The problem of harmful casting resins has been present in foundries for many years. Manufacturers are introducing new products that contain in their composition environmentally and eco-friendly ingredients. Unfortunately, not all types of technology can be used, sometimes environmental benefits are disproportionate to the quality of castings and their price. In the foundry industry, the most popular binders are based on organic compounds (often carcinogenic) and other harmful substances. Due to strict legal regulations regarding environmental protection, as well as care for the foundry's workers' comfort - their occurrence should be reduce to a minimum. These compounds often behave also depending on the conditions of use (temperature, atmosphere). The application of various methods of thermal analysis and spectroscopic methods allows to verify the mechanism of resin decomposition process in relation to conditions in the form in both inert and oxidizing atmosphere. For analysis the resins from cold-box technology, were used TG–DTG–DSC, Py-GC/MS methods and specified the course of changes occurring in combination of different atmosphere.

Recently, some major changes have occurred in the structure of the European foundry industry, such as a rapid development in the production of castings from compacted graphite iron and light alloys at the expense of limiting the production of steel castings. This created a significant gap in the production of heavy steel castings (exceeding the weight of 30 Mg) for the metallurgical, cement and energy industries. The problem is proper moulding technology for such heavy castings, whose solidification and cooling time may take even several days, exposing the moulding material to a long-term thermal and mechanical load. Owing to their technological properties, sands with organic binders (synthetic resins) are the compositions used most often in industrial practice. Their main advantages include high strength, good collapsibility and knocking out properties, as well as easy mechanical reclamation. The main disadvantage of these sands is their harmful effect on the environment, manifesting itself at various stages of the casting process, especially during mould pouring. This is why new solutions are sought for sands based on organic binders to ensure their high technological properties but at the same time less harmfulness for the environment. This paper discusses the possibility of reducing the harmful effect of sands with furfuryl binders owing to the use of resins with reduced content of free furfuryl alcohol and hardeners with reduced sulphur content. The use of alkyd binder as an alternative to furfuryl binder has also been proposed and possible application of phenol-formaldehyde resins was considered.

Mechanical reclamation process of spent moulding sands generate large amounts dusts containing mainly rubbed spent binding agents and quartz dust. The amounts of post-reclamation dusts, depending of the reclamation system efficiency and reclaim dedusting system, can reach 5 -10% in relation to the total reclaimed moulding sand. This dust due to the high content of the organic substances is a threat to the environment and therefore requires the storage on landfills specially adapted for this type of waste. On the other hand, the presence of organic substances causes that these dusts have relatively high energy values that could be used. However, at present there is no coherent, environmentally friendly concept for the management of this type of dust. The paper presents the results of tests of thermal utilization the dusts (as a source of energy) were carried out at AGH University of Science and Technology. Thermal utilization of dusts was carried out in the co-burning with carbon carriers process or in individual burning (Patent PL 227878 B1 and patent application PL - 411 902).

No-bake process refers to the use of chemical binders to bond the moulding sand. Sand is moved to the mould fill station in preparation for

filling of the mould. A mixer is used to blend the sand with the chemical binder and activator. As the sand exits the mixer, the binder

begins the chemical process of hardening. This paper presents the results of decomposition of the moulding sands with modified ureafurfuryl

resin (with the low content of furfuryl alcohol below 25 % and different activators: organic and inorganic) on a quartz matrix,

under semi-industrial conditions. Investigations of the gases emission in the test foundry plant were executed according to the method

extended in the Faculty of Foundry Engineering (AGH University of Science and Technology). Article presents the results of the emitted

chosen aromatic hydrocarbons and loss on ignition compared with the different activators used to harden this resin. On the bases of the

data, it is possible to determine the content of the emitted dangerous substances from the moulding sand according to the content of loss on

ignition.

The results of mechanical reclamation of waste moulding sands with furfuryl resin and activators of new generation are presented.

The aim of the research described in this study was to determine what effect the addition of reclaim obtained in the process of dry mechanical reclamation could have on the properties of furan sands.

The sand supplied by one of the domestic foundries was after the initial reclamation subjected to a two-step proper reclamation

process. The following tests were carried out on the obtained reclaim: pH, S and N content, loss on ignition and comprehensive

sieve analysis. The obtained reclaim was next used as a component of moulding sands with furfuryl resin, wherein it formed 50%

and 80% of the base moulding material, respectively. The strength properties of the ready sand mixtures (bending strength Rg u and tensile strength Rm u ) were determined after the hardening time of 0.5, 1, 2, 4 and 24 hours.

