CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O aumento do perÃodo de conservaÃÃo dos frutos climatÃricos ocorre pela inibiÃÃo da sÃntese ou da aÃÃo do etileno de forma a retardar o amadurecimento. Uma das formas de controle deste processo pode ser a aplicaÃÃo de reguladores vegetais como o aminoetoxivinilglicina (AVG), um inibidor da biossÃntese do etileno. O AVG evita a formaÃÃo autocatalÃtica do etileno, reduz a respiraÃÃo climatÃrica, a abscisÃo de frutos e aumenta a firmeza da polpa quando pulverizado nas Ãrvores frutÃferas em prÃ-colheita. Este trabalho teve como objetivos avaliar o efeito da aplicaÃÃo de AVG na maturaÃÃo e qualidade de frutos do meloeiro cantaloupe em condiÃÃes de casa de vegetaÃÃo e de campo. O delineamento experimental foi o inteiramente casualizado, em fatorial 3 x 5, com trÃs datas de aplicaÃÃo e cinco doses do princÃpio ativo para os dois experimentos, sendo utilizado duas repetiÃÃes, tendo oito plantas por repetiÃÃo no plantio em ambiente protegido e trÃs repetiÃÃes, formadas por cinco frutos em campo. As respostas em cada ambiente foram especÃficas sendo que em casa de vegetaÃÃo o uso do AVG influencia na qualidade dos melÃes, quanto ao tamanho de fruto e cavidade interna; nÃo altera o teor de sÃlidos solÃveis, aÃÃcares totais e firmeza independentemente da dose e aplicaÃÃo do produto e influencia na maturaÃÃo dos frutos de meloeiro promovendo aumento na permanÃncia do fruto à planta quando pulverizados duas ou trÃs vezes, na dose de 270 mg. L-1. Em condiÃÃes de campo o AVG influencia na qualidade dos frutos do meloeiro, proporcionando frutos maiores com cavidade interna menor, maior teor de sÃlidos solÃveis e mais firmes e influencia na maturaÃÃo, promovendo maior permanÃncia dos frutos na planta. Portanto, o AVG influenciou na qualidade e na maturaÃÃo dos frutos de melÃo, sob ambas condiÃÃes de cultivo. / Increased retention of climacteric fruits occurs by inhibiting the synthesis or action of ethylene in order to delay ripening. One way to control this process may be the application of plant growth regulators such as aminoethoxivinilglicin (AVG), an inhibitor of ethylene biosynthesis. AVG prevents the formation of autocatalytic ethylene reduces respiration climacteric fruit abscission and increases firmness when sprayed on fruit trees before the harvest. This study aimed to evaluate the effect of AVG on ripening and fruit quality of muskmelon cantaloupe in greenhouse and field. The experimental design was completely randomized, with a 3 x 5, with three dates of application and five doses of the active ingredient for the two experiment, being used two replicates, with eight plants per replication at planting in a greenhouse and three replicates of five fruits formed in field. The responses were specific for each environment and in a greenhouse using AVG influences the quality of melons, as the fruit size and internal cavity; does not change the content of soluble solids, total sugars and firmness regardless of dose and application of the product and influences the maturation of melon fruits for increasing the permanence the fruit to the plant when sprayed two or three times at a dose of 270 mg. L-1. Under field conditions the AVG influences the quality of the melon fruit, providing larger fruits with internal cavity smaller, higher soluble solids content and firmness and influences the maturation promoting greater permanence of fruit on the plant. Therefore, AVG influenced the quality and maturity of melon fruits under both culture conditions.

