Mixture Of High Molecular Weight Research Articles

The degradation profile of high molecular weight textile reactive dyes: A daylight induced photocatalytic activity of ZnO/carbon quantum dot photocatalyst

Advancement in developing daylight-induced photocatalyst has received enormous potential to degrade textile toxic dyes. In textile industry, while processing to fabricate an appealing color shade on cotton fabrics, it is inevitable to use mixture of high molecular weight (HMW) reactive dyes. Indeed, most of the recent reports mainly focused on degrading low molecular weight (Mol.wt: <400) dyes including methyl orange, methylene blue, malachite green and rhodamine dyes. However, it is hard to find reports on degrading HMW textile dyes particularly under daylight irradiation. Herein, three different HMW reactive dyes such as reactive orange (RO, Mol.wt: 762.04) reactive red (RR, Mol.wt: 1469.98), and reactive blue (RB, Mol.wt: 2248.57) were chosen to investigate the real time photocatalytic performance using zinc oxide/carbon quantum dots (ZnO/C-dots) under daylight irradiation. The maximum dye degradation of 85 % of RO dye was achieved after 8 h of daylight irradiation. The total time required for complete degradation of an individual HMW dye also measured. The impact of pH and amount of photocatalysts towards the degradation profile of HMW dyes were examined and compared the degradation profile with relevant reports. The formation of OH and holes are the main active reactive species for the ZnO/C-dots photocatalyst to degrade HMW dyes under daylight irradiation. Thus, it is confirmed that the ZnO/C-dot photocatalyst can be useful for real-time wastewater treatment in textile industry to degrade HMW dyes under daylight irradiation.

Viscosities of mixtures of hyaluronic acids with different molecular weights and their effects on enzymatic activities of lysozyme and peroxidase.

To investigate the viscosity values of mixtures of hyaluronic acids with different molecular weights and the effects of these mixtures on the enzymatic activities of lysozyme and peroxidase. Mixtures of high molecular weight (1 or 2MDa) and low molecular weight (10 or 100kDa) hyaluronic acids at different concentrations were used for viscosity measurements. Hyaluronic acid mixtures showing viscosity values similar to those of human whole saliva were used for enzyme experiments in solution and on hydroxyapatite surface. Hen egg-white lysozyme, bovine lactoperoxidase, and human whole saliva were used as enzyme sources. Lysozyme activity was measured by hydrolysis of fluorescein-labeled Micrococcus lysodeikticus. Peroxidase activity was measured by oxidation of fluorogenic 2',7'-dichlorofluorescein to fluorescing 2',7'-dichlorofluorescein. The mixtures of 1MDa (0.5mg/mL) or 2MDa (0.2mg/mL) hyaluronic acid with 10kDa (2.0mg/mL) or 100kDa (0.1mg/mL) hyaluronic acid had viscosity values similar to those of human whole saliva at shear rates, reflecting normal oral functions. Compared with single molecular weight hyaluronic acids, these mixtures showed viscosity values more similar to those of human whole saliva. The mixtures inhibited lysozyme and peroxidase activities on the hydroxyapatite surfaces; however, the degree of inhibition did not differ from that of hyaluronic acid of 1 or 2MDa only. Compared with single molecular weight hyaluronic acids, hyaluronic acid mixtures showed viscosity values more similar to those of human whole saliva, without additional inhibitory effects on lysozyme and peroxidase activities. Hyaluronic acid mixtures offer distinct advantages for the development of saliva substitutes.

