Impact of Macromonomer Molar Mass and Feed Composition on Branch Distributions in Model Graft Copolymerizations

One-pot free-radical polymerization of N-acryloyl glycinamide in the presence of hyaluronic acid as transfer-termination agent led to new copolymers in high yields without any chemical activation of hyaluronic acid before. All the copolymers formed thermoresponsive hydrogels of the Upper Critical Solution Temperature-type in aqueous media. Gel properties and the temperature of the reversible gel ↔ sol transition depended on feed composition and copolymer concentration. Comparison with mixtures of hyaluronic acid-poly(N-acryloyl glycinamide) failed in showing the expected formation of graft copolymers conclusively because poly(N-acryloyl glycinamide) homopolymers are also thermoresponsive. Grafting and formation of comb-like copolymers were proved after degradation of inter-graft hyaluronic acid segments by hyaluronidase. Enzymatic degradation yielded poly(N-acryloyl glycinamide) with sugar residues end groups as shown by NMR. In agreement with the radical transfer mechanism, the molar mass of these released poly(N-acryloyl glycinamide) grafts depended on the feed composition. The higher the proportion of hyaluronic acid in the feed, the lower the molar mass of poly(N-acryloyl glycinamide) grafts was. Whether molar mass can be made low enough to allow kidney filtration remains to be proved in vivo. Last but not least, Prednisolone was used as model drug to show the ability of the new enzymatically degradable hydrogels to sustain progressive delivery for rather long periods of time in vitro.

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Paper Chemistry: Interactions of thermo mechanical pulp fractions with high molar mass cationic polyacrylamides: Part 2. Flocculation

Nordic Pulp & Paper Research Journal ◽

10.3183/npprj-2010-25-03-p310-318 ◽

2010 ◽

Vol 25 (3) ◽

pp. 310-318 ◽

Cited By ~ 2

Author(s):

Tero Taipale ◽

Janne Laine ◽

Susanna Holappa ◽

Jonni Ahlgren ◽

Juan Cecchini

Keyword(s):

Molar Mass ◽

High Molar Mass ◽

Mechanical Pulp ◽

Paper Chemistry

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Environmental impact of nutrients from nordic fish farming

Water Science & Technology ◽

10.2166/wst.1995.0364 ◽

1995 ◽

Vol 31 (10) ◽

pp. 61-71 ◽

Cited By ~ 14

Author(s):

M. Enell

Keyword(s):

Major Part ◽

Fish Farming ◽

Fish Farms ◽

Feed Composition ◽

The North ◽

Comprehensive Development ◽

The Baltic ◽

Inland Water Bodies ◽

The Impact ◽

Feed Coefficient

During the last 20 years there has been an interesting development of the Nordic fish farming, with regard to the feeding and farming technology and to the increase in production quantities. During the period 1974-1994 the production increased from 15,800 to about 250,000 tonnes/year. In 1974 the major part of the production was in Denmark, and in 1994 the major part was in Norway. The nutrient impact of fish farming on surrounding sea areas is mainly a function of the feed coefficient, the feed composition and metabolic processes in the fish. The comprehensive development of the feed composition and the feeding technology has resulted in reduced load of unmetabolized nutrients from fish farms, calculated per tonne fish produced. In 1974 the mean Nordic feed coefficient was 2.08 and in 1994 the coefficient was 1.25. Feed coefficients of 1.0-1.1 are now reported for Danish and Norwegian freshwater and marine fish farms. The nitrogen (N) and phosphorus (P) content of the feed has decreased, in addition the quality of the nutrient substances in the feed has changed, especially for N. The N content has decreased from 7.8 to 6.8% during the period 1974-1994 and the content of P has decreased from 1.7 to 0.7% during the same period. This development of the feed coefficient and the feed composition has resulted in a present load from a typical Nordic fish farm of 55 kg N and 4.8 kg P/t fish produced. The figures for 1974 were 132 kg N and 31 kg P/t fish produced. The Nordic fish farming production in 1994 resulted in a load of about 13,750 t N and about 1,200 t P on the actual recipients. The load from the Swedish, Finnish and Danish fish farming operations, with the Baltic Sea and the Skagerrak as the recipients, is negligible in comparison with other pollution sources. The quantities of N and P from the fish farming are equal to 0.5% of the atmospheric deposition on the sea surface and 3% of the atmospheric P load. Norwegian, Icelandic and the Faroe Islands fish farming operations are using the North Sea and the Norwegian Sea as the recipients. However, the nutrient load from single fish farms in certain coastal and inland water bodies can be significant and must be considered in the impact assessment together with other sources.

