Hydrophilic monolith with ethylene glycol-based grafts prepared via surface confined thiol-ene click photoaddition

Macroporous polymeric monolith bearing thiol-reactive surface functionalities was prepared within micrometer-sized fused silica capillary column by photochemically-driven free radical copolymerization of N-acryloxysuccininimide and ethylene dimethacrylate in the presence of toluene as porogenic solvent, hereafter poly(NAS-co-EDMA), and subsequent surface grafting of allylamine through nucleophilic substitution reaction. The pore surface with pendant allyl moieties was further functionalized via a two-step thiol-ene click reaction with thiol-containing oligo(ethylene glycol) and mercaptoethanol, successively. The surface hydration ability, i.e. hydrophilic character, of the as-obtained monolith was evaluated as a function of the water-content of the liquid fluid environment through electrochromatographic evaluation of the retention properties of the -(O-CH₂-CH₂)-like surface-functionalized capillary monolith. A major result was that the so called hydrophilic interaction electrochromatographic mode was observed at a given mobile phase composition. An example is given for the separation of phenol-derivatives, with the most hydrophilic one being the most retained. In addition, the hydrophilic interaction based separation allowed for reduced analysis time as compared to the separation observed under reversed-phase separation mode using analogous monolithic stationary phase. Finally, the versatility of the thiol-ene photoaddition approach is demonstrated with an example of C18-like monolith for reversed-phase separation application.     

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microinertial impactor with transmission electron microscopy (TEM) grids on two stages. Micro- and nanostructural characteristics of single particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot agglomerates were found to be collapsed after scrubber, reflected by their change in fractal dimension (D_f ) from 1.88 to 2.13. Soot was predominantly found internally mixed with other components, with a higher degree of internal mixing observed after scrubber. Soot nanostructural characteristics on the near atomic scale such as layer distance, lamella length, and tortuosity were not observed to be influenced by the scrubber. We also found that particles in the size range between 30 and 50 nm, which were abundant in the exhaust before and after scrubber, were not graphitic soot. Furthermore, we found indications that these particles are composed of other crystalline material (salts).

Copyright 2013 American Association for Aerosol Research     

Co‐operative Formation of Monolithic Tungsten Oxide–Polybenzylene Hybrids via Polymerization of Benzyl Alcohol and Study of the Catalytic Activity of the Tungsten Oxide Nanoparticles

Hard and brittle monolithic tungsten oxide‐polybenzylene nanohybrids can be obtained in one step by reacting tungsten iso‐propoxide with benzyl alcohol. In a first step, crystalline tungsten oxide W₁₈O₄₉ nanowires with a diameter of about 1.5 nm form via ether elimination reaction. Subsequently, the large residue of the benzyl alcohol is transformed to dibenzyl ether, which then polymerizes to polybenzylene, incorporating the nanoparticles into the forming polymer. The catalytic effect of the tungsten oxide nanowires on the quantitative formation of polybenzylene is proven by reacting them in different concentrations and at varying temperatures either with benzyl alcohol or with dibenzyl ether. Complete polymerization of benzyl alcohol is achieved within just 30 min by using a particle‐to‐monomer molar ratio of 1:115 at 160 °C. Lower reaction temperatures (100–130 °C) or higher ratios (1:340 and 1:680) prolong the reaction time to several hours. Further studies show that the tungsten oxide nanoparticles are able to completely polymerize various other alcohols with an aryl methanol group.     

Crosslinking of epoxidized natural oils with diepoxy reactive diluents

The different natural oils epoxidized with 3‐chloroperbenzoic acid were crosslinked with diepoxy reactive diluents, bisphenol A propoxylate diglycidyl ether, and 3,4‐epoxycyclohexylmethyl‐3,4‐epoxyclohexane‐carboxylate, using cationic initiator at 60°C and photoinitiators at the room temperature. The insoluble fraction of the polymeric products was 59–90%. The Young modulus of the crosslinked polymer films ranged from 2 to 861 MPa. The 10% weight loss temperatures of the crosslinked polymers estimated by thermogravimetric analysis were in the range from 250 to 420°C. The water vapor transmission rate of the crosslinked biopolymer films ranged from 6 to 49 g/m²/24 h. Biochemical oxygen demand and biodegradation in soil of the crosslinked polymers were studied. The crosslinked polymers showed higher biodegradation rate than cellulose, starch, and polyvinylalcohol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study of plastic compounds containing polypropylene and wood derived fillers from waste of different origin

The scope of the article was to study the perspectives of the using of wood derived fillers (WDF) from waste of different origin as fillers of polypropylene. The WDF used in this study was hard wood flour (HW), birch veneer polishing dust (VD) and tetra‐pack carton cellulose fiber (TC). Some mechanical strength parameters, water uptake in the static and cyclic test and resistance to fungal decay of polypropylene (PP) composites containing these three types of WDF were studied and compared with similar loading (40 wt %) talc‐filled PP. Composites containing TC and VD fibers as filler showed the highest flexural strength at three test temperatures (?40, +20, and +40°C) and flexural modulus and tensile strength at plus temperatures. On the other hand talc‐filled PP exhibited greatest flexural modulus at minus temperature, greatest impact strength at room temperature and best flow ability. Significant difference was observed between PP composites with HW and VD fillers regarding water uptake in cyclic tests, however flexural strength and modulus change of composites were reversible after drying. No weight loss of WDF/PP composites was observed after 6 week exposure to brown‐ and white‐rot fungi, however, degradation of the surface of samples was detected by SEM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Low‐temperature synthesis of nanocrystalline hydroxyapatite: Effect of Mg and Sr content

