FTIR spectroscopic and thermogravimetric characterization of ground tyre rubber devulcanized by microwave treatment

In this work the phenomena involved with the microwave devulcanization of ground tyre rubber (GTR) were investigated. During studies three types of GTR characterized by different content of organic compounds (elastomers, plasticizers, etc..), carbon black and ash have been analyzed. The chemical structure of GTR before and after microwave devulcanization process was studied by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Furthermore, efficiency of microwave devulcanization conducted at different time was evaluated based on the crosslinking density and sol content values. FTIR spectroscopy results shown that devulcanization of GTR causes a decrease in carbon black with generation of CO2 due to its thermo oxidation, a decrease in structural groups of elastomeric components (mainly methylene and methine) and a breaking of C-S groups and S-S bridges. The presented results indicate the strong correlation between content of SiO2 in GTR and its degree of devulcanization. It was observed that GTR with a high content of SiO2 are easier devulcanized than samples with low content of SiO2, which suggest the presence of silica fillers improve microwave devulcanization efficiencyPostprint (author's final draft

Investigating the impact of curing system on structure-property relationship of natural rubber modified with brewery by-product and ground tire rubber

The application of wastes as a filler/reinforcement phase in polymers is a new strategy to modify the performance properties and reduce the price of biocomposites. The use of these fillers, coming from agricultural waste (cellulose/lignocellulose-based fillers) and waste rubbers, constitutes a method for the management of post-consumer waste. In this paper, highly-filled biocomposites based on natural rubber (NR) and ground tire rubber (GTR)/brewers’ spent grain (BSG) hybrid reinforcements, were prepared using two different curing systems: (i) sulfur-based and (ii) dicumyl peroxide (DCP). The influence of the amount of fillers (in 100/0, 50/50, and 0/100 ratios in parts per hundred of rubber) and type of curing system on the final properties of biocomposites was evaluated by the oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, swelling behavior, tensile testing, and impedance tube measurements. The results show, that the scorch time and the optimum curing time values of sulfur cured biocomposites are affected by the change of the hybrid filler ratio while using the DCP curing system, and the obtained values do not show significant variations. The results conclude that the biocomposites cured with sulfur have better physico-mechanical and acoustic absorption, and that the type of curing system does not influence their thermal stability. The overall analysis indicates that the difference in final properties of highly filled biocomposites cured with two different systems is mainly affected by the: (i) cross-linking efficiency, (ii) partial absorption and reactions between fillers and used additives, and (iii) affinity of additives to applied fillersPostprint (published version

Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: influence of GTR source and irradiation time

Ground tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160¿. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical behaviour, thermal properties and morphology of natural rubber/ground tire rubber composites was studied. The interfacial interactions between ground tire rubber and natural rubber as function of ground tire rubber source and irradiation time were evaluated by Fourier transform infrared spectroscopy, thermogravimetric analysis, tensile tests, swelling measurements and scanning electron microscopy. The results showed that irradiation of ground tire rubber slightly enhanced tensile properties and cross-link density of natural rubber/ground tire rubber composites. This effect was more evident in the case of ground tire rubbertruck because of its higher content of natural rubber and was reflected in changes in the interfacial adhesion, which were confirmed by the results of Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy analysisPostprint (author's final draft

Processing and structure-property relationships of natural rubber/wheat bran biocomposites

In this work, wheat bran was used as cellulosic filler in biocomposites based on natural rubber. The impact of wheat bran content [ranging from 10 to 50 parts per hundred rubber (phr)] on processing, structure, dynamic mechanical properties, thermal properties, physico-mechanical properties and morphology of resulting biocomposites was investigated. For better characterization of interfacial interactions between natural rubber and wheat bran, achieved results were compared with properties of biocomposites filled with commercially available cellulosic fillers—wood flour and microcellulose. It was observed that wheat bran, unlike commercial cellulosic fillers, contains high amount of proteins, which act like plasticizers having profitable impact on processing, physical, thermo-mechanical and morphological properties of biocomposites. This is due to better dispersion and distribution of wheat bran particles in natural rubber, which results in reduction of stiffness and porosity of the biocomposites. Regardless of cellulosic filler type, Wolff activity coefficient was positive for all studied biocomposites implying reinforcing effect of the applied fillers, while tensile strength and elongation at break decreased with increasing filler content. This phenomenon is related to restricted strain-induced crystallization of NR matrix due to limited mobility of polymer chains in the biocomposites. Furthermore, this explains negligible impact of particle size distribution, chemical composition and crystallinity degree of applied cellulosic filler on static mechanical properties of highly-filled NR biocomposites. The conducted investigations show that wheat bran presents interesting alternative for commercially available cellulosic fillers and could be successfully applied as a low-cost filler in polymer compositesPostprint (author's final draft