RESERCH THE COMPOSITION OF PEATS IN OLIGOTROPHIC MIRE

Specific and most representative group of biologically active substances of peat are humic acid (HA) and bitumen, which is a complex mixture of high molecular weight and polyfunctional alicyclic compounds, hydroaromatic, aromatic and heterocyclic nature. Preparations from HA and bitumen are used in medicine and veterinary medicine. However, the spectrum of peat BAS is quite wide and heterogeneous in individual peatlands and depends of peat formation of the swamp, the depth of peat deposit, botanical composition and other factors. The identification of the highest quality raw material base for the production of specific drugs requires the study of the organic composition of peat, including HA and bitumen on all swamp depth. The article substantiates the need to identify the highest quality raw material base (peat deposit or combinations peat deposits) for the production of specific products. On the example of the peat deposit Gazoprovodnoe, presents the results of the analysis of HA and bitumens throughout the profile of the peat deposit and establishes the possibility of using peat resources of this peat deposit in the production of a wide range of drugs for medical purposes and household chemicals.

INVESTIGATION OF CATALYTIC CONVERSION OF FISCHER-TROPSCH WAX ON Pt/AlSBA-15 AND Pt/BETA ZEOLITE CATALYSTS

Because of the more serious problems with the environment (e.g. greenhouse effect) and the crude oil supply (e.g. import dependence) the use of fuels and lubricants produced from renewable feedstocks have come to the front nowadays. The Fischer-Tropsch wax (60–80% of the Fischer-Tropsch products) which is produced on synthesis gas from different sources (biological or waste), is a mixture of high molecular weight (C20-C60) n-paraffins, which are in solid state (high pour point) at normal conditions. The products (fuels and base oils) which can be produced from this paraffin mixture have high quality and have fewer negative effects on the environment (practically zero sulphur- and nitrogen content, low aromatic content, excellent application properties) thus theydo not demand changes in the fuel supply infrastructure and in the engine constructions. The isomerization of high molecular weight n-paraffins can be effectively carried out on bifunctional catalysts. There are only a few indications about the application of metal catalysts on mesoporous carrier in the literature. Consequently our objective was to investigate some Pt/AlSBA-15 (SBA: Santa Barbara Amorphous) catalysts which have not been investigated in detail in this reaction system yet, and compare its properties with a Pt/beta zeolite catalyst which has been recommended for this reaction earlier. The applicability and catalytic activity of Pt/AlSBA-15 and Pt/beta zeolite catalysts of 0.5% platinum content for the selective isomerization of Fischer-Tropsch wax was investigated in the present experiment. The experiments werecarried out in a high-pressure microreactor system in continuous operation and on a catalyst with steady-state activity. The main properties of the feedstock which was a mixture of paraffin produced by Fischer-Tropsch synthesis (the synthesis gas was produced from biomass) were: n-paraffin content (C18-C57): 97.4%, sulphur content: 5 mg/kg, pour point: 72 °C. In the experiment the following process parameters were applied: T=275–375 °C, P=40–80 bar, LHSV=1.0–3.0 h-1, H2/hydrocarbon ratio: 400–800 Nm3/m3. The composition of the products was determined by gas chromatography. From the catalysts with different support the best results were gained on the catalysts with AlSBA-15 support, and with increasing temperature the yield of liquid products (C5+) decreased, but until 325 °C this value was above 93% in every case. Incase of the beta zeolite high amount of cracking took place. Increasing the pressure shifted back the hydrocracking reactions(with the increasing number of moles) so it had a decreasing effect on the volume of the gas products and the lower contact time (higher liquid hour space velocity) had the same effect. In the gas products mainly branched isobutane was identified, which indicated that the cracking enacted partly after the isomerization reactions. The isoparaffin contents of the liquid products in the function of process parameters increased with increasing temperature and decreased with increasing pressure and LHSV in every case while other parameters were kept constant. Based on the isoparaffin contents of the different fractions it can be concluded that on Pt/AlSBA-15 catalyst at advantageous process parameter combinations (T=300–325 °C (C11-C20)/ 275–300 °C (C21-C30), P=40–80 bar, LHSV=1.0–2.0 h-1) the catalyst was applicable to produce C11-C20 and C21-C30 fractions with high isoparaffin content (63.5–85.6% and 34.1–58.7%) with adequate yields (29.9–36.6% and 46.2–58.8%). We experienced that the gas oil fractions having the lowest pour point were obtained in the case of high concentrations of 5-methyl isomers. The C21-C30 fraction is a high viscosity index (VI ≥125) base oil. The selectivity of the target product fractions was high, and based on these facts the selective isomerization of the Fischer-Tropsch wax can be a new application area of the Pt/AlSBA-15 catalyst.

