The metabolic flexibility of various bacteria in producing unusual poly($\beta$-hydroxyalkanoates), PHAs, was studied. A major effort was undertaken to produce bacterial polyesters other than the usual poly($\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate), P(HB-co-HV), by growing bacteria on non-natural carbon substrates, in the form of carboxylic acids or lactones. The three bacteria studies were: Rhodospirillum rubrum, Alcaligenes eutrophus, and Rhodobacter sphaeroides. All three bacteria favored the metabolization of shorter, carboxylic acids of seven carbons or less. R. rubrum was shown to be the most versatile bacterium in being able to incorporate unusual repeat units into the polymer. The bacterium produced PHAs containing longer, pendent groups of n-propyl and n-butyl. The bacterium was able to incorporate pendent groups of olefin groups, hydroxy groups, and possible chloro groups into the PHAs. R. rubrum also showed the ability in incorporating longer, main-chain, carbon spacers into the polyester backbone. The bacterium seemed to incorporate $\alpha$-substituted methyl groups into the PHAs when grown on $\alpha$-substituted acids. A. eutrophus showed the production of PHAs containing units of varying, main-chain, carbon spacers. However, this was the only flexibility which A. eutrophus showed in PHA production other than the production of usual P(HB-co-HV) copolymers. Rb. sphaeroides, like A. eutrophus, only showed flexibility in producing PHAs having units of longer, main-chain, carbon spacers. Both A. eutrophus and Rb. sphaeroides were able to biosynthesize large amounts of deuterated PHB. The growth and polymer production of both R. rubrum and A. eutrophus were effected by the use of a cofeed when fed in combination with another acid to the bacteria. The cofeed caused the bacteria to incorporate various acids into polymer as unusual polymer units, which were not incorporated when the bacteria was grown on the unusual carbon source alone. Most of the bacterial polymers analyzed were determined to be physical mixtures of various copolymers. Aerobic growth of R. rubrum generally increased the amount of intracellular polymer accumulated by the bacterium, when compared to the polymer yields obtained by R. rubrum grown anaerobically in the light.

Block copolymers comprised of incompatible blocks form ordered microphase separated domains. The domains orient within a microscopic granular structure. But, the director of the grains varies randomly from grain to grain, giving a macroscopically isotropic structure. However, application of flow orients the domains, producing a macroscopically anisotropic structure that dictates the final properties. The effects of flow on domain orientation and the resulting anisotropic properties of triblock copolymers were investigated. Domain orientation effects were best seen in the most ideal structure where all the domains are aligned uniformly throughout the sample, known as 'single crystal' structure. Appropriate deformation conditions to produce single crystal in microphase separated triblock copolymers were developed. The flow induced morphologies were studied by transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS). The linear viscoelastic properties of the anisotropic morphologies were investigated as a function of domain orientation with small amplitude oscillatory shear flow. Two triblock copolymer materials were studied: polystyrene-polybutadiene-polystyrene (SBS81) and polystyrene-polyisoprene-polystyrene (SIS56). Both materials have an equilibrium morphology of hexagonally packed cylinders of polystyrene in a rubbery matrix. However, the phase behavior of these two materials is quite different. SBS81 remains phase separated at all accessible temperatures while SIS56 has an accessible homogeneous phase. SBS81 samples were subjected to planar extension to produce single crystal structure. Optimum extension criteria were defined by following domain orientation as a function of extension conditions. Development of a novel sample preparation technique allowed linear viscoelastic property measurements with respect to the domain orientation. Dynamic shear moduli revealed the flow mechanism for domain orientation is dependent on the domain orientation direction. Large strain behavior of single crystal structure in combination with SAXS provided information about the flow processes during domain orientation. The second material studied has an accessible homogeneous phase, where the transition to the homogeneous phase was characterized with rheology and SAXS. These two experimental techniques were in good agreement. The ordering kinetics of SIS56 were exploited to produce single crystal structure with large amplitude oscillatory shear during phase separation. The linear viscoelastic properties of SIS56 single crystal were found to be influenced by domain orientation.

The deformation behavior of several different polyurethane thermoplastic elastomers was investigated. Four chemically distinct systems were synthesized, each with hard segment contents of 30, 40, and 50 percent by weight for a total of twelve different elastomers. Chemical components for the elastomer synthesis were as follows: diisocyanates, 4,4$\prime$-Diphenyl Methanediisocyanate (MDI) and 4,4$\prime$-Dicyclohexyl Methanediisocyanate (H$\sb{12}$MDI), diol chain extenders, Butanediol (BD) and 4,4$\prime$-Bis(6-hydroxyhexoxy) biphenyl (BHHBP), and a soft segment oligomer of 2000 molecular weight Poly(tetramethylene oxide) ether (PTMO). Elastomers synthesized with H$\sb{12}$MDI were found to contain hard segment which were essentially glassy in nature while those elastomers based on MDI contained crystalline hard segments. Infrared (IR) analysis was used to investigate the extent of hydrogen bonding in the hard segment as well as to assess segmental orientation with deformation. Crystalline hard segment materials were found to exhibit higher levels of hydrogen bonding. A significant difference in the orientation behavior of the hard segments as a function of elongation was observed while little difference in the soft segment orientation behavior was noted. The development of crystallinity in the soft segments of the materials was followed with both wide angle x-ray scattering (WAXS) and deformation calorimetry. Soft segments were found to undergo strain induced crystallization at extensions greater than 100 percent. No change was observed in the hard segment structure after deformation with WAXS, although an internal energy increase in all of the elastomers was measured after a complete deformation cycle of extension and retraction. The elastomers based upon H$\sb{12}$MDI were found to exhibit superior mechanical properties, especially reduced permanent set and hysteresis. This improvement in properties was primarily associated with decreased hard segment chemistry and amount. Other mechanical properties investigated included stress relaxation, dynamic mechanical thermal analysis, and stress development with film casting.

The non-Newtonian rheology of dilute polymer solutions can be traced to the flow-induced rearrangements in the conformation of flexible, isolated macromolecules. Such rearrangements are most pronounced in strong elongational flows; when such a flow is imposed on a random coil polymer for a sufficient time, the chain can become highly distorted and the fluid properties highly non-Newtonian. A direct determination of the magnitude of flow-induced polymer stretching will lead to a better understanding of the physical mechanisms responsible for the unique rheology of polymer solutions. In this study, light scattering methods are employed for the first time to probe the deformation of flexible polymer coils in dilute solutions undergoing uniaxial elongational flows. Such flows are created at the stagnation point region of an opposed jets flow device. This device is positioned so that its stagnation point can be superimposed on the scattering volume of a specially constructed variable angle light scattering instrument. Flow birefringence is also monitored. After suitable analysis, the two optical measurements provide the radius of gyration parallel to the stretching direction and the degree of segmental orientation; both quantities are averages over a 100 $\mu$m size region. Data are collected from the good solvent pair polystyrene/toluene as a function of elongation rate and polymer molecular weight. The scattering results indicate limited stretching, even at elongation rates greatly exceeding the reciprocal of the Zimm relaxation time. No evidence is found for complete chain unravelling. The birefringence does saturate at large elongation rates, indicating that segmental orientation and global deformation are not necessarily achieved simultaneously. It is suggested that measurements performed at the stagnation point actually reflect a larger spatial region of limited average residence time and that this time is sufficient for segmental orientation but not for chain unravelling. In addition to flexible polymer solutions, birefringence is also used to monitor the behavior of stiff polymers in the same flow. Distinctions between flexible and stiff chains are readily discerned in the spatial variation of the birefringence intensity.

This dissertation presents a new technique for determining the residual stresses and material properties of polyimide coatings. The primary materials studied are polyimides, pyromellitic dianhydride-oxydianiline (PMDA-ODA) and poly (N,N$\sp\prime$(phenylene)-3,3$\sp\prime4,4\sp\prime$-biphenyl tetracarboxylic diimide) (BPDA-PDA). The determination of the internal stresses which develop during processing in these coatings is critical for reliability prediction and material selection for the microelectronics industry. For any given coating on a rigid substrate, the shear and normal tractions between the two materials goes to zero away from the edges. A portion of the substrate can therefore be removed leaving a simply supported membrane (coating) with its original state of stress intact. Classical vibration theory states that the square of the resonant frequency of a membrane is proportional to its biaxial stress. Real-time holographic interferometry is used to identify the resonant modes of vibration. It is also shown that using this technique the orthotropic axes of polymer films can be identified, thus simplifying the determination of all nine orthotropic elasticity coefficients.

