Janusz Datta

Synthesis and Investigation of Glycolysates and Obtained Polyurethane Elastomers

The polyurethane (PU) intermediates were obtained by glycolysis of waste PU foam in the reaction with 1,6-hexamethylene glycol (HDO). The effects of different weight ratios of HDO to PUR foam on selected physicochemical properties were also determined. The polyurethanes were synthesized from the obtained intermediates by a two-step method using diisocyanate and a glycolysis product in the molecular mass range 700—1000. Hexamethylene glycol, 1,4-butylene, and ethylene glycol were used as chain extenders. The influence of the NCO group concentration in prepolymer on the glass transition temperature (Tg) and storage modulus of PU elastomers were investigated by the DMTA method. Thermal decomposition of the obtained glycolysates and polyurethanes was investigated by thermogravimetry coupled with Fourier transform infrared spectroscopy (FTIR). Tensile strength and elongation at break of polyurethanes were determined using Zwick universal tensile tester. FTIR spectra showed that main decomposition occurs at about 400°C in both glycolysates and PU elastomers. The main products of thermal decomposition are carbon monoxide, carbon dioxide, compounds containing ether and hydroxyl groups, and probably acetaldehyde. The synthesized PU’s had tensile strength in the range 13.4—15.6 MPa and elongation at break in the range 59.3—122.9%.

Chemical modifications of natural oils and examples of their usage for polyurethane synthesis

Natural oils have been used in the production of plastics for a long time. However, the number of studies dedicated to polyurethane research has shown an increase only recently. Usually, petrochemical components are used in polyurethane synthesis. Nowadays, there have been attempts made to replace polyols in polyurethanes with the modified oils and other natural raw materials. It is a promising and important scenario because the flexible segment of such polyurethanes can contain even up to 60 wt % of the novel ingredient. In the case of material evaluation for industry, one can additionally count on lowering the product price because natural oil is generally 2 to 3 times cheaper as compared to its synthetic equivalent. Oils most commonly used in industrial applications are soybean oil, palm oil, rapeseed oil, castor oil and tung oil. In this work the study results and the possibilities of applying natural oils in polyurethane synthesis are presented.

Progress in non-isocyanate polyurethanes synthesized from cyclic carbonate intermediates and di- or polyamines in the context of structure–properties relationship and from an environmental point of view

Commercially, polyurethanes are produced by the reaction of diisocyanates, polyols (polyester or polyether) and low molecular weight chain extender. Toxicity, moisture sensitivity and phosgene-based synthesis of diisocyanates resulted in investigations focused on obtaining the non-isocyanate polyurethanes (NIPUs). This work presents the review of synthesis and structure–properties relationship of non-isocyanate polyurethanes obtained by reacting cyclic carbonated intermediates with diamines or polyamines. Moreover, the presented methods of NIPU synthesis were analysed from the environmental point of view. Described five-membered ring cyclic carbonate intermediates were obtained by carbonation of glycidyl ethers or thiol-ene coupling of unsaturated cyclic carbonate monomers and thiols. The special interest was put on the bio-based non-isocyanate polyurethanes, obtained from chemically modified bio-based substances, e.g. carbonated vegetable oils. The mechanical and thermal properties of NIPUs are affected by functionality, structure and molecular weight of cyclic carbonate intermediates and diamines or polyamines.

From polymer waste to potential main industrial products: Actual state of recycling and recovering

ABSTRACT Plastics have become widely used materials in everyday life due to their special properties such as durability, easy processing, lightweight nature, and low cost of production. However, because of their stable and nonbiodegradable nature, postconsumer plastics become an issue to the environment. The growing amounts of waste are generated, as plastic products are commonly used only once before disposal. The alternatives of practical techniques for solid waste management are redesign, reprocessing, and recycling. Thus, even recycling is not the most profitable technique for the treatment of plastic waste, and it should be constantly developed. The recycling of plastic waste helps to conserve natural resources due to polymeric materials being made from oil and gas. There are four main recycling methods: reuse, mechanical recycling, chemical recycling, and energy recovery. Mechanical recycling turns polymeric waste into new polymer products when energy recovery process releases the energy contained within plastics through combustion and chemical recycling converts waste polymers into feedstock for chemicals/monomers/fuels production. Nowadays chemical recycling of plastic waste is the most noteworthy polymer recovery technique. The manuscript presents a literature review on chemical recycling methods of various polymers, such as polyethylene (PE; low-density PE [LDPE] or high-density PE [HDPE]), polypropylene, or mixture of these polymers, poly(ethylene terephthalate), polycarbonate, and polyurethane. We describe the effect of the reaction parameters on obtained products, used catalysts and agents, and used equipment for specific methods of chemical recycling. In this way, the state of the art of the chemical recycling methods of several polymers is presented.

Selected biotrends in development of epoxy resins and their composites

Epoxy resins and their fibre or particulate composites are widely used in various industries, including building, naval, aircraft, automotive and aerospace. Modern polymer science and technology focus on the development of green polymers and composites. There are two major areas of interest in the case of epoxy resins: the development of bio-based resins and the production of composites with natural fibres. One of the most interesting challenges is developing fully bio-based composites: that is, epoxy resins based on renewable resources and natural fibres. This paper presents a review of literature on epoxy resins and hardeners based on renewable resources (especially vegetable oils) and epoxy composites with natural fibres. We also describe some of the effective methods of improving the mechanical properties of epoxy–natural fibres composites, including chemical modification of the fibre surface and the application of hybrid reinforcements.

