Technological features of extrusion processes of modified polylactide materials.
Students Name: Taranenko Bohdan Pavlovych
Qualification Level: magister
Speciality: Chemical Technologies of Polymeric and Composite Materials Processing
Institute: Institute of Chemistry and Chemical Technologies
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: англійська
Abstract: Polymeric materials capable of self-degradation in natural or artificially created conditions are becoming increasingly popular in industry. Given the current environmental situation in the world, biodegradable polymers and composites based on them are rapidly occupying their niche in the production of packaging and other polymer products. The most common and studied biodegradable material among others is polylactide. [1] However, polylactides still have inferior properties to their analogues such as polyethylene, polystyrene, etc. To provide polylactide with improved and specific properties, the question arises in the selection of appropriate modifiers and additives to create compositions with high expediency of use and increase their competitiveness. The difficulty arises in the selection of the modifiers themselves, since the question is not only to improve certain properties, but also to preserve the main, valuable characteristic of polylactide, as biodegradability. [2] Technological and operational properties of polylactide materials significantly depend on their morphology (molecular weight, degree of crystallinity), inorganic and organic additives (modifiers, nucleators, etc.) and on the conditions and parameters of their processing. Among the main factors limiting the widespread use of polylactide in the production of polymer products is their cost: 4.5 - 5 $/kg. [3] To reduce the cost of polylactide materials, it is advisable to combine them with fillers. It is most rational to fill polylactides with such ecological fillers as chalk, talc and starch. Object of research: extrusion processes of polylactide processing, modified composites based on it. Subject of research: features of obtaining polylactide-starch composites, studying their properties and developing a basic technological scheme for their processing. Aim of research: To develop the basics of the technology of modification and processing of polylactide-starch compositions by extrusion methods, in particular granulation, to establish the influence of technological parameters on the morphology and properties of modified materials. The master’s qualification work describes the processes of modification of such natural substances as: polylactide, native potato starch. Modification of the above was carried out with the help of: epoxidized soybean oil and glycerin for pharmaceutical purposes. To conduct the research, composites of different composition were prepared, namely polylactide with the addition of natural starch, polylactide with the addition of thermoplastic (modified) starch with different quantitative content of epoxidized soybean oil and glycerin. The experimental data in this work were obtained using standard methods and modern research methods (physical-mechanical, thermophysical, thermography and microscopy). X-ray diffraction, thermogravimetric, differential thermal and SEM analysis were used. The method of modification of polylactide by additives of different nature: starch, glycerin, epoxidized soybean oil and fine chalk was developed. The rational technological parameters of obtaining modified polylactide-starch materials and products based on them by injection molding and extrusion are proposed. The principal technological schemes of processes are proposed. The properties of composite mixtures were studied using traditional and standardized methods. Such properties as: water and moisture resistance, impact strength, tensile strength, relative elongation at break, change of structure at addition of modifiers and melt fluidity index are investigated. The basic technological scheme of processing of composites of polylactide and thermoplastic starch by the method of stretch pelletizing is presented. Due to the conducted economic calculations it is established that the main costs of scientific and technological research consist of depreciation costs, wages of employees and purchase of materials. At the same time, the total cost of the research is 64 430,368 UAH. Master’s qualification work consists of an introduction, 4 chapters, conclusions, a list of references containing 40 titles and appendices. The main content is presented on 55 pages of printed text, containing 13 figures and 8 tables. Keywords:polylactide, thermoplastic starch, epoxidized soybean oil, biodegradation, biodegradation, plasticization, properties, extrusion, extruder, granulation, modification, composites. List of used sources and references: Список використаних джерел та літератури: 1. Iovino R, Zullo R, Rao MA et al (2008) Biodegradation of poly(lactic acid)/starch/coir biocomposites under controlled composting conditions. Polym DegradStab93:147157.https://doi.org/10.1016/j.polymdegradstab.2007.10.011; 2. Cuevas-Carballo ZB, Duarte-Aranda S, Canche-EscamillaG (2019) Properties and Biodegradation of Thermoplastic Starch Obtained from Grafted Starches with Poly(lactic acid). J Polym Environ 27:2607–2617. https:// doi. org/ 10. 1007/s10924-019-01540-w; 3. Каталог полімерної сировини: https://www.sigmaaldrich.com/UA/en/search/polylactic-acid?focus=products&page=1&perpage=30&sort=relevance&term=polylactic %20acid&type=product_name 4. Plackett D, VAzquez A, (2004) Natural polymer sources. Green composites: polymer composites and the environment. Elsevier, New York, pp 123–153 5. Loureiro NC, Esteves JL (2018) Green composites in automotive interior parts: a solution using cellulosic fibers. Green composites for automotive applications. Elsevier, New York, pp 81–97