The goal of this thesis is to quantitatively study the relationship between interchange reaction and blend phase behavior in polyester/bisphenol-A-polycarbonate (PC) blends. Before transreaction studies are conducted, equilibrium phase behavior prior to reaction is identified and used as a basis to judge the reacting blends. To facilitate all of these studies, poly(2-ethyl-2-methyl-1,3-propylene terephthalate) (PEMPT) has been selected as a model polyester for blends with PC. PEMPTs having M$\sb{\rm n}$s from 4,100-37,500 g/mol were synthesized and fully characterized by a variety of elemental, spectroscopic and thermal analysis techniques. In addition, PEMPT was end capped to produce samples having heptafluorobutyrate (HFB) and benzylate (BNZ) end groups. These end capped samples exhibit different thermal characteristics compared to the hydroxyl (OH) terminated PEMPTs. Blends of PEMPT with PCs having M$\sb{\rm n}$s of 11,000 and 21,000 g/mol were prepared by solution casting techniques. Equilibrium phase behavior studies were conducted as a function of blend composition, molecular weight and end group type. In most cases, PEMPT/PC blends exhibited partial miscibility, which was monitored by the shifting of glass transition temperatures as measured by DSC. Blend composition had little effect on the phase behavior. Molecular weight reduction lead to improved intermixing between components for the OH and BNZ terminated PEMPTs. No improvement in the degree of intermixing was observed with decreasing M$\sb{\rm n}$ in the HFB terminated PEMPT/PC blends. Detailed $\sp1$H NMR spectroscopy enabled the identification of separate resonances corresponding to direct midchain and alcoholysis interchange reactions in PEMPT/PC non-stabilized blends. It was found that transreaction of $\sim$4% of the terephthalate groups was required to shift the phase behavior from two phase to single phase in a PEMPT/PC 50/50 wt. % blend of high molecular weight. This reaction extent represented 2.8% alcoholysis and 1.2% direct midchain reaction. These results were in agreement with calculations based on simplified models of the reacting blend. Alcoholysis exchange reaction was also observed at varying degrees in stabilized blends. Complete alcoholysis led to the formation of single phase blends at low PEMPT molecular weights.

Solid-state $\sp{13}$C cross-polarization magic-angle-spinning (CPMAS) nuclear magnetic resonance (NMR) spectra have been obtained for films of poly (p-phenylene vinylene) (PPV) and PPV-$d\sb4,$ poly (p-2,3,5,6-tetradeutero-phenylene vinylene). All four phenylene and vinylene resonance have been assigned. The $\sp{13}$C CPMAS NMR spectra show the presence of phenylene ring 180$\sp\circ$ rotation jumps. Solid-state $\sp2$H quadrupole-echo nuclear magnetic resonance spectra of PPV-$d\sb4$ films show that all the phenylene rings of PPV undergo 180$\sp\circ$ rotational jumps about the 1,4 ring axis with a median activation energy, E$\sb{\rm a}$ = 15 kcal/mol and a distribution of activation energies of less than $\pm$2 kcal/mol. The effects of concentrated sulfurice acid doping of PPV-$d\sb4$ have been examined with $\sp2$H quadrupole echo NMR spectroscopy. The activation energy for ring flips is observed to increase upon doping, as does the width of the jump rate distribution. Stretched PPV films have been prepared in which the vinylene protons have been substituted with deuterium (PPV-$d\sb2).$ $\sp2$H spectra of aligned samples at high temperature show molecular motion. The observed chain motion is consistent with a 180$\sp\circ$ rotational jump of the PPV chain about the crystallographic c axis. Inversion recovery quadrupole echo spectra also support a chain jump model and indicate the jump rate distribution is similar to that of the phenylene rings. $\sp2$H quadrupole echo NMR spectra of oriented PPV-$d\sb4$ aligned in the NMR magnetic field have been simulated and thereby have yielded the chain orientation distribution in these films. $\sp2$H spectra obtained at $-58\sp\circ$C are well simulated by an orientation distribution consisting of two Gaussian components. In addition, the average tilt of the phenylene ring relative to the chain axis has been found to be 7.7$\sp\circ,$ not the 9.2$\sp\circ$ predicted for a trans-stilbene-like structure. PPV has been doped with sodium metal. The chemistry of this process has been examined with elemental analysis. ESR spectroscopy has followed the evolution of unpaired spins as the doping reaction proceeds. The $\sp2$H NMR line shape of sodium-doped PPV-$d\sb4$ is relatively insensitive to changes in temperature and consists of two distinct components. The origin of these components is considered. Two-dimensional $\sp{13}$C-$\sp1$H HETCOR CP-MAS NMR spectra of p-dimethoxybenzene (DMB) and poly(2,5-dimethoxy-p-phenylene vinylene) (PDMPV) with variable $\sp1$H dipolar mixing times have been analyzed to determine the rates of $\sp1$H magnetization transfer between chemically distinct protons. Internuclear distances have been obtained from these rates and the conformation of the PDMPV repeat unit has been calculated and discussed.

