Narrow molecular weight fractions of Poly(ε-caprolactone) were successfully obtained using the successive precipitation fractionation technique with toluene/n-heptane as a solvent/nonsolvent pair. Calorimetric studies of the melting behavior of fractions that were crystallized either isothermally or under constant cooling rate conditions suggested that the isothermal crystallization of the samples should be used for a proper evaluation of the molecular weight dependence of the observed melting temperature and degree of crystallinity in PCL. The molecular weight and temperature dependence of the spherulitic growth rate of fractions was studied in the context of the Lauritzen-Hoffman two-phase model and the Strobl three-phase model of polymer crystallization. The zero-growth rate temperatures, determined from spherulitic growth rates using four different methods, are consistent with each other and increase with chain length. The concomitant increase in the apparent secondary nucleation constant was attributed to two factors. First, for longer chains there is an increase in the probability that crystalline stems belong to loose chain-folds, hence, an increase in fold surface free energy. It is speculated that the increase in loose folding and resulting decrease in crystallinity with increasing chain length are associated with the ester group registration requirement in PCL crystals. The second contribution to the apparent nucleation constant arises from chain friction associated with segmental transport across the melt/crystal interface. These factors were responsible for the much stronger chain length dependence of spherulitic growth rates at fixed undercooling observed here with PCL than previously reported for PE and PEO. In the case of PCL, the scaling exponent associated with the chain length dependence of spherulitic growth rates exceeds the upper theoretical bound of 2 predicted from the Brochard-DeGennes chain pullout model. Observation that zero-growth and equilibrium melting temperature values are identical with each other within the uncertainty of their determinations casts serious doubt on the validity of Strobl three-phase model. A novel method is proposed to determine the Porod constant necessary to extrapolate the small angle X-ray scattering intensity data to large scattering vectors. The one-dimensional correlation function determined using this Porod constant yielded the values of lamellar crystal thickness, which were similar to these estimated using the Hosemann-Bagchi Paracrystalline Lattice model. The temperature dependence of the lamellar crystal thickness was consistent with both LH and the Strobl model of polymer crystallization. However, in contrast to the predictions of Strobl’s model, the value of the mesomorph-to-crystal equilibrium transition temperature was very close to the zero-growth temperature. Moreover, the lateral block sizes (obtained using wide angle X-ray diffraction) and the lamellar thicknesses were not found to be controlled by the mesomorph-to-crystal equilibrium transition temperature. Hence, we concluded that the crystallization of PCL is not mediated by a mesophase. Metallocene-catalyzed linear low-density (m-LLDPE with 3.4 mol% 1-octene) and conventional low-density (LDPE) polyethylene blends of different compositions were investigated for their melt-state miscibility and concurrent crystallization tendency. Differential scanning calorimetric studies and morphological studies using atomic force microscopy confirm that these blends are miscible in the melt-state for all compositions. LDPE chains are found to crystallize concurrently with m-LLDPE chains during cooling in the m-LLDPE crystallization temperature range. While the extent of concurrent crystallization was found to be optimal in blends with highest m-LLDPE content studied, strong evidence was uncovered for the existence of a saturation effect in the concurrent crystallization behavior. This observation leads us to suggest that co-crystallization, rather than mere concurrent crystallization, of LDPE with m-LLDPE can indeed take place. Matching of the respective sequence length distributions in LDPE and m-LLDPE is suggested to control the extent of co-crystallization. / Ph. D.

