Sławomir Maślanka

Thermogravimetric Analysis of Composites Obtained from Polyurethane and Rubber Waste

The thermogravimetric analysis was applied for indication of the thermal stability of polyurethane-rubber composites received from polyurethane and rubber waste. The results of the thermogravimetric analysis show that the decomposition of rubber granulate depends on the speed of heating. It starts within the temperature range from 320°C to 360°C and is completed at the temperature range from 500°C to 550°C. The evaporation of small-molecular substances probably takes place below 300°C. At temperatures above 320°C, two-stage decomposition of rubber and polyurethane-rubber waste composites was observed. The low temperature decomposition of rubber probably corresponds to the decomposition of natural rubber (NR) while the high temperature decomposition corresponds to decomposition of styrene-butadiene rubber (SBR) or/and butadiene rubber (BR). The thermogravimetric studies of the polyurethanes obtained from different isocyanates showed that the increase of thermal stability depends on the isocyanate used. The one-stage decompositions of different polyurethanes were observed. Polyurethane-rubber composites undergo two-stage decomposition. Thus, the low temperature decomposition of composites may be connected to the decomposition of suitable polyurethane and NR, and the high temperature decomposition may be connected to the decomposition of SBR or/and BR as it was observed for rubber granulate. Tested samples of composites contained polyols of the trade name Recypol® 201 and Recypol®601 received from used polyurethane foam and of rubber recyclate received from tyres in the form of a granulate of dimensions ranging from 1.5 to 2.0 mm. The percentage ratio of polyurethane glue/rubber granulate: 5/95; 7.5/92.5; 10/90 was chosen. The profiles of composites were held at the temperature of 90°C for 90 min under the load of and 2 ·106 Pa. Thermogravimetric analysis of the samples was conducted using Perkin Elmer TGA PYRIS. Measurements were performed at the temperatures from 25°C to 900°C, with heating rates of 20°C/min, 40°C/min, 80°C/min using nitrogen as the purge gas. The value of the apparent activation energy of decomposition processes of the composites is reported.

Study of the Cross-Linking Process of Model Oligoesters by DMTA Method

Some oligoesters were synthesized in order to study changes of the useful properties of hyper-branched unsaturated polyesters. The determination of the polymer relaxation properties allows for characterization of their structure. Useful properties of the polymers such as stability and persistence depend on their structure. The aim of the investigation was to obtain model oligoesters with low molecular weight and to study their properties by spectroscopic and the dynamic mechanical thermal analysis (DMTA) methods. The synthesis was performed with the use of ethylene glycol and the mixture of maleic anhydride and phthalic acid which allowed us to obtain linear unsaturated polyesters. The cross-linking process of synthesized model oligoesters was performed using styrene as a cross-linking agent. The NMR and IR spectroscopy and elemental analysis were used for the description of purity and the structure of the obtained products. Relaxation properties of the synthesized oligoesters, course of their cross-linking and relaxation properties of the cross-linked products were studied by DMTA methods. In the synthesized oligoesters and cross-linked products α and β-relaxation processes were observed.

Relaxation Properties of Composites Obtained from Polyurethane and Rubber Waste

The aim of the investigation was the dynamic thermo-mechanical analysis (DMTA) study of the polyurethane-rubber composites obtained from used polymer products. Polyols obtained in the glycolysis process from used semi-rigid polyurethane foams, hardened by diphenylmethane 4,4′-diisocyanate (MDI) and rubber granules obtained from mechanical granulation of used car tyres were used to receive polyurethane-rubber composites. On the basis of the DMTA spectra the glass transition temperature Tg was determined. The analysis of loss module E′′ allowed us to observe two relaxation processes for polyurethane-waste rubber composites α – originating from the rubber and α′ – from the polyurethane glue. The dependence of the changes of activation energy of relaxation processes with the change of weight ratio of polyurethane glue in polyurethane-waste rubber composites was observed.

X-ray, Hirshfeld surface analysis, spectroscopic and DFT studies of PAHs: fluoranthene and acenaphthene

The X-ray structure, theoretical calculation, Hirshfeld surfaces analysis, IR and Raman spectra of fluoranthene and acenaphthene were reported. The acenaphthene crystallizes in the orthorhombic crystal system and space group P 2 1 ma , with crystal parameters a = 7.2053 (9) A, b = 13.9800 (15) A, c = 8.2638 (8) A, Z = 4 and V = 2135.5 (4) A 3 . In turn, the grown crystals of fluoranthene are in monoclinic system with space group P2 1 /n. The unit cell parameters are a = 18.349 (2) A, b = 6.2273 (5) A, c = 19.861 (2) A, β = 109.787 (13) °, Z = 8 and unit cell volume is 832.41 (16) A 3 . The structure was solved by direct methods and refined by full-matrix least squares based on F2 with weight w=1/[σ 2 (F 0 2 )+(0.0702P) 2 +0.5131P] where P=(F 0 2 +2F c 2 )/3 and w=1/[σ 2 (F 0 2 )+(0.0589P) 2 ] where P = (F 0 2 +2F c 2 )/3 for fluoranthene and acenaphthene respectively . Theoretical calculations of the title compounds isolated molecule have been carried out using DFT at the B3LYP level. The intermolecular interactions in the crystal structure, for both the title PAHs, were analyzed using Hirshfeld surfaces computational method.

