O polietileno de ultra alto peso molecular (UHMWPE) é um plástico de engenharia que tem várias aplicações atualmente, mormente em áreas específicas da indústria e da medicina. O UHMWPE pode ser utilizado ainda em outras aplicações: defensas portuárias; guias de corrente; revestimentos de caçambas, silos e calhas; engrenagens; buchas; guias de correias e próteses cirúrgicas. Esta gama de aplicações se deve ao fato das excelentes características técnicas que este material possui, como: alta resistência a abrasão, elevada resistência ao impacto, anti-aderência, atóxico, excelente resistência química, baixo peso específico, fácil usinagem e alta resistência a fadiga. Os tipos de polietileno de ultra alto peso molecular (UHMWPE) utilizados neste trabalho foram o UTEC 3041 e UTEC 6541 da Braskem. A reciclabilidade do UHMWPE ganhou interesse, porque a utilização desta matéria-prima na última década cresceu mais de 600%, tornando-se um dos plásticos de engenharia mais utilizados para obtenção de peças usinadas depois da poliamida. Com o crescimento na utilização deste polímero na confecção de peças para maquinários, o seu desperdício tem sido muito grande, porque o resto deste material é desprezado, geralmente não sendo reaproveitado. Este trabalho tem como objetivo reciclar o UHMWPE UTEC 3041 e estudar as propriedades deste material virgem e reciclado e comparar os resultados entre si e com o UHMWPE UTEC 6541, e com estes materiais submetidos a diferentes doses de radiação. / Ultra High Molecular Weight Polyethylene (UHMWPE) is an engineering plastic which has several applications, chiefly, in specific areas of the industry and medicine. UHMWPE can be even for other applications such as: port fenders, current guide, bucket coating, silos and gutters, plugs, pulleys and surgical prosthesis. This range of applications is due to the excellent technical characteristics that this material owns, such as; high resistance to wear, high resistance to impact, anti-adherence, non toxic, excellent chemical resistance, low specific weight, easy mill processing, and high resistance to fatigue. The UHMWPE type used in this work were UTEC 3041 and UTEC 6541 of the Braskem. The recycling process of UHMWPE raised much interest, because the utilization of this rawmaterial grew over 600% in the last decade, becoming one of the most used engineering plastics for attainment of mill processed parts after polyamide. As the utilization of this polymer in the manufacturing of parts for machinery has grown, its waste is very big, because the rest of this material is thrown out, usually not being reused. The goal of this work is to recycle the UHMWPE UTEC 3041 and study the properties of this recycled and virgin material and compare the results between both with these materials submitted to different radiation dose.

In this study, membranes were made from three polyvinylidene fluoride (PVDF) polymers individually and the blend systems of high (H) and low (L) molecular weight PVDF by phase inversion process. After investigating membrane casting solutions’ viscous and thermodynamic properties, the membranes so fabricated were characterized by scanning electron microscopy, gas permeation tests, porosity measurement, contact angle (CA) and liquid entry pressure of water (LEPw) measurement, and further subjected to vacuum membrane distillation (VMD) in a scenario that was applicable for cooling processes, where the feed water temperature was maintained at 27℃. It was found that PVDF solutions’ viscosities and thermodynamic instabilities were determined by the types of PVDF employed in single polymer systems and the mixing ratios of two PVDF polymers in blend systems. Thus the membrane properties and performances were influenced by the aforesaid factors as well. In single polymer systems, it was found that the membrane surface roughness and porosity increased with an increase in molecular weight. Among all the membranes casted in this study, the water vapor flux of VMD was found to be the highest at the intermediate range of H:L ratio, i.e., 4:6, at which the thickness of the sponge-like layer showed a minimum, the finger-like macro-voids formed a more orderly single-layer structure, and the LEPw showed a minimum. A conclusion can be made that blend systems of high molecular weight PVDF polymers and low molecular weight PVDF polymers could be used to optimize membrane performance in vacuum membrane distillation.

