Hyaluronan is a polymer that among other things is used in fillers. Products containing Hyaluronan is sometimes discoloured over time and the mechanism behind this discolouration is still unknown. However, it was suspected that discolouration occurs during the degradation due to high pH values or with a phosphate buffer. The discolouration of Hyaluronan that occurs with phosphate buffer was studied in more detail in this project. The samples of Hyaluronan with different concentrations of phosphate buffer were left at 90 °C in an oven to speed up the discolouration. These samples were then analyzed byusing UV/Vis spectrophotometry to measure the absorption and capillary viscometry to measure the molecular weight. The results showed that the discolouration increased with time and that the samples with the higher concentration of buffer got more discoloured faster. The molecular weight showed a decreasing trend with time. It also suggested that the phosphate buffer had an impact on the molecular weight. The samples with the highest concentration of phosphate buffer had a lower molecular weight compared to samples with no phosphate buffer. The main conclusion from this study is that the phosphate buffer had an effect on the discolouration of Hyaluronan.

Termiskt expanderbara mikrosfärer är ihåliga polymera partiklar i vilka en flyktig drivgas har kapslats in. När mikrosfärerna upphettas förgasas drivgasen, vilket ökar trycket i mikrosfärerna så att de expanderar och deras volym ökar avsevärt. Denna unika egenskap gör att expanderade mikrosfärer har en låg densitet och är lämpliga för applikationer där låg vikt är väsentligt, och för att förändra ytstrukturer, så som i till exempel konstläder och textiler. Syftet med denna studie har varit att utveckla ett stabilt system för suspensionspolymerisation för att ge en liten mikrosfär (~20 μm efter expansion) som expanderar vid relativt höga temperaturer. Detta har uppnåtts genom att undersöka effekterna av förändringar i stabiliseringssystemet. Komponenterna som varierades var mängden silika (LX), kondensationsoligomeren mellan adipinsyra och dietanolamin (KO), olika formuleringar och mängd av dilauryl peroxid, samt mängden m(III)nitrat. Ytterligare tester gjordes runt effekten av tvärbindning, tillsats av monomeren metyl metakrylat (MMA), samt tillsats av salt (NaCl). Ett stabilt system för polymerisation i 1L-skala med en homogen dispersion uppnåddes med en av dilauryl peroxide formuleringarna tillsammans med en större mängde LX och KO. Studien visar även att kvoten mellan LX och KO har en signifikant effekt på systemets stabilitet och att mängden av både LX och KO påverkar partikelstorleken. / Thermally expandable microspheres are hollow polymeric particles in which a blowing agent has been encapsulated. Upon heating the blowing agent will vaporize, causing the internal pressure to increase, thereby expanding the microspheres. This unique expandable property reduces the density of the microspheres tremendously and makes them excellent for many applications, as for example as light weight fillers and to alter surface textures, such as in artificial leather and textiles. The purpose of this study has been to develop a viable system for the suspension polymerization of a small microsphere (~20 μm when expanded) expanding at fairly high temperatures. This has been accomplished by investigating the effect of changes in the stabilization system. Components of the stabilization system that have been varied were the amounts of silica (LX), condensation oligomer from adipic acid and diethanol amine (KO), and m(III)nitrate, as well as different formulations and amounts of the initiator dilauryl peroxide. Additional tests were performed concerning the effect of the crosslinking, adding the monomer methyl methacrylate (MMA), and the addition of salt (NaCl). A system for polymerization in 1L-scale was accomplished where it was found that one of the dilauryl peroxide formulations together with a higher amount of LX and KO provided a stable system giving homogeneous dispersions in which the microspheres have the desired expansion properties. Also, the ratio between LX and KO had a significant effect on the stability of the system and the amount of both LX and KO affects the particle size.