Orientador: Maria Isabel Pedreira de Freitas Ceribelli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T03:14:42Z (GMT). No. of bitstreams: 1 Abdo_Nelyan_D.pdf: 1704147 bytes, checksum: 34b769db6d0f1c4ead0ac4c2a3cca581 (MD5) Previous issue date: 2006 / Resumo: A etapa da aeração em um ciclo de esterilização a Óxido de Etileno (OE) corresponde à fase de retirada de resíduos tóxicos dos artigos processados neste método. A aeração pode ocorrer por meio de equipamentos destinados para o processo ou ainda em ambientes projetados para essa finalidade. O presente estudo tem como objetivo descrever como vem se desenvolvendo a prática da aeração dos artigos odonto-médico-hospitalares (AOMH) em empresas terceirizadoras de esterilização a OE, na região sudeste do país, tendo como referência a Portaria Interministerial No. 482, de 16 de Abril de 1999 vigente e orientações internacionais relacionadas ao tema.Trata-se de um estudo descritivo, com dados coletados através de instrumento aplicado presencialmente pela pesquisadora, que versou sobre a caracterização das empresas, dos parâmetros do processo de esterilização, período e características da aeração realizada. Foram entrevistados os responsáveis técnicos de 10 das 12 empresas existentes na referida região. Para tratamento dos dados foram utilizadas tabelas de freqüência para variáveis categóricas e estatísticas descritivas para as variáveis contínuas. Como resultado, observou-se que as empresas foram caracterizadas com número de clientes acima de 300 para 60% dos respondentes, concentramse no interior da região sudeste e todas apresentam profissionais responsáveis graduados na área da saúde. Com referência aos parâmetros do ciclo de esterilização os dados foram bastante heterogêneos. Sobre a aeração, 60% das empresas usam a aeração ambiental e 40% a mecânica. Em todas as questões sobre aeração, os dados foram dispersos indicando uma não homogeneidade de ação. A PI482 (1999) não menciona o tempo de aeração ambiental (AA) indicado para o processo, apesar de orientar sobre a existência de uma sala de aeração e também não menciona qualquer informação sobre aeração mecânica (AM). Neste aspecto, as empresas estão adequadas sendo que 100% delas possuem sala de aeração, mas apresentam parâmetros heterogêneos para utilização da AA. As orientações internacionais analisadas, oferecem dados objetivos sobre os tipos de aeração e sobre quais fatores que podem interferir no processo. Devido à diversidade de fatores que interferem no processo de aeração, uma orientação genérica é indicada pelas principais organizações internacionais e que preconiza o uso de aeração mecânica aquecida por 8h a 60ºC ou 12h a 50ºC. Neste aspecto, nenhuma das empresas pesquisadas mostrou adequação sendo que as que utilizam AM, trabalham com temperaturas e tempos diferentes dos preconizados. Quanto ao fator que determina o tempo de entrega do AOMH para uso, não houve consenso e obteve-se a maioria dos respondentes indicando o tempo de resposta de teste biológico como o fator preponderante. Conclui-se que a aeração de AOMH realizado em empresas terceirizadas de esterilização a OE na região sudeste, encontra-se adequada em relação à PI 482 (1999), no que se refere à estrutura física enquanto as orientações sobre parâmetros da aeração, não são bem estabelecidas nas empresas estudadas. Quanto às orientações internacionais para aeração de AOMH, as empresas não se encontram em conformidade com o preconizado o que conduz à necessidade da avaliação efetiva do processo realizado atualmente / Abstract: The stage of the aeration in a sterilization cycle the Oxide of Etileno (OE) corresponds to the phase of withdrawal of toxic residues of articles processed in this method. The aeration can still occur by means of equipment destined for the process or in projected environments for this purpose. The present study it has as objective to describe as it comes if developing practical of the aeration of dentalmedical- hospital devices (AOMH) in outsourced companies of sterilization the OE, in the Southeastern region of the country, having as reference Inter-ministerial PI 482, dated April 16, 1999 of effective related international guidelines. One is about a descriptive study, with data collected through instrument applied actually for the researcher, that turned on the characterization of the companies, of the parameters of the process of sterilization, period and characteristics of the carried through aeration. They had been interviewed responsible the technician of 10 of the 12 existing companies in the related region. For treatment of the data tables of frequency for categorical variable had been used and statistical descriptive for the continuous variable. As result, it was observed that the companies had been characterized with number of customers above of 300 for 60% of the respondents, are concentrated in the interior of the Southeastern region and all present responsible professionals graduated the area of the health. Regarding to the parameters of