Despite the recognized advances in the treatment of breast cancer, it still accounts for 15% of all cancer-related deaths. 90% of breast cancer deaths are due to unpredicted metastasis. There is neither successful treatment for metastatic patients nor a specific test to predict or detect secondary lesions. Patients with primary tumor will be either over-treated with cytotoxic side effects or under-treated and risk recurrence. This necessitates the need for personalized treatment, which is hard to offer for such heterogeneous disease. Obstacles in treating breast cancer metastasis are mainly due to the gaps exist in the understanding of the molecular mechanism of metastasis. The linear model of metastasis is supported by several observations that reflect an early crosstalk between the primary and secondary tumor, which in turn makes the secondary microenvironment fertile for the growth of disseminated cells. This communication occurs through circulation and utilizes molecules which have not been identified to date. Identifying such molecules may help in detecting initial stages of tumor colonization and predict the target organ of metastasis. Furthermore, these molecules may help to provide a personalized therapy that aims to tailor treatment according to the biology of the individual tumor. Advances in proteomics allows for more reproducible and sensitive biomarker discovery. Proteomic biomarkers are often more translatable to the clinic compared to biomarkers identified using other omics approaches. Further, protein biomarkers can be found in biological fluids making them a non-invasive way to treat or investigate cancer patients. We present in this manuscript our study of the use of a proteomic approach on blood serum samples of metastatic and non-metastatic patients using LC-MS/MS quantitative analysis machine to identify molecules that could be associated with different stages of breast cancer metastasis. We focused on the deferential expression of low molecular weight biomolecules known to reflect disease-specific signatures. We manually analyzed 2500 individual small biomolecules in each serum sample of total of 51 samples. Comparisons between different sample types (from stage I and III Breast Cancer patients in this case) allows for the detection of unique short peptide biomarkers present in one sample type. We built a multi-biomarker model with more sensitivity and specificity to identify the stage of the tumor and applied them on blinded set of samples to validate prediction power. We hope that our study will provide insights for future work on the collection, analysis, and understanding of role of molecules in metastatic breast cancer.

The chemical binders used to make sand molds and cores thermally decompose and release gas when subjected to the high temperature conditions in sand casting processes. Computational models that predict the evolution of the binder gas are being introduced into casting simulations in order to better predict and eliminate gas defects in metal castings. These models require knowledge of the evolved binder gas mass and molecular weight as a function of temperature, but available gas evolution data are limited. In the present study, the mass and molecular weight of gas evolved from PUNB bonded sand are measured as a function of temperature for use with binder gas models. Thermogravimetric analysis of bonded sand is employed to measure the binder gas mass evolution as a function of temperature for heating rates experienced in molds and cores during casting. The volume and pressure of gas evolved from bonded sand are measured as a function of temperature in a specially designed quartz manometer during heating and cooling in a furnace. The results from these experiments are combined with the ideal gas law to determine the binder gas molecular weight as a function of temperature. Thermogravimetric analysis reveals that the PUNB binder significantly decomposes when heated to elevated temperatures, and the PUNB binder gas mass evolution is not strongly influenced by heating rate. During heating of PUNB bonded sand at a rate of 2°C/min, the binder gas molecular weight rapidly decreases from 375 g/mol at 115°C to 99.8 g/mol at 200°C. The molecular weight is relatively constant until 270°C, after which it decreases to 47.7 g/mol at 550°C. The molecular weight then steeply decreases to 30.3 g/mol at 585°C and then steeply increases to 47.2 g/mol at 630°C, where it remains constant until 750°C. Above 750°C, the binder gas molecular weight gradually decreases to 33.3 g/mol at 898°C. The present measurements are consistent with the molecular weights calculated using the binder gas composition data from previous studies. The binder gas is composed of incondensable gases above 709°C, and the binder gas partially condenses during cooling at 165°C if the bonded sand is previously heated below 507°C.