Policosanol Contents and Compositions of Wheat Varieties

Policosanol (PC) is the common name for a mixture of high molecular weight (20-36 carbon) aliphatic primary alcohols, which are constituents of plant epicuticular waxes. Wheat germ oil has been reported to improve human physical fitness, and this effect is attributed to its high PC, specifically its high octacosanol (OC) content. Although the PC composition of wheat leaves has been studied extensively, information on PC content and composition of wheat grain fractions is scarce. The objective of this study was to examine the PC contents and compositions of wheat grain fractions of 31 varieties grown in Oklahoma. PC compositions of the samples were identified using a gas chromatograph coupled with a mass spectrometer. The PC content of wheat bran was higher than that of the germ, shorts, and flour. The Trego and Intrada varieties had the highest PC content among the 31 wheat varieties studied. Tetracosanol (C24), hexacosanol (C26), and OC (C28) were the major PC components in all varieties. This study showed that wheat varieties grown under identical growing conditions and management differ significantly in PC content and composition.

Microencapsulation of linoleic acid with low- and high-molecular-weight components of soluble soybean polysaccharide and its oxidation process.

Soluble soybean polysaccharide (SSPS) was fractionated into its low- (LMW) and high-molecular-weight (HMW) components to test their antioxidative and emulsifying properties. Linoleic acid was emulsified with an aqueous solution of SSPS, HMW, a mixture of LMW or HMW with maltodextrin, or maltodextrin alone. The emulsions prepared with SSPS, HWM and the mixture of HMW with maltodextrin were stable. These emulsions were spay-dried to produce microcapsules. The encapsulated linoleic acid was oxidized at 37 degrees C and at various levels of relative humidity. Linoleic acid encapsulated with the mixture of LMW with maltodextrin or HMW was stable to oxidation, and this stability increased as the weight fraction of LMW in the mixture was increased. The LMW components also had high DPPH-radical scavenging activity. These results indicate that LMW played an important role in suppressing or retarding the oxidation of linoleic acid encapsulated with SSPS. The oxidative stability of linoleic acid encapsulated with a mixture of the LMW and HMW components was high at low and high relative humidity, but not at intermediate levels of relative humidity.

Phase structure and deformation behavior of polyester blends

The supermolecular structure, deformation behavior and tensile properties were studied for the blends of a high molecular weight (HMW) poly(ethylene 2,6-naphthalate) (PEN) and a commercially available low molecular weight (LMW) PEN. The HMW with an intrinsic viscosity (IV) of 3.30dl/g was obtained by solid-state polymerization of the LMW with IV of 0.65dl/g. The mixture of HMW and LMW prepared by a freeze-dried method from the polymer solutions showed two Tgs, independent of the blend ratio. These Tgs corresponded to those for the HMW and the LMW. After melting or even annealing above the Tg of HMW, these blends showed a single Tg, which was dependent on the blend ratio. The deformation behavior of the blends and the tensile properties of the resultant drawn films were greatly affected by the draw temperature (Td). For the drawing above the Tg of HMW (Td=150°C), the LMW behaved as a plasticizer of the HMW. In that case, the draw efficiency evaluated from the Young's modulus of the samples increased systematically with increasing the fraction of HMW in the blends. For the drawing around the Tg of LMW (Td=120°C), the deformation behavior and tensile properties of the resultant drawn films were primarily governed by those for the component polymer with higher fractions in the blends. The results were discussed in connection with the phase structure of the blends.