the sterilization cycle the data had been sufficiently heterogeneous. On the aeration, 60% of the companies use ambient aeration and 40% the mechanics. In all the questions on aeration, the data had been dispersed indicating not a homogeneity of action. The PI482 (1999) does not mention the time of ambient aeration (AA) indicated for the process, although to guide on the existence of a aeration room and also it does not mention any information on aeration mechanics (AM). In this aspect, the companies are adjusted being that 100% of them they possess aeration room, but present heterogeneous parameters for use of the AA. The analyzed international guidelines, offer given objective on the types of aeration and which factors that can intervene with the process. Due to diversity of factors that intervene with the aeration process, a generic orientation is indicated by the main international organizations and that it praises the aeration use warm mechanics for 8h 60ºC or 12h 50ºC. In this aspect, none of the searched companies showed adequacy being that the ones that use AM, work with temperatures and different times of the praised ones. How much to the factor that it determines the time of delivery of the DMHD for use, did not have consensus and got it majority of the respondents indicating the time of reply of biological test as the preponderant factor. The aeration of DMHD is concluded that carried through in outsourced companies of sterilization the OE in the Southeastern region, meets adequate in relation to PI 482 (1999), as for the physical structure while the guidelines on parameters of the aeration, well are not established in the studied companies. How much to the international guidelines for aeration of DMHD, the companies do not meet in compliance with the praised one what she leads to the necessity of the evaluation accomplishes of the process carried through currently / Doutorado / Enfermagem e Trabalho / Mestre em Enfermagem

Orientadores: Maria Alvina Krähenbühl, José Roberto Nunhez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-16T15:11:20Z (GMT). No. of bitstreams: 1 Mello_FaustoHenriquede_M.pdf: 1167990 bytes, checksum: e645a2438e712db3fe9b9ea7d7a66077 (MD5) Previous issue date: 2010 / Resumo: Neste trabalho foi simulado o processo de Absorção, Stripping e Reabsorção de Óxido de Etileno, avaliando-se a influência da não idealidade da fase líquida, os melhores modelos para representar essa não idealidade, diferentes formas de cálculo de eficiência de coluna e os perfis de temperatura e concentração gerados pelo simulador comercial Aspen Plus®. Foi mostrado também, como a representação pontual de um processo de separação pelo ajuste da eficiência de separação, pode levar à falsa idéia de se ter obtido a representação de um sistema de separação. Foram realizadas análises de sensibilidade que, além de permitir um maior entendimento do comportamento operacional dos equipamentos, também permitiu avaliar a adequação do modelo termodinâmico e dos parâmetros binários utilizados na simulação desse sistema de separação. No caso estudado, é muito importante a representação do equilíbrio líquido vapor entre o óxido de etileno (OE) e a água, em função da forte não idealidade da fase líquida. Para a mistura OE + água, apesar de comum na indústria, é difícil de se encontrar na literatura dados de equilíbrio em condições próximas às de operação da unidade industrial, em função da alta reatividade entre o OE e a água, e por o OE ser um produto muito tóxico e de alta periculosidade. Os resultados da simulação apresentaram-se em sua maioria, bastante satisfatórios em relação aos dados de processo / Abstract: In this work the process of Absorption, Stripping and Reabsorption of Ethylene Oxide was simulated, evaluating the influence of non-ideality of the liquid phase, the best models to represent this non-ideality, different ways to calculate the efficiency of the column and temperature and concentration profiles generated by the commercial simulator Aspen Plus®. It was also shown, how the punctual representation of a separation process by adjusting the separation efficiency, can lead to the false idea of having obtained the representation of a separation system. Sensitivity analysis were performed which, besides allowing a better understanding of the operational performance of the equipment, also allowed to evaluate the adequacy of thermodynamic model and the binary parameters used in the simulation of this separation system. In the case studied, the representation of the vapor liquid equilibrium between the Ethylene Oxide (EO) and water is very important, due to the strong non-ideality of the liquid phase. For EO + water mixture, although common in the industry, it is hard to find in the literature equilibrium data for conditions similar to the operation of the plant, due to the high reactivity between EO and water, and EO be a product very toxic and highly hazardous. The simulation results presented are mostly quite satisfactory in relation to process data / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientador: Jose Vicente Hallak D'Angelo / Teses (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T17:52:28Z (GMT). No. of bitstreams: 1 Fabrega_FrancinedeMendonca_D.pdf: 2288769 bytes, checksum: 42c859846af4183cbee87d9363d4cffb (MD5) Previous issue date: 2010 / Resumo: A indústria petroquímica é o setor industrial que utiliza como matéria prima derivados do petróleo, principalmente a nafta petroquímica, da qual se produzem substâncias como o etileno e propileno. Nesse processo industrial utilizam-se ciclos de refrigeração de larga escala que fornecem utilidades frias ao processo, em especial aos condensadores das colunas de destilação e destacam-se por serem grandes consumidores de energia, sendo de extrema importância que estes ciclos operem de forma otimizada visando a redução de custos. A Quattor Unidade de Químicos Básicos Cracker ABC, localizada no Pólo Petroquímico de Capuava, em Santo André (SP) vem produzindo atualmente 700 mil t/ano de etileno, sendo umas das principais produtoras do setor. A fim de reduzir os custos de processos industriais, as análises exergética e exergoeconômica seguidas da otimização termoeconômica são ferramentas que têm sido empregadas com sucesso. Neste trabalho, com o objetivo de otimizar o sistema de refrigeração que produz as utilidades frias, foi utilizado o simulador comercial Hysys© versão 3.2 para a simulação do processo produtivo e do ciclo de refrigeração, obtendo-se as grandezas termodinâmicas necessárias para o cálculo da análise exergética. Aplicando a metodologia desenvolvida por Lozano e Valero (1993) foi possível calcular os custos de cada corrente do processo utilizando o software Matlab 7.0. A otimização do processo foi realizada utilizando-se a ferramenta Optimizer presente no próprio simulador. A função objetivo foi definida visando minimizar a exergia destruída no processo e o método de otimização utilizado foi o SQP (Sequential Quadratic Programing). Com a metodologia aplicada a exergia destruída foi reduzida em 19,95%. Em relação aos custos exergéticos foi obtida uma redução de 10,94% e os custos exergoeconômicos foram reduzidos em 6,45% (SQP) representando uma economia de 77000 R$/h / Abstract: Petrochemical industries use many oil derivatives as raw materials, especially petrochemical naphtha, from which many chemicals, like ethylene and propylene, are obtained. The industrial process that produces these products uses large scale refrigeration cycles which generate the cold utilities streams used in the condensers of the distillation columns. These refrigeration cycles are great energy consumers, so it is very important that they operate in an optimized way in order to reduce operational costs. Quattor Unidade de Químicos Básicos Cracker ABC, located at Capuava Petrochemical Pole in Santo André (São Paulo State) produces 700 thousand tons of ethylene per year and is one of the main producers of the petrochemical sector in Brazil. Exergetic and exergoeconomic analysis followed by a procedure of thermoeconomic optimization are a set of important tools used to improve industrial processes and they have been used successfully in many cases. In this work, aiming the optimization of the refrigeration system that generates the cold utilities for the process, a commercial simulator, Hysys© version 3.2, was used to simulate both the industrial process of ethylene and propylene production and the refrigeration cycles of the process, obtaining the thermodynamic properties of the streams present in the process, which are necessary for the exergetic analysis. Using the methodology developed by Lozano and Valero (1993) it was possible to calculate the costs of each process stream using software Matlab 7.0. The optimization of the process was performed using the Optimizer Tool available in the simulator, by defining an objective function to be minimized as being the total destroyed exergy in the process. The chosen optimization method was SQP (Sequential Quadratic Programming). With these tools and using the referred methodology, the total destroyed exergy in the process was reduced in 19.95%. Considering exergetic costs, a reduction of 10.94% was achieved and the exergoeconomic costs were reduced in 6.45%, representing an economy of 77000 R$/h for the process / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