Polymer surface modification can be accomplished by several techniques including chemical reaction and adsorption. In Chapter I, a simple and versatile technique to introduce carboxylic acid functionality to the surfaces of three fluoropolymer film samples is described. In Chapter II, the adsorption of neutral poly(scL-lysine) (PLL) from solution to the water-fluoropolymer interface is described. Chapter III combines the methods of surface modification described in Chapters I and II and discusses the adsorption of charged PLL to a carboxylic acid-functionalized fluoropolymer film surface. The hydrophobic interaction as a driving force for adsorption is further studied in Chapter IV where the synthesis and adsorption of poly(ethylene oxide) (PEO) and its derivatives are discussed. The syntheses of carboxylic acid-functionalized fluoropolymer films rely upon a two step mechanism where unsaturation, introduced in the first step, is oxidatively removed in the second step; one acidic group per twelve to sixteen repeat units was introduced to the surface. Contact angles ($\theta\sb{\rm A}$/$\theta\sb{\rm R}$) of the acid-functionalized fluoropolymer films decrease with increasing pH: PVF$\sb2$-CO$\sb2$H (77$\sp\circ$/39$\sp\circ$ decreases to 68$\sp\circ$/25$\sp\circ$); PCTFE-CO$\sb2$H (93$\sp\circ$/55$\sp\circ$ decreases to 93$\sp\circ$/43$\sp\circ$); and FEP-CO$\sb2$H (101$\sp\circ$/78$\sp\circ$ decreases to 97$\sp\circ$/61$\sp\circ$). The adsorption of poly(scL-lysine) (PLL) to the water-FEP interface was controlled by pH of the aqueous solution and PLL solution conformation. Only neutral, $\alpha$-helical PLL adsorbed to FEP (FEP-PLL). The adsorption of PLL to carboxylic acid-functionalized FEP, FEP-CO$\sb2$H, was controlled by an electrostatic interaction; both a hydrogen bonding interaction between FEP-carboxylic acid and PLL backbone and an ionic interaction between FEP-carboxylate and PLL-ammonium enhanced adsorption. Both FEP-PLL (80$\sp\circ$/16$\sp\circ$) and FEP-CO$\sb2$H-PLL (78$\sp\circ$/29$\sp\circ$) are more hydrophilic than FEP. FEP-PLL-$\varepsilon$-amine reacts with 3,5-dinitrobenzoyl chloride in 65% yield whereas FEP-CO$\sb2$H-PLL-$\varepsilon$-amine reacts in 100% yield. Adsorption of PLL to FEP and FEP-CO$\sb2$H improves the peel strength of adhesive joints prepared with these substrates and the adhesion and growth of biological cells on these film samples. PEO (5,000 to 50,000 g/mole and polydispersity indices of 1.07 to 1.17) was synthesized by anionic ring opening polymerization of ethylene oxide in THF with triethylene glycol monomethyl ether potassium initiation. PEO was end-capped (PEO-R) by reaction with a (perfluoro)alkyl acid chloride in THF with pyridine catalysis. A polar interaction between substrate and segment controlled adsorption at the fluoropolymer-water interface; PEO adsorbed preferentially to PVF$\sb2$ over PCTFE and FEP. Both PEO and PEO-R adsorbed to the polystyrene latex-water interface; the latter formed a thicker adsorbed layer. PEO-R showed increased surface activity over PEO at the air-water interface; PEO-perfluorodecanoate decreased the surface tension of water to 35 dyn/cm.

