This article presents a waterborne nanocellulose coating process to change the surface characteristics and mitigate fouling of commercially available polyethersulfone (PES) microfiltration membranes. An extensive comparative study between nanoporous and nano-textured layers composed of cellulose nanocrystals (CNC) or TEMPO-oxidized cellulose nanofibrils (T-CNF), which were coated on the PES membrane by taking advantage of the electrostatic interactions between the PES substrate, a polyallylamine hydrochloride (PAHC1) anchoring layer, and the nanocellulose functional layer. Coated PES membranes exhibited decreased surface roughness and pore sizes as well as rejection of compounds with a M-w above 150 kDa, while the water permeability and mechanical properties of remained largely unaffected. The coatings improved the wettability as confirmed by a reduction of the contact angle by up to 52% and exhibited a higher negative surface charge compared to the uncoated membranes over a pH range of 4-8. A significant reduction in organic fouling was observed for the coated membranes demonstrated by bovine serum albumin (BSA) adsorption studies on T-CNF and CNC surfaces using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), UV-vis spectroscopy and FTIR mapping after exposing the membranes to dynamic adsorption of BSA. The T-CNF coating exhibited effective antibacterial action against Escherichia coli (E. coli) attributed to the pH reduction effect induced by the carboxyl groups; while CNC coatings did not show this property. This work demonstrates a simple, green, and easy-to-scale layer-by-layer coating process to tune the membrane rejection and to improve antifouling and antibacterial properties of commercially available membranes.

Chemo-enzymatic methods are powerful tools for the synthesis of novel materials. By combining the flexibility of chemical synthesis and the high selectivity of enzymes, a variety of functional materials can be achieved. In the present study, a series of α,ω-thiol telechelic oligoesters with varying amount of internal alkenes are prepared using selective lipase catalysis and are subsequently cross-linked by thiol-ene chemistry yielding alkene functional networks. Due to the reactivity of thiols and alkenes almost all present thiol-ene systems consist of two components. This work demonstrates that selective lipase catalysis in combination with renewable monomers with internal alkenes is a promising system for achieving one-component thiol-alkene functional resins with good storage stability and a high degree of thiol end-groups. The developed chemo-enzymatic route yields polymer networks with tailored amount of alkene functionalities in the final thermoset, which facilitate further postmodification.

I arbetet som presenteras i denna avhandling undersöktes epoxifettsyraderivat vid bildandet av härdplaster för ytmodifieringsapplikationer. Förnybara råvarorna björkbark och epoxiderad linolja andändes för att erhålla epoxifettsyraderivaten. Björkbarken användes för att isolera 9,10-epoxi-18-hydroxidekansyra (EFA) och epoxoderad linolja användes för att extrahera metylstearat och 3 olika epoximetylestrar: epoximetyl oleat/linoleat/linolenat (EMO/EMLO/EMLEN). Epoxifettsyraderivaten användes i olika hartsformuleringar tillammans med andra reaktanter eller vid syntes av multifunktionella oligomerhartser med hjälp av enzymatisk katalys. Med hjälp av olika polymerisationstekniker så härdades alla hartser till härdplaster med en mängd olika egenskaper.Multifunktionella oligomerhartser syntetiserades med hjälp av enzymet Candida Antarctica lipas-b (CALB). Syntesen visade sig vara effektiv och oligomererna erhölls från en sats. Dessutom var selektiviteten hos CALB användbar för att bevara en mängd olika funktionella grupper (epoxider, alkener och tioler) i de slutliga oligomererna. Tiol-ene kemi eller katjonisk polymerisation användes sedan för att härda oligomererna, vilket resulterade i funktionella härdplaster. Vidare visades att ytegenskaperna kunde ändras genom möjlighet till funktionalisering av härdplasterna.Mjuka material återfås då man härdar rena fettsyrametylestrar. Ett sätt att öka de termiska och mekaniska egenskaperna undersöktes. De tre olika epoxifunktionella metylestrarna tillsammans med furan-2,5-dicarboxylsyraderivat blandades i hartser och härdades. Genom att variera de stökiometriska förhållanderna av reaktanterna så erhölls glastemperaturer (Tg) under 0°C och över 100 °C.Undersökningen av termisk härdning av EFA som ett komponentssystem studerades genom modelstudier. Studierna visade att en självkatalyserad process sker då EFA värms upp. Detta leder således till att EFA kan termiskt härda utan behov av en tillsatt katalysator. Dessutom uppvisade härdplasten limegenskaper.Rå blandning innehållande metylstearate, EMO, EMLO och EMLEN som erhölls från epoxiderad linolja undersöktes som en reaktiv utspädare i spolbeläggningar. Blandningen jämfördes även med kommersiellt tillgängliga utspädare så som fettsyrametylestrar (FAME) erhållna från rapsolja. De erhållna resultaten påvisade att fler feta metylestrar kunde integreras i slutliga beläggningen när fettsyraderivat från epoxideradlinolja användes.Realtids Fourier-transform infrarödspektroskopi (RT-FTIR) användes under det mesta av arbetet som presenteras i denna avhandling. RT-FTIR visade sig vara ett kraftfullt vektyg för att övervaka de olika reaktionerna samt jämföra relativa reaktionshastigheter.