Different native starches, modified starches and plant proteins were evaluated as wood adhesives. They were combined with different synthetic polymers in order to achieve improved adhesive properties. The study was divided into two parts: development of starch based adhesive formulations and evaluation of an existing protein based adhesive.  Eight different starches and two different plant proteins were used in the first part. Starch 1 and starch 2 as well as protein 1 and protein 2 were some of the used materials. These materials were dispersed in synthetic polymers such as poly (vinyl acetate) (PVAc), styrene-butadiene rubber (SBR), poly (vinyl alcohol) (PVA), poly (acrylic acid) (PAA) and poly (ethylene-co-vinyl acetate) (EVA). Five different cross-linking agents were also tested. In the second part of the study, protein 2 was used as a renewable material. It was dispersed in dispersing media 2 and filler 1 was used. In an effort to increase the amount of renewable material in the adhesive composition, six different renewable fillers were examined. Lower pressing temperatures as well as lower amounts of cross-linking agent 1 were evaluated in order to observe their influence on the adhesive properties of the protein based adhesive. All formulations were characterized by measurement of viscosity, solid content and pH. The adhesive properties of some of the formulations in both parts of the study were characterized according to SS-EN 204:2001 and EN 14257 (WATT 91). The best results, of the starch based formulations, were obtained when starch 1 and protein 2 were dispersed in dispersing media 2 or dispersing media 7. These formulations in combination with cross-linking agents were classified as D2 and passed the criteria for heat resistance (WATT 91). However, the results were comparable with the reference sample. It was possible to replace filler 1, totally or partly, in the protein based adhesive with renewable fillers. Protein based adhesive formulations with filler 2 and filler 4, amongst others, showed improvement of the adhesive properties. These formulations passed D3 and D4 – wet criteria and almost passed D4 – boiling criteria. The amount of renewable material in the protein based adhesive was increased from ~32 % to ~56 % in the formulations that obtained the best adhesive properties. The amount of non-petrochemical material was ~67 % in all new formulations as well as in the reference sample.  By decreasing the pressing temperature from 110 °C to 90 °C or by decreasing the amount of cross-linking agent 1 from 15 % to 5 %, a protein based system that passes D3 criteria can be obtained.

Oxidative degradation of adhesives based on silane terminated polypropylene oxide and polypropylene oxide (PPO) was studied. The combination of rapeseed oil and PPO as plasticizer in the parquet adhesive gave rise to oxidative degradation in contact with screeds of certain minerals. In order to investigate the degradation process in parquet adhesive two experimental approaches were employed in parallel. The first method was ageing of a solid adhesive-screed system at elevated temperature. It was done in order to evaluate the effect of contact between adhesives and screed in different adhesive-screed systems. Another purpose was also to identify the degradation procedure in a system resembling reality. The second method used was ageing of a soluble mixture of pure PPO with selected plant oils; in order to study the affect of oils unsaturations on the PPO by FTIR. FTIR was used to monitor the degradation of samples after different exposure periods. Unfortunately, interference from the adhesive additives made monitoring of the degradation process difficult in this approach. On the other hand, the optical inspection of the samples degradation process gave a clearer overview. A second method, looking only at two components mixed e.g. PPO and Oil, gave clear FTIR spectra showing that the oxidation process of rapeseed oil started in the period before fifteen days ageing at 75 oC. The combination of FTIR and optical inspection gave a clear image of the adhesive degradation process. Interaction between unsaturated carboxylic acid in the vegetable oils and PPO can increase the degradation rate of parquet adhesives by a radical mechanism. Another parameter affecting the degradation is the interfacial interaction between adhesive containing PPO-Rapeseed oil as plasticizer and screed with high alkalinity, porosity and humidity. The alkaline and humid conditions in the screed probably increase the hydrolysis of rapeseed oil. Further, the porosity of the screed provides a large surface area enabling the plasticizer to be exposed to plenty of oxygen from the air. Therefore, the plasticizer is not only exposed to hydrolysis but also oxidation. This would support the observation of migration of the rapeseed oil, since it is known that carboxylic acid has affinity to calcium sulfate anhydrite in the screed material. Migration and oxidation of rapeseed oils carboxylic acid generate radicals, which accelerate the degradation of PPO in the adhesive film. This process correlated with disappearance of PPO absorbance band from the spectrum.

The commercial field of radical polymerized polymers, such as polyvinyl alcohol, is very broad partly because they are easy to polymerize and cheap. One aspect that could improve their commercial range is to enhance their degradation rate. As the environmental aspect of polymers grows bigger an enhancement of biological degradation is a great improvement. This thesis deals with the prospect of polymerizing polyvinyl alcohol with degradable linkages in the main chain. In order to achieve the aim the monomer 2-methylene-1,3-dioxepane is successfully synthesized and characterized. The synthesis is followed by copolymerization of 2-methylene-1,3-dioxepane with vinylacetate at the feed compositions; 30/70, 50/50, 70/30 mol% respectively. The copolymerization was successful and reached over 90% conversion at the reaction time 3-4 hours with the conditions 60°C and 5mol% 2,2-Azobis(2-methylpropionitrile) as initiator. The copolymerization is followed by hydrolysis with potassium hydroxide or Candida Rugosa Lipase. The results show that chain scission occurs when the polymer is hydrolyzed by potassium hydroxide but not by lipase. There is also a tendency toward hydrolysis of the chain with lipase.

