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1,2-polibütadiene fosfit grupları ve türevlerinin UV ışık ile modifikasyonu

Phosphite and their derivative modification of 1,2- polybutadiene with UV light

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  1. Tez No: 665727
  2. Yazar: MERVE CINDIK
  3. Danışmanlar: PROF. DR. ÜMİT TUNCA
  4. Tez Türü: Yüksek Lisans
  5. Konular: Kimya, Chemistry
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 2021
  8. Dil: Türkçe
  9. Üniversite: İstanbul Teknik Üniversitesi
  10. Enstitü: Lisansüstü Eğitim Enstitüsü
  11. Ana Bilim Dalı: Kimya Ana Bilim Dalı
  12. Bilim Dalı: Kimya Bilim Dalı
  13. Sayfa Sayısı: 77

Özet

Polibütadien ilk olarak 20. yüzyılın başında bütadienin sodyum katalizli polimerizasyonu ile hazırlanmıştır. Bununla birlikte, bu yöntemlerle ve daha sonra serbest radikal emülsiyon polimerizasyon teknikleri ile üretilen polimerler, istenilen onları kauçuk yapan özelliklere sahip değildi. Polibütadienler, yüksek cis içeriği yüzde 95 ila yüzde 97 veya sadece yüzde 35 cis içeriği ile birlikte yüzde 55 trans ve yüzde 10“yan vinil”içerirler. Bu iki polimerin özellikleri oldukça farklıdır. Çoğu sentetik fonksiyonel polimer, olefinik polimer türevlerinin fonksiyonel monomerlerin serbest radikalik veya iyonik polimerizasyonuyla sınırlıdır veya olefinik polimerlerin hazırlandıktan sonra fonksiyonel grupların polimer zincirlerine eklenmesiyle meydana gelirler. Olefinik yapılar, sahip olduğu C=C çift bağları sebebiyle katılma tepkimeleri için ideal oganik bileşiklerdir. Yeni polimerik malzemelerin sentezinde olefinik yapılardan yola çıkılarak meydana getirilebilir. Birçoğu dialkil H-fosfonatların türevleri olan organofosfor bileşikleri, şu anda kullanılmakta olan en büyük pestisit sınıflarından birini temsil etmektedir. Esas olarak böcek öldürücüler, fungisitler, herbisitler, bakterisitler olarak ve ayrıca bitki büyüme düzenleyicileri olarak endüstride kullanılırlar. H-fosfonatlar ve bunların türevleri tarım, sanayi, ilaç vb. gibi farklı pratik alanlarda çok sayıda uygulamaya sahiptir. Bu sebeplerle büyük ölçüde, çeşitli substratlar için fosforilasyon ajanları olarak kullanılmalarına yol açan bu çok yönlülük bileşiğin yapısından kaynaklanmaktadır. Radikalik olarak meydana getirilen sentezler hem endüstride hem de laboratuvar ölçeğine rahatça uygulanabilir olduğundan tercih edilir. Radikalik polimerizasyonla birkaç adımda yapıya istenilen fonksiyonel grup bağlanabilir. Çoğu sentetik fonksiyonel polimer, fonksiyonel monomerlerle serbest radikal veya iyonik polimerizasyon yöntemleri kullanılarak üretilen olefinik polimerlerlerle sınırlıdır. UV-ışığın absorbsiyonu ile kimyasal reaksiyonlar kısa sürede büyük enerji engellerini aşarak meydana gelirler. Termal olarak meydana gelmesi zahmetli olan reaksiyonların daha kolay ve verimli gerçekleşmesi fotokimyasal yolun daha çok tercih edilmesine sebep olur. Foto-katılma reaksiyonlarında, UV ışığı ile moleküle fonksiyonel grup katılır. Bu tezde UV ışığı altında 1,2-Polibütadien yapısının fosforilizasyonuna odaklanıldı. İlgimiz UV ışık yardımıyla polimerin fonksiyonel grup kazanmasını sağlamak. Endüstriyel ve akademik alanda yeni malzemelerin sentezlenmesi amaçlanmıştır. Bu çalışmada H-Fosfonat ve türevleri, 1,2-Polibütadien yapısına fonksiyonlandırıldı. Tüm karakterizasyon işlemleri GPC ve 1H NMR kullanılarak yapıldı.

Özet (Çeviri)

Polybutadiene is a synthetic rubber. Russian chemist Sergei Vasilyevich Lebedev was the first to polymerise butadiene in 1910. In 1926 he invented a process for producing from ethanol and 1928 he developed a method for producing polybutadiene using sodium as a catalyst. 1,3-Butadiene, CH2=CH¬¬-CH=CH2 is a simple diene structure. Because of the rich chemistry assoiated with conjugated diene strucruture, the reactivity butadiene has been investigated. As a result at this the hundreds of polymers defined in the literature represent by butadiene. Butadiene polymerizes by addition. Double bonds allows to be formed with many types of polymers. One of these, known as the vinyl or 1,2 type. Actually tthree vinyl structures possible depending on theposition of bonds; isotactic polybutadiene, syndiotactic polybutadiene and atactic polybutadiene. Several methods an be followed to carry out the polymerization. Due to the reactants of the radical species, the formation of polymerization products with high branching takes place by free radical polymerization method. Ziegler-Natta polymerization, since the polymer moleules obtainedby this technique contain a stereospeific order, this method is called stereospeifi polymerization. Coordination catalysts that lead to stereospecific or Ziegler-Natta catalysts. Coordination catalysts achieve stereospeific settlement. Lastly, anionic polymerization based on alkali metal alkyl initiating systems can also afford a wide range of macrostructural possibilities for polybutadiene products. Most functional polymers are synