Finn Knut Hansen

• Levchenko, Vladimir; Sundsli, Bård Edgar Vestheim; Øien-Ødegaard, Sigurd; Tilset, Mats; Hansen, Finn Knut & Hansen, Tore Bonge (2018). Bottom-Up Synthesis of Acrylic and Styrylic Rh11 Carboxylate Polymer Beads: Solid-Supported Analogs Rh2(OAc)4. European Journal of Organic Chemistry. ISSN 1434-193X. p. 6150–6157. doi: 10.1002/ejoc.201800953.
• (2017). A Computational Study of Density of Some High Energy Molecules. Propellants, explosives, pyrotechnics. ISSN 0721-3115. 42(2), p. 204–212. doi: 10.1002/prep.201600105. Show summary

  The detonation pressure depends quadratically on the loading density of the explosives. A precise estimate of the density is thus crucial to decide if a novel energetic material is worth pursuing. In this work we investigate theoretically the crystal densities of the energetic compounds RDX, TNT, NTO, DNAM, CL-20, DADNE, and HMX. We calculate the crystal densities by using Materials Studio 7.0 Polymorph Predictor, employing force fields and exploring molecular packing arrangements with minima in total energy. Geometry optimized molecular structures computed by density functional theory (DFT) are used as input to the density predictions. In an additional DFT study we apply two functionals, B3LYP and M06 with the 6-31G(d) and the 6-31G(d,p) basis sets, and the program package GAUSSIAN09. In this part of the work crystal densities are calculated by using the molecular isosurface volume (defined by the volume within a surface with an electron density of 0.001 electrons per Bohr3) alone or combined with the variance of the electrostatic potential (ESP). The Polymorph Predictor seems to overestimate the densities, but the values are very dependent on the force field strength determined by charges assigned to atoms. In the GAUSSIAN09 DFT study the densities derived by using the M06 functional are in similar agreement with experimental data as what we experienced for the B3LYP results, although both functionals appear to give slightly lower densities than reported experimentally for the majority of the molecules. On average, the densities derived by the ESP method correlate equally well with measured values as the results obtained by the isosurface method.

• Scheie, Anne Aamdal; Chamgordani, Elahe Jafari; Naemi, Ali-Oddin; Hansen, Finn Knut & Benneche, Tore (2016). Staphylococcus epidermidis biofilm on implant material is reduced by a covalently linked thiophenone. Journal of Applied Microbiology. ISSN 1364-5072. 121(2), p. 547–553. doi: 10.1111/jam.13188.
• (2015). Investigation of Theoretical Models for the Elastic Stiffness of Nanoparticle-Modified Polymer Composites. Journal of Nanomaterials. ISSN 1687-4110. 2015, p. 1–17. doi: 10.1155/2015/281308. Full text in Research Archive
• Lausund, Kristian Blindheim; Johnsen, Bernt Brønmo; Rahbek, Dennis Bo & Hansen, Finn Knut (2015). Surface treatment of alumina ceramic for improved adhesion to a glass fibre-reinforced polyester composite. International Journal of Adhesion and Adhesives. ISSN 0143-7496. 63, p. 34–45. doi: 10.1016/j.ijadhadh.2015.07.015.
• Christensen, Mikkel; Larnøy, Erik; Kutzke, Hartmut & Hansen, Finn Knut (2015). Treatment of waterlogged archaeological wood using chitosan and modified chitosan solutions. Part 1: Chemical compatibility and microstructure. Journal of the American Institute for Conservation. ISSN 0197-1360. 54(1), p. 3–13. doi: 10.1179/1945233014Y.0000000034.
• Frømyr, Tomas Roll; Bourgeaux-Goget, Marie & Hansen, Finn Knut (2015). A comparative study of the dispersion of multi-wall carbon nanotubes made by arc-discharge and chemical vapour deposition. Journal of Nanoscience and Nanotechnology. ISSN 1533-4880. 15(5), p. 3496–3506. doi: 10.1166/jnn.2015.9860.
• Christensen, Mikkel; Kutzke, Hartmut & Hansen, Finn Knut (2014). Phenol formaldehyde revisited – novolac resins for the treatment of degraded archaeological wood. Archaeometry. ISSN 0003-813X. doi: 10.1111/arcm.12097. Show summary