A eletrooxidação de etileno glicol e de seus produtos parciais de oxidação foram estudadas em eletrodos de Pt e eletrodos binários de PtRu, utilizando-se técnicas eletroquímicas fundamentais, espectroscopia de infravermelho por reflexão externa e cromatografia líquida de alta eficiência. Os resultados evidenciam um efeito catalítico na oxidação de etileno glicol com a quantidade de Ru no eletrodo até um máximo de corrente de 11mA cm-2 entre 30% a 40% em Ru. Experimentos de espectroscopia de infravermelho in situ detectaram espécies adsorvidas, como o CO, e espécies residuais contendo dois átomos de carbono. Os produtos solúveis foram glicolaldeído, ácido glicólico e CO2. Bandas bipolares de CO indicam que o etileno glicol já está totalmente dissociado no potencial de referência (0,05 V vs. RHE). Espécies contendo o grupo carbonila como o glicolaldeído também são observadas no potencial de referência (0,05 V vs RHE). A formação de CO2 é influenciada não só pela concentração do álcool em solução como também pela quantidade superficial de Ru no eletrodo. A eletrooxidação de ácido glicólico mostra a formação de CO2 a baixos potenciais (0,20 vs. RHE) e CO adsorvido a um potencial de 0,40 V. / The eletrooxidation of ethylene glycol and its partial oxidation products, glycolic acid and glycolaldehyde was studied on Pt and PtRu electrodes. Cyclic voltammetry and chronoamperometry were used for the electrochemical characterization. The nature of the reaction products and intermediates was studied by in situ Fourier transform infrared spectroscopy and high performance liquid chromatography. The oxidation reaction is catalyzed by PtRu; the maximum current density observed was 11 μA cm-2 for a ruthenium content between 30% and 40%. Adsorbed CO and residual species containing two carbon atoms as well as CO2 glycolaldehide and glycolic acid were detected by FTIR spectroscopy. Although the quantitative determination of glycolaldehyde was not possible, the results allowed an indirect estimation of this product, which starts to be formed already at 0.05V. It was found that glycolaldehyde is the main reaction product. PtRu favors the scission of the C-C bond. Thus, much higher CO coverage was found at the alloy than at pure Pt. An increase in the amount of glycolaldehyde at PtRu indicates that this material also catalyzes the scission of the C-H bond. This effect is probably due to an electronic modification of Pt caused by the presence of ruthenium, since pure Ru is not active for adsorbing or oxidizing ethylene glycol and much less Pt sites are available at PtRu.

No presente trabalho foram estudados alguns aspectos não lineares da catálise da oxidação de etileno glicol (EG) sob platina em meio alcalino (KOH). A dinâmica do sistema foi investigada através de voltametria cíclica, séries temporais de corrente e potencial e por espectroscopia de impedância eletroquímica. (EIE). Os resultados da EIE revelaram a presença de uma região de resistência diferencial negativa escondida nas proximidades o pico principal obtido na voltametria cíclica. De modo geral o sistema se mostrou apto a oscilar tanto sob regime potenciostático quanto galvanostático e por longos períodos de tempo apresentando uma miríade de estados dinâmicos que incluem oscilações harmônicas, de baixa e alta amplitudes, períodos 2, 3, 4 e modos mistos, além da duplicação de período na transição para o caos. A concentração tanto de EG como de KOH tiveram caráter essencial nos padrões temporais observados. A complexidade dos períodos aumenta com o aumento da concentração de EG resultando em 90% do tempo em que o sistema passa oscilando devotado às oscilações caóticas quando a concentração de EG é de 1,6 M. O aumento da densidade de corrente produz um efeito contrário nos padrões, ou seja, quanto mais alta é a corrente mais simples são os períodos. A influência de alguns produtos de oxidação parcial do EG foi estudada em diferentes condições. Os resultados das mudanças de morfologia das oscilações são racionalizados em termos das eventuais conexões com os intermediários de reação formados durante o processo de oxidação que, por sua vez, dependem da concentração do álcool e da densidade de corrente. / In the present work were studied some nonlinear aspects of the catalytic oxidation of ethylene glycol (EG) on platinum electrodes in alkaline media (KOH). The system\'s dynamics was investigated by means of cyclic voltammetry, current and potential time series, and electrochemical impedance spectroscopy (EIS). The EIS results reveal the presence of a hidden negative differential resistance around the main voltammetric peak. Overall, the system was able to oscillate for several periods, displaying a myriad of dynamic states which includes harmonic, small and large amplitude, periods 2, 3, and 4, and mixed-mode oscillations, as well as period doubling transition to chaos. The concentration of both EG and KOH were found to play an essential role in the temporal patterns observed. The complexity of the periods increase with EG concentration resulting in 90% of the oscillating time devoted to chaotic patters when EG concentration is 1.6 M. The increment of the current density produces an opposite behavior of the patters: the higher the applied current the simpler the oscillatory dynamics. The influence of some products of partial EG oxidation was studied under different conditions and compared. The results of the changes in the oscillatory morphology are rationalized in terms of its eventual connection with reaction intermediates formed during the oxidation process that, in turn, depends on the alcohol concentration and on the current density.

