Abstract. Presented research shows the results of a study on the mechanical properties of materials obtained in the course of innovatory application of epoxidized vegetable oil in the synthesis of new bio-based epoxy resins, crosslinked with curing agents which are not typical for epoxy materials. The product was obtained via modern and pro-ecological modification of a well-known synthesis method of epoxies, namely the epoxy fusion process, then it was crosslinked using polyisocyanates of different structure: toluene-2,4-diisocyanate (TDI), hexamethylene diisocyanate (HDI) and 4,4′-methylene diphenyl diisocyanate (MDI). The obtained epoxy-polyurethane materials are characterized by various mechanical properties, which depend on the type of chosen isocyanate. Compositions based on HDI exhibit better mechanical characteristics than elastic polyurethane materials based on hydroxylated soybean oil. Materials cured with aromatic isocyanates MDI and TDI are characterized by higher mechanical resistance comparable with cast polyurethane based on petrochemical resources. Epoxy fusion product cured with toluene-2,4-diisocyanate in a presence of Dabco T9 appears to have the best mechanical properties among all tested compositions.

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Due to the thermal and fire sensitivity of polymer bio-composite materials, especially in the case of plant-based fillers applied for them, next to intensive research on the better mechanical performance of composites, it is extremely important to improve their reaction to fire. This is necessary due to the current widespread practical use of bio-based composites. The first part of this work relates to an overview of the most commonly used techniques and different approaches towards the increasing the fire resistance of petrochemical-based polymeric materials. The next few sections present commonly used methods of reducing the flammability of polymers and characterize the most frequently used compounds. It is highlighted that despite adverse health effects in animals and humans, some of mentioned fire retardants (such as halogenated organic derivatives e.g., hexabromocyclododecane, polybrominated diphenyl ether) are unfortunately also still in use, even for bio-composite materials. The most recent studies related to the development of the flame retardation of polymeric materials are then summarized. Particular attention is paid to the issue of flame retardation of bio-based polymer composites and the specifics of reducing the flammability of these materials. Strategies for retarding composites are discussed on examples of particular bio-polymers (such as: polylactide, polyhydroxyalkanoates or polyamide-11), as well as polymers obtained on the basis of natural raw materials (e.g., bio-based polyurethanes or bio-based epoxies). The advantages and disadvantages of these strategies, as well as the flame retardants used in them, are highlighted.

The presented research shows the results of matrix-assisted laser desorption/ionization mass spectrometry, which was used as a means of monitoring the synthesis of novel high-molecular weight epoxy resins. The products were obtained by the reaction of epoxidized soybean oil (ESBO) and bisphenol A (BPA), using a modern and pro-ecological modification of the well-known method of the synthesis of epoxy resins, called “the epoxy fusion process”. On the basis of the obtained spectrograms, the manner in which substrates reacted with each other during the conducted synthesis was determined. Initially, after the reaction of the oxirane group of ESBO with the hydroxyl group of BPA, subsequent reactions occurred, involving other molecules of bisphenol and the remaining oxirane rings of epoxidized vegetable oil or the reaction of a free phenolic group with the following macromolecule of modified oil. It was found that the final product of the polyaddition (ESBO_BPA), obtained by the epoxy fusion process conducted in bulk, consists of macromolecules with various structure. First, smaller oligomers such as 1ESBO + 1BPA and ESBO + 2BPA were formed, and as the reaction proceeded, they rapidly reacted with each other forming larger macromolecules: 2ESBO + 2BPA, ESBO + 3BPA, 2ESBO + 3BPA, 3ESBO + 3BPA, and 3ESBO + 4BPA. On the basis of the course of the ESBO_BPA polyaddition process in the registered m/z range, it was found that 1ESBO + 1BPA tends to react with other substrates from the reacting mixture to create a linear product. Bisphenol A is a rigid element, which connects the elastic alkyl chains of epoxidized soybean oil in the obtained macromolecule.

Presented research shows the results of a study on the synthesis and mechanical properties of materials obtained by crosslinking polyaddition bio-products with blocked isocyanate based on toluene diisocyanate (TDI) as curing agent. Bio-resins, polyaddition product of epoxidized soybean oil and bisphenol A or hydroxylated soybean oil and low molecular weight epoxy resin, were synthesized via modern and pro-ecological modification of the synthesis of epoxies, namely, the epoxy fusion process. The obtained polyaddition product contains free epoxy and hydroxyl groups, which are suitable for the curing purposes. Material cured with Desmodur BL 1265/MPA/X in the presence of organometallic or amine catalyst (respectively: Dabco T9 and Dabco 33-LV) is characterized by mechanical properties better than the composition crosslinked without the catalyst. Additionally, there is a possibility of the synthesis of two-layer materials by chemical bonding of two different compositions via the previously unused oxirane groups of the cured ESBO_BPA or SMEG_EPR products.