The aim of the study was to evaluate the influence of different fillers on the chosen functional properties of experimental composites based on typical polymeric matrix, in order to understand the effect of different fillers on their properties and to develop a simple base composite for further investigations with experimental fillers, e.g. with antimicrobial properties. Previous experiments have been usually based on commercially available composites of unknown composition or compilation of monomers, without reinforcing fillers. Scanning electron microscopy was used to investigate the quality of fillers’ dispersion, which was satisfying. Results showed significant differences between materials’ diametral tensile strength (p = 0.0019), compressive strength (p < 0.0001), Vickers micro-hardness (p < 0.0001), flexural modules (p = 0.0018), and the degree of conversion (p < 0.0001), but flexural strength was not significantly different (p = 0.0583). Investigations indicated that no filler type had an especially positive impact on the mechanical properties, but reinforcement effect was achieved by proper compilation of silica nanofiller and variable glass fillers. Nanofiller decreased the degree of conversion.

The study evaluated the curing properties of natural silica sand moulded with 1% by weight Furotec 132 resin binder catalysed by Furocure CH Fast acid and Furocure CH Slow acid. Physical properties of this sand included an AFS number of 47.35, 4.40 % clay, 0 % magnetic components, 0.13 % moisture, and 64.5 % of the size distribution spread over three consecutive sieves (150 – 600 μm). The sand was washed repeatedly to remove all the clay and oven dried. 2 kg washed sand samples were mulled with pre-determined weights of either catalyst to give 30 %, 50 % and 70 % by weight of 20 g Furotec 132 resin which was added last. Furotec 132 resin + Furocure CH Slow acid catalyst system gives longer bench lives and strip times but the maximum compressive strength in excess of 5000 N/cm2 is attained after more than 8.5 hours curing time irrespective of the weight % of catalyst added relative to the resin. On that basis, exceeding 30 weight % Furocure CH Slow acid catalyst when sand moulding with Furotec 132 resin has neither technical nor economic justification. In comparison, the Furotec 132 resin + Furocure CH Fast acid catalyst system was only capable of producing mould specimens with maximum compressive strength above 5000 N/cm2 at 30 weight % catalyst addition rate. At 50 and 70 weight % catalyst addition rates, the mulled sand rapidly turned dark green then bluish with a significant spike in temperature to about 40 oC, far exceeding the optimum curing temperature of Furotec 132. This high temperature accelerates the curing rate but with a very low degree of resin curing which explains the low compressive strength. In fact the sand grains fail to bond and have a dry, crumbly texture implying dehydration. Thus, not more than 30 weight % Furocure CH Fast acid catalyst should be used in sand moulding.

Increasing demands are imposed on foundries to enforce the manufacture of castings characterized by tight dimensional tolerances, high surface finish and total absence of casting defects. To face these challenges, castings are increasingly made in loose self-hardening sands with furfuryl resin, commonly known as furan sands. In the group of self-hardening sands with synthetic resins, loose self-hardening sands with furfuryl resin enjoy the greatest popularity. The sand mixtures based on furan resins are usually subjected to mechanical reclamation. The consumption of binder and hardener and thus the cost of the sand depend on the quality of reclaim, and mainly on the dust removal degree.

The planned tightening of the environmental protection regulations in the EU countries, including limiting the content of free furfuryl alcohol in resins and reducing the emission of furfuryl alcohol, formaldehyde and BTEX compounds at workplaces, necessitated the development of a new generation of eco-friendly furfuryl resins that have recently appeared on the market.

The main aim of this article was to determine the effect of reclaim content on the sand parameters, such as bending strength, tensile strength, bench life, gas-forming tendency and loss on ignition. Tests were carried out with reclaim content in the sand mixture varying from 50 to 90%. The reclaim obtained by dry mechanical reclamation was supplied by one of the domestic foundries.

The results showed that the highest mechanical properties were obtained in sands containing 60% of the reclaim.

The article discusses results of pull-off adhesion strength tests on poly-p- phenylene benzobisoxazole (PBO) mesh bonded to fir timber beams using epoxy resin. The tests were performed in accordance with the PN-EN 1542 standard. Timber elements reinforced with PBO fibres were subjected to pull-off tests to measure the adhesive strength of the mesh to the beams.The factors occurring during the test were also characterized, which may affect its results such as the method of application of the tearing force, selection of epoxy glue, surface preparation of the tested elements, occurrence of material defects in the wood and types of substrate destruction.The experimental data show that failure of the timber layer was not observed in all the specimens tested.

In order to improve the toughness of traditional epoxy resin, dibutyl phthalate (DBP) was introduced into the epoxy resin. The static mechanical performance of plasticized and unplasticized epoxy resin was evaluated. The test results showed that the DBP modified epoxy resin can obtain a higher toughness than conventional epoxy resin, but the elastic modulus and the tensile strength were slightly reduced. The low cycle fatigue test results indicated that the stress ratio and the stress level were two critical factors of fatigue life, which was increased with the growth of stress ratio. It was also found that the fatigue life of plasticized specimen was much less than that of the unplasticized specimen because of the plastic deformation. A logarithmic linear relationship was then established to predict the fatigue life for plasticized epoxy resin. The strain energy density was also applied to demonstrate the accumulation of energy loss. In addition, the fatigue toughness can be obtained by the hysteresis loop area method.