The properties of the aged gel and subsequent softgels were examined using mechanical and chemical testing methods. Our hypothesis was that a negligible variation will exist between the aged gel of the same type. The greater difference is expected to be seen between the types of gels described as 150 Bloom (alkaline treated collagen) and 195 Bloom (acid treated collagen). The types of gelatin used were the acid processed (195 Acid Bone) and alkaline processed (150 Lime Bone). Because of the differences expressed as the result of their manufacture sequence (namely their molecular weights), it follows that physical attributes will further contribute to their distinction. In addition to observing different characteristics between the types of gels, we aged the gelatin and produced softgel capsules to qualify and quantify the changes that occur as a function of time. Two production lots of over 1 million softgel capsules were executed to produce a population that lends itself to statistical analysis. Softgel capsules were manufactured with gelatin which was aged at intervals of 0-8 hrs, 32-40 hrs, 66-72 hrs and 88-96 hrs. The manufacturing process made use of this strategy for the acid and alkaline treated gelatin where a total of eight lots were made (4 acid and 4 alkaline). One hundred thousand softgels were manufactured for the acid processed gelatin, per lot. Additionally, one hundred and fifty thousand softgels were manufactured for the alkaline processed gelatin per lot. The results of the different tests provided trends that were not solely a function of time. Gel extensibility for both gel types showed a decrease in the amount of force needed to rupture the gelatin ribbon, as a function of time. The resilience of the tested ribbon remained constant throughout the aging process. The burst strength was the only test showing an inverse relationship between the two gel types. The amount of force needed to rupture the 150 Bloom softgels decrease in time whereas the amount of force needed to rupture the 195 Bloom softgels increase with time. The rheological testing was described in the literature as being associated with the molecular weight distribution. Such association was seen in our research and both the results of the rheological and the molecular weight tests decreased with the aging process.

Modeling methods are required for predicting the chemical stability of macromolecular materials used in critical spacecraft components of satellites orbiting in the high-energy radiation environment of near earth and deep space planetary magnetic belts. Methods for establishing degradation mechanisms and predicting and simulating the total absorbed dose and ionization for long term space missions are presented herein. This investigation evaluates cross-linking, main-chain scission and elimination products in a linear series of narrowly dispersed poly(methyl methacrylate) (PMMA) and polystyrene (PS) polymers. A comparison is made of the scission radiation yield (Gs) and crosslinking (Gx) predicted for the simulated ionization data to the results of degradation in a ground-based simulation of the space radiation environment using a 60Co source. The influence of molecular weight on the stability of post-irradiated polymer is evident in the degree of change observed for each molecular weight series with respect to the degradation products produced by exposure to gamma radiation. The analysis of the specific polymer degradation products and changes in the average molecular weight (Mw) were performed using chemical analysis (FTIR and GPC) and thermal analysis (DSC). The analytical results for PMMA and polystyrene radiation-induced degradation products demonstrate that, depending on Mw, the amount and types of degradation products will vary with respect to crosslinking, chain scission and other oxidative pathways. The results support the preference for end group loss with free volume properties driving the observed differences in the G(s) and (Gx) values. The cross-linking observed for polystyrene is controlled by molecular weight as well wherein the lowest molecular weight molecules display greater resistance to cross-linking. This research investigation employs proven tools of analysis (NASA AP8 and AE8) that accurately predict the amount of energy applied to spacecraft materials during a typical near-earth, aggressive mission environment . Another model (SPENVIS) is applied to determine the amount of total energy absorbed by the spacecraft materials from proton, electron and Brehmsstralung radiation throughout the mission life. Another set of models (SRIM and CASINO) are used to asses the range of penetration of particles into the materials and the extent of ionization caused by the particle spectrum and fluence. The absorption coefficients for the PS and PMMA structure are determined to ensure good correlation between ground simulation and the true space environment. The total dose values are used to establish the total dose that is to be deposited during the ground simulation experiments. A 60Co irradiator was used as the ground simulation source. Dosimetry was used to determine the exposure time needed to deposit an equivalent amount of dose accumulation needed to simulate the total dose modeled for the space mission. Using gel permeation chromatography, previous studies have demonstrated that the characteristic Gaussian distribution of narrowly-dispersed PS and PMMA is perturbed by the accumulation of degradation products following irradiation. The change in distribution provides insight into the preferred path of degradation. The role of free volume in the glass transition temperature are reported with respect to Tg variation with molecular weight. Using differential scanning calorimetry. The role of free volume in the determination of the mechanism of radiation-induced degradation is a primary focus of this investigation when considering the ability of the main chain to recombine or undergo abstraction as opposed to crosslinking or scission where motion is restricted in the solid state. The subtle distinction of structural changes brought about by the loss of side groups, double bond formation and crosslinking have been characterized by infrared spectroscopy. The resultant spectra of irradiated polymers offer considerable information on verifying the extent of competing reactions that involve structural features of the molecule. These instrumental methods are the tools of research that will assess the affect of molecular structure on polymer radiation resistance, and will support the rationale explaining the preference for one degradation mechanism over another. This research investigation has yielded information on the affect of polymer molecular structure on radiation resistance. The work goes beyond previous studies that define empirical observations for a change in radiation resistance by virtue of a change in side group. The effect of free volume, stabilized intermediates and reactive intermediates are related to molecular weight and side group functionality. The understanding of the mechanistic rationale behind the effect of structural features on polymer radiation resistance are essential to the development of modeling systems for predicting polymer stability in space mission environments.

