Aim: To investigate whether the sample preparation process of poly(ethylene oxide) (PEO) affects kinetic analysis of the thermal degradation process. Kinetic analysis was performed to describe the course of a chemical reaction regardless of the reaction conditions and the reaction system complexity. One differential method, the Friedman method, and one integral Kissinger-Akahira-Sunose method (KAS), were applied in this work. Methods: The PEO sample was prepared in 4 different ways. Thermogravimetric analysis was performed to determine the thermal degradation of prepared samples. Infrared spectroscopic analysis was performed during the preparation of the PEO film obtained by casting from the solution. Results: Dynamic thermal decomposition of PEO, regardless of the method of preparation, takes place through a single decomposition stage, which is manifested by the appearance of one peak on derivative thermogravimetric (DTG) curve. During the preparation of the PEO film, the procedure was carried out at a temperature higher than its melting temperature (Tm=65°C). After the cooling, the obtained sample didn’t solidify and it had an intense odor of acetic acid, which was confirmed by infrared spectroscopic analysis. Samples III and IV were re-prepared at a temperature lower than the melting point of PEO, obtaining samples of satisfactory quality. Conclusion: In order to prepare poly(ethylene oxide) films by solution casting technique, drying should be carried out at temperatures below the melting point of PEO. If TG analysis of pure PEO powder is compared with the results of hot pressed samples and solution cast samples, it can be concluded that the preparation of the sample doesn’t affect the thermal stability of the PEO. The dependence of activation energy calculated by the differential Friedman and integral KAS method on conversion is constant for all samples in a broad conversion range, regardless of how the samples were prepared. The hot pressed samples and solution cast samples have lower activation energy than the commercial PEO powder.

The use of natural materials, such as natural fibres, in the construction industry is becoming more frequent. The source of natural fibres should be sought in local plants, such as Spanish Broom in the Mediterranean area. The fibre treatment process was carried out in 8 different ways with alkali 4%, 5%, 6%, 8%, 10% and 15% NaOH solution, and 5% NaOH and 2% Na2SO3 mixture solution and seawater. The fibres were tested for tensile strength. No relationship was established between the concentration of the solution and the tensile strength of the fibres. The influence of the reuse of treatment solution on fibre quality was monitored by X-ray diffraction (XRD), ATR-FTIR, and TG/DTG analysis. Fibres with lengths of 1, 2, and 3 cm were added to cement mortar specimens in amounts of 0.5 and 1 vol%. The flexural and compressive strengths were tested on mortar specimens after 28 days. For fibres 1 and 3 cm long, 0.5% natural fibre content gives higher strength results: about 9% for flexural strength and 13.5% and 11.7% for compressive strength in regard to mortar reinforced with fibres of the same length but with a proportion of 1%. For mortar reinforced with fibre 2 cm long, better results are achieved with 1% fibre content, namely 9% higher flexural strength and 11.2% higher compressive strength compared to mortars with 0.5% fibre content. SEM/EDS analysis showed that the fibres are integrated into the cement matrix but that there is no strong interaction with the binder. For examination and 3D visualisation of mortar specimens, a medical device MSCT (Multi-slice Computed Tomography) was also used. For three consecutive years of Spanish Broom harvesting, an analysis of meteorological conditions and the results of the mechanical strength of reinforced mortars is given. For the examined years, the meteorological conditions did not affect the obtained results. Additional knowledge about the Spanish Broom fibres can introduce this plant to the application of new sustainable building materials.