  Archaeological wood is usually severely degraded. The Norwegian Viking Age Oseberg find exemplifies problems arising due to past conservation treatments and the need for new types of preservatives. Phenol formaldehyde (PF) has been investigated as a consolidant for alum-treated wood. X-ray tomography has revealed that it is possible to obtain a porous structure inside the wood, ensuring ethical acceptability by allowing re-treatment. In order to understand the curing mechanics, the kinetics of the initial condensation reaction were elucidated at room temperature. It was found that a second-order reaction using both phenol and formaldehyde concentrations is the most probable mechanism.

• Landsem, Eva; Jensen, Tomas Lunde; Kristensen, Tor Erik Holt; Hansen, Finn Knut; Benneche, Tore & Unneberg, Erik (2013). Isocyanate-Free and Dual Curing of Smokeless Composite Rocket Propellants. Propellants, explosives, pyrotechnics. ISSN 0721-3115. 38(1), p. 75–86. doi: 10.1002/prep.201200108.
• (2012). Mechanical Properties of Smokeless Composite Rocket Propellants Based on Prilled Ammonium Dinitramide. Propellants, explosives, pyrotechnics. ISSN 0721-3115. 37(6), p. 691–698. doi: 10.1002/prep.201200004.
• (2012). Neutral Polymeric Bonding Agents (NPBA) and Their Use in Smokeless Composite Rocket Propellants Based on HMXGAP- BuNENA. Propellants, explosives, pyrotechnics. ISSN 0721-3115. 37(5), p. 581–591. doi: 10.1002/prep.201100136.
• Christensen, Mikkel; Kutzke, Hartmut & Hansen, Finn Knut (2012). New materials used for the consolidation of archaeological wood – past attempts, present struggles, and future requirements. Journal of Cultural Heritage. ISSN 1296-2074. 13(3), p. S183–S190. doi: 10.1016/j.culher.2012.02.013.
• (2012). The Optimum Dispersion of Carbon Nanotubes for Epoxy Nanocomposites: Evolution of the Particle Size Distribution by Ultrasonic Treatment. Journal of Nanotechnology. ISSN 1687-9503. doi: 10.1155/2012/545930.
• Truong, Thuy le; Larsen, Åge Gellein; Holme, Børge; Hansen, Finn Knut & Roots, Jaan (2011). Morphology of syndiotactic polypropylene/alumina nanocomposites. Polymer. ISSN 0032-3861. 52(4), p. 1116–1123. doi: 10.1016/j.polymer.2011.01.014. Show summary

  The effect of the addition of 50 nm spherical alumina nanoparticles with hydrophilic or hydrophobic surfaces on the morphology of syndiotactic polypropylene (sPP) was investigated. The filler content in the nanocomposites was 3 wt%. Polarized Optical Microscopy and Small Angle Light Scattering (SALS) studies showed that sPP and the nanocomposites form hedrites. The addition of alumina nanoparticles significantly increased the number of hedrites. A higher number of nucleation sites in the nanocomposites promote a higher crystallization rate, and thus hedritic growth was stopped at the early stage of crystallization. Quantitative evaluations by SALS analysis show that the object size is decreased by not only the crystallization conditions but also the presence of Al2O3 nanoparticles. A small amount of Al2O3 nanoparticles did not noticeably affect the crystallinity of sPP, but increased the melting point. Transmission Electron Microscopy images showed that the lamellar thickness did not change significantly with the incorporation of nanoparticles. The lamella thickness, however, depends on cooling rates. X-ray diffraction characterization indicated that the sPP and the nanocomposites were crystallized in disordered “form I”. The incorporation of alumina nanoparticles had a small effect on the crystal structure of syndiotactic polypropylene.