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Selective determination of non-biodegradable polar, organic pollutants in waste water related to functional groups using flow injection combined with tandem mass spectrometry

Water Science & Technology ◽

10.2166/wst.1996.0597 ◽

1996 ◽

Vol 34 (7-8) ◽

pp. 21-28 ◽

Cited By ~ 5

Author(s):

H. Fr. Schröder

Keyword(s):

Mass Spectrometry ◽

Tandem Mass Spectrometry ◽

Functional Groups ◽

Organic Pollutants ◽

Molar Mass ◽

Sewage Treatment ◽

Tandem Mass ◽

Screening Process ◽

Selective Determination ◽

Characteristic Fragment

Effluents of biological sewage treatment plants mainly contain non-biodegradable, polar, organic pollutants of biogenic and anthropogenic origin. This paper presents a substance-specific determination method for these compounds, which are partly able to reach drinking water during the soil filtration process. Tandem mass spectrometry (MS/MS) combined with softly ionizing interfaces is applied for this purpose. The behaviour of the functional groups of these pollutants - forming characteristic fragment ions under MS/MS conditions and abstracting neutral particles - is used for detection. With help from this screening process on specific functional groups it is possible to establish the presence of substance groups with similar behaviour in the aquatic environment. Additionally this analytical procedure provides information on the molar mass of the pollutants detected. In a second step the compounds characterized by the molar mass and belonging to a group of pollutants with specific functional groups can be identified using MS/MS.

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Effect of nickel(II) on the biomass yield of the activated sludge

Water Science & Technology ◽

10.2166/wst.1996.0548 ◽

1996 ◽

Vol 34 (5-6) ◽

pp. 163-171 ◽

Cited By ~ 12

Author(s):

Celal F. Gökçay ◽

Ulku Yetis

Keyword(s):

Activated Sludge ◽

Decay Constant ◽

Biomass Yield ◽

Culture Conditions ◽

Synthetic Wastewater ◽

Base Line ◽

Microbial Culture ◽

Feed Composition ◽

Steady State Condition ◽

Applied Microbiology

Biomass yield of microorganisms is important in applied microbiology since it is the ultimate factor determining the amount of product produced regardless of whether product is growth-linked or not. In the case of environmental microbiology the opposite is true and minimizing the biomass produced, or the sludge in the relevant jargon, often is the prime goal. In this paper, a unique means of manipulating the microbial biomass yield of a heterogeneous culture to fulfil either of the two goals is presented. 5.0 mgl−1 Ni(II) in the feed composition to a completely mixed, once- through, activated sludge was found to induce the observed biomass yield of the microbial culture developed from sewage. As compared with the base-line study without Ni(II), where the reactor received synthetic wastewater only, true biomass yield was found to have increased along with the increased decay constant with the net effect of lowering observed biomass yield drastically at lower dilution rates and increasing it over that observed in the base-line study at higher dilution rates. At 10.0 mgl−1 influent Ni(II) concentration the culture conditions almost reverted back to the base- line study and at 25 mgl−1 Ni(II) concentration a truly steady-state condition could not be attained.

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QELSS diffusion data for moderately broad molar mass distribution polymer samples compared with data from classical gradient techniques

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891821 ◽

1989 ◽

Vol 54 (7) ◽

pp. 1821-1829

Author(s):

Bedřich Porsch ◽

Simon King ◽

Lars-Olof Sundelöf

Keyword(s):

Diffusion Coefficient ◽

Mass Distribution ◽

Molar Mass ◽

Molar Mass Distribution ◽

Diffusion Data ◽

Mass Distributions ◽

Classical Diffusion ◽

Polydisperse Polymer

The differences between the QELSS and classical diffusion coefficient of a polydisperse polymer resulting from distinct definitions of experimentally accessible average values are calculated for two assumed specific forms of molar mass distributions. Predicted deviations are compared with the experiment using NBS 706 standard polystyrene. QELSS Dz of this sample relates within 2-4% to the classical diffusion coefficient, if the Schulz-Zimm molar mass distribution is assumed to be valid. In general, differences between the height-area and QELSS diffusion coefficient of about 20% may be found for Mw/Mn ~ 2, and this value may increase above 35%, if strongly tailing molar mass distribution pertains to the sample.

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Activities of Components in the Ca2MgSi2O7-CaSiO3Molten System

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19960837 ◽

1996 ◽

Vol 61 (6) ◽

pp. 837-843

Author(s):

Ladislav Kosa ◽

Ivan Nerád ◽

Katarína Adamkovičová ◽

Jozef Strečko ◽

Ivo Proks

Keyword(s):

Gibbs Energy ◽

Molar Mass ◽

Excess Entropy ◽

Enthalpy Of Mixing ◽

Real Particle ◽

Entropy Of Mixing ◽

Energy Of Mixing ◽

Gibbs Energy Of Mixing

Activities of the components, the Gibbs energy of mixing, and the excess entropy of mixing have been calculated for the Ca2MgSi2O7-CaSiO3 system. The mole fractions of the components were calculated assuming that in the point of the formal component Ca2MgSi2O7, the molar mass of the quasi-real particle in the melt corresponds to its formula molar mass, whereas in the point of the formal component CaSiO3 the molar mass of the quasi-real particle in the melt is 8.5 times higher than as corresponds to its formula. The fact that the enthalpy of mixing is zero whereas the excess entropy of mixing is non-zero suggests that Ca2MgSi2O7-CaSiO3 melts behave as athermal solutions.