Liquid based electrolytes are known to have safety issues and for their low volumetric energy densities to meet the future energy storage demand. Solid electrolytes based on ion conducting solid ceramic and solid polymer electrolytes are being studied and considered as an alternative to alleviate the issues with liquid electrolytes. Their mechanical property to better suppress dendrite formation gives them an edge to be considered in the realization of high - capacity lithium metal batteries. However, each have such issues associated with them as low ionic conductivity in the case of polymer electrolytes and bad interfacial contact with the lithium anode in the case of inorganic ionic conducting solid electrolytes. Polymer – ceramic composite electrolytes are regarded as a promising option to take advantage of the merits of both and obtain a solid electrolyte which can conduct lithium ions as high as in the mS/cm scale with good electrode – electrolyte interfacial contact, a high electrochemical stability window and high lithium dendrite suppression. This work has aimed to tune the surface of the garnet type ceramic electrolyte, Li7La3Zr2O7, referred to as LLZO, by acid treatment to bring about a better conductivity and lithium – ion transference number of the composite it is applied to. The acid, oxalic acid in this work, treatment has produced the required surface groups, hydroxide ion and oxalate ion, which are hypothesised to help improve the conductivity through the beneficial interactions they bring into the matrix. The conductivity and transference number measurements have revealed the treatment of the LLZO with the acid to have a positive impact on the conductivity and lithium – ion transference number of the composite compared to the untreated counterpart. Typical of the results obtained are the increment in conductivity and the lithium-ion transference number of composites containing 50 % ceramic (LLZO) mass loading. Across all the temperatures the conductivity is measured, an increment by a range of 2.5 times (at room temperature) to 7.8 times (at 60 0C) was obtained. Similarly, the lithium-ion transference number has increased from 0.121 in the composite containing 50 % untreated (pristine) LLZO to 0.159 in the composite containing the same mass loading of oxalic acid treated LLZO.

Målet med projektet var att förbättra polypropens gasbarriär genom att addera olika nanofyllmedel, grafenoxid och kalciumkarbonat. I detta projekt undersöktes främst hur genomsläppligheten av syrgasmolekyler, syrgaspermeabiliteten, ändrades när man tillsätter fyllmedel till polypropen med hjälp av MOCON. Resultaten visade att genomsläppligheten av syrgas minskade något med grafenoxid men blev sämre med den mindre tillsatsen av  kalciumkarbonat. Tester som utfördes gjordes med TGA och DSC men permabilitetstestet framhävs som det mest centrala. Resultaten som erhölls vid permabilitetsundersökningen tros komma av hål i filmerna på molekylär nivå, i dessa hål kan då molekylerna passera igenom filmen fritt.  Övriga resultat pekar på att fyllmedlen inte påverkar polypropens smält- eller kristallisationstemperatur nämnvärt men att dess styrka reduceras.  Då polypropen är en mycket stark polymer så försämrar tillsatsen av fyllmedel styrkan hos materialet, däremot ökade E-modulen. Utöver det verkar inte fyllmedelet ha påverkat de fysikaliska egenskaperna så som Tg och Tc. Samtidigt som den termiska stabiliteten ökade med en tillsatts av GO förändrades den inte nämnvärt när kalciumkarbonat adderades utan den bröts ned vid ungefär samma temperatur som rent polypropen.

Den här rapporten behandlar framställning av nanocellulosa, CNF, och hur det kemiska innehållet för barr- respektive lövmassa påverkar framställningen. De massor som använts i undersökningen var båda ursprungligen från oblekta sulfatmassor. De blev först kloritdelignifierde och genomgick sedan alkalisk extraktion för att ta bort hemicellulosan. Innan massorna homogeniserades enzymbehandlades de med endoglukanas. De erhållna nanofibrerna karakteriserades genom kolhydratsanalys, mätning av polymerisationsgraden, konduktometrisk titrering, mätning av transmittans, AFM, röntgendiffraktion, centrifugering och DLS. Utifrån resultaten kunde det ses att mellan barr- och lövmassorna var barrmassan det bästa alternativet vid framställning av nanocellulosa. Inom barrmassorna var den kloritdelignifierade barrmassan det bästa alternativet vid framställning av nanocellulosa.