• Kristensen, Tor Erik Holt; Vestli, Kristian; Jakobsen, Martin Gjerde; Hansen, Finn Knut & Hansen, Tore (2010). General Approach for Preparation of Polymer-Supported Chiral Organocatalysts via Acrylic Copolymerization. Journal of Organic Chemistry. ISSN 0022-3263. 75(5), p. 1620–1629. doi: 10.1021/jo902585j.
• Truong, Thuy le; Larsen, Åge; Holme, Børge; Diplas, Spyridon; Hansen, Finn Knut & Roots, Jaan (2010). Dispersibility of silane-functionalized alumina nanoparticles in syndiotactic polypropylene. Surface and Interface Analysis. ISSN 0142-2421. 42(6-7), p. 1046–1049. doi: 10.1002/sia.3166.
• Kristensen, Tor Erik Holt; Hansen, Finn Knut & Hansen, Tore (2009). The Selective O-Acylation of Hydroxyproline as a Convenient Method for the Large-Scale Preparation of Novel Proline Polymers and Amphiphiles. European Journal of Organic Chemistry. ISSN 1434-193X. p. 387–395. doi: 10.1002/ejoc.200800941.
• Kristensen, Tor Erik Holt; Vestli, Kristian; Fredriksen, Kim A; Hansen, Finn Knut & Hansen, Tore (2009). Synthesis of Acrylic Polymer Beads for Solid-Supported Proline-Derived Organocatalysts. Organic Letters. ISSN 1523-7060. 11(14), p. 2968–2971. doi: 10.1021/ol901134v.
• Kristensen, Tor Erik Holt; Vestli, Kristian; Hansen, Finn Knut & Hansen, Tore (2009). New Phenylglycine-Derived Primary Amine Organocatalysts for the Preparation of Optically Active Warfarin. European Journal of Organic Chemistry. ISSN 1434-193X. p. 5185–5191. doi: 10.1002/ejoc.200900664.
• (2008). Surface dilatational elasticity of poly(oxy ethylene)-based Surfactants by oscillation and relaxation measurements of sessile bubbles. Langmuir. ISSN 0743-7463. 24(1), p. 189–197. doi: 10.1021/la7024582. Show summary

  Surface dilatational elasticities and viscosities have been measured by means of the axisymmetric bubble shape method. Two different techniques using sinusoidal oscillations and step relaxations have been used, and the results are treated by means of the bulk/surface diffusional exchange model. Three different nonionic surfactants based on poly(oxy ethylene) as the hydrophilic group have been used: one simple surfactant, Brij 35, and two block copolymers, Pluronic F68 and P9400. Step relaxation and oscillation give mostly the same limiting surface dilatational elasticities, but step relaxation is a more model-dependent method. In the cases where the bulk/surface diffusion model is correct, the two methods give the same results, but otherwise step relaxation gives average values of the limiting elasticity E0 and the typical relaxation frequency 0. Limiting elasticities up to ca. 25 mN m-1 have been found for these substances. The surface/bulk diffusion model describes quite well the two relatively hydrophilic substances Brij 35 and F68, especially at low concentrations, but less so for the more hydrophobic P9400. The surface dilatational elasticity as a function of the surface pressure of the surface-active polymers goes through at least one maximum as a result of surface conformational changes.

• Grythe, Kai Frode & Hansen, Finn Knut (2007). Diffusion Rates and the Role of Diffusion in Solid Propellant Rocket Motor Adhesion. Journal of Applied Polymer Science. ISSN 0021-8995. 103(3), p. 1529–1538. doi: 10.1002/app.25086. Show summary

  Diffusion rates can give important information for the adhesion process across the bondline between insulation and propellant in solid propellant rocket motors. Diffusion coefficients of low molecular weight species such as crosslinkers and plasticizers have been measured by the weight of uptake method in polymer materials that are candidates for propellant contact. The materials were EPDM insulation sheets and ‘‘liners,’’ based on HTPB, HTPE, or GAP, and with different degrees of particle filling. Plots of relative mass gain as a function of the square root of time showed good linearity up to 20 50% weight increase and the diffusion coefficients could thus be determined with good accuracy. The diffusion coefficients for the low molecular weight isocyanates and plasticizers in these materials vary between 10 11 and 10 17 m2 s1, dependent on material types and particle filling. In most cases, the results can be explained by the solubility parameters of the organic liquids and polymers. For the particle filled samples, the diffusion coefficients decrease with increasing degree of particle filling, and the decrease if faster than predicted by the Maxwell Fricke or the Keller models for arrays of smooth spheres.

