-Nitrosodiphenylamine, which is used as a scorch retarder [1, 2], is a toxic substance affecting the central nervous system and the activity of blood and liver enzymes; it is a potentially carcinogenic substance [3]. It causes colouring of rubber compounds and can break down during vulcanisation, which leads to the production of porous vulcanisates.
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