Enzymatic degradation of biostatic materials based on polylactide

The paper presents the research results for enzymatic degradation of biodegradable materials in proteinase K. Polylactide and its composites containing a biostatic substance in the form of sulphanilic acid salt PHMG were tested as part of the research project. Three different concentrations of the biostatic substance were used: 0.2%, 0.6% and 1.0 % of the mass. The research results of differential scanning calorimetry (DSC) for the tested materials were compared both before and after the enzymatic degradation. Photographs obtained from a scanning electron microscope (SEM) and the analysis of the foil physical mass loss confirmed that these materials were susceptible to enzymes

Growth of selected fungi on biodegradable films

This study presents the data summary on growth speed of selected species of fungi on some of biodegradable polymer materials. Growth speed was assessed on films composed of poly(lactide), poly(ε-caprolactone) and poly(hydroxybutyrate) after a month of incubation in 24oC. To assess growth of fungi optical microscopy on densitometric measurements were used. Through these analyses the best growth was confirmed for fungus: Chaetomium globosum (ATTC 6205) on a film made of poly(ε -caprolactone)

Polylactide-based films with the addition of poly(ethylene glycol) and extract of propolis—physico-chemical and storage properties

Polymeric films based on polylactide (PLA) with the addition of poly(ethylene glycol) (PEG) and a chloroformic extract of propolis were obtained. In the case of the studied films, polylactide (PLA) played the role of polymeric matrix and poly(ethylene glycol) was used as a plasticizer, while the extract of propolis was incorporated as a compound that could significantly affect the properties of the obtained materials, especially the water vapour permeation rate and the stability of the food products. Moreover, changes in structure, morphology, mechanical and storage properties as well as differences in colour, thickness and transparency after introducing propolis into the PLA–PEG system were determined. Based on the obtained results, it was established that the addition of the chloroformic extract of propolis significantly influences the most important properties taken into account during food packaging. It was also noticed that films with incorporated propolis were characterised by a significant improvement in the water vapour barrier property. Moreover, the obtained results prove that packaging containing a chloroformic propolis extract allow for the maintenance of the quality of the fruit stored for an extended period of time. To summarise, the application of a chloroformic propolis extract enables the formation of packaging materials that extend the shelf life of stored food products

Antibacterial films based on PVA and PVA-chitosan modified with poly(hexamethylene guanidine)

In this study, thin, polymeric films consisting of poly(vinyl alcohol) (PVA) and chitosan (Ch) with the addition of poly(hexamethylene guanidine) (PHMG) were successfully prepared. The obtained materials were analyzed to determine their physicochemical and biocidal properties. In order to confirm the structure of PHMG, nuclear magnetic resonance spectroscopy (H-1 NMR) was applied, while in the case of the obtained films, attenuated total reflectance infrared spectroscopy with Fourier transform (FTIR-ATR) was used. The surface morphology of the polymer films was evaluated based on atomic force microscopy. Furthermore, the mechanical properties, color changes, and thermal stability of the obtained materials were determined. Microbiological tests were performed to evaluate the biocidal properties of the new materials with and without the addition of PHMG. These analyses confirmed the biocidal potential of films modified by PHMG and allowed for comparisons of their physicochemical properties with the properties of native films. In summary, films consisting of PVA and PHMG displayed higher antimicrobial potentials against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in comparison to PVA:Ch-based films with the addition of PHMG.Nicolaus Copernicus University in Torun, Poland (Faculty of Chemistry) [2019/1023]; Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LO1504

Biological Effects and Toxicity of Compounds Based on Cured Epoxy Resins

The aim of this work was to investigate selected biological and toxicity properties of cured epoxy resin-based compounds based on a bisphenol A epoxy resin, cold-cured by a polyamide and containing two types of metal powders (aluminum and copper). This study involved cytotoxicity analysis, pH measurements, absorbance measurements and sterilization. The cytotoxicity analysis was conducted to determine the harmful degree of the cured epoxy resin. Aimed at identifying toxic agents in cured compounds, the cytotoxicity analysis involved absorbance measurements in an entire wavelength range. Cytotoxicity and absorbance results demonstrated that the extracts of all the tested resin samples had no cytotoxic effects on the cells of living organisms. The absorbance values obtained over the entire wavelength range did not point to the formation of aggregations, which proved that no toxic agents harmful to living organisms were extracted from the resin samples. Based on the results obtained, it can be concluded that all tested compounds, based on epoxy resins, which are also used as adhesives in various applications, are essentially safe materials when using such formulations in a cured state

Polylactide-Based Films Incorporated with Berberine—Physicochemical and Antibacterial Properties

A series of new polymeric materials consisting of polylactide (PLA), polyethylene glycol (PEG) and berberine chloride (B) was evaluated. PEG was incorporated into the polymer matrix with the aim of obtaining a plasticizing effect, while berberine was added in order to obtain antibacterial properties in formed packaging materials. Materials were formed using the solvent-casting procedure. Fourier transform infrared spectroscopy and scanning electron microscopy were used so as to establish the structural changes resulting from the introduction of berberine. Thermogravimetry and differential scanning calorimetry were applied to study the thermal properties. Further, mechanical properties and differences in colour and transparency between the control sample and films containing berberine were also studied. The recorded data indicates that berberine formed a network on the surface of the PLA-based materials. Introduction of an active compound significantly improved thermal stability and greatly affected the Young’s modulus values of the studied polymeric films. Moreover, it should be stressed that the addition of the studied active compound leads to an improvement of the antibacterial properties, resulting in a significant decrease in growth of E. coli and the S. aureus bacteria cultures