Résumé confidentiel / Résumé confidentiel

M.Sc. / The commercial value of cut flowers, whether for ornamental use or as an export product, has increased significantly over the years. Much attention is given to flower quality and flower longevity. These two factors are influenced by preharvest and postharvest treatments. The major postharvest loss reduction techniques in carnation flowers include regulation of preharvest growing, use of improved harvesting techniques, use of various storage techniques, use of growth regulators and use of floral preservatives. Senescence of carnation flowers (Dianthus caryophyllus L. cv. White Candy), is accompanied by a climacteric rise in ethylene synthesis and an increased sensitivity of the flowers to ethylene. A pulse treatment with sucrose caused a delay and suppression of the climacteric rise in ethylene synthesis. The action of sucrose, with reference to ethylene, was similar to that of cytolcinins. Dry storage also caused an increase in flower longevity. This is due to the flower's ability to maintain water balance by lowering the cells osmotic potential. Dry storage is of importance, as transportation of the flowers occurs under these conditions. Although sucrose increased the longevity of freshly cut carnations, it caused a decrease in longevity of flowers that were subjected to water stress. With the lowering of the tissue water potential through treatment with sucrose and thereafter by dry storage, the flowers are subjected to stress, and are not able to recover even after rehydration. Applied sucrose increased the carbohydrate pool, thereby resulting in a gradual decline of starch. Administering both sucrose and water stress to the carnation flowers resulted in an early peak in the sugar content, as well as an early depletion of sugar in the flower petals. Cytokinin activity in untreated carnation flowers appeared to be higher compared to flowers treated with sucrose. Water stress have the effect of decreasing cytokinin levels and activity. It is thus clear from the results of this study, that carnations subjected to water stress through dry storage, should not be pretreated with any preservative containing sucrose, as it leads to a reduction in vase life.

Polyethylene (PE) resins being non-polar in nature and having a high degree of crystallinity have limited miscibility and compatibility when blended with polar polymers. The miscibility and compatibility of these blends are generally worsened when they are prepared by direct injection moulding without a precompounding process. Such situations are commonly encountered in particular by polymer converters when blending colour and/or additive concentrates, commonly known as masterbatches. Typically, masterbatches are mixtures containing high loading of pigments and/or additives predispersed in a suitable solid vehicle (commonly known as carrier) such as a polyethylene resin. These masterbatches are usually used for the colouration of a wide range of polymers and the carrier used must therefore be compatible with these matrix (host) polymers. The preliminary stage of this study involved the investigation of the properties of blends based on high density polyethylene (HDPE) and a range of engineering thermoplastics (ABS, PC, PBT, PA6), prepared by injection moulding. Five different types of compatibilisers namely, ethylene-vinyl acetate (EVA) copolymer, ethylene-methyl acrylate (EMA) copolymer, ethylene-glycidyl methacrylate (E-GMA) copolymer, ethylene-methyl acrylateglycidyl methacrylate (E-MA-GMA) terpolymer and maleic anhydride grafted HDPE (HDPE-g-MAH) copolymer were evaluated with respect to their efficiencies in compatibilising HDPE with the four engineering polymers. The pre-compounded HDPE/compatibiliser binary blends at 2 different blend ratios (1:1 and 3:1) were added at 15 wt% concentration to each engineering thermoplastics and test samples were produced directly by injection moulding. Results of mechanical testing and characterisation of the blends showed that glycidyl methacrylate compatibilisers, E-MA-GMA, in particular have the most universal compatibilising effectiveness for a range of engineering thermoplastics including ABS, PC, PBT, and PA6. Blends compatibilised with E-MA-GMA compatibiliser had the best notched impact performance irrespective of matrix polymer type. The presence of an acrylic ester (methyl acrylate) comonomer in E-MA-GMA resulted in increased polarity of the ii compatibiliser leading to improved miscibility with the polar matrix polymers demonstrated