The crystallization and melting behaviors of an ethylene/1-hexene copolymer and series of narrow molecular weight linear polyethylene and poly(ethylene oxide) fractions were studied using a combination of ultra-fast and conventional differential scanning calorimetry, optical microscopy, small angle X-ray scattering, and wide angle X-ray diffraction. In the case of linear polyethylene and poly(ethylene oxide), the zero-entropy production melting temperatures of initial lamellae of isothermally crystallized fractions were analyzed in the context of the non-linear Hoffman-Weeks method. Using the Huggins equation, limiting equilibrium melting temperatures of 141.4 ± 0.8oC and 81.4 ± 1.0oC were estimated for linear polyethylene and poly(ethylene oxide), respectively. The former and the latter are about 4oC lower and 12.5oC higher than these predicted by Flory/Vrij and Buckley/Kovacs, respectively. Accuracy of the non-linear Hoffman-Weeks method was also examined using initial lamellar thickness literature data for a linear polyethylene fraction at different crystallization temperatures. The equilibrium melting temperature obtained by the Gibbs-Thomson approach and the C2 value extracted from the initial lamellar thickness vs. reciprocal of undercooling plot were similar within the limits of experimental error to those obtained here through the non-linear Hoffman-Weeks method. In the next step, the Lauritzen-Hoffman (LH) secondary nucleation theory was modified to account for the effect of stem length fluctuations, tilt angle of the crystallized stems, and temperature dependence of the lateral surface free energy. Analysis of spherulite growth rate and wide angle X-ray diffraction data for 26 linear polyethylene and 5 poly(ethylene oxide) fractions revealed that the undercooling at the regime I/II transition, the equilibrium fold surface free energy, the strength of the stem length fluctuations and the substrate length at the regime I/II transition are independent of chain length. The value of the equilibrium fold surface free energy derived from crystal growth rate data using the modified Lauritzen-Hoffman theory matches that calculated from lamellar thickness and melting data through the Gibbs-Thomson equation for both linear polyethylene and poly(ethylene oxide). Larger spherulitic growth rates for linear polyethylene than for poly(ethylene oxide) at low undercooling is explained by the higher secondary nucleation constant of poly(ethylene oxide). While the apparent friction coefficient of a crystallizing linear polyethylene chain is 2 to 8 times higher than that of a chain undergoing reptation in the melt state, the apparent friction coefficient of a crystallizing poly(ethylene oxide) chain is about two orders of magnitude lower. This observation suggests that segmental mobility on the crystal phase plays a significant role in the crystal growth process. In case of the statistical ethylene/1-hexene copolymer, the fold surface free energies of the copolymer lamellae at the time of crystallization and melting increase with increasing undercooling, approaching the same magnitude at high undercooling. As a result of this temperature dependence, the experimental melting vs. crystallization temperature plot is parallel to the Tm = Tc line and the corresponding Gibbs-Thomson plot is non-linear. This behavior is attributed to the fact that longer ethylene sequences form a chain-folded structure with lower concentration of branch points on the lamellar surface at lower undercooling, while shorter ethylene sequences form lamellar structures at higher undercooling exhibiting a higher concentration of branch points on the lamellar surface. Branch points limit the ability of lamellar structures to relax their kinetic stem-length fluctuations during heating prior to melting. / Ph. D. / Morphology of semi-crystalline polymers is strongly affected by their crystallization conditions. Thermodynamic and kinetic models allow us to understand the crystallization mechanism of a semi-crystalline polymer and relate its crystallization conditions to the final morphology. In this research, we studied the molar mass dependence of the crystallization and melting behaviors of narrow molecular weight distribution linear polyethylene (LPE) and poly(ethylene oxide) (PEO) fractions using a modified Lauritzen-Hoffman (LH) secondary nucleation theory. We have shown that the equilibrium melting temperature of LPE and PEO fractions found from the non-linear Hoffman-Weeks method are within the experimental uncertainty identical with these measured directly for extended chain crystals or derived from a Gibbs-Thomson analysis. The value of the equilibrium fold surface free energy derived from crystal growth rate data using the modified LH theory matches that calculated from lamellar thickness and melting data through the Gibbs-Thomson equation for both LPE and PEO. We reported that the higher segmental mobility of PEO in the crystalline phase leads to significantly lower apparent chain friction coefficients during crystal growth compared to LPE. We also studied the role of short-chain branching in the crystal growth kinetics of ethylene/1-hexene copolymers. We observed that the fold surface free energies during crystallization and during melting are both function of the undercooling while the ratio of the former to the latter decreases with increasing undercooling. We proposed that this behavior may be related to the concentration of short-chain branches at the surface of the lamellae, where higher concentration leads to lower relaxation.

