Fluorinated polymers of substantial high performance such as perfluorocyclobutyl (PFCB) and fluorinated aryl vinyl ether (FAVE) polymers can readily be synthesized by thermal [2+2] cyclopolymerization as a melt or by classical polycondensation. These fluoropolymers naturally possess high thermal and chemical resistance, low conductivity properties, and other mechanical properties. In this work, a method using 0th order kinetics is proposed and thermal degradation studies were conducted on six different aromatic ether-based polymers to gauge trends in activation energy barrier and differences in thermal stability by 0th order degradation kinetics. The activation barrier (E_a) obtained can give accurate insight into the stability of the polymer based only on structure for external applications. Activation energies ranging from 17 to 41 kcal/mol were obtained for the various polymers. Overall, this study provides an established method using TGA for thermal stability studies through 0th order kinetics that can be potentially used for future lab applications.

Forced alignment, a speech recognition software performing semi-automatic phonological transcription, constitutes a methodological revolution in the recent history of linguistic research. Its use is progressively becoming the norm in research fields such as sociophonetics, but its general performance and range of applications have been relatively understudied. This thesis investigates the performance and portability of the Forced Alignment and Vowel Extraction program suite (FAVE), an aligner that was trained on, and designed to study, American English. It was decided to test FAVE on four non-American varieties of English (Scottish, Irish, Australian and Indian English) and a control variety (General American). First, the performance of FAVE was compared with human annotators, and then it was tested on three potentially problematic variables: /p, t, k/ realization, rhotic consonants and /l/. Although FAVE was found to perform significantly differently from human annotators on identical datasets, further analysis revealed that the aligner performed quite similarly on the non-standard varieties and the control variety, suggesting that the difference in accuracy does not constitute a major drawback to its extended usage. The study discusses the implications of the findings in relation to doubts expressed about the usage of such technology and argues for a wider implementation of forced alignment tools such as FAVE in sociophonetic research.

La qualità delle fave di cacao disponibili in commercio, che rappresentano la principale materia prima per la produzione di cioccolato, dipende da diversi fattori inclusi: il tipo di piantagione, le pratiche agricole ed il processo di post raccolta. Tra queste; fermentazione ed essicazzione sono generalmente considerate le più rilevanti, dal momento in cui, durante queste fasi, vengono formati e fissati i precursori degli aromi del cacao. Inoltre, esse rappresentano un step cruciale durante il quale possono verificarsi contaminazioni da parte dei funghi filamentosi. La fermentazione è caratterizzata da una successione ben definita di lieviti, batteri lattici e batteri acetici, a tal fine, lo scopo del presente lavoro di tesi è stato quello di esplorare e descrivere in modo completo le comunità batteriche e fungine coinvolte nella fermentazione delle fave di cacao e valutare se l’origine geografica ed il metodo di fermentazione potessero influenzare la loro composizione. Per ottenere tali risultati il gene 16s rRNA è stato usato come marker per descrivere la comunità batterica totale mediante High Throughput Sequencing (HTS), dimostrando come tale approccio abbia la capacità di evidenziare la totalità delle comunità batteriche a livello di specie. In un secondo approccio l’Internal Transcribed Spacer 1 (ITS1) ed il dominio D1/D2 della sub unità maggiore dell’RNA ribosomiale (26s rRNA) sono stati selezionati per descrivere la popolazione fungina. I risultati hanno evidenziato come le due regioni abbiano la capacità di descrivere la composizione generale delle popolazioni, sebbene il dominio D1/D2 sia stato in grado di analizzare più nel dettaglio la composizione. Infine gli stessi campioni sottoposti all’analisi mediante HTS sono stati analizzati mediante SPME-GC-MS per evidenziare i principali composti aromatici formatisi durante il processo di post raccolta. Complessivamente i risultati indicano chiaramente che l’approccio mediante HTS ha le potenzialità per fornire una dettagliata visione d’insieme delle comunità batteriche e fungine presenti durante le fasi di post raccolta delle fave di cacao, inoltre le analisi statistiche hanno evidenziato come l’ITS1 ed i composti volatili possano essere utilizzati per la tracciabilità geografica. / The quality of commercial cocoa beans, the principal raw material for chocolate production, depends on several factors including type of plantations, the agricultural practices and the post-harvest processing. Among these, fermentation and drying are generally considered the most relevant, since during these phases cocoa flavors precursors are formed and fixed. Furthermore, they represent crucial steps during which filamentous fungi contamination might occur. Fermentation is characterized by a well-defined succession of yeasts, lactic acid bacteria and acetic acid bacteria, so that, the aim of the described studies was to explore total bacterial and fungal communities involved in cocoa bean fermentation and to evaluate if geographical origin and fermentation method might affect their composition. To achieve these results, 16s rRNA gene was used as marker to assess the total bacterial community by using High Throughput Sequencing (HTS), indicating that this approach has the ability to provide a comprehensive view of the cocoa bean microbiota at the species level. In a second approach, Internal Transcribed Spacer 1 (ITS1) and the D1/D2 domain of the Large subunit (LSU) of the nuclear ribosomal RNA (26S rRNA) were screened to assess the total fungal community. Results revealed the ability of these two genomic regions to describe reliably the general composition, even if D1/D2domain was able to go deeper into the fungal composition resulting in a higher resolution. In the last approach the same samples subjected to HTS investigation were analyzed through SPME-GC-MS in order to underline the principal key-aroma compounds formed during the post-harvest processing. Overall, results point out clearly that HTS approach has the ability to provide a comprehensive view of the total bacterial and fungal communities, and statistical analyses have shown how analyses of ITS1 sequences and volatile compounds might be useful for the geographical traceability of the processed cocoa beans samples.