• Grythe, Kai Frode; Hansen, Finn Knut & Olsen, Torbjørn (2007). Adhesion in Solid Propellant Rocket Motors. The journal of adhesion. ISSN 0021-8464. 83(3), p. 223–254. doi: 10.1080/00218460701239059. Show summary

  Plasma treatment of EPDM based rocket motor insulation materials may change the peel strength between these materials and polyurethane polymers with a factor of 0.5 to 10. The matching of surface energies seems to be important for this adhesion process. The surface tension of the components was measured to between ca 30 and 50 mNm-1. The total surface energy of the insulation could be increased from 27.2 mNm-1 to ca 70 mNm-1 by the plasma process. Maximum peel strength could be obtained by less than one minute treatment, while longer times in most cases gave lower values. In some cases very long treatment also gave good strength, probably due to a rougher surface structure. The rate of cure of the polymer was important for the adhesion process as longer curing time correlated with higher peel strengths, which can be explained by diffusion of the polymer’s components into the insulation.

• Grythe, Kai Frode & Hansen, Finn Knut (2006). Surface modification of EPDM rubber by plasma treatment. Langmuir. ISSN 0743-7463. 22(14), p. 6109–6124. Show summary

  The effect of argon, oxygen, and nitrogen plasma treatment of solvent cast EPDM rubber films has been investigated by means of atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and surface energy measurements. Plasma treatment leads to changes in the surface energy from 25 to 70 mN/m. Treatment conditions influenced both the changes in surface energy and the stability, and it became more difficult to obtain good contact angle measurements after longer (> ca. 4 min) treatment times, probably because of an increasingly uneven surface structure. XPS analyses revealed that up to 20 at. % oxygen can be easily incorporated and that variations of /-%5 can be controlled by the plasma conditions. Oxygen was mainly found in hydroxyl groups, but also as carbonyl and carboxyl. XPS analyses showed more stable surfaces than expected from contact angles, probably because XPS analysis is less surface sensitive than contact angle measurements. AFM measurements revealed different surface structures with the three gases. The surface roughness increased generally with treatment time, and dramatic changes could be observed at longer times. At short times, surface energy changes were much faster than the changes in surface structure, showing that plasma treatment conditions can be utilized to tailor both surface energies and surface structure of EPDM rubber.

• (2005). Historic Overview. In Van Herk, Alex (Eds.), Chemistry and Technology of Emulsion Polymerisation. Blackwell Publishing. ISSN 1-4051-2113-0. p. 3–24.
• Grythe, Kai Frode; Hansen, Finn Knut & Walderhaug, Harald (2004). NMR self-diffusion and viscosity of polyurethane formulations for rocket propellants. Journal of Physical Chemistry B. ISSN 1520-6106. 108, p. 12404–12412.
• Davis, J.; Foegeding, E.A. & Hansen, Finn Knut (2004). Electrostatic effects on the yield stress of whey protein isolate foams. Colloids and Surfaces B: Biointerfaces. ISSN 0927-7765. 34, p. 13–23.
• Frømyr, T.; Hansen, Finn Knut; Kotzev, A. & Laschewsky, A. (2001). Adsorption and surface elastic properties of corresponding fluorinated and non-fluorinated cationic polymer films measured by drop shape analyis. Langmuir. ISSN 0743-7463. 17, p. 5256–5254.
• Hansen, Finn Knut & Kopperud, Hilde Beate Molvig (2001). Surface tension and surface dilatational elasticity of associating hydrophobically modified polyacrylamides in aqueous solutions. Macromolecules. ISSN 0024-9297. 34, p. 5635–5643.
• Myrvold, Rolf; Hansen, Finn Knut & Lindman, Björn (2000). The Adsorption and Surface Dilatational Rheology of Unmodified and Hydrophobically Modified EHEC, Measured by Means of Axisymmetric Drop Shape Analysis. ACS Symposium Series.
• Hansen, Finn Knut & Hveem, J. (1999). The Interfacial Tension between Acrylic Monomers and Polymers and Non-ionic Surfactants Investigated by the Automatic Sessile Drop. Journal of Colloid and Interface Science. ISSN 0021-9797. 210, p. 144–151.
• Myrvold, Rolf; Hansen, Finn Knut; Balinov, Balin & Skurtveit, Roald (1999). Monolayers of Some Poly(oxyethylene)-Based Surfactants at the Air-Water Interface: The Effect of Structural Variations and Salt Concentration. Journal of Colloid and Interface Science. ISSN 0021-9797. 215, p. 409–419.
• Kopperud, Hilde Beate Molvig; Walderhaug, Harald & Hansen, Finn Knut (1999). Polymer self-diffusion and surfactant bindig in aqueous solutions of unmodified and hydrophobocally modofied polyacrylamide studied by pulsed field gradient NMR and surface tension measurements. Macromolecular Chemistry and Physics. ISSN 1022-1352. 200, p. 1839–1845.
• Kopperud, Hilde Beate Molvig; Hansen, Finn Knut & Nyström, Bo (1998). Effect of surfactant and temperature on the rheological properties of aqueous solutions of unmodified and hydrophobically modified polyacrylamide. Macromolecular Chemistry and Physics. ISSN 1022-1352. 199(11), p. 2385–2394. Show summary

