Die polymerisation von lactamen, 86. Verzweigung der autopolymerisationsprodukte von 8-octanlactam

Assumed branching of polymer chains of poly(8-octane lactam) was proved from the study of solution properties of polymers prepared under the conditions of autopolymerization in the temperature range 240–260°C. The amidine structures in the polymer chains which were found out by hydrazinolysis are not in relation to the branching in the full extent.     

Sugar and nutritional extremism

For many, sugar represents a threat to their health, a perception that is driven by increase in the prevalence of obesity, diabetes, and metabolic disorders, which directly or indirectly is connected with the consumption of sugar. However, is sugar to blame for this health crisis, or are sedentary lifestyle and unhealthy diet equally important? Today, sugars and fats are being targeted for restriction or even prohibition. Should we get rid of sugar altogether and/or does it merit a reprieve? Is the effort to “outlaw” sugars a symptom of nutritional extremism that can be as harmful as any other type of extremism?     

“Building hope: from a shack to 3E house”—Innovative housing approach in the provision of affordable housing for Roma in Slovakia

The post-1989 objectives of the Slovak housing policy have resulted in the large-scale privatisation of state rental flats and the reduction in new rental housing. State-subsidised social rental housing programmes have been unable to meet the social demand for affordable rental dwellings. Socially marginalised groups, in particular Roma people, have been hit the most by the post-1989 changes and the lack of official social housing construction. Project Building Hope is an alternative integrated housing approach, offering Roma people better life conditions by integrating housing issues with other policies related to social empowerment. In order to implement the innovative project, a broad coalition between public and private sector actors is established, which is able to change the perception of Roma in the community and influence local policy-making processes.     

Direct mercury determination in natural waters by chronopotentiometric stripping analysis in macroelectrode process vessel

By using a specific electrochemical cell with a rotating glassy carbon process vessel as the working electrode, a significant enhancement of mercury determination comparing to commonly used disc electrodes of glassy carbon was achieved. Detection limit obtained for electrolysis time of 600 s was 0.1 ng dm^− 3 of Hg(II). The influence of the most important experimental factors of chronopotentiometric stripping analysis was investigated and the defined method was applied for mercury determination in different types of waters without any pretreatment. Methods accuracy was confirmed by analysing standard reference material. Obtained results showed that similar electrochemical systems can be proposed for continual or semicontinual monitoring of mercury content in different types of waters.     

The waterborne polyurethane dispersions based on polycarbonate diol: Effect of ionic content

Three water-based polyurethane dispersions (PUD) were synthesized by modified dispersing procedure using polycarbonate diol (PCD), isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), triethylamine (TEA) and ethylenediamine (EDA). The ionic group content in the polyurethane-ionomer structure was varied by changing the amount of the internal emulsifier, DMPA (4.5, 7.5 and 10 wt.% to the prepolymer weight). The expected structures of obtained materials were confirmed by FTIR spectroscopy. The effect of the DMPA content on the thermal properties of polyurethane films was measured by TGA, DTA, DSC and DMTA methods. Increased DMPA amounts result in the higher hard segment contents and in the increase of the weight loss corresponding to the degradation of the hard segments. The reduction of hard segment content led to the elevated temperature of decomposition and to the decrease of the glass transition temperature and thermoplasticity. The atomic force microscopy (AFM), results indicated that phase separation between hard and soft segment of PUD with higher DMPA content is more significant than of PUD with lower DMPA content. The physico-mechanical properties, such as hardness, adhesion test and gloss of the dried films were also determined considering the effect of DMPA content on coating properties.     

The effect of conditions of mixing of polypropylene/ethylene-propylene elastomer blends on their morphological structure and impact strength

The dependence of morphological structure and notch impact strength of polypropylene/ethylene-propylene elastomer blends on conditions of mixing was investigated. Two types of polypropylene and two types of ethylene-propylene elastomer having different viscosities were used. At low rates and short times of mixing the samples contain both regions showing fine dispersion and regions showing large elastomeric inclusions surrounded with pure polypropylene. With increasing rate and time of mixing the large inclusions gradually disappear. The conditions of mixing which are necessary for reaching a homogeneous structure of the blends depend on viscosities of the components. The independence of particle size of the rate of mixing in homogeneous samples is discussed on the basis of a dynamic equilibrium between the break up and coalescence of droplets. The notch impact strength of the individual samples of the same blend is determined by the size and number of inhomogeneities (large inclusions) in the given sample.     