Influence of Glycols on the Glycolysis Process and the Structure and Properties of Polyurethane Elastomers

In this work, the influence of glycols on the glycolysis process and the properties of obtained polyurethanes were investigated. The glycolysates were produced via glycolysis of waste polyurethane foam in the reaction with one of the following glycols: 1,3-propanediol, 1,5-pentanediol, and 1,6-hexanediol.The reactions were carried out for different mass ratios of polyurethane wastes to glycolysis agent, i.e. 6:1, 8:1, and 10:1. Polyurethanes were synthesized from the obtained intermediates by a one-step method of mixing polymeric di-isocyanate and the glycolysis products with molecular masses ranging from 700 to 1000, while a polyol (Poles 55/20) was used as a chain elongation agent. The influence of glycolysates on tensile strength and elongation at break of polyurethanes was investigated using a Zwick universal tensile tester. Thermal decomposition of the obtained glycolysates and polyurethanes was investigated by thermogravimetry coupled with Fourier transform infrared spectroscopy. It has been found that of all used glycols, 1,6-hexanediol gives the best improvement in the thermal stability of polyurethanes during the glycolysis process. The mean hardness of polyurethanes decreases but rebound resilience increases with chain length of the glycol used for obtaining glycolysates.

Advanced coating of interior of tanks for rising environmental safety - novel applications of polyurethanes

Advanced coating of interior of tanks for rising environmental safety - novel applications of polyurethanes The aim of this study was to develop urethane elastomers of predefined properties to be used as elastic coating in the cargo tanks of tankers. A method for coating the liquid polyurethane system onto steel and steel-concrete elements, and a way to join polyurethane coating with the aforementioned elements, were elaborated. The technique of injection the reactive liquid polyurethane system onto cold steel elements was used. The method for utilization and recovery of urethane oligomerols from the waste polyurethane coating in chemical recycling by using low molecular weight glycols as glycolysis agents was proposed.

Morphology and properties of recycled polyethylene/ground tyre rubber/thermoplastic poly(ester-urethane) blends

The growing amount of plastics waste produced every year resulted in development of mechanical and chemical recycling methods of polymers and their blends or composites. From the environmental point of view, the possibility of plastics waste reusing and recycling is desirable. In this study three polymer blends were obtained with using recycled polyethylene (RPE), ground tyre rubber (GTR) and thermoplastic poly(ester-urethane) (TPU). The reference samples, without TPU, were also made. The mass ratio of RPE to GTR was the same in each prepared materials. The morphology and selected mechanical properties of prepared polymer systems were investigated. It was found that increasing amount of TPU in polymer blends resulted in decreasing of tensile properties, rebound resilience and abrasion resistance of the final materials. Microstructural analysis showed that material breaks at interface between GTR and RPE or TPU, during the static tensile test.

Synthesis, structure and properties of poly(ester-urethane)s obtained using bio-based and petrochemical 1,3-propanediol and 1,4-butanediol

In this paper, the poly(ester-urethane)s obtained using petrochemical and bio-based chain extenders were prepared and characterized. The influence of glycols’ origin on the chemical structure, mechanical and thermal properties of the prepared polyurethanes was studied. The materials were synthesized by prepolymer method. The first step involved the reaction of α,ω-dihydroxy(ethylene-butylene adipate) (POLIOS 55/20) with 4,4′-diphenylmethane diisocyanate (MDI). In the next step, obtained prepolymer terminated with isocyanate group was extended using 1,3-propanediol and 1,4-butanediol at three different molar ratios of NCO group (presented in prepolymer chains) to OH groups (presented in chain extender structure), i.e., 0.95, 1.0 and 1.05. The results showed that applying the different types (diversified chemical structure and origin) of glycols results in obtaining materials with diversified mechanical properties and slight different thermal stabilities. The results of Fourier transform infrared spectroscopy showed that the chemical structure of the obtained polyurethanes was not affected by the presence of glycols with the same chemical structure and different origins (petrochemical and bio-based nature).

Effect of high loading of titanium dioxide particles on the morphology, mechanical and thermo-mechanical properties of the natural rubber-based composites

The aim of this work was to prepare and characterize the natural rubber vulcanizates containing different amounts of titanium dioxide particles. At first, a rubber mixture was prepared using a laboratory two-roll mill and then samples were vulcanized by a hydraulic press. The formulation of the rubber mixture and rubber-processing technique were based on our earlier investigations. Samples were obtained with different titanium dioxide loadings of 15, 25, 45, and 85 parts by weight per hundred parts of natural rubber. This research is focused on the determination of the influence of different loadings of titanium oxide particles on the chemical structure, morphology, mechanical and thermo-mechanical properties of the natural rubber-based composites. It was found that vulcanizates with different amounts of TiO2 particles possess good characteristic in terms of all measured properties. The results of Fourier transform infrared spectroscopy analysis showed that the chemical structure of the obtained natural-based composites was not influenced by titanium dioxide particles. The SEM micrographs showed the uniform dispersion of TiO2 particles in the natural rubber matrix. The agglomeration of filler was seen at the higher contents of TiO2 in the matrix. The thermogravimetric analysis showed slightly different thermal stability for the obtained natural rubber composites. The dynamic mechanical thermal analysis showed that the prepared materials have similar glass transition temperatures. However, increase in the content of titanium dioxide in the obtained materials is connected with higher energy loss (higher dissipation of energy) during the mechanical work of material and higher cross-link density of the prepared materials.