Effect of a compatibilizong agent on thermal properties of polylactide-based composites exposed to UVC radiation

Folie zawierające polilaktyd jako osnowę polimerową, montmorylonit jako napełniacz oraz poli(ε-kaprolakton) jako kompatybilizator naświetlano promieniowaniem UV-C (max 254nm) w odstępach dwu godzinnych do 16 godzin. Wpływ napełniacza oraz obecności kompatybilizatora na proces fotodegradacji analizowano przeprowadzając badania właściwości termicznych, zarówno wyjściowych materiałów jak i po różnych czasach ekspozycji na UV. Pod uwagę brano między innymi następujące parametry: stabilność termiczną, temperaturę zeszklenia czy stopień krystaliczności. Otrzymane wartości wskazują, iż wprowadzenie poli(ε-kaprolaktonu) jak i montmorylonitu powoduje wzrost stopnia krystaliczności materiałów, co jest jednym z kluczowych czynników wpływających na proces fotodegradacji. Na podstawie uzyskanych wyników stwierdzono, iż obecność napełniacza podobnie jak i kompatybilizatora poprawia odporność kompozytów polilaktydowych na działanie promieniowania UV.Films consisting of polylactide as polymer matrix, montmorillonite as filler and poly(ε-caprolactone) as compatibilizing agent were irradiated with UV (254 nm) at intervals of 2-16 hours. Effect the presence of filler and compatibilizing agent has got on photodegradation process was analyzed by examination of thermal properties of both the starting material and the material after various times of exposure to UV radiation. The following parameters were taken into account: thermal stability, temperature of glass transition as well as degree of crystallinity. Determined values indicate that the introduction of a compatibilizing agent and a nanofiller into polymer matrix increases degree of crystallinity of obtained materials. Degree of crystallinity is an important factor influencing photodegradation process. Based on obtained results it has been established that the presence of a nanofiller as well as a compatibilizing agent improves thermal stability of polylactide composites exposed to UV radiation

Effect of extrusion conditions on thermal and mechanical properties of polyethylene filled with bentonite modifiedwith N-nonylquinolinium

W celu poprawy właściwości mechanicznych i stabilności termicznej polietylenu wprowadzono do niego bentonit w ilości 5% modyfikowany N-nonylochinoliną (NCh). W celu określenia modyfikacji bentonitu (BNT) wykonano analizę XRD. Istotnym z punktu widzenie właściwości otrzymanych kompozytów okazało się ustalenie odpowiednich warunków otrzymywania nowych materiałów na bazie polietylenu. Materiały otrzymywano w warunkach różniących się temperaturami stref zasilania i mieszania oraz czasem mieszania. W celu określenia wpływu wybranych parametrów na właściwości otrzymanych kompozytów wykonano analizę termograwimetryczną oraz zbadano właściwości mechaniczne przy statycznym rozciąganiu. Pod uwagę brano między innymi następujące parametry: stabilność termiczną określaną poprzez temperaturę przy 10 i 50% ubytku masy, moduł Younga oraz wartość siły rozciągającej. Otrzymane wartości wskazują, iż warunki otrzymywania nowych materiałów na bazie polietylenu i bentonitu modyfikowanego N-nonylochinoliną mają istotny wpływ na właściwości badanych układów.In order to improve mechanical properties and thermal stability of the polyethylene, bentonite modified with N-nonylquinoline (NCh) was introduced into the polymer matrix in an amount of 5%. In aim to determine the modification of bentonite (BNT), an XRD analysis was performed. Taking into account the properties of the obtained composites it has been established that appropriate conditions for the production of new polyethylene-based materials are essential. Materials were obtained under conditions of varying temperatures of flow and mixing zones as well as in varying mixing time. In aim to determine the influence of selected parameters on thermal and mechanical properties of the newly formed materials, a thermogravimetric analysis has been conducted and mechanical properties during static tension have been investigated. The following parameters were taken into account: thermal stability determined by temperature at 10 and 50% mass loss, Young’s modulus and tensile strength. The obtained values indicate that the conditions for obtaining new materials based on polyethylene and bentonite modified with N-nonylquinoline have a significant influence on theproperties of PE-based composites

Structural and thermal properties of nanocomposites based on polyolefins and montmorillonite modified with ethyl 2-aminobenzoate

Our efforts were focused on improving thermal stability of polyethylene (PE) and polypropylene (PP) through incorporation of new organically modified montmorillonite.The reactive organofilic montmorillonite (MMT-EA) was prepared by exchanging the interlayer inorganic cations in montmorillonite by a large excess of ethyl 2-aminobenzoate (EA). Organic modification can affect not only microstructures, but also the properties of the polymer - montmorillonite nanocomposites. In the next step, novel polyolefins/ organoclay nanocomposites were prepared by melt intercalation process. In order to obtain this new family of materials and enhance their properties very low filler level, from 1.5 to 5 wt.% was used.The dispersion of the montmorillonite layers in the polymers was characterized by using X-ray diffraction (XRD). The thermal properties and structure changes were studied by different scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Further studies indicated that the exfoliated clay modified with EA improved thermal stability of the PE and PP/MMT-EA nanocomposites