The isothermal crystallization and melting temperatures of poly(ε-caprolactone) were correlated using fast differential scanning calorimetry. The melting kinetics was found to be independent of isothermal crystallization temperature and time. The conventional Hoffman-Weeks method could not be used to determine the equilibrium melting temperature because the observed melting temperatures were greater than the crystallization temperatures by a constant, so the Gibbs-Thomson method was used instead, yielding an equilibrium melting temperature of 103.4 ± 2.3°C. A modification was proposed to the non-linear Hoffman-Weeks equation that included a non-linear undercooling dependence for the kinetic fold surface free energy upon crystallization and permitted accurate modeling of the observed melting behavior. The isothermal crystallization rates of four narrow molecular weight poly(ethylene oxide) fractions were characterized using fast differential scanning calorimetry for crystallization temperatures spanning 100°C range with the lower limit approaching the glass transition. A transition from homogeneous to heterogeneous primary nucleation was observed at −5°C. The kinetic analysis suggested that the crystal growth geometry depends strongly on temperature, where rod-like structures begin to appear near the glass transition temperature, highly branched solid sheaves grow throughout the homogeneous primary nucleation temperature range, and spherulites grow in the heterogenous primary nucleation range. Poly(δ-valerolactone) was synthesized using microwave-assisted techniques. Narrow molecular weight fractions were obtained using successive precipitation fractionation. Preliminary isothermal crystallization studies suggest that conventional thermal analysis methods are not adequate to measure the melting temperatures accurately due to reorganization during heating. / Doctor of Philosophy / Plastics may be classified into two general categories: those which form ordered domains upon solidification, i.e. undergo crystallization, and those which remain disordered upon solidification, i.e. form glasses. This work is focused on studying the crystallization and melting processes in two linear polymers, poly(ε-caprolactone) and poly(ethylene oxide), using new experimental technology. In the case of poly(ε-caprolactone), the experimental data could not be rationalized by existing theories, and we have proposed modifications to these theories that explained the results. In the case of poly(ethylene oxide), the application of new experimental technology resulted in previously unreported data that indicated novel behavior at very low crystallization temperatures. In the last portion of this work, poly(δ-valerolactone) was made using a novel approach. Conventional experimental approaches to measuring the crystallization and melting behavior were shown to be inadequate.

The crystallization and melting behavior of linear polyethylene and of a series of random ethylene/styrene copolymers was investigated using a combination of classical and temperature modulated differential scanning calorimetry. In the case of linear polyethylene and low styrene content copolymers, the temporal evolutions of the melting temperature, degree of crystallinity, and excess heat capacity were studied during crystallization. The following correlations were established: 1) the evolution of the melting temperature with time parallels that of the degree of crystallinity, 2) the excess heat capacity increases linearly with the degree of crystallinity during primary crystallization, reaches a maximum during the mixed stage and decays during secondary crystallization, 3) the rates of shift of the melting temperature and decay of the excess heat capacity lead to apparent activation energies that are very similar to these reported for the crystal ac relaxation by other techniques. Strong correlations in the time domain between the secondary crystallization and the evolution of the excess heat capacity suggest that the reversible crystallization/melting phenomenon is associated with molecular events in the melt-crystal fold interfacial region. In the case of higher styrene content copolymers, the multiple melting behavior at high temperature is investigated through studies of the overall crystallization kinetics, heating rate effects and partial melting. Low melting crystals can be classified into two categories according to their melting behavior, superheating and reorganization characteristics. Low styrene content copolymers still exhibit some chain folded lamellar structure. The shift of the low melting temperature with time in this case is tentatively explained in terms of reorganization effects. Decreasing the crystallization temperature or increasing the styrene content leads to low melting crystals more akin to fringed-micelles. These crystals exhibit a lower tendency to reorganize during heating. The shift of their melting temperature with time is attributed to a decrease in the conformational entropy of the amorphous fraction as a result of constraints imposed by primary and secondary crystals. To further understand the mechanism of formation of low melting crystals, quasi-isothermal crystallization experiments were carried out using temperature modulation. The evolution of the excess heat capacity was correlated with that of the melting behavior. On the basis of these results, it is speculated that the generation of excess heat capacity at high temperature results from reversible segmental exchange on the fold surface. On the other hand, the temporal evolution of the excess heat capacity at low temperature for high styrene content copolymers is attributed to the reversible segment attachment and detachment on the lateral surface of primary crystals. The existence of different mechanisms for the generation of excess heat capacity in different temperature ranges is consistent with the observation of two temperature regimes for the degree of reversibility inferred from quasi-isothermal melting experiments. In a second project, the chain length and temperature dependences of spherulitic growth rates were studied for a series of narrow fractions of poly(ethylene oxide) with molecular weight ranging from 11 to 917 kg/mol. The crystal growth rate data spanning crystallization temperatures in regimes I and II was analyzed using the formalism of the Lauritzen-Hoffman (LH) theory. Our results are found to be in conflict with predictions from LH theory. The Kg ratio increases with molecular weight instead of remaining constant. The chain length dependence of the exponential prefactor, G0, does not follow the power law predicted by Hoffman and Miller (HM). On this basis, the simple reptation argument proposed in the HM treatment and the nucleation regime concept advanced by the LH model are questioned. We proposed that the observed I/II regime transition in growth rate data may be related to a transition in the friction coefficient, as postulated by the Brochard-de Gennnes slippage model. This mechanism is also consistent with recent calculations published by Toda in which both the rates of surface nucleation and substrate completion processes exhibit a strong temperature dependence. / Ph. D.