Die polymerisation von lactamen, 50. Die polymerisation von 8-octanlactam in gegenwart von wasser in niedrigen konzentrationen

The polymerization of 8-octanelactam in the presence of 0,15–0,95 mol-% water at 250°C was studied. The kinetic data obtained gave evidence for a different function of water at concentrations up to 0,35 mol-% and higher concentrations. With respect to the results of the end-group analysis of the polymers, which were prepared without added water or other initiators (autopolymerization), a cationic mechanism for the polymerization of 8-octanelactam in the presence of water up to 0,35 mol-% was suggested.     

Fusarium mycotoxins in various barley cultivars and their transfer into malt

BACKGROUND: Fusarium toxins, secondary metabolites of toxinogenic Fusarium species, are found in a range of cereal grains. In this study the occurrence of the most commonest Fusarium toxins, namely nivalenol (NIV), deoxynivalenol (DON), deoxynivalenol‐3‐glucoside, fusarenon‐X, 3‐ and 15‐acetyldeoxynivalenol, HT‐2 and T‐2 toxins and zearalenone, in various barley cultivars harvested in 2005–2008 was monitored. The impact of weather, locality, fungicide treatment and barley cultivar (hulless or covered) on contamination was evaluated. The transfer of these mycotoxins into malt was assessed. RESULTS: The most prevalent toxin was DON, which was found in 83% of samples (maximum level 180 µg kg^?1), while HT‐2 was detected in 62% of samples (maximum level 716 µg kg^?1). Using analysis of covariance, weather was found to be the key factor in all years (P < 0.001). A relationship between cultivar and contamination was confirmed only for HT‐2 (P < 0.001) and T‐2 (P = 0.037), with higher levels of these toxins being observed in hulless cultivars. With the exception of NIV (P = 0.008), no significant relationship was found between fungicide treatment and contamination. No distinct trend regarding DON levels in malt was found, with both decreases and increases occurring. CONCLUSION: The results show an inter‐annual variation in mycotoxin occurrence in barley cultivars as well as differences in contamination of malt produced from fungicide‐treated and untreated barley. Copyright © 2010 Society of Chemical Industry     

The properties of polyurethane hybrid materials based on castor oil

The goal of this work was to investigate the properties of environmentally friendly, castor oil based polyurethane hybrid materials with titanium(IV) oxide nanoparticles, as a filler, and different types of diisocyanate (toluene diisocyanate and isophorone diisocyanate). In the sample synthesis, different ratios of the reactive groups (NCO/OH), r, were used (1, 1.15 and 0.92). In the composite preparation, only toluene diisocyanate was used, and the filler particles were premixed in a glass vessel with the castor oil polyol before the reaction with diisocyanate. For all the composite samples, the r value was 1. Polyurethane formation was confirmed by ATR-FT-IR by detecting the urethane band at 1515 cm⁻¹. It was determined that the hydroxyl groups had reacted because the broad band corresponding to the OH groups (3400 cm⁻¹) was not detected or detected at a reduced intensity depending on the r value. As was expected, the presence of the unreacted NCO groups was detected only for samples with r > 1 (band at 2300 cm⁻¹, which corresponds to the existence of these groups). The dynamic mechanical measurements were performed at a temperature range from −50 °C to 100 °C at different frequencies. For investigation of reinforcement effect of filler on polymer matrix, tensile testing was applied. The glass transition temperature, T_g, was determined by DSC measurement. It was estimated that the T_g of the samples decreased as the nanofiller content increased due to the changes in the segmental mobility influenced by the interaction between the nanoparticles and polymer chains.