  Linear and nonlinear viscoelasticity of semidilute aqueous solutions of an unmodified reference poly(acrylamide) (PAM) and of a hydrophobically modified poly(acrylamide) (HM-PAM) in the presence of various amounts of sodium dodecyl sulfate (SDS) and at different temperatures have been examined. Oscillatory shear experiments in the linear viscoelastic domain revealed significant polymer-surfactant interaction for the HM-PAM-SDS system at a surfactant concentration of ca. 8 mmolal, whereas practically no surfactant effect was observed for the PAM-SDS system. The rheological features for the HM-PAM-SDS system were found to be strongly dependent upon the level of surfactant addition, with first an increase and then a decrease in the values of parameters such as the dynamic viscosity. While the position of the maximum of the viscosity curve, with regard to the surfactant concentration, was independent of polymer concentration and temperature, the strength of the network was promoted by increasing polymer content and decreasing temperature. At higher surfactant concentrations, a breakdown of chain associations occurred. A non-Newtonian shear thinning behavior, as well as a thixotropy, was detected for HM-PAM solutions in the presence of surfactant. These effects were most pronounced at ca. 8 mmolal SDS at the lowest temperature. The rheological features reveal that the hydrophobic associations, induced by HM-PAM-SDS interactions, play an important role for the viscoelastic properties of the system.

