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Preparation and characterization of biodegradable composites based on polyhydroxyalkanoates and coffee grounds
Cisáriková, Barbora ; Němcová, Andrea (referee) ; Kovalčík, Adriána (advisor)
This diploma thesis was focused on the preparation and characterization of biodegradable composites based on poly-3-hydroxybutyrate (PHB) and spent coffee grounds (SCG). The aim was to prepare biocomposites based on PHB and coffee grounds. Biocomposites were prepared by solution casting in chloroform. Films with a thickness of about 150-200 µm were prepared with the addition of 20% unmodified and modified coffee grounds. The PHB/SCG films were modified by an addition of a plasticizer and a crosslinking agent or by blending with polybutylene adipate terephthalate (PBAT). The thermal properties of the films were determined by differential scanning calorimetry. The compatibility filler/polymer matrix compatibility was assessed morphologically with the naked eye. It has been found that the direct addition of spent coffee grounds to the PHB is not suitable due to the deterioration of the morphology of the film surfaces and the formation of aggregates. The compatibility between the spent coffee grounds and the PHB was improved after the addition of the plasticizer and the crosslinking agent. However, the highest compatibility between SCG and PHB was achieved in the case of esterified coffee grounds. Another way to improve the resulting morphological properties of the films thus prepared was to use coffee grounds fractions.
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Biokompozitní materiály v nábytkářství
Kopecká, Magdaléna
This bachelor thesis deals with the issue of using biomaterials as an alternative substitute for non-renewable materials and raw materials to ensure future ecological sustainability. The referential biocomposite chosen as an alternative to non-renewable materials was fungal mycelium. The basic properties of this biomaterial, the method of production, and the safety requirements are described in this thesis. Furthermore, selected tests of physical and mechanical properties were undertaken. There tests included moisture, density, swelling and determination of transverse tensile strength perpendicular to the plane of the board. All measurements were carried out in accordance with ČSN, the tests results were described and statistically verified.
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The influence of internal structure on mechanical properties of 3D printed femoral segment from novel optimized biocomposite
Nečas, Aleš ; Schmid, Pavel (referee) ; Přikryl, Radek (advisor)
This diploma thesis presents the development of a new anatomical model of the femur segment based on a biocomposite of poly-3-hydroxybutyrate, polylactic acid, tricalcium phosphate and hydroxyapatite (PHB/PLA/TCP/HA). The model was designed using computed tomography of the patient‘s femur in twelve variants (A1 to A4, B1 to B4, C1 to C4) with different percentages of gyroid filling at the site of the compaction and spongiosis of the real bone. The biocomposite was then 3D printed after the optimized mixture of the new biocomposite (OPT1) was prepared, the printing string‘s chemical and structural characteristics were determined, and the most suitable parameters for 3D printing of the body from this biocomposite were optimized and verified. Furthermore, the pressure load capacity of all twelve variants of 3D printed femur segment models with different percentage densities of their internal gyroid filling was determined. Subsequently, the possibility of predicting the pressure load capacity of the newly developed anatomical femur segment was studied by computer simulation using the numerical model in ANSYS, and the differences in the pressure load capacity values of the PHB/PLA/TCP/HA femur segment in its real mechanical testing were found, compared to the values of the virtual tests using ANSYS. In order to determine the possible tissue resorption rate of this 3D PHB/PLA/TCP/HA biocomposite, the long-term effect (for 4 months) of simulated body fluid on the biodegradation of 3D PHB/PLA/TCP/HA biocomposite bodies with different percentages of gyroid filling (variant I to V) was examined. Subsequently, the biocomposites were subjected to pressure tests while their surface was analyzed by confocal microscopy. The femur segments with 75% filling at the compaction site (variant A) showed the highest average load capacity of 22.20 ± 0.50 kN, while the real femur segment samples had approximately one-quarter lower pressure load capacity compared to the computer simulation. The PHB/PLA/TCP/HA biodegradable bodies with more porous filling (variants II to V) degraded more slowly than the body with 100% filling (variant I), which offers benefits for their clinical use. Their slow degradation also had a beneficial effect on their load-bearing capacity after 4 months.The PHB/PLA/TCP/HA anatomical model of the femoral segment was developed for possible medical use in bone replacement for extensive femoral defects. However, further research is needed before its potential use in medicine.
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Preparation and characterization of biodegradable composites based on polyhydroxyalkanoates and coffee grounds
Cisáriková, Barbora ; Němcová, Andrea (referee) ; Kovalčík, Adriána (advisor)
This diploma thesis was focused on the preparation and characterization of biodegradable composites based on poly-3-hydroxybutyrate (PHB) and spent coffee grounds (SCG). The aim was to prepare biocomposites based on PHB and coffee grounds. Biocomposites were prepared by solution casting in chloroform. Films with a thickness of about 150-200 µm were prepared with the addition of 20% unmodified and modified coffee grounds. The PHB/SCG films were modified by an addition of a plasticizer and a crosslinking agent or by blending with polybutylene adipate terephthalate (PBAT). The thermal properties of the films were determined by differential scanning calorimetry. The compatibility filler/polymer matrix compatibility was assessed morphologically with the naked eye. It has been found that the direct addition of spent coffee grounds to the PHB is not suitable due to the deterioration of the morphology of the film surfaces and the formation of aggregates. The compatibility between the spent coffee grounds and the PHB was improved after the addition of the plasticizer and the crosslinking agent. However, the highest compatibility between SCG and PHB was achieved in the case of esterified coffee grounds. Another way to improve the resulting morphological properties of the films thus prepared was to use coffee grounds fractions.
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