The aim of this work was to characterise the diffusive properties of superabsorbent polymer systems prepared by free radical crosslinking polymerisation of acrylic acid. The polyelectrolyte nature of these hydrogels gives rise to high swelling capacities, and their ability to absorb and retain water is highly dependent on the precise network structure. Modifying the synthesis formulation results in considerable changes to the dynamic and structural properties of these gels, providing the motive for the work presented here. The influence of two factors, namely the extent of monomer neutralisation and the level of crosslinker in the pre-gel solution, were investigated. The dynamic properties of gels were examined using Quasi-Elastic Light Scattering (QELS), from which the cooperative diffusion coefficient and degree of heterogeneity could be determined. The former was found to increase linearly with neutralisation, due to the introduction of electrostatic interactions. The diffusion coefficient initially remained constant with the addition of crosslinker, due to the dominating influence of physical entanglements, but increased above a threshold crosslinking degree, corresponding to a reduction of the network mesh size. The extent of large-scale inhomogeneity increased for higher ionisations, as both the crosslinker solubility and the efficiency of monomer-crosslinker reaction decreased. However, there was a tendency for concentration fluctuations to be minimised for higher neutralisations, making the gel more microscopically homogeneous. Kinetics of swelling experiments were used to investigate gels of varying composition. The macroscopic diffusion coefficient was found to increase rapidly with increasing neutralisation until the monomer was approximately 35% neutralised, beyond which point counterion condensation caused insignificant variation. This trend was also reflected in the equilibrium swelling ratios, and mode of diffusion. For the majority of gels, the diffusion process was characterised as case II transport. Variation of crosslinking degree caused an overall increase in the diffusion coefficient, reflecting the trend observed in the QELS studies. Nuclear Reaction Analysis (NRA) was used to probe the penetration of heavy water into dry network slabs. The concentration-depth profiles revealed a discontinuity in the diffusion coefficient, corresponding to the transition between glassy and rubbery states, for which the diffusivities differed by several orders of magnitude. The kinetics of plasticisation was assumed to be the rate determining factor in the swelling process, on the timescale of the NRA experiments. The diffusion coefficient for the swollen rubbery region, representative of the macroscopic diffusion process, was found to increase linearly with neutralisation, and decrease with crosslinking degree. The latter observation was explained as due to a reduction in the free volume available for solvent diffusion with higher levels of crosslinker.

Oil sand processing to extract bitumen generates large volumes of slurry comprising water, silt, sand, clay, unrecovered bitumen, and residual chemical aides and solvents added during the extraction process. The by-product stream of the bitumen extraction is pumped into constructed tailings ponds. Managing these tailings is one of the most difficult environmental challenges for the oil sand industry. This study aims to develop a novel technique to assist in the assessment of the technologies for managing mature fine tailings (MFT) in oil sands. Innovative application of a superabsorbent polymer in the oil sands industry may provide a new method for tailings management. However, thus far, no study has addressed this research gap. In fact, fundamental knowledge of the behavior of MFTs pre-dewatered with the superabsorbent polymer could provide an important way to positively affect the speed of reclamation. To this end, comprehensive instrumentation, geo-environmental, and geotechnical analyses are carried out to obtain essential knowledge on the behavior of MFTs pre-dewatered with the polymer. The results of this study reveal that the mechanical, hydraulic, and thermal properties of the MFTs are related. Evaporation and drying shrinkage can affect the hydro-mechanical properties of the tailings and have a significant influence on the developed shear strength of the MFTs. In addition, the process-affected water includes a high concentration of the dissolved ions and organic chemicals that stem from ore extraction chemicals and tailings treatments, or that may be released from oil sands ores. Through the application of a superabsorbent polymer in the dewatering of oil sand MFTs, the chemical components are entrapped in the polymer chains, thus limiting the mobility of the major ions and trace metals in water bodies beneath the oil sand tailings pond. Results show that the application of the superabsorbent polymer considerably reduces the rate of drainage from the oil sand MFTs into water bodies, which can help mitigate the risk of seepage. The author believes that the superabsorbent polymer dewatering technique can be considered as an environmentally friendly promising approach for management of oil sands MFTs. This new technique can accelerate the pace of reclamation and thus minimize the footprint of the oil industry in Canada.