Imagine a theater. Build one in your mind. I do not care if it is the largest theater in the universe or if it is the size of a shoebox. The theater can be an elaborate construction with gilded cherubs and priceless jewels. If you would prefer the theater to be a minimal design, imagine it that way. Maybe the theater is made out of glass or crystal. You can be all alone in the theater or maybe you are seated next to an alien, a cave man, or a robot. As the curtain rises an enormous pipe organ is spewing out J.S. Bach’s Toccata and Fugue in D minor. The sound is colossal. The stage is designed to look like a filthy and bleak art studio. Sculptures that look like decaying flesh hang from the ceiling. Papers and dirty painting rags are scattered all over the floor. A roach crawls towards some moldy food in the wastebasket. A piece of beef jerky sits next to a pile of paint tubes and paintbrushes. Canvases are stacked against the wall. Dried paint is splattered everywhere. A woman enters stage left. As she begins to speak, the music fades… “My most recent paintings are meant to serve as gateways between daily life and an exotic utopian fantasy. These strange psychological spaces function as portals into a new frontier inhabited with the most stupendous creatures. Active volcanoes, carnivorous plants, terrible lizards, pink Chihuahuas, flesh-eating insects, unidentified flying objects, and a host of other amazing things coexist in this cruel tropical paradise. “Everything I do is a self-portrait and a disguise. I imagine the characters in my paintings to be mutant clones. The act of painting is like looking in the mirror. I like to spend most of my time doing one or the other. I am driven by an insatiable urge to see what I truly look like. I suffer from an unfulfilled desire to meet myself. I am frustrated with impressions and reflections. These confessions reveal my work as possibly the most disgusting display of narcissism in the entire history of art. “The act of painting is an absurd and self-indulgent enterprise. I paint with the ridiculous and frivolous purpose of delighting the eye. Nevertheless, my hope is that my paintings capture an important aspect of my utopian fantasy with their sumptuous surroundings embellished with rainbows, natural disasters, butterflies, exotic grasses and bizarre costumes. “My paintings can be read on many different levels from surface to deep allegory. The finished product is the result of hours upon hours of painting, pondering, and dreaming. Below the surface lies a nauseating abyss. “My work is a delicious feast for the aesthetic consumer. I am a villainous mad scientist with a hunger for immortality. My eyes are gluttonous fools. I am a mystery and a deception. Vermillion is my opulent fetish. Lemon yellow is my nemesis.” The music grows louder again. The woman begins to cackle. She then takes a deep breath and a deeper and more dramatic bow. She exits stage right--you find that you want to applaud--but unfortunately, this story is not over. I suggest that you get yourself a snack like some popcorn, chocolate, or gummy bears before reading any further. The curtain slowly and elegantly comes down.

Dans cette thèse nous proposons quelques contributions à l'analyse variationnelle dans les espaces métriques et à l'optimisation : régularité métrique, théorie métrique des points critiques, sensibilité de constantes de Hoffman, stabilité en programmation quadratique. Dans le cas polyèdral nous établissons des formules explicites de constantes de Hoffman des polyèdres avec égalités explicites. Ensuite, en mettant en évidence le caractère lipschitzien de ces constantes, nous calculons le sous-différentiel de Clarke des fonctions associées. Nous faisons également une revue de la régularité métrique des multi-applications, et nous traitons la stabilité d'un problème quadratique convexe. La considération du concept de pente faible, et donc des techniques de déformation appropriées, nous permet d'établir des résultats de stabilité homotopique des points critiques isolés des fonctions continues.