Coupled two-dimensional HPLC systems were developed for the separation of complex sample matrices. Low molecular weight polystyrene oligomers were used as model compounds for the development of these systems since the sample dimensionality of oligostyrenes could be defined and classified according to two sample characteristics. That is, oligostyrenes could be classed as a two-dimensional sample, where one sample dimension is the variation in the number of monomers that make up oligomeric units determining the weight of the polymer, with a second sample dimension being the variation in stereoisomerism of each oligomer. During this study it was found that by combining two separation dimensions consisting of C18 and carbon clad zirconia (CCZ) phases separation of oligostyrenes according to molecular weight and stereochemistry was possible in coupled two-dimensional systems. The C18 phase separated the sample according to molecular weight, while the CCZ phase separated the sample according to the stereochemistry. The stereoisomer separations of the oligostyrenes reported on the CCZ surface were far superior to those previously reported in the literature. The efficiency of the separation process in a coupled two-dimensional system was then evaluated by studying the variation in band variance of a test probe. The results of the study indicated that the performance of a two-dimensional separation process was highly dependent upon the mobile phase compatibility, even when solvents were completely miscible and of similar polarities. Extracts from 17 species of Australian native plants were examined for xanthine oxidase inhibitory activity, the enzyme responsible for the formation of the disease gout. Chromatographic separation was conducted on plant extracts found to possess significant inhibitory activity against xanthine oxidase, with an extract from the species Clerodendrum floribundum R. Br. found to possess the greatest activity of the species examined. A two-dimensional separation of a crude extract from Clerodendrum floribundum R. Br. was conducted using one of the developed HPLC systems, to illustrate the use of such a system for the separation of a non-model complex sample mixture / Doctor of Philosophy (PhD)

There are two main goals of this thesis: to investigate the flow-induced crystallization behaviour of Polybutene-1 (PB-1 samples, and to study the effects of molecular parameters on the crystallization behaviour While flow-induced crystallization is not a new area in polymer research, well-defined experimental methods that allow access to high flow rate range comparable to that encountered in real processing are still lacking. Two types of flow are considered: shear and uniaxial elongational. Regarding the second aim, several molecular parameters considered are: molecular weight, molecular weight distribution, isotacticity, presence of nucleating agents, and copolymer content. For this purpose an array of PB-1 samples were used. It is found that each of these parameters can have significant effect on the crystallization behaviour. Mainly rheological methods were utilized to conduct the flow-induced crystallization experiments. Crystallization onset time is define d from the change in viscosity or other related parameters. The experiments begin with low shear rate range, to ensure that the results are comparable with literature data. In this range we encounter the quasi-quiescent onset time at very small. shear rates, which draws an interesting comparison with another physical parameter, the gel time. Beyond a critical flow rate a decrease in the onset time is seen, and a plateau-and-slope trend is evident for a curve of onset time vs. shear rate. Using a combination of three experimental methods, shear rates ranging from Q0001 - 500 s-1 are successfully achieved, and a good agreement between these methods is observed. Furthermore, a normalization procedure is introduced, which yields temperature-invariant curves for the mentioned range of shear rate. For the uniaxial elongation flow, the Elongational Viscosity Fixture (EVF) is employed, with the strain rate ranging from 0.0001 - 10 s'. A greater reduction in onset time as compared to shear (at the same shear/strain r ate) is observed, and the difference in the onset times for shear and elongation already reaches more than one decade for a flow rate of 10 5. This quantitative comparison is particularly important; since not so many data on elongation-induced crystallization are available in the literature. Finally, the thesis compares several flow induced crystallization models that can be useful as prediction tools and selects one of these models to be compared with the experimental data. A qualitative agreement is found, however, for better quantitative prediction the model still needs to be.