This dissertation reports the synthesis and characterization of semi-fluorinated polymers derived from the polymerization of bisphenols with fluoroalkenes. A series of diverse bisphenols were chosen from popular commercial bisphenols and new polycyclic aromatic hydrocarbon (PAH) derived bisphenols requiring synthesis. Step-growth condensation polymerization of bisphenols with three different fluoroalkene types was performed while probing polymerization conditions and the structure/properties relationship of the resulting fluoropolymers. The fluoroalkene monomers were chosen from bis(trifluorovinyloxy)biphenyl (TFVE), perfluorocyclohexene (PFCH), and perfluoro acyclic monomers, namely, perfluoro(4-methyl-2-pentene) and 1-perfluoroheptene to undergo this chemistry. This work is divided into four parts based on the polymerization methodology. The first section focuses on the development of a new class of fluorinated arylene vinylene ether (FAVE) and their chain extended polymers prepared via base-catalyzed step-growth polymerization of PAH bisphenols with the TFVE monomer. These reactions afforded polymers containing controlled terminal and enchained fluoroalkenylenes for latent reactivity such as post polymerization functionalization, chain extension, and/or crosslinking. In general, these PAH cores resulted in polymers with improved thermal properties The second portion describes the investigation of step-growth addition/elimination polymerizations of PAH bisphenols and PFCH to prepare a new class of fluoropolymers containing alternating rigid PAH linkages and enchained PFCH vinylene ether moieties in the backbone. The third section covers the preparation and characterization of semi-fluorinated poly(aryl ether sulfone)s by nucleophilic addition/elimination reactions of PFCH with sulfone bisphenols. From commercially bisphenols combined with PAH bisphenols, we introduced the industrially valuable and property enhancing diaryl sulfone unit in a series of semi-fluorinated copolymers. This modular approach greatly expands access to partially fluorinated aryl ether sulfone polymers intended for high performance applications in optoelectronics, separation/purification membranes, and composites. Finally, in the fourth section, a new class of semifluorinated polymers was synthesized via nucleophilic addition/elimination reactions of acyclic perfluoroalkenes with bisphenols. In particular, environmental concerns for biopersistent and highly regulated perfluorooctanoic acid (PFOA) is the driver for using perfluoroheptene, which is derived cleanly by the decarboxylation of these pollutants in one step. This provided a new class of semi-fluorinated materials with promising properties including thermal stable, processability, and transparent film formation.