Detection of High Molecular Weight Organic Tracers in Vegetation Smoke Samples by High-Temperature Gas Chromatography−Mass Spectrometry

High-temperature high-resolution gas chromatography (HTGC) is an established technique for the separation of complex mixtures of high molecular weight (HMW) compounds which do not elute when analyzed on conventional GC columns. The combination of this technique with mass spectrometry (i.e., HTGC−MS) is not so common and application to aerosols is novel. The HTGC and HTGC−MS analyses of smoke samples taken by particle filtration from combustion of different species of plants provided the characterization of various classes of HMW compounds reported to occur for the first time in emissions from biomass burning. Among these components are a series of wax esters (long chain alcohols esterified with long chain fatty acids) with up to 58 carbon numbers, aliphatic hydrocarbons (C15−C40; Cmax = C31; odd predominance), triglycerides, long chain methyl ketones (up to 37 carbons; Cmax = C33; odd predominance), alkanols (up to 40 carbons; Cmax = C32; even predominance), and a series of triterpenyl fatty acid esters (e.g., α- and β-amyryl stearate) which have been characterized as novel natural products. Long chain fatty acids with more than 32 carbon numbers are not present in the smoke samples analyzed. The HMW compounds in smoke samples from the burning of plants from Amazonia indicate the input of directly volatilized natural products in the original plants during their combustion. However, the major organic compounds extracted from smoke consist of a series of lower molecular weight polar components, which are not natural products but the result of the thermal breakdown of cellulose and lignin. In contrast, the HMW natural products may be suitable tracers for specific sources of vegetation combustion because they are emitted as particles without thermal alteration in the smoke and can thus be related directly to the original plant material.

Fouling Colloids During Microporous Alumina Membrane Filtration of Wine

ABSTRACTThree different wines, from the same cultivar, were microfiltered using a device operating under static conditions and equipped with a section of monochanelled tubular alumina membrane, pore size 0.2 μm. Filtration flux curves resembled permeation profiles observed in dynamic cross‐flow conditions using a similar membrane. Minute amounts of colloidal material deposited on the surface and inside the membrane were isolated for the first time and characterized as mixtures of high molecular weight moderately acidic grape proteoglycans (surface deposit) and low molecular weight acidic moieties (inner deposit). These fouling colloids were likely deposited by trace amounts not detectable in crude starting wines.

Magnetic resonance spectroscopy of wheat proteins: a magic-angle-spinning 13C nuclear magnetic resonance and an electron spin resonance spin label study

The freeze-dried wheat protein fractions, glutenin and gliadin, mixtures of high molecular weight (HMW) subunits of glutenin from flour, and gliadin-enriched and glutenin-enriched fractions from a gluten ball, were investigated by cross-polarization magic-angle-spinning 13 C nuclear magnetic resonance spectroscopy. No characteristic differences in the molecular structure of these systems could be recognised in the spectra obtained. Sharp resonances in the aliphatic and aromatic spectral regions in the glutenin-enriched fraction, which have been described by other workers, were not observed: these may be artefacts arising from impurities present in the materials used. Isolated HMW subunits 2, 3, 10 and 11 were studied in solution using electron spin resonance after alkylation of cysteine residues with a maleimide spin label. Spectra obtained in 3 m urea were identical for all HMW subunits, with similar rotational correlation times (τ c ) of 0·22 ± 0·02 ns. Spectra obtained in a less denaturing solvent (10 mM acetic acid) indicated that τ c increased for all HMW subunits ranging from 0·38 to 0·52 ns and that τ c for HMW subunit 10 was significantly lower than τ c for subunit 11. It is suggested that a high spin label mobility in 10 m m acetic acid is related to a better crosslinking function of subunit 10 in forming the extended, disulphide-bonded network of glutenin.

New Rotary Condenser Still Separates Mixtures of High Molecular Weight

New Rotary Condenser Still Separates Mixtures of High Molecular Weight