Bøger af Mohammed Assouag

The first part of this work describes the ozonization of low- and high-density polyethylene (LDPE and HDPE) using an ozone/air stream to create peroxide and hydroperoxide groups. These reactive groups were used to initiate the free-radical copolymerization reaction.The peroxide and hydroperoxide functions formed during ozonization were assayed by diphenyl picryl hydrazyl (DPPH).The other part of the work deals with the synthesis of graft copolymers by copolymerization of different monomers such as acrylic acid (AA), acrylonitrile (AN), chloromethylstyrene (CMS), 4-vinyl pyridine (4VP), acrylic acid-co-vinyl phosphonic acid (AA-co-AVP), acrylonitrile-co-vinyl phosphonic acid (AN-co-AVP) on ozonation-activated low-density polyethylene.The grafting reaction was carried out in bulk and in solution. The ozonized polyethylenes and corresponding graft copolymers were characterized by FTIR infrared spectroscopy and elemental analysis.

Organic chemistry is the branch of chemistry that studies organic compounds, i.e. carbon compounds (with the exception of a few simple compounds that traditionally come under inorganic chemistry). These compounds may be natural or synthetic.One characteristic of carbon is the ability of its atoms to link to each other, by covalent bonds, in an almost indefinite way, to form a wide variety of carbon chains. Organic compounds are thus made up of molecules characterized by carbon chains specific to "organic" molecules.The characteristic aptitude of carbon means that "a few other elements are all that's needed to form millions of different molecules with it, with molecular masses of up to 100,000 or even 1,000,000, known as macromolecules".Organic molecules frequently contain hydrogen atoms and often oxygen or nitrogen atoms, and synthetic molecules are often derived from petroleum.

I materiali ci accompagnano dall'inizio della nostra esistenza sulla Terra. Sono solidi che siamo stati in grado di utilizzare non solo per costruire le nostre case, i nostri vestiti, i nostri mezzi di trasporto (automobili, aerei, barche, veicoli spaziali), le nostre comunicazioni e le nostre informazioni, ma anche per costruire le nostre attrezzature industriali e sviluppare il nostro ambiente (strutture pubbliche, strade, ponti, sviluppo urbano). La padronanza di nuovi materiali ha portato a vere e proprie rivoluzioni nella storia della tecnologia. Le grandi epoche della preistoria sono definite dai materiali che si padroneggiano: l'età della pietra, l'età del bronzo e l'età del ferro. Oggi il numero di materiali, o almeno il numero di riferimenti, è considerevole e in costante aumento. La scienza dei materiali ci permette di progettare nuovi materiali adatti a ogni nuova applicazione tecnologica. La progettazione di un nuovo oggetto tecnico può comportare la selezione di un materiale da una banca dati esistente, oppure la progettazione di un nuovo materiale che sia il più adatto all'applicazione prevista e al suo processo di fabbricazione.

Materials have been with man since the beginning of his existence on Earth. They are solids that we have been able to use not only to make our homes, clothes, means of transport (cars, planes, boats, spacecraft), communication and information, but also to build our industrial equipment and develop our environment (public facilities, roads, bridges, urban planning). The mastery of new materials has led to real revolutions in the history of technology. The great periods of prehistory are defined by the materials mastered: Stone Age, Bronze Age, Iron Age. Today, the number of materials, or at least the number of references, is considerable and constantly increasing. Materials science enables us to design new materials adapted to each new technological application. The design of a new technical object may involve selecting a material from an existing base, or designing a new material best suited to the intended application, and its manufacturing process.

Materialien haben den Menschen seit Beginn seiner Existenz auf der Erde begleitet. Sie sind Feststoffe, die er nicht nur zur Herstellung seiner Häuser, seiner Kleidung, seiner Transportmittel (Autos, Flugzeuge, Schiffe, Raumfahrzeuge), seiner Kommunikations- und Informationsmittel, sondern auch zum Bau seiner Industrieanlagen und zur Gestaltung seiner Umwelt (öffentliche Einrichtungen, Straßen, Brücken, Stadtplanung) zu nutzen wusste. Die Beherrschung neuer Materialien hat zu regelrechten Revolutionen in der Geschichte der Technik geführt. Die großen Perioden der Vorgeschichte werden übrigens durch die beherrschten Materialien definiert: Steinzeit, Bronzezeit, Eisenzeit. Heute ist die Anzahl der Materialien oder zumindest die Anzahl der Referenzen beträchtlich und nimmt ständig zu. Die Materialwissenschaft ermöglicht es, neue Materialien zu entwerfen, die für jede neue technische Anwendung geeignet sind. Die Entwicklung eines neuen technischen Gegenstands kann durch die Auswahl eines Materials aus einer bestehenden Datenbank erfolgen, aber auch durch die Entwicklung eines neuen Materials, das für die angestrebte Anwendung am besten geeignet ist, und seines Herstellungsverfahrens.

Os materiais estão connosco desde o início da nossa existência na Terra. São sólidos que pudemos utilizar não só para fazer as nossas casas, roupas, meios de transporte (carros, aviões, barcos, naves espaciais), comunicações e informação, mas também para construir o nosso equipamento industrial e desenvolver o nosso ambiente (instalações públicas, estradas, pontes, desenvolvimento urbano). O domínio de novos materiais conduziu a verdadeiras revoluções na história da tecnologia. Os grandes períodos da pré-história são definidos pelos materiais dominados: a Idade da Pedra, a Idade do Bronze e a Idade do Ferro. Atualmente, o número de materiais, ou pelo menos o número de referências, é considerável e não pára de aumentar. A ciência dos materiais permite-nos conceber novos materiais adaptados a cada nova aplicação tecnológica. A conceção de um novo objeto técnico pode implicar a seleção de um material a partir de uma base de dados existente ou a conceção de um novo material que melhor se adapte à aplicação pretendida e ao seu processo de fabrico.

Materialy byli s nami s samogo nachala nashego suschestwowaniq na Zemle. Jeto twerdye tela, kotorye my ispol'zuem ne tol'ko dlq sozdaniq nashih domow, odezhdy, sredstw peredwizheniq (awtomobilej, samoletow, lodok, kosmicheskih korablej), swqzi i informacii, no i dlq sozdaniq promyshlennogo oborudowaniq i obustrojstwa okruzhaüschej sredy (obschestwennyh ob#ektow, dorog, mostow, gorodskoj zastrojki). Oswoenie nowyh materialow priwelo k nastoqschim rewolüciqm w istorii tehniki. Velikie periody doistoricheskogo perioda opredelqütsq oswoennymi materialami: kamennyj wek, bronzowyj wek i zheleznyj wek. Segodnq kolichestwo materialow, ili, po krajnej mere, kolichestwo ssylok, znachitel'no i postoqnno rastet. Materialowedenie pozwolqet razrabatywat' nowye materialy, adaptirowannye k kazhdomu nowomu tehnologicheskomu primeneniü. Proektirowanie nowogo tehnicheskogo ob#ekta mozhet wklüchat' wybor materiala iz suschestwuüschej bazy dannyh ili razrabotku nowogo materiala, kotoryj nailuchshim obrazom podhodit dlq predpolagaemogo primeneniq i processa ego izgotowleniq.