The viscoelastic behavior of a delignified birch and poly(methyl methacrylate) (PMMA) composite was investigated, in an effort to learn more about the mechanical properties of transparent wood-polymer biocomposites. Tensile creep tests with constant load were performed for native wood, non-delignified, and delignified wood-polymer composites. Both longitudinal (fibre direction) and transverse (perpendicular to fibre direction) loading directions were tested. Full-field strain analysis was performed using a digital image correlation (DIC) technique. The time-dependence of transverse strain, longitudinal strain, elastic modulus, and Poisson ratio was reported. The creep strain in the transverse fibre direction increased more than two times the longitudinal creep strain. The polymer phase in the wood-polymer biocomposites reduces the relative creep strain compared to native wood. A Kelvin model was used to determine the creep properties of the nominal strain data. Model parameters were obtained for the materials and the model shows a good fit for most materials. However, the Kelvin model parameters were not validated against other tests and are only used here for material comparison. / Det viskoelastiska beteendet hos en delignifierad björk och poly(metylmetakrylat) (PMMA) komposit undersöktes i ett försök att lära sig mer om de mekaniska egenskaperna hos transparenta träpolymerkompositer. Dragkryptester med konstant belastning utfördes för rent trä, icke-delignifierat och delignifierat träpolymerkompositer. Belastning längsgående och tvärgående fiberriktning testades. Töjningsfältsanalyser utfördes med användning av en digital bildkorrelationsteknik (DIC). Tidsberoendet av transversell töjning, longitudinell töjning, elasticitetsmodul och tvärkontraktion rapporterades. Kryptöjningen i den tvärgående fiberriktningen ökade mer än två gånger den längsgående kryptöjningen. Polymerfasen i träpolymerbiokompositerna minskar den relativa kryptöjningen jämfört med rent trä. En Kelvin-modell användes för att bestämma krypegenskaperna för nominell töjningsdata. Modellparametrar erhölls för materialen och modellen visar en god anpassning till de flesta material. Kelvin-modellens parametrar validerades dock inte mot andra tester och används endast här för materialjämförelse.

This degree project was performed in collaboration with ECORUB AB. Polymeric materials like thermoplastic and rubber are produced in massive quantities all over the world. However, the percentage of items that are recycled is quite low. Instead of using virgin material as the raw material for production, in this thesis, it is mainly focused on equipping the recycled raw materials to fabricate the 3D-printable filaments to be used as a feedstock material for FDM technique. This step helps to move towards a circular economy to ensure the sustainable usage of material resources. In this thesis, the material selection was constrained to recycled PETG and recycled PP. The objective of this thesis is to identify the problems faced during the utilization of recycled raw materials for 3D-printable filament production. The identified problem was resolved by tailoring the material properties by adding recycled EPDM powder as a filler material. This thermoplastic composite has shown improvement in the material and mechanical properties. The 3D-printable filaments were fabricated using thermoplastic composite materials and the mechanical properties of the parts printed using the thermoplastic composite material were investigated according to the ISO standards. Finally, it was concluded that equipping the recycled EPDM powder as a filler material with recycled PETG, showed an improvement in the impact properties of recycled PETG. When the recycled EPDM powder was combined with the recycled PP materials it helped to improve the shrinkage and the warping issues of recycled PP. The recyclability of the recycled PETG composites was investigated. Keywords: Additive Manufacturing, FDM technique, recycled raw materials, 3D-Printable Filament production faculty of Science and Technology, Uppsala University. Place of publication