Preliminary investigation on auto-thermal extrusion of ground tire rubber

Ground tire rubber (GTR) was processed using an auto-thermal extrusion as prerequisite to green reclaiming of GTR. The reclaimed GTR underwent a series of tests: thermogravimetric analysis combined with Fourier-transform infrared spectroscopy (TGA-FTIR), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) in order to evaluate the impact of barrel heating solution (with/without external barrel heating) on reclaiming process of GTR. Moreover, samples were cured to assess the impact of reclaiming heating solution on curing characteristics and physico-mechanical properties. Detailed analysis of the results indicated that the heat supplied by the machinery was replaced by energy generated due to the high shearing phenomenon, what significantly influenced energy consumption and hereby lowered processing costPostprint (published version

Comparison of the Calculated Wind Loads to the Power Generated by the Main Propulsion and Thrusters of the Ship with the Results of Simulation Tests

One of the main factors affecting the safe port maneuvers by ships is wind, which directly affects the ship's movement. The article presents a comparison of calculated wind loads to the power generated by thrusters and the main propulsion of the ship with the results of simulation tests in order to determine the safe wind force limits allowing safe port maneuvers with a particular ship model

Rola biblioteki w przestrzeni miejskiej na przykładzie Biblioteki Manhattan w Gdańsku

The article addresses the problem of the functions of modern public libraries. Due attention has to be given to their role and new tasks carried out in accordance with the needs of the information society. These problems were discussed based on the example of the Manhattan Library (one of the branches of the Voivodeship and Municipal Public Library in Gdańsk), which emphasizes meeting the social, cultural and information needs of various audiences. The article presents the results of surveys which shows the perception of the role of the media library by its users.W artykule został poruszony problem funkcji nowoczesnych bibliotek publicznych. Zwrócono uwagę na ich rolę oraz nowe zadania realizowane zgodnie z potrzebami społeczeństwa informacyjnego. Jako przykład omówiono Bibliotekę Manhattan – jedną z filii Wojewódzkiej i Miejskiej Biblioteki Publicznej w Gdańsku, która kładzie nacisk na zaspokajanie potrzeb kulturalnych, informacyjnych i społecznych różnych grup odbiorców. Przedstawione zostały także wyniki badania ankietowego pokazującego postrzeganie roli mediateki przez jej użytkowników

Rola nowoczesnych bibliotek miejskich w zapewnianiu dostępu do kultury i realizowaniu funkcji społecznych

Biblioteki publiczne, szczególnie w dużych miastach, są ośrodkami szeroko pojętej kultury. Nie ograniczają się jedynie do prowadzenia wypożyczalni i czytelni. Zrzeszają mieszkańców w różnym wieku, o różnych światopoglądach i wykształceniu, których łączy chęć uczestniczenia w życiu kulturalnym, wpływanie na jego różnorodność i rozwój. W artykule zaprezentowano wybrane funkcje i zadania bibliotek w dużych miastach. Omówiono wybrane polskie i zagraniczne projekty nowoczesnych placówek, których architektura, struktura lub usługi mają innowacyjnych charakter

Rola biblioteki w przestrzeni miejskiej na przykładzie Biblioteki Manhattan w Gdańsku

W artykule został poruszony problem funkcji nowoczesnych bibliotek publicznych. Zwrócono uwagę na ich rolę oraz nowe zadania realizowane zgodnie z potrzebami społeczeństwa informacyjnego. Jako przykład omówiono Bibliotekę Manhattan – jedną z filii Wojewódzkiej i Miejskiej Biblioteki Publicznej w Gdańsku, która kładzie nacisk na zaspokajanie potrzeb kulturalnych, informacyjnych i społecznych różnych grup odbiorców. Przedstawione zostały także wyniki badania ankietowego pokazującego postrzeganie roli mediateki przez jej użytkowników