by fine blend morphologies, melting point depression and reduction in crystallinity of the HDPE dispersed phase. The second stage of this study involved the reactive modification of HDPE using a low molecular weight di-functional solid diglycidyl ether of bisphenol A (DGEBA) type epoxy resin compatibilised with HDPE-g-MAH in an attempt to improve its compatibility with ABS, PBT and PA6. The maleic anhydride moieties in HDPE-g-MAH served as reactive sites for anchoring the epoxy moieties while the HDPE backbone was miscible with the HDPE resin. An excessive amount of reactive groups resulted in the formation of crosslinked gels while the addition of EVA co-compatibiliser helped in the reduction of gel content and further improved the dispersion of the epoxy. The effectiveness of epoxy grafted HDPE (with and without EVA co-compatibiliser) in compatibilising ABS/HDPE, PBT/HDPE, and PA6/HDPE was investigated by injection moulding of 5 wt% functionalised HDPE with these matrix polymers into test bars for mechanical testing, and characterisation by differential scanning calorimtery (DSC) and optical microscopy. The reactively functionalised HDPE blends, improved the mechanical properties of ABS and PA6 blends especially with EVA as co-compatibiliser. However, the mechanical properties of PBT blends were unmodified by the functionalised HDPE which was believed to be due to end-capping of the PBT chain-ends by ungrafted epoxy resins.

Les α-oléfines jouent un rôle très important en tant qu'intermédiaires réactionnels dans l'industrie chimique et pétrochimique. Leur utilisation principale est la production de diverses qualités de polyéthylène dans lequel l'α-oléfine est engagée en tant que co-monomère (butène-1, hexène-1 et octène-1). Les systèmes capables de dimériser, trimériser voir tétramériser sélectivement l'éthylène en α-oléfines supérieures, utilisent principalement le titane et le chrome. Du fait de la toxicité potentielle du chrome, la recherche industrielle et académique s’oriente de plus en plus vers des systèmes à base de titane.Notre objectif dans ce contexte était d’étudier le potentiel des systèmes « phénoxy-tridente » du Ti(IV) pour la trimérisation sélective de l’éthylène en hexène-1. De nombreux systèmes de formules générales [(ArO-X-L)TiCl3] (X=O,P,N et L=O,P,N) ont ainsi été isolés et caractérisés. L’étude de leurs propriétés électroniques et stériques et ses conséquences sur leurs performances en oligomérisation/polymérisation de l’éthylène ont été discutées. Elles mettent en évidence la criticité de l’ensemble des paramètres à la fois électroniques et structuraux du ligand. Un seul système de cette famille est capable de produire sélectivement de l’hexène-1, les autres conduisant à la polymérisation de l’éthylène.Une étude DFT associée à une étude expérimentale des propriétés redox des précurseurs catalytiques ou encore du comportement hémilabile des ligands mis en jeu, nous a conduit à proposer un mécanisme identifiant la phase d’activation comme l’élément clé permettant d’orienter les systèmes étudiés vers la polymérisation ou la production sélective d’hexène-1. / Linear α-olefins (LAOs) are crucial importance for the chemical and petrochemical industry as they are highly valuable feedstock for a variety of process mainly as co-monomer for the production of different grade of polyethylene (1-butene, 1-hexene and 1-octene). Some systems and predominantly chromium and titanium systems have performed selective dimerization, trimerization and tetramerization of ethylene to higher α-olefins. For toxicity reasons, industrial and academic research focus more and more on titanium-based systems.Our objective in this context was the study of potential “tridentate phenoxy” systems of Ti(IV) for selective trimerization of ethylene to 1-hexene. Numerous systems with general formula [(ArO-X-L)TiCl3] (X=O,P,N and L=O,P,N) were described and characterized. The study of electronic and steric properties and their consequences on catalytic performances in oligomerization/polymerization of ethylene were discussed. They showed the criticity of all electronic and structural parameters of ligands. Only one system of this family is able to produce selectively 1-hexene, others give mainly polyethylene.DFT study associated with an experimental study of redox properties on catalytic precursors or the hemilabile behavior of ligands involved, led us to propose a mechanism identifying the activation phase as the key to switch between polymerization or selective trimerization of ethylene.