Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of highly precise complex three-dimensional objects for a large range of applications. The principle of FDM is an extrusion of the molten filament and gradual deposition of layers and their solidification. Potential applications in pharmaceutical and medical fields require the development of biodegradable and biocompatible thermoplastics for the processing of filaments. In this work, the potential of production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) filaments for FDM was investigated in respect to its thermal stability. Copolymer P(3HB-co-4HB) was biosynthesised by Cupriavidus malaysiensis. Rheological and mechanical properties of the copolymer were modified by the addition of plasticizers or blending with poly(lactic acid). Thermal stability of mixtures was studied employing thermogravimetric analysis and rheological analyses by monitoring the time-dependent changes in the complex viscosity of melt samples. The plasticization of P(3HB-co-4HB) slightly hindered its thermal degradation but the best stabilization effect was found in case of the copolymer blended with poly(lactic acid). Overall, rheological, thermal and mechanical properties demonstrated that the plasticized P(3HB-co-4HB) is a potential candidate of biodegradable polymer for FDM processes.
Hybrid inorganic-organic fillers based on nanostructured silver/zinc oxide decorations on micro-cellulose carrier particles were prepared by stepwise microwave assisted hydrothermal synthesis using soluble salts as precursors of silver and zinc oxide. Hexamethylenetetramine was used as precipitating agent for zinc oxide and reducing agent for silver. The inorganics covered all available surfaces of the cellulose particles with a morphology resembling a coral reef. Prepared particulate fillers were compounded to medical grade poly(vinyl chloride) matrix. Scanning electron microscopy and powder X-ray diffractometry were used to investigate the morphology and crystalline phase structure of fillers. The scanning electron microscopy was used for morphological study of composites. With respect to prospective application, the composites were tested on electrical and antibacterial properties. A small effect of water absorption in polymer composites on their dielectric properties was observed but no adverse effect of water exposure on prepared materials was manifested. Electrical conductivity of fillers and composites was measured and no influence of water soaking of composites was found at all. The surface antibacterial activity of prepared composites was evaluated according to the standard ISO 22196. Excellent performance against Escherichia coli and very high against Staphylococcus aureus was achieved.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- biokompatibilní materiály chemická syntéza MeSH
- celulosa chemie MeSH
- fyziologie bakterií účinky léků MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- nanokompozity chemie ultrastruktura MeSH
- oxid zinečnatý chemie MeSH
- polyvinylchlorid chemie MeSH
- povrchové vlastnosti MeSH
- prášky, zásypy, pudry MeSH
- stříbro chemie farmakologie MeSH
- testování materiálů MeSH
- velikost částic MeSH
- viabilita buněk fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Three different ZnO-based antibacterial fillers having different morphologies in microscale region were prepared by the use of the microwave assisted synthesis protocol created in our laboratory with additional annealing in one case. Further, PVC composites containing 0.5-5 wt.% of ZnO based antibacterial fillers were prepared by melt mixing and characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Mechanical testing showed no adverse effect on the working of polymer composites due to either of the fillers used or the applied processing conditions in comparison with the neat medical grade PVC. The surface antibacterial activity of the compounded PVC composites was assessed against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P according to ISO 22196: 2007 (E). All materials at almost all filler loading levels were efficient against both species of bacteria. The material with the most expanding morphology assuring the largest contact between filler and matrix achieved an excellent level of more than 99.9999% reduction of viable cells of E. coli in comparison to untreated PVC and performed very well against S. aureus, too. A correlation between the morphology and efficacy of the filler was observed and, as a result, a general rule was formulated which links the proneness of the microparticles to perform well against bacteria to their shape and morphology.