• Myrvold, Rolf & Hansen, Finn Knut (1998). Surface Elasticity and Viscosity From Oscillating Bubbles Measured by Automatic Axisymmetric Drop Shape Analysis. Journal of Colloid and Interface Science. ISSN 0021-9797. 207, p. 97–105.
• Aabakken, Lars; Rosseland, Arne Retvedt; Osnes, Magne; Wara, Pål & Hansen, Finn Knut (1997). Utstyr, sikkerhet og dokumentasjon. In Aabakken, Lars; Osnes, Magne & Rosseland, Arne Retvedt (Ed.), Gastrointestinal endoscopi (The SADE book). Scandinavian Association of Digestive Endoscopy, Oslo. ISSN 82-994298-0-3. p. 1–28.
• Hansen, Finn Knut & Fagerheim, Hege (1997). The Influence of Oil Phase on the Adsorption of Non-ionic Surfactants Investigated by the Automatic Sessile Drop Method. Colloids and Surfaces A: Physicochemical and Engineering Aspects. ISSN 0927-7757. 137, p. 217–230.
• Hansen, Finn Knut; Nyström, Bo & Walderhaug, Harald (1995). Dynamic Interactions and Adsorption in Systems of Hydrophobically Modified Water-soluble Polymers. Macromolecular Symposia (1986-1993). ISSN 0258-0322. 92.
• Walderhaug, Harald; Nyström, Bo; Hansen, Finn Knut & Lindman, Björn (1995). Surfactant-polymer interaction in thermo-induced gelling systems of ethyl(hydroxyethyl) cellulose (EHEC) studied by NMR self-diffusion, dynamic light scattering and rheology. Progress in Colloid and Polymer Science. ISSN 0340-255X. 98.
• Nyström, Bo; Walderhaug, Harald; Hansen, Finn Knut & Lindman, Björn (1995). Rheological Behavior During Thermoreversible Gelation of Aqueous Mixtures of Ethyl(hydroxyethyl) cellulose and Surfactants. Langmuir. ISSN 0743-7463. 11.
• Walderhaug, Harald; Nyström, Bo; Hansen, Finn Knut & Lindman, Björn (1995). Interactions of Ionic Surfactants with a Nonionic Cellulose Ether in Solution and in the Gel State Studied by Pulsed Field Gradient NMR. Journal of Physical Chemistry. ISSN 0022-3654. 99.
• Nyström, Bo; Walderhaug, Harald & Hansen, Finn Knut (1995). Dynamic Light Scattering and Rheological Studies of Thermoreversible Gelation of a Poly(ethylene oxide)-Poly(propyleneoxide)-Poly(ethyleneoxide) Triblock Copolymer in Aqueous Solution. Faraday discussions. ISSN 1359-6640. 101.
• Hansen, Finn Knut & Myrvold, Rolf (1995). The Kinetics of Albumin Adsorption to the Air/Water Interface Measured by Automatic Axisymmetric Drop Shape Analysis. Journal of Colloid and Interface Science. ISSN 0021-9797. 177.
• Nyström, Bo; Walderhaug, Harald & Hansen, Finn Knut (1993). Dynamic Crossover Effects Observed in Solutions of a Hydrophobically Associating Water-soluble Polymer. Journal of Physical Chemistry. ISSN 0022-3654. 97.
• Walderhaug, Harald; Hansen, Finn Knut; Abrahmsen, Susanna; Persson, Karin & Stilbs, Peter (1993). Associative Thickeners. NMR Self-diffusion and Rheology Studies of Aqueous Solutions of Hydrophobically Modified Poly(oxyethylene) Polymers. Journal of Physical Chemistry. ISSN 0022-3654. 97.
• (1993). Surface Tension by Image Analysis. Fast and Automatic Measurements of Pendant and Sessile Drops and Bubbles. Journal of Colloid and Interface Science. ISSN 0021-9797. 160, p. 209–217.
• Persson, Karin; Abrahmsen, Susanna; Stilbs, Peter; Walderhaug, Harald & Hansen, Finn Knut (1992). The association of urethane-polyethyleneoxide (HEUR) thickeners, as studied by NMR self-diffusion measurements. Colloid and Polymer Science. ISSN 0303-402X. 270.

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• (2016). Theoretical modelling of the elastic modulus of polymer nanocomposites.
• Moxnes, John F.; Jensen, Tomas Lunde; Kjønstad, Eirik F.; Unneberg, Erik; Hansen, Finn Knut & Ødegårdstuen, Gard (2015). Detonation performance of high energy compounds determined by quantum mechanics. Show summary

  Density, impact sensitivity and detonation performance for new explosives are calculated by QM. Use of isosurface volume or electrostatic potential is a good alternative for the Polymorph predictor. The B3LYP and M06-2X functionals, both with the 6-31G(d) basis set, show significantly different bond dissociation energies in the nitrimino functional group.

• Johnsen, Bernt Brønmo; Lausund, Kristian Blindheim; Rahbek, Dennis Bo & Hansen, Finn Knut (2015). Adhesion between alumina ceramic and glass fibre-reinforced polyester composite in hybrid armour systems.
• (2012). Achieving Good Mechanical Properties in Smokeless Propellant Formulations Based on HMX-GAP-BUNENA with Polymeric Bonding Agents.
• Hansen, Finn Knut & Hansen, Tore (2012). Polymer particles with organocatalytic functionality. Abstract of Papers of the American Chemical Society. ISSN 0065-7727. 244.
• Landsem, Eva; Jensen, Tomas Lunde; Kristensen, Tor Erik; Unneberg, Erik; Benneche, Tore & Hansen, Finn Knut (2012). Improving the properties of minimum smoke composite rocket propellants.
• Kutzke, Hartmut; Braovac, Susan; Christensen, Mikkel & Hansen, Finn Knut (2011). Old treatments – new solutions? Summary of activities of the Alum Research Group.
• Landsem, Eva; Tungen, Jørn Eivind; Kristensen, Tor Erik; Unneberg, Erik; Benneche, Tore & Hansen, Finn Knut (2011). Isocyanate-Free Curing of Glycidyl Azide Polymer (GAP).
• Christensen, Mikkel; Kutzke, Hartmut & Hansen, Finn Knut (2011). Biomimetic conservation: Cellulose and chitosan for wood preservation.
• (2010). The effects of sonication on the degree of dispersion of carbon nanotubes in epoxy systems. Show summary