In this study, surface modification of both organic and inorganic substrates (in terms of cellulose and silica nanoparticles, respectively) has been explored using surface-initiated atom transfer radical polymerisation (ATRP). The desire to modify bio-based materials to fit into new application areas and the need for bio-based materials with improved material properties is steadily increasing due to environmental concern. Superhydrophobic and self-cleaning cellulose surfaces were fabricated by combining ATRP with post-functionalisation. Glycidyl methacrylate was grafted from filter paper, and the epoxide groups were used as reactive handles to create a branched “graft-on-graft” architecture. Post-functionalisation of this architecture with perfluorinated chains or alkyl chains resulted in the formation of superhydrophobic surfaces. Grafting of N-isopropylacrylamide (NIPAAm) from filter paper yielded cellulose surfaces capable of switching the wettability, from hydrophilic to hydrophobic, in response to changes in temperature. The wettability of cellulose surfaces grafted with poly(4-vinylpyridine) (P4VP) could be adjusted from hydrophilic to hydrophobic by changing pH. Furthermore, cellulose surfaces responding to changes in both pH and temperature were obtained via grafting of block copolymers of PNIPAAm and P4VP. The use of inorganic nano-particles in composites has attracted considerable academic and industrial interest due to their excellent mechanical and thermal properties. Styrene was grafted from the surface of silica nanoparticles using ATRP. The resulting organic-inorganic hybrid materials did not aggregate to the same extent as the un-modified silica particles. The polystyrene-modified silica particles were used for the fabrication of honeycomb membranes. It was evident that the pore sizes and the number of porous layers could be tuned by varying the conditions used for film casting. To broaden the range of polymers available for film casting into honeycomb membranes, a block copolymer of polystyrene and poly(methyl methacrylate) was grafted from silica nanoparticles. Polymer-blends of polystyrene-modified particles and poly(9,9´-dihexylfluorene) (PDHF) were also used as an alternative to incorporate functionality into honeycomb membranes. / QC 20100901

The knowledge regarding certain issues in polymer crystallization e.g. the possible existence of short–lived mesophases remains inconclusive due to experimental limitations. Polymers undergo chain folding upon crystallization, which introduces some complications that are not found in crystallization of low molar mass materials. Chain–folded crystals are far from their equilibrium shape and they rearrange rapidly at the crystallization temperature. This, together with the slow experimental techniques traditionally used, impedes the observation of the originally formed structures. To approach this problem, molecularly constrained polymer structures (in which the crystallizing chains are fixed at one end whereas the other end is free to move) have been studied by X–ray diffraction, differential scanning calorimetry, polarized optical microscopy, transmission electron microscopy and atomic force microscopy. The crystallization studies performed in star–branched polyesters showed that the dendritic cores have a pronounced effect on the crystallization of the linear poly(ε–caprolactone) (PCL) arms attached to them. The star–branched polymers showed slower crystal rearrangement, higher equilibrium melting point, higher fold surface free energy, moderately lower crystallinity, and a greater tendency to form spherulites in comparison with linear PCL. The crystal unit cell was the same in both linear and star–branched PCL. Single crystals of the star–branched polymers were more irregular and showed smoother fold surfaces than linear PCL crystals. No sectorial preference was observed in the crystals of the star–branched polymers upon melting while the single crystals of linear PCL showed earlier melting in the {100} sectors than in the {110} sectors. Some of the differences observed can be attributed to the dendritic cores, which must be placed in the vicinity of the fold surface and thus influence the fold surface structure, the possibility of major crystal rearrangement and the presence of a significant cilia phase during crystal growth causing diverging crystal lamellae and consequent spherulite formation. The attachment of the many crystallizable chains to a single core reduces the melt entropy, which explains the higher equilibrium melting point of star–branched PCL. The crystallization behavior of a series of poly(ethylene oxybenzoate)s was also studied. The polymers showed a profound tendency for crystal rearrangement during melting even at high heating rates. The Hoffman–Weeks extrapolation method was found to be unsuitable to calculate the equilibrium melting point of the samples studied because the melting point vs. crystallization temperature data were sensitive to the variations in crystallisation time, which led to significant variations in the equilibrium melting points obtained. / QC 20100914