The Influence of the Type of Catalyst on the Polymer Waste Thermodestruction

Used polymer plastics have high fuel values (approximately 40 MJ/kg for polyolefines). Therefore, they constitute perfect energy materials. Thermodestruction of used products and wastes of polymer plastics on specialized installations seems to be a long-term method to manage this group of wastes in chemical recycling with the destination to obtain fuel ingredients. Application of this technology allows for reduction the quantity of municipal waste. This enables also to obtain the valuable fuel components. In the Department of Environment Chemistry and Technology of Institute of Chemistry at the University of Silesia and in enterprises using the installation for the thermodestruction of used polymer plastics it was studied influence of different catalyst on course of thermodestruction. According to an innovatory technology elaborated in the enterprise called “Speranda-1” Sp. z o.o. the dirty used products of polymer plastics and wastes after melting flow down to the bottom part of the reactor, where they undergo thermal degradation due to a contact with the catalyst. It was ascertained that type of catalyst influences the course of the primary and secondary destruction processes and is of fundamental importance for capacity of this process and for the composition of the obtained products.

Application of Spin Labels for Research of Vanadyl Acetylacetonate Concentration in Model Bilayer Membranes by EPR Spectroscopy

The compounds and complexes of vanadium are used to treat diabetes and cancer. Research on the effectiveness and mechanism of action of new derivatives of vanadium, and their toxicity is currently very intense. The research shows that the vanadium(IV) acetylacetonate complex [VO(acac)2] shows a synergism with insulin in treating diabetes, high pharmacological activity and low toxicity. In order to improve the effectiveness of drugs and minimize their toxicity, the active compounds are often closed in the liposome membranes. The objective of the work was preparation of bilayer liposomes from egg yolk phosphatidylcholine (EYPC), closing the complex VO(acac)2 in these membranes and estimating the concentration of vanadium complex after incorporation into liposomes membranes. Due to the paramagnetic properties of vanadium(IV) the concentration of this metal complex can be determined directly by EPR. Entering the spin label CTPO in the water phase into the studied arrangement allows for the indirect measurement of the concentration of complex, on the basis of changes of the EPR spectrum of the spin label caused by the presence of the vanadium(IV) complex. In the work the dependence of the α parameter based on the analysis of CTPO EPR spectra on the concentration of VO(acac)2 was determined. To demonstrate the presence of the complex in the membrane directly by measuring the EPR sulfate(IV) sodium was used in order to remove the EPR signal of vanadium(IV) from the water phase. The presence of vanadium(IV) in the membrane was also demonstrated indirectly using a spin label 12-SASL. Based on the results of EPR spectroscopy the concentration of the complex in the membrane was determined together with the partition coefficient of VO(acac)2 between the membrane and outer water environment of the membrane.

Synthesis and Relaxation Properties of Model Oligoester – Tetrakis(5-hydroxypentyl)piromelite

The study of polymer properties requires the synthesis and analysis of simple model compounds. The aim of this work was the synthesis and investigation one of model compounds are needed to perform the physicochemical characteristics of linear, branched and dendrite polyesters. The description of relaxations processes of model oligoesters can make it easier to interpret the dependence between the useful properties of polyesters and the molecular structure of their macromolecules. Instrumental methods as NMR, FTIR and dielectric spectroscopy, calorimetry (DSC), thermogravimetric analysis and mechanical spectroscopy are used to this goal. The structure of the synthesized tetrakis(5-hydroxypentyl)piromelite (oligoester) was confirmed with the use of NMR, FTIR spectroscopy and elemental analysis. A detailed study of the relaxation properties using broadband dielectric spectroscopy and Dynamic Mechanical Thermal Analysis (DMTA) was also performed. A description of different dielectric and DMTA α-relaxation processes for the oligoester are indispensable to determine the relaxation properties of the suitable polyesters. For the synthesized oligoester glass temperature (Tg), relaxation time (τ) and activation energy (Ea) were determined from the results of DSC, DMTA and dielectric spectroscopy.