  Epoxy systems filled with multiwall carbon nanotubes (MWNT) have been studied. It is generally believed that nanotubes must be well dispersed as single tubes in the matrix to utilize their excellent mechanical properties. Bath or tip sonicators are usually employed for the dispersion of the MWNTs. A bath sonicator treats the sample homogenously, but the power and the intensity is low. This results in very long sonication times to reach acceptable dispersions. Tip sonicators on the other hand, can have a high power output, but the acoustic field is very inhomogeneous. For larger volumes, stirring of the solution is necessary. Alternatively, the sonication can be done inside a flow-cell, resulting in a more homogenous sonication and a better ability to handle larger sample volumes. The efficiency of a bath sonicator has been compared with a tip sonicator in a flow-cell. Different types of MWNTs were dispersed in an epoxy curing agent. The degree of dispersion was determined by differential sedimentation particle analysis using a disc centrifuge. The results show that the particle size distribution is bi-modal with a narrow distribution of dispersed nanotubes and a broader distribution of agglomerates ranging from 100 nm to several micrometers in size. Furthermore, the separation of MWNTs from these agglomerates is controlled by a more complex mechanism than the energy input alone. At comparable energy inputs, a better dispersion is achieved using a higher acoustic intensity. The rate and degree of dispersion varies with different types of MWNTs.

• Bourgeaux-Goget, Marie; Frømyr, Tomas Roll; Hansen, Finn Knut & Pinheiro, Jean Patrick (2010). Dispersion study of multi-wall carbon nanotubes synthesized by arc-discharge technique. Show summary

  Carbon nanotubes (CNTs) have received a great amount of interest because of their intrinsic and unique chemical, physical and mechanical properties that are suitable for versatile applications, especially for composite materials. Unfortunately, these materials are plagued with challenging dispersion protocols concomitant with difficult characterization techniques which complicate discovering their comprehensive properties in composite products. Our approach uses CNTs synthesized by arc-discharge technique as they offer fewer structural defects than those produced by other known techniques. A method was developed to characterize the dispersed medium using disc centrifuge for the detection of individual CNTs and residual aggregates. Studies performed on both pristine and purified CNTs show that interactions in between nanotubes are rather strong and high ultra-sound intensity is required to achieve complete dispersion of CNT bundles. Achieving such dispersion is a key advantage suggesting better properties on future composite materials.

• Christensen, Mikkel; Kutzke, Hartmut & Hansen, Finn Knut (2009). New materials used for the consolidation of archaeological wood – past attempts, present struggles, and future requirements.
• Truong, Le Thuy; Larsen, Åge Gellein; Holme, Børge; Diplas, Spyros; Hansen, Finn Knut & Roots, Jaan (2009). Dispersibility of Silane-functionalized Alumina Nanoparticles in Syndiotactic Polypropylene.
• Truong, Le Thuy; Larsen, Åge; Holme, Børge; Hansen, Finn Knut & Roots, Jaan (2009). Morphology and crystallization behavior of syndiotactic polypropylene-alumina nanocomposites.
• Hansen, Finn Knut; Hansen, Tore & Kristensen, Tor Erik (2007). Solid phase organocatalysis. Show summary

  Organocatalysis is a quite novel research field within asymmetric organic synthesis. Instead of the traditional metal based catalysts, small organic molecules, e.g. amino acids, have been shown to give interesting results. This has several advantages such as low cost, potential use in aqueous solutions, better biodegradability, no traces of metals and less health risk due to mild conditions. Almost all known organocatalytic processes are presently carried out under homogenous conditions. In order to increase the usability of these processes in practical applications, a heterogeneous catalytical process is necessary, but this has not yet been utilised significantly in organocatalysis. Different solid supports are used in bio-organic processes such as peptide synthesis, chromatography, ion exchange etc. These are either based on macroporous silica or solid or macroporous cross linked polymer particles. We have for many years been producing large (5 – 50 m) monodisperse macroporous polymer particles based on the Ugelstad method and similar processes for chromatography, biomedicin etc. These particles can be given functional groups such as double bonds, chloromethyl, hydroxyl, carboxyl, glycidyl, etc. which can be used to immobilize the organocatalysts. Different types of grafting can also be performed. The activity of these solid phase catalysts will be dependent of the type of catalyst, the structure of the particles, the method of binding, the degree of functionalization, etc.