Nanocrystalline Mg‐ or Sr‐containing hydroxyapatite powders were synthesized through low‐temperature chemical precipitation. The most significant factor for reduction in particle sizes included adjusting the reaction temperature between 0°C and 50°C. Syntheses products were characterized using several analytical tools to determine purity and influence of added amount (up to 15 mol%) of Mg or Sr on the composition and structure. Qualitative analysis by Fourier transform infrared spectroscopy and low intensity, broad X‐ray diffraction peaks indicated the presence of nanocrystalline and/or amorphous hydroxyapatite in all the products. Moreover, a significant decrease in the crystallinity was observed with increasing Mg (up to 2.8 ± 0.3 wt%) and Sr (up to 9.6 ± 1.0 wt%) concentration. N₂ adsorption and scanning electron microscopy characterizations confirmed the nanocrystalline nature of the synthesized products. The synthesized products had nanosized spherical‐like particle morphology with the specific surface area ranging from 89 ± 7 to 150 ± 20 m²/g.     

Fatty Acids,Tocopherols, Tocotrienols,Phytosterols, Carotenoids,and Squalene in Seed Oils of Hyptis suaveolens,Leonotis nepetifolia,and Ocimum sanctum

The oil yield and composition of fatty acids, tocopherols, tocotrienols, sterols, carotenoids, and squalene in the seeds of three species—Hyptis suaveolens, Leonotis nepetifolia, Ocimum sanctum—belonging to the Lamiaceae family, are studied. The oil yields are 12.1%, 16.1%, and 29.0% in O. sanctum, H. suaveolens, and L. nepetifolia, respectively. The unsaturated fatty acids are a predominant group (86.8–92.1%) in all three investigated plants; however, the profile for each species is unique. The main fatty acid differs as follows: H. suaveolens—linoleic acid (85.8%), L. nepetifolia—oleic acid (58.3%), and O. sanctum—α‐linolenic (48.6%). γ‐Tocopherol accounts for over 97%, 90%, and 93% of the total tocochromanol content (sum of tocopherols and tocotrienols) in H. suaveolens, L. nepetifolia, and O. sanctum, respectively. Two tocotrienol homologues, α and γ, are detected only in L. nepetifolia. β‐Sitosterol is the main detected sterol (38–59%) in all three species. High levels of campesterol (18–20%), Δ5‐stigmasterol (9–21%), and Δ5‐avenasterol (7–12%) are also detected. Squalene is detected only in O. sanctum (45.8 mg/100 g oil). The content of sterols, tocochromanols, and carotenoids in the investigated Lamiaceae plant seed oils ranges between 279.5–576.3, 54.5–66.7, and 0.3–3.1 mg/100 g oil, respectively. Practical Applications: Lamiaceae plants are of medicinal interest due to the presence of a broad spectrum of bioactive molecules. The present study demonstrates that seeds of the species H. suaveolens, L. nepetifolia, and O. sanctum are rich sources of bioactive compounds of lipophilic nature. There is limited knowledge associated with the composition of tocopherols, tocotrienols, sterols, carotenoids, and squalene. The results of the studied medicinal plants may enhance future targeted applications in various sectors.     

Two abbreviated versions of the Wechsler Adult Intelligence Scale-III: Validation among persons with traumatic brain injury.

Objective: To examine the clinical value of two 7-subtest versions of the Wechsler Adult Intelligence Scale-III (WAIS-111): one using Block Design (WAIS-III/BD7) and another using Matrix Reasoning (WAIS-III/MR7) among persons with traumatic brain injury (TBI). Study Design: Actual obtained scores from the full WAIS-111 were compared with scores that would have been obtained using each of the two abbreviated versions. Participants: One hundred eighteen persons with TBI tested consecutively in an academic medical center outpatient neuropsychology laboratory. Results: For the WAIS-IIVBD7, corrected validity coefficients were .97 (Verbal IQ [VIQI), .94 (Performance IQ [PIQ]), and .97 (Full Scale IQ [FSIQJ); 92%, 70%, and 92% of scores fell within 5 points of full version scores for VIQ, PIQ, and FSIQ, respectively. WAIS-III/MR7 corrected validity coefficients were .97 (VIQ), .95 (PIQ), and .97 (FSIQ); 92%, 76%, and 92% of short-form scores were within 5 points of actual scores for VIQ, PIQ, and FSIQ, respectively. Conclusions: Both abbreviated versions demonstrated acceptable psychometric characteristics, but the matrix reasoning version may be more advantageous in assessing persons with TBI because it can be used with persons who have TBI-related motor skills impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Software-guided Microfluidic Reaction Calorimeter Based on Thermoelectric Modules

A software-guided, continuous reaction calorimeter based on thermoelectric modules for direct heat flux measurements is presented. Sensors and actuators of the calorimeter's setup are implemented within a lab automation system, which enables the automated calibration of the heat flux sensors and investigations of chemical reactions through sequential function charts. Functionality of the calibration is shown by heat transfer experiments. Additionally, the calorimeter's performance is demonstrated by good agreement of conducted neutralization experiments with literature data.