No description available.

In the current study, SAPs of cationic monomer [2 - (Methacryloyloxy) ethyl] trimethylammonium chloride have been prepared by free radical solution polymerisation with different crosslinkers. They were subjected to repeated cycles of swelling and de-swelling in DI water and NaCl solution. The conductivity of the swelling medium was measured and related to the swelling/de-swelling characteristics of the SAPs. The swelling capacity was also determined in saline solution. The swelling and de-swelling processes were described by first-order kinetics. The SAPs exhibited varied swelling capacity for crosslinkers of the same functionality as well as different functionality. The SAPs were used to adsorb, the dye Orange G at different initial concentrations of the dye. The equilibrium adsorption data followed the Langmuir adsorption isotherms. The SAPs were also used to adsorb three other dyes, Congo red, Amido black and Alizarin cyanine green. They exhibited different adsorption capacity for different dyes. The adsorption phenomenon was found to follow first order kinetics. In the later part of the study, the co-monomers of [2 - (Methacryloyloxy) ethyl] trimethylammonium chloride with zwitter-ionic monomers [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide and [3-(Methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide inner salt were prepared in turns at two different concentrations. The effect of the addition of the zwitter-ionic monomers and their concentration of the swelling capacity and dye adsorption capacity was studied. There was no effect on the swelling capacity of the polymers due to either the species of the zwitter-ionic monomer or their concentration. However, there was a reduction in soluble content of the polymers. The dye adsorption capacity decreased at the higher concentration of the zwitter-ionic monomer.

The new forms of superabsorbent polymers (SAP) on the base of acrylic acid were developed and studied in this thesis. The SAP are focused on agricultural and environmental applications. While they are applied to the soil, SAP can prevent water losing and they become a reservoir of humidity in case of dry season, moreover in combination with fertiliser they play role of controlled release medium. Eight various samples of SAP were experimentally prepared by networking of partially neutralized acrylic acid. Potassium peroxydisulfate was used as the initiator and N,N–methylenebisacrylamide as the crossing agent. Some of samples contained addition of second monomer of acrylamide. All of them were enriched by fertilisers – natural lignohumate or synthetic NPK or combination of both. The swelling characteristics of prepared samples were investigated in conditions of various ionic strength. The influence of xerogels’ particles size on swelling properties was also observed. The viscoelastic characteristics of hydrogel form of all SAP were determined by using of rotation rheometer. The changing of viscoelastic properties were studied in dependence on time, on freezing and on repeating swelling cycles. On top of that the controlled releasing ability of SAP was tested due to three modelling experiments. The biological activity of all polymer products was tested at the end of the thesis. All samples of SAP were incorporated into the artificial soil and the ability of the water retention in the soil was observed. The growing experiments were running by using of corn plants. The size and the mass of each plant were measured and branching of the root was objectively evaluated by programme Harmonic and Fractal Image Analyzer.

Abstract Superabsorbent water beads have found many uses as household decorative items, crafts, and other industrial uses. We report a case of ingestion of several LiquiBlock Rainbow brand superabsorbent beads by a ten month old girl leading to small bowel obstruction requiring laparotomy and removal of the beads.

Denna studie beskriver effekterna beträffande överlevnad och tillväxt hos gran (Picea abeis L. Karst) vid tillsats av superabsorbent Luquasorb 1280R i samband med plantering under olika betingelser. Plantor i form av täckrot och barrot studerades. Tillsats av superabsorbent visade sig ha en positiv inverkan på de studerade parametrarna i jämförelse med referensmaterial utan tillsats av superabsorbent. Detta visade sig särskilt vid extremförsök under tak utan tillgång till vattentillförsel under försöksperioden, förutom vattentillsats i samband med plantering. / This study describes the effects concerning survival and growth of Norway spruce seedelings (Picea abeis L. Karst) by addition of superabsorbent Luquasorb 1280R in connection with planting under differnt conditions. Container seedlings and bare-root seedlings were studied. The addition of superabsorbent showed a positive influence regarding the studied parameters in comparision with reference material without the addition of superabsorbent. This was most obvious at the the extreme test under roof without access to additional water during the test period, except water added in connection with planting.