L'étude du pouvoir moussant de la gélatine trouve son origine dans un problème industriel important, non résolu jusqu'à présent : le choix des lots de gélatine en fonction des applications (par exemple : les gelées sucrées ou salées ainsi que les gommes nécessitent pour leur fabrication des gélatines peu moussantes ; les produits foisonnés et les "lards" requièrent des gélatines à pouvoir moussant élevé). Pour ce faire, quatre objectifs ont été définis : la caractérisation du pouvoir moussant de la gélatine - la mise en évidence des paramètres influençant les propriétés moussantes - la maîtrise de la formation non contrôlée de mousse spontanée dans les solutions de gélatine - la définition du process à appliquer à la matière première pour l'obtention de gélatine de pouvoir moussant souhaité. Dans le cadre de ce travail, seuls les deux premiers objectifs ont été entièrement réalisés.

Growth of bacteria in drinking water distribution and storage systems can lead to the deterioration of water quality, violation of water standards, and increased operating costs. Growth or Regrowth results from viable bacteria surviving the disinfection process and utilizing nutrient in the water and biofilm to sustain growth. Factors other than nutrients that influence regrowth include temperature, residence time in mains and storage units, and the efficacy of disinfection. Tests to determine the potential for bacterial regrowth focus on the concentration of nutrients. Not all organic compounds are equally susceptible to microbial decomposition; the fraction that provides energy and carbon for bacterial growth has been called labile dissolved organic carbon, biodegradable organic carbon (BDOC), or Assimilable Organic Carbon (AOC). Easily measured chemical surrogates for AOC are not available now. As alternative to chemical methods, bioassays have been proposed. Assimilable Organic Carbon (AOC) is that portion of the biodegradable organic carbon that can be converted to cell mass and expressed as a carbon concentration by means of a conversion factor. In this study, two organisms, namely Psuedomonas fluorescens strain P17 and Spirillum species NOX were selected for the AOC determination. The growth of the bacteria was determined by periodic colony counts with spread plate technique on LLA (Lab-Lemco nutrient agar) cultivation medium until the growth reached maximum (maximum colony count, Nmax). Results showed that AOC follows a trend based on the climatic and seasonal changes (local climate) with peaks in summer and low during winter season and vice versa in term of AOC removing capability. In addition to confirm AOC removal rate in biofiltration bed was evaluated with a test column containing the same filling materials, Granular Activated Carbon (GAC). Long term test showed that GAC would last for forty weeks without any special treatment. Other result showed that biofiltration bed has a better removal efficiency rate 72% (average based on four year), than the test column 49% since it experience frequent back-washing, thus maintaining a healthy removal rate. In the test column change in total organic carbon was quite abnormal. AOC yearly distribution was also studied and differentiated into four stages. AOC removal of each stage was 48%, 70%, 83% and 77%. Total organic carbon concentration was much higher in the effluent 384 than influent 334 £gg C/L; later methionine was found in water sample (effluent) which strongly suggests that the indigenous microbes had been reducing organic material such as cystein to methionine thus increasing the organic carbon content of the effluent. The microbial growths inside the GAC test column is entirely based on the long term feed of water at the treatment plant. Several other parameters such as Scanning Electron Microscope (SEM), Excitation Emissions Fluorescence Matrix (EEFM), Molecular Weight and Amino acids detection were selected and coupled with the AOC to shed light on the working mechanisms of both GAC as filtration material and characteristics of indigenous microbes towards the removal of organic contaminants and changes they can bring about to the quality of clear water.