This project argues that there is a previously unnamed canon of literature called Magical Feminism which exists across many current popular (even lowbrow) genres such as science-fiction, fantasy, so-called realistic literature, and contemporary television and film. I define Magical Feminism as a genre quite similar to Magical Realism, but assert that its main political thrust is to model a feminist agency for its readers. To define this genre, I closely-read the image of the female magic user as one of the most important Magical Feminist metaphors. I argue that the female magic user–commonly called the witch, but also labeled priestess, mistress, shaman, mambo, healer, midwife– is a metaphor for female unruliness and disruption to patriarchy and as such, is usually portrayed as evil and deserving of punishment. I assert that many (although not all) of the popular texts this genre includes are overlooked or ignored by the academy, and thus, that an important focus for contemporary feminism is missed. When the texts are noticed by parts of the academy, they are mostly considered popular culture novelty acts, not serious political genres. As part of my argument, I analyze third wave feminism’s attempt to reconcile traits previously considered less than feminist, such as the domestic. I also deconstruct the popular media’s negative portrayal of contemporary feminism and the resulting reluctance for many young women to identify themselves as feminist. I also argue that this reluctance goes hand in hand with a growing attempt to seek new models for empowering female epistemologies. My assertion is that these texts are the classrooms where many readers learn their feminism. Finally, I list a short bibliography as a way of defining canon of texts that should be considered Magical Feminist.

This diploma thesis delves into the possibility of the Western democratic state waging hybrid warfare. The hybrid warfare has been throughout its existence almost exclusively attributed to undemocratic regimes, which often utilize it in an aggressive fashion. In order to challenge this notion, this thesis seeks to reinterpret the conduct of the USA during the opening stages of the Operation Enduring Freedom in Afghanistan 2001, through the lenses of hybrid warfare. Since hybrid warfare is very wide, often poorly defined term, the author chose to conceptualize a well- known description of Russian hybrid warfare, created by András Rácz in 2015, through which the studied case is then reinterpreted. The possibility of the Western democratic state waging hybrid warfare is, as far as existing research goes, completely unexplored, this thesis is hence delving into a completely new research area. This thesis also ponders on how this realization of Western ability to wage hybrid war can influence our outlook on the phenomenon itself. With this thesis, the author seeks to offer a new, factual outlook on hybrid warfare, unhindered by biases and emotional undertone which sadly mires many contributions to the academic debate on the topic. This new perspective on hybrid warfare, in authors personal opinion, can...

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‘The Ophelia Versions: Representations of a Dramatic Type from 1600-1633’ interrogates early modern drama’s use of the Ophelia type, which is defined in reference to Hamlet’s Ophelia and the behavioural patterns she exhibits: abandonment, derangement and suicide. Chapter one investigates Shakespeare’s Ophelia in Hamlet, finding that Ophelia is strongly identified with the ballad corpus. I argue that the popular ballad medium that Shakespeare imports into the play via Ophelia is a subversive force that contends with and destabilizes the linear trajectory of Hamlet’s revenge tragedy narrative. The alternative space of Ophelia’s ballad narrative is, however, shut down by her suicide which, I argue, is influenced by the models of classical theatre. This ending conspires with the repressive legal and social restrictions placed upon early modern unmarried women and sets up a dangerous precedent by killing off the unassimilated abandoned woman. Chapter two argues that Shakespeare and Fletcher’s The Two Noble Kinsmen amplifies Ophelia’s folk and ballad associations in their portrayal of the Jailer’s Daughter. Her comedic marital ending is enabled by a collaborative, communal, folk-cure. The play nevertheless registers a proto-feminist awareness of the peculiar losses suffered by early modern women in marriage and this knowledge deeply troubles the Jailer’s Daughter’s happy ending. Chapter three explores the role of Lucibella in The Tragedy of Hoffman arguing that the play is a direct response to Hamlet’s treatment of revenge and that Lucibella is caught up in an authorial project of disambiguation which attempts to return the revenge plot to its morality roots. Chapters four and five explore the narratives of Aspatia in The Maid’s Tragedy and Penthea in The Broken Heart, finding in their very conformism to the behaviours prescribed for them, both by the Ophelia type itself and by early modern society in general, a radical protest against the limitations and repressions of those roles. This thesis is consistently invested in the competing dialectics and authorities of oral and textual mediums in these plays. The Ophelia type, perhaps because of Hamlet’s Ophelia’s identification with the ballad corpus, proves an interesting gauge of each play’s engagement with emergent notions of textual authority in the early modern period.