A series of acrylate functionalized samples based on hyperbranched hydroxy-terminated polyesters with different molecular weights and different degrees of acrylation were synthesized. The obtained urethane acrylates were slightly yellow viscose liquids. Their composition was characterized by FTIR and 1H-NMR spectroscopy and their molecular weights were measured by GPC. All the synthesized samples were diluted with 25 wt.% 1,4-butanediol dimethacrylate (BDDM). The rheological properties of the uncured samples and the dynamic mechanical properties of the UV cured samples were examined. All the samples exhibit Newtonian behavior, which indicates the absence of physical entanglements in these polymers. The viscosity increases with increasing number of acrylic groups permolecule. The glass transition temperature of the UV cured samples increases with increasing the number of acrylic groups permolecule. The value of the storage modulus in the rubber-elastic plateau and the cross-link density increase with increasing number of acrylic groups permolecule. The formed networks are inhomogeneous and the residual unsaturation is the highest in the samples with the largest number of acrylic groups per molecule.

TiO 2 nanoparticles, obtained by acid catalyzed hydrolysis of titanium isopropoxide, were surface modified by three gallic acid esters with different hydrophobic part length: octyl, decyl and lauryl gallate, and then used to prepare TiO 2 /epoxy nanocomposites. The characterization of the surface modified TiO 2 nanoparticles was performed by FTIR and UV-Vis spectroscopy. The influence of different gallic acid esters and content of modified TiO 2 nanoparticles on the glass transition temperature (Tg), rheological, barrier and mechanical properties of the nanocomposites was investigated by DSC, DMA, water vapor permeability test and König pendulum. The presence of the surface modified TiO 2 nanoparticles in epoxy resin caused the increase of Tg and decrease of the water vapor permeability. However, the length of the nonpolar gallate part showed no effect on Tg of the synthesized nanocomposites, while the increase of the nanofiller content resulted in the increase of Tg. With increasing the hydrophobic part chain length of gallate ligand, the water vapor transmission rate decreased, while the hardness of the nanocomposites did not change.

IzvodSferne čestice TiO 2 različitih veličina dispergovane su u alkidnoj smoli. Površinska modifikacija nanočestica TiO 2 izvedena je propil galatom i lauril galatom. Ispitivan je uticaj veličine nanočestica TiO 2 , koncentracije, kao i vrste površinske modifikacije na reološka svojstva alkidne smole. Dobijeno je da je viskoznost pripremljenih disperzija veća od viskoznosti čiste smole, da raste sa smanjenjem prečnika čestica i opada sa povećanjem frekvencije. Površinski modifikovane čestice imaju veći uticaj na viskoznost alkidne smole nego nemodifikovane zbog povećanja efektivnog zapreminskog udela čestica u disperziji. Za najmanju koncentraciju TiO 2 viskoznost je veća kada je modifikacija izvršena lauril galatom, dok sa povećanjem koncentracije, zbog manje disperzione stabilnosti čestica modifikovanih propil galatom, dolazi do njihove aglomerizacije i naglog povećanja viskoznosti.

Twelve modified dithiocarbamates and a thiuramdisulfide used for the initiation of methyl methacrylate (MMA) polymerization were synthesized in this study. The polymerization of MMA was followed by determine the yield and molar mass of the obtained PMMA as a function of polymerization time. Four of the synthesized dithiocarbamates S-benzyl-N,N-dibenzyldithiocarbamate, S-allyl-N,N-dibenzyldithiocarbamate S-benzyl-N,N-diisobutyldithiocarbamate and S-benzoyl-N,N-diisobutyldithiocarbamate, as well as N,N,N',N'-tetrabenzylthiuramdisulfide acted as iniferters. They were active as the initiators of the photo and/or thermally initiated radical polymerization of MMA in bulk and inert solvents (benzene and toluene). S Benzyl - N,N - dibenzyldithiocarbamate can be successfully used for the initiation of MMA polymerization in a polar solvent such as dimethylacetamide

Incorporation of inorganic nanoparticles can significantly affect the properties of the polymer matrix. The properties of polymer nanocomposites depend on the type of incorporated nanoparticles, their size and shape, their concentration, and interactions with the polymer matrix. Homogeneity of polymer nanocomposites is influenced very much by the preparation method. In this study, TiO2 nanoparticles surface modified with 6-palmitate ascorbic acid (6-PAA) were incapsulated in poly(methyl methacrylate) (PMMA) by in situ radical polymerization of methyl methacrylate initiated by 2,2'-azobisisobutyronitrile (AIBN). The surface modification of the TiO2 nanoparticles was achieved by the formation of a charge transfer complex between TiO2 nanoparticles and 6-palmitate ascorbic acid. The radical polymerization of MMA in the presence of TiO2-PAA nanoparticles was conducted in solution (PMMA/TiO2-PAA-R), in bulk (PMMA/TiO2-PAA-M) or in suspension (PMMA/TiO2-PAA-S). The main purpose of this study was to investigate the influence of the preparation method on the molar masses and thermal properties of PMMA/TiO2-PAA nanocomposite. It was obtained that molar masses of PMMA extracted from the composites had smaller values compared to molar masses of pure PMMA synthesized in the same manner, which indicated that TiO2-PAA nanoparticles affected the reaction of termination. Thermal properties were investigated by DSC and TGA. The values of glass transition temperature, Tg, were influenced by the way the radical polymerization was conducted, even in the case of the pure PMMA. The Tg of composite samples was always smaller than the value of the corresponding PMMA sample and the smallest value was obtained for PMMA/TiO2-PAA-M since they contained the largest amount of low molar mass residue. The TGA results showed that thermal and thermooxidative stability of polymer composites obtained in solution and in suspension was better than for the pure PMMA obtained in the same way