Molecular and Morphological Characterization of Immiscible SAN/EPDM Blends Filled by Nano Filler

The compatibilizing effect of nano sized calcium carbonate filler on immiscible blends of styrene‐co‐acrylonitrile/ethylene propylene diene (SAN/EPDM) was examined. The surface energy of the calcium carbonate was modified by stearic acid. The compatibility of SAN/EPDM blends was studied by following the glass transition temperature T_g by DSC. SEM was used to observe the blend morphology and the X‐ray analyzer was used to detect the calcium from filler in samples. Mechanical properties of the blends were determined, and related to changes of polymer‐filler interactions and morphology. The results suggest that the morphology of the SAN/EPDM blends studied was affected by the reduction of surface energy of the filler.

SEM micrograph of an SAN/EPDM blend with 5% of maximally treated filler.     

Influence of condensed water on heat radiation absorptivity at cryogenic temperatures

Influence of water deposit on heat radiation absorptivity of a metallic surface was measured in a device designed for investigation of thermal radiative properties of materials at cryogenic temperatures. In this device heat transfer between planparallel surfaces of radiator and absorber is measured. An aluminium sample of 40 mm in diameter was used as absorber. A radiator consisting of an organic composite on a copper disk was used in two experiment stages. At temperature of 298 K, water outgassed from the organic layer formed the deposit on the absorber. Then the heat emitted from the radiator at temperatures from 45 K up to 250 K was used for the absorptivity measurement. Substantial influence of deposit of 85 mg/m² on the sample absorptivity was found.     

Influence of calcium carbonate filler and mixing type process on structure and properties of styrene–acrylonitrile/ethylene–propylene–diene polymer blends

The properties of styrene–acrylonitrile (SAN) and ethylene–propylene–diene (EPDM) blends containing different types of calcium carbonate filler were studied. The influence of mixing type process on the blend properties was also studied. Two different mixing processes were used. The first one includes mixing of all components together. The other process is a two‐step mixing procedure: masterbatch (MB; EPDM/SAN/filler blend) was prepared and then it was mixed with previously prepared polymer blend. Surface energy of samples was determined to predict the strength of interactions between polymer blend components and used fillers. The phase morphology of blends and their thermal and mechanical properties were studied. From the results, it can be concluded that the type of mixing process has a strong influence on the morphological, thermal, and mechanical properties of blends. The two‐step mixing process causes better dispersion of fillers in blends as well as better dispersion of EPDM in SAN matrix, and therefore, the finest morphology and improved properties are observed in blends with MB. It can be concluded that the type of mixing process and carefully chosen compatibilizer are the important factors for obtaining the improved compatibility of SAN/EPDM blends. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The surface energy as an indicator of miscibility of SAN/EDPM polymer blends

Surface properties of blends prepared of styrene-acrylonitrile and ethylene-propylene-diene changing the homopolymer proportions and compatibilized by high impact polystyrene have been studied by contact angle measurement. The surface free energy of interphase of homopolymers pairs, work of adhesion, and wetting coefficient were calculated using Wu’s geometric mean method and the total surface free energy and acid–base components of the blends by using van Oss, Good and Chaudhury method. Blends were also characterized by dynamic mechanical analysis and by scanning electron microscopy. The miscibility of studied blends was estimated through changes of surface free energy, energy of interface and through the shifts of glass transition temperature and changes in morphology. From the results, it can be seen that added compatibilizer reduces the interface energy and provides more homogenous system by interfacial segregation and rearrangements of molecules at the blend surface. The results of morphological observations reveal that the addition of a small percentage of compatibilizer decreases the domain size of the dispersed phase and enhances the compatibility of the blends.     

Thermal radiative properties of a DLC coating

Thermal radiative properties of a DLC coating were measured in the range of cryogenic and room temperatures. Both the total hemispherical emissivity and absorptivity are significantly dependent on the radiation temperature and change from the value of 0.032 at 15 K to 0.65 at 300 K.     

Volatility and phase stability of petrol blends with ethanol

Blending ethanol in to petrol can be associated with problems related to volatility and phase stability of the blends. Ethanol up to 20 vol% in petrol forms an azeotropic mixture with hydrocarbons. Ethanol has affinity to water and air humidity and it increases the water solubility in ethanol-petrol blends. In this work, the influence of ethanol up to 10 vol%, ETBE up to 10 vol% and hydrocarbon composition over volatility, distillation characteristics and miscibility of ethanol-petrol blends with water was studied. It was found that higher content of saturated hydrocarbons in petrol increased the vapour pressure of azeotropic ethanol blend. Aromatics and alkenes influenced the azeotrope vapour pressure, phase separation temperature and ethanol extraction in a positive way. The results showed that the ETBE can soften effects of the ethanol blending to petrol. ETBE decreased the vapour pressure and the phase separation temperature of the ethanol-petrol blends.     

Inhibitory Control and Response Selection in Problem Solving: How Cotton-Top Tamarins (Saguinus oedipus) Overcome a Bias for Selecting the Larger Quantity of Food.

When presented with a choice between 1 and 3 pieces of food in a type of reversed contingency task, 4 cotton-top tamarins (Saguinus oedipus) consistently chose the 3 pieces of food and received nothing, even though the choice of 1 piece would have yielded 3. However, in a task in which the tamarins received the 1 piece of food when they chose it, all subjects learned to select 1 over 3. Thus, the tamarins' prior failure on the reversed contingency task did not result entirely from an inherent inability to suppress the prepotent response of reaching to the larger of 2 quantities of food. After the experience of selecting the smaller quantity and receiving it, all of the tamarins solved the version of the reversed contingency task that they failed initially. These results suggest that the tamarins' initial failure may have reflected a difficulty with selecting an alternative response option. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Low temperature radiative properties of materials used in cryogenics

Radiative heat transfer between two parallel surfaces, a sample surface and a black surface, was measured. One of the surfaces was cooled with liquid helium to about 5 K and the other one was step by step heated to temperatures ranging between 30 and 140 K. As a result, the total hemispherical absorptivity and emissivity of the sample surface were determined in dependence on the temperature of the heat radiation. Aluminium samples were made of Al sheet, Al foil and aluminized mylar. Further measurements were performed on sheets of aluminium alloy, Cu, zinc brass and stainless steel. The influence of different types of sample treatment such as chemical and mechanical surface finishing and material annealing on the radiative properties is presented.