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Development and Characterization of Amine-Clay Hybrid Adsorbents for CO2 Capture

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.547 ◽

2016 ◽

Vol 1133 ◽

pp. 547-551 ◽

Cited By ~ 2

Author(s):

Ali E.I. Elkhalifah ◽

Mohammad Azmi Bustam ◽

Azmi Mohd Shariff ◽

Sami Ullah ◽

Nadia Riaz ◽

...

Keyword(s):

Adsorption Capacity ◽

Surface Area ◽

Surface Properties ◽

Molar Mass ◽

Adsorption Ability ◽

Stepwise Increase ◽

Inverse Effect ◽

Bet Method ◽

Sodium Form

The present work aims at a better understanding of the influences of the intercalated mono-, di- and triethanolamines on the characteristics and CO2 adsorption ability of sodium form of bentonite (Na-bentonite). The results revealed that the molar mass of intercalated amines significantly influenced the structural and surface properties as well as the CO2 adsorption capacity of Na-bentonite. In this respect, a stepwise increase in the d-spacing of Na-bentonite with the molar mass of amine was recorded by XRD technique. However, an inverse effect of the molar mass of amine on the surface area was confirmed by BET method. CO2 adsorption experiments on amine-bentonite hybrid adsorbents showed that the CO2 adsorption capacity inversly related to the molar mass of amine at 25 ͦC and 101 kPa. Accordingly, Na-bentonite modified by monoethanolammonium cations adsorbed as high as 0.475 mmol CO2/g compared to 0.148 and 0.087 mmol CO2/g for that one treated with di- and triethanolammonium cations, respectively.

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Highly Efficient MOF Catalyst Systems for CO2 Conversion to Bis-Cyclic Carbonates as Building Blocks for NIPHUs (Non-Isocyanate Polyhydroxyurethanes) Synthesis

Catalysts ◽

10.3390/catal11050628 ◽

2021 ◽

Vol 11 (5) ◽

pp. 628

Author(s):

Adolfo Benedito ◽

Eider Acarreta ◽

Enrique Giménez

Keyword(s):

Molar Mass ◽

Cycloaddition Reaction ◽

Building Blocks ◽

Catalyst System ◽

Cyclic Carbonate ◽

Ammonium Bromide ◽

Cyclic Carbonates ◽

High Molar Mass ◽

Highly Efficient ◽

Free Process

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.

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Adsorption for efficient low carbon hydrogen production: part 2—Cyclic experiments and model predictions

Adsorption ◽

10.1007/s10450-021-00308-w ◽

2021 ◽

Author(s):

Anne Streb ◽

Marco Mazzotti

Keyword(s):

Hydrogen Production ◽

Carbon Capture And Storage ◽

Clean Energy ◽

Separation Performance ◽

Low Carbon ◽

Solution Theory ◽

Feed Composition ◽

Ideal Adsorbed Solution Theory ◽

Adsorbed Solution ◽

Adsorbed Solution Theory

Abstract Hydrogen as clean energy carrier is expected to play a key role in future low-carbon energy systems. In this paper, we demonstrate a new technology for coupling fossil-fuel based hydrogen production with carbon capture and storage (CCS): the integration of CO2 capture and H2 purification in a single vacuum pressure swing adsorption (VPSA) cycle. An eight step VPSA cycle is tested in a two-column lab-pilot for a ternary CO2–H2–CH4 stream representative of shifted steam methane reformer (SMR) syngas, while using commercial zeolite 13X as adsorbent. The cycle can co-purify CO2 and H2, thus reaching H2 purities up to 99.96%, CO2 purities up to 98.9%, CO2 recoveries up to 94.3% and H2 recoveries up to 81%. The key decision variables for adjusting the separation performance to reach the required targets are the heavy purge (HP) duration, the feed duration, the evacuation pressure and the flow rate of the light purge (LP). In contrast to that, the separation performance is rather insensitive towards small changes in feed composition and in HP inlet composition. Comparing the experimental results with simulation results shows that the model for describing multi-component adsorption is critical in determining the predictive capabilities of the column model. Here, the real adsorbed solution theory (RAST) is necessary to describe all experiments well, whereas neither extended isotherms nor the ideal adsorbed solution theory (IAST) can reproduce all effects observed experimentally.

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