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The aim of this work was to examine a new family of composites based on the matrix produced of photocrosslinked resins filled with various types of natural or highly oriented synthetic thermoplastics fibers, and finally to examine the properties of such composites in comparison with samples produced from neat photocured resins. The matrix of the composites was the UV-cured epoxyacrylate or epoxymethacrylate resin. The isotactic polypropylene (iPP) fibre, modified with ethylene vinyl acetate (EVA) copolymer, or hemp fibre was used as the reinforcement. An increase in certain mechanical properties was reached in most of the composite materials studied. In case of iPP fibres reinforced composites, a brittle to ductile fracture transition was observed.

Theoretical fundamentals of inverse gas chromatography (IGC) method applied to evaluation of surface properties of various materials, especially glass-ionomer cements as the subjects of investigations, were presented. The values of dispersive component of surface free energy (γ d s ) of two such cements, used as the dental fillings, were determined by IGC (Table 1). The following parameters, except of the cement type, were investigated: relative humidity of carrier gas used in IGC method (RH = 60 or 80 %), type of medium for the sample storage before the measurements (water or artificial saliva) and storage time (up to 180 days). RH value appeared to be the most important parameter: at lower humidity of a carrier gas the surface activity of cements has usually been greater. Unambiguous determination of the effects of another parameters appeared to be impossible because of non-directed fluctuations of γ d s values. The results obtained suggest similar surface activity of both fillings.

The diffusion control of termination in radical polymerization involving multivinyl monomers results in an alternative mechanism of bimolecular termination, namely in the reaction diffusion. By studying photo-initiated polymerization and copolymerization of mono- and dimethacrylates, the influence of polymer cross-linking density and monomer structure on reaction diffusion parameter R was determined. A reduction of cross-linking density results in the shift of reaction diffusion controlled termination towards high conversion. In loosely cross-linked systems, the reaction diffusion may not control the termination. It is proposed that the apparent increase in R with conversion beyond its steady value that begins at the conversion range of maximum polymerization rate is associated with a change of termination mechanism. Then the rate equations for bimolecular reaction fail to describe the process.

The work presents the results of determination of reactivity ratios for vinyl/divinyl systems based on dodecyl methacrylate and four oxyethylene glycol dimethacrylates. Various methods (based on terminal model and penultimate effect) were used for calculation of experimental results. The experimental data were obtained by gas chromatography (determination of unreacted monomers in the feed) and by NMR analysis of the soluble copolymer. It was found that dimethacrylates were preferentially built into the copolymer chain. These results were in good agreement with quantum-mechanical calculations based on the analysis of heats of formation of short-chain oligomers.