Fluffmassa är ett förnybart material bestående av cellulosafiber som utvinns under massakokning. Dessa fiber används för att tillverka olika absorberande produkter som till exempel servetter. Fluffmassa används även för att tillverka absorptionskärnor i damhygienprodukter, inkontinensprodukter och blöjor. Vissa av dessa absorptionskärnor (speciellt i ultratunna bindor) tillverkas med airlaid. Airlaid är en tillverkingsteknik som ger fiberstrukturer med slumpmässig orientering genom att applicera ett undertryck.  Syftet med detta examensarbete var att utveckla metoder för att tillverka servetter och absorptionskärnor till damhygienprodukter i laboratoriemiljö genom att använda en airlaid maskin i laboratorieskala. Detta utfördes genom att analysera viktiga egenskaper som exempelvis ytvikt, tjocklek, densitet, böjlängd och förmågan att absorbera vätska i kommersiella servetter och absorptionskärnor inom damhygien. Även dragprov och SEM-analys utfördes. Resultatet från dessa analyser användes som ett riktvärde under metodutvecklingen.  Två metoder utvecklades - en för att tillverka en servettstruktur och en för att tillverka en absorptionskärna för damhygien. De olika tillverkningsstegen inkluderar defibrering, formering, pressning, prägling, latexsprayning samt härdning. Båda strukturerna tillverkades, och dess egenskaper analyserades och jämfördes med de kommersiella produkterna. Analyserna visade att de utvecklade metoderna genererade struktuer vars ytvikt stämde väl överrens med de kommersialla produkterna. Strukturerna var dock tjockare och hade en lägre densitet än de kommmersiella produkterna. Den minskade densiteten påverkade förmodligen resultatet från de andra analyserna som utfördes i detta projekt. Servettstrukturen hade en lägre böjlängd än de kommersiella servetterna och damhygienstrukturen hade bättre absorption än de kommersiella produkterna.  Båda strukturerna hade en ytfinish som överensstämmde väl med de kommersiella produkterna. Dock visade SEM-analysen att latex saknades i mitten av de båda tillverkade strukturerna. / Fluff pulp is a renewable material consisting of pure cellulose fibers which are obtained during pulping. These fibers are commonly used to form Airlaid-nonwoven products such as napkins and wipes. Fluff pulp is also used in absorbent cores in femcare products, incontinence products and diapers. Some of these absorbent core structures (especially in ultrathin pads) are produced through airlaid. Airlaid is a manufacturing technique which forms a randomly oriented fiber structure by using an applied suction.  This degree project aimed at developing methods for producing napkins and femcare absorbent cores on a laboratory scale by using an airlaid former. Important properties such as grammage, thickness, density, bending length and absorption capacity were therefore measured on commercial napkins and femcare absorbent cores. Other analyses which were performed include tensile testing and SEM. Findings from these analyses were then used as a target reference during the method development.  Two methods were developed; one for producing a napkin structure and one for producing a femcare absorbent core structure. The different manufacturing steps included fiber defiberization, sample formation, pressing, embossing, latex spraying and curing. Napkin structures and femcare absorbent core structures were produced by using the developed methods, and their properties were analyzed and compared with the commercial products.  Analysis showed that the developed methods generated structures with grammages that corresponded well with the grammages in the commercial products. However, both developed structures were thicker and had lower density than the commercial products. This decreased density probably influenced the results in other analyses performed in this project. The developed napkin structure had a shorter bending length compared to the commercial napkins and the developed femcare structure had a better absorption capacity compared to the commercial femcare absorbent cores. Both developed structures obtained nice surface finish which corresponded well with the surface finish in the commercial products. However, SEM analysis indicated that no latex managed to reach the center in the developed structures.