• Hansen, Finn Knut & Grythe, Kai Frode (2005). Surface modification of EPDM rubber by plasma treatment.
• Hansen, Finn Knut & Grythe, Kai Frode (2005). Surface modification of EPDM rubber by plasma treatment.
• Grythe, Kai Frode; Hansen, Finn Knut & Walderhaug, Harald (2004). NMR Self Diffusion and Viscosity of Polyurethane Formulations for Rocket Propellants.
• Hansen, Finn Knut & Kopperud, Hilde Beate Molvig (2000). Surface elasticity and viscosity of adsorbed films from drop shape analysis.
• (2000). Måling av overflateenergi av polymerer ved hjelp av kontaktvinkler av væsker på faste overflater.
• Hansen, Finn Knut; Frømyr, T.; Laschewsky, A. & Kotzev, A. (1999). Adsorption and surface elastic properties of corresponding fluorinated and non-fluorinated cationic polymer films measured by drop shape analysis.
• Hansen, Finn Knut; Nyström, Bo & Walderhaug, Harald (1996). Introduction. Colloids and Surfaces A: Physicochemical and Engineering Aspects. ISSN 0927-7757. 117.
• Hansen, Finn Knut; Nyström, Bo & Walderhaug, Harald (1994). Assosierende polymerer-et moderne og aktuelt forskningsfelt. Kjemi. ISSN 0023-1983.
• Tesfu, Teame Kiros; Hansen, Finn Knut & Roots, Jaan (2016). Surface characterization of amphoteric and anionic membranes. Universitetet i Oslo.
• Araba, Taofik Olasile; Bonge-Hansen, Tore & Hansen, Finn Knut (2016). Progress towards the synthesis and self-assembly of amphiphilic drug conjugates of Iodinin. Universitetet i Oslo. Show summary

  Despite recent improvement in therapy, acute myeloid leukaemia (AML) is still associated with high lethality. Iodinin (1, 6-dihydroxyphenazine 5, 10-dioxide) is a compound of interest in leukaemia research, as it is showing very promising anti-cancer properties with low toxicity. However, since the drug is essentially water-insoluble, effective administration is problematic and requires other chemical modification or encapsulation in nanoparticles e.g. liposomes, micelles etc. To this end we seek to develop an amphiphilic drug conjugate by first alkylating the phenolic group on iodinin C-1 and lastly attaching a PEG unit on the iodinin C-6 phenolic group with the aim of altering the physiochemical properties i.e. electrostatic binding and hydrophobicity in iodinin, so that this drug conjugate can be further studied in a nanoparticle motif to be released slowly upon hydrolysis in biological systems.

• Chamgordani, Elahe Jafari; Benneche, Tore & Hansen, Finn Knut (2015). Synthesis of 5-Membered Heterocycles as Quorum Sensing Inhibitors. Universitetet i Oslo.
• Truong, Thuy le; Larsen, Åge Gellein; Holme, Børge; Hansen, Finn Knut & Roots, Jaan (2013). Syndiotactic polypropylene nanocomposites and blends: Morphology, crystallization behavior and tensile properties. Universitetet i Oslo.
• Christensen, Mikkel; Hansen, Finn Knut & Kutzke, Hartmut (2013). Developing new consolidants for archaeological wood. Universitetet i Oslo.
• Landsem, Eva; Hansen, Finn Knut; Unneberg, Erik & Benneche, Tore (2012). Development of Smokeless Composite Rocket Propellants. Universitetet i Oslo.
• Kristensen, Tor Erik Holt; Hansen, Tore & Hansen, Finn Knut (2010). Polymer-Supported Chiral Organocatalysts. Universitetet i Oslo.
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