The increased environmental awareness has driven academia and industry to utilize environmentally benign sources. An industrially available process that is effective in the coatings industry is the coil-coating process where sheet steel can be pre-coated. During this process volatile organic compounds (VOCs) are generated and incinerated for energy recovery. One way to minimize VOCs is to use a reactive diluent i.e. a molecule that acts both as a solvent as well as chemically react into the final coating upon curing. Fatty acid methyl esters obtained from renewable resources such as vegetable oils are suitable candidates as reactive diluents. In this paper epoxidized fatty acid methyl esters (e-FAMEs) obtained from epoxidized linseed oil where compared with fatty acid methyl esters (FAMEs) obtained from rapeseed oil as reactive diluents in coil-coating formulations. Coil-coating formulations were followed by real-time Fourier transform infrared spectroscopy (RT-FTIR) in order to evaluate the e-FAMEs or the FAMEs reactivity in the coating system. In addition, coil-coating formulation containing e-FAME or FAME where cured in a pilot scale simulated coil-coating process. Moreover, thermal properties of the final coatings were evaluated by differential scanning calorimetry (DSC).

The use of bio-based raw material is regarded as a sustainable way to address environmental concerns. A naturally occurring monomer, 9,10-epoxy-18-hydroxyoctadecanoic acid (EFA), was retrieved from outer birch bark. A series of model experiments revealing relative reaction rates for epoxide, carboxylic acid, and alcohol functional groups was investigated. Real-time Fourier transform infrared spectroscopy and nuclear magnetic resonance were used to follow the different model experiments. The results on the model systems were then compared to the thermoset formation of thermally cured EFA. Finally, the adhesive properties of crosslinked EFA on different substrates were evaluated.

In the pursuit of environmentally friendly building blocks in polymer chemistry the utilization of biobased monomers is highly desired. In the present study, the biobased monomer 2,5-furandicarboxylic acid (FDCA) has been extended into epoxy thermosets. The study presents the synthesis of diallyl furan-2,5-dicarboxylate (DAFDC) followed by an epoxidation of the allyls to form diglycidyl furan-2,5-dicarboxylate (DGFDC). DGFDC was then copolymerized in both stoichiometric and off-stoichiometric ratios with epoxidized fatty methyl esters to form a range of thermosets. The cross-linking reaction was either thermally or UV-induced cationic polymerization utilizing onium salt initiators where the reactivity was studied by DSC and real-time fourier transform infrared analysis. Furthermore, the structure-property relationships of the final thermosets were determined by dynamic mechanical thermal analysis revealing a possibility to tune the properties over a wide range. In addition thermosets were made from diglycidyl Bisphenol-A (DGEBA) with epoxidized fatty methyl esters made for comparative purposes.

Selective enzyme catalysis is a valuable tool for the processing of monomers into value-added materials. In the present study natural resources were used to retrieve an omega-hydroxy fatty acid monomer containing an epoxide functionality. A procedure was developed for the synthesis of dual-functional oligomers by utilizing lipase catalysis in a one-pot synthesis route. The chemoselectivity of the enzyme allowed addition of thiol monomers to the retrieved epoxy monomers, without harming the epoxides, achieving a thiol-epoxy functional polyester resin. The synthesis reached full conversion (> 99%) after 8 h. It was possible to selectively crosslink the resin through UV-initiated cationic polymerization of the epoxides into thiol-functional thermosets. The curing performance was followed in situ by real-time FTIR. The thiol groups on the surface of the film were accessible for post-modification.