Super absorbent polymers (SAP) can absorb liquid many times its own weight and is used in diapers and incontinence pads. The most common type of SAP is cross-linked polyacrylic acid. The production of acrylic acid uses crude oil as starting material. This means that the final price of acrylic acid is affected by the price of crude oil which is expected to rise. This has led to an increasing interest in developing a sustainable bioproduction process that uses renewable lignocellulosic raw material for the making of acrylic acid. Lignocellulose is the material that plants and trees consist of and it contains big amounts of sugar. Sugar molecules in lignocellulose can serve as substrate for microorganisms that can transform them into 3-hydroxipropionic acid, which in turn can be converted to acrylic acid. In order to use the sugar molecules from lignocellulose, some type of pretreatment is required. However, the pretreatments that are available today are not efficient enough to be applied on a large scale and some also cause the formation of microbial inhibitors. The microbial conversion of sugar to 3-hydroxipropionic acid do not show sufficient efficacy so far, but the process is under development and improvements are regularly made. Furthermore would it be advantageous if polymerization of acrylic acid could be made directly in the fermentation broth without any energy consuming separation stepsAttempts to polymerize acrylic acid in fermentations broths from yeast have been performed. The SAP properties; absorption capacity, absorption capacity under pressure and gel strength were evaluated by methods commonly used in the hygiene industry. These characteristics are important if the SAP is to be used in diapers and incontinence pads. To examine what compounds in the fermentations broth that affected the polymerization process and SAP properties, an experimental design was made. With help of the design quantitative and statistical methods were used to determine which compound had an impact. Four groups of compounds were selected for examination; sugars, alcohols, acids and aromatic compounds. The results of the experiments conducted showed that it is possible to polymerize SAP in fermentation broth from yeast using acid pretreated spruce as sugar source. The characterization showed that the absorption capacity was unchanged while the gel strength deteriorated significantly. It was also noted that SAP polymerized in fermentations broths had strong colors in contrast to conventional SAP, which is white. Qualitative and statistical analysis showed that the aromatic compounds affected the polymerization and SAP properties negative.

Soil moisture deficits often hinder rangeland revegetation efforts. Due to sheer numbers and germination timing, invasive annual species can easily outcompete those of desired seeded species for resources, including water. One way to increase seedling establishment may be to increase the amount of water available to seeded species. Superabsorbent polymers (SAPs) can absorb and release hundreds of times their weight in water and slowly release it. Concentrated SAP bands at or near seedling rooting depth may act as a soil water reservoir for germinating seedlings and increase rangeland seedling establishment. The objective of these studies was to evaluate the effect of banded SAP on soil moisture and seedling establishment through a series of eight glasshouse and field trials with different combinations of: species, SAP band rate, SAP band placement depth, seeding rate, fertilizer application, and seedling distance from the SAP band. Two grasses, bottlebrush squirreltail (Elymus elymoides) or Siberian wheatgrass (Agropyron fragile) were used as test species in all studies but one. In that study six species commonly used in rangeland restoration [bottlebrush squirreltail, crested wheatgrass (Agropyron cristatum (L.)), Lewis flax (Linum lewisii Pursh), yellow sweet clover (Melilotus officinalis), Wyoming big sagebrush (Artemisia tridentata Nuttall ssp. wyomingensis Beetle Young), and forage kochia (Kochia prostrata (L.) Schrad.)] were used. Concentrated band of SAP at rates up to 6000 kg ha-1 were placed below the seeds at depths ranging from the soil surface to 15 cm deep or mixed into the top 8 or 15 cm of soil. Measurements varied with trial. Soil moisture measurements included gravimetric water content, volumetric water content, and/or soil matric potential. Seedling growth parameters included seedling time to emerge, number emerged, longevity, percent of seedlings alive, shoot length, blade count, root length, root biomass, shoot biomass, and/or root:shoot ratio. Banded SAP at high rates increased usable soil moisture up to 49 days in the glasshouse and in spring of the first year after installation in the field. Rates ? 1500 kg ha-1 increased seedling longevity up to 12 days in the glasshouse but resulted in raised and cracked soil. This negatively impacted seedling survival in the field but not the glasshouse and may also reduce the amount of available soil moisture over time. Banded SAP at rates < 1500 kg ha-1, intended to reduce soil cracking, had no impact on soil moisture or live seedlings in the field. Further work is needed to investigate alternative application methods, such as blending the SAP into the soil.