Purpose: Poly(3-hydroxybutyrate) (P3HB) is a biopolymer, but storing products from P3HB causes the deterioration of their properties leading to their brittleness. P3HB has also low thermal stability. Its melting point almost equals its degradation temperature. To obtain biodegradable and biocompatible materials characterized by higher thermal stability and better strength parameters than the unfilled P3HB, composites with the addition of polyurethanes were produced. Methods: The morphology, thermal, and mechanical property parameters of the biocomposites were examined using scanning electron microscopy, thermogravimetric analysis, standard differential scanning calorimetry, and typical strength machines. Results: Aliphatic polyurethanes, obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycols, were used as modifiers. To check the influence of the glycol molar mass on the properties of the biocomposites, glycols with a molecular weight of 400 and 1000 g/mol were used. New biocomposites based on P3HB were produced with 5, 10, 15, and 20 wt. % content of polyurethane by direct mixing using a twin-screw extruder. The following property parameters of the prepared biocomposites were tested: degradation temperature, glass transition temperature, tensile strength, impact strength, and Brinell hardness. Conclusions: Improvement of the processing property parameters of P3HB-biocomposites with the addition of aliphatic polyurethanes was achieved by increasing the degradation temperature in relation to the degradation temperature of the unfilled P3HB by over 30 °C. The performance property parameters have also been improved by reducing the brittleness compared to the P3HB, as evidenced by the increase in impact strength and the decrease in hardness with an increase in the amount of polyurethane obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycol with a molecular weight of 400 g/mol (PU400) as modifier.

Polyurethane foam materials are the majority among all foam materials. Additionally, they are main part of all produced polyurethanes. Therefore, the problem of selection of suitable blowing agents is very crucial from the point of view of technological, economic and environmental protection benefits. The work is collected and discussed all kinds of physical blowing agents which are used in the production of polyurethane foams. The basic blowing agents used in the polyurethane technology include: chlorofluorocarbons (CFCs), hydrogenated fluorocarbons (HFCs), hydrogenated chlorofluorocarbons (HCFCs), low-boiling saturated and unsaturated hydrocarbons, hydrofluoroethers (HFEs) and carbon dioxide. Issues related to the problem of selecting a suitable foaming agent, taking into account the environmental impacts, foam production costs and the impact on their properties, especially on the heat-insulation, combustibility, have been widely discussed in the work.

In the work, the design of experiments (DOE) method was used to obtain a modified epoxy resin of reduced fragility. As modifiers of commercial epoxy resin, urethane prepolymers with isocyanate terminal groups were used. Experimental points (samples of specified composition of resin prepolymer and a curing agent) were generated by the STATISTICA program module Design of Experiments using a central composition design. A study of the mechanical properties of modified resin samples was carried out for five intermediate values of input variables x1 (resin/hardener ratio) and x2 (modifier, wt %), designated for the normalized values 0, ± 1, and ±1.414. The STATISTICA algorithms analyzing the results of the practical implementation of the planned experiments allowed us to develop a model describing the dependence of the mechanical properties of composite resins on the composition and then to select the optimal compositions of epoxy resin for their practical applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46761.

The article describes the authors’ experience of distance learning at Rzeszow University of Technology during COVID-19 lockdown. The problems associated with the didactics in the pandemic period were discussed. They concerned hardware, software, and teaching rooms. Technical and organisational issues were discussed. The aspect of student involvement in the distance learning process and the learning outcomes achieved by the students was also addressed. Finally, the conclusions that emerged from this stage of work with students were presented, as well as suggestions related to the improvement of the distance learning process for the future.

Poly(3-hydroxybutyrate) (P3HB) is the most important of the polyhydroxyalkanoates. It is biosynthesized, biodegradable, biocompatible, and shows no cytotoxicity and mutagenicity. P3HB is a natural metabolite in the human body and, therefore, it could replace the synthetic, hard-to-degrade polymers used in the production of implants. However, P3HB is a brittle material with limited thermal stability. Therefore, in order to improve its mechanical properties and processing parameters by separating its melting point and degradation temperature, P3HB-based composites can be produced using, for example, linear aliphatic polyurethanes as modifiers. The aim of the study is a modification of P3HB properties with the use of linear aliphatic polyurethanes synthesized in reaction of hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) by producing their composites. Prepared biocomposites were tested by the scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TGA). Furthermore, selected mechanical properties were evaluated. It has been confirmed that new biocomposites showed an increase in impact strength, relative strain at break, decrease of hardness and higher degradation temperature compared to the unfilled P3HB. The biocomposites also showed a decrease in the glass transition temperature and the degree of crystallinity. Biocomposites obtained with 10 wt. % polyurethane synthesized with polypropylene glycol having 1000 g · mole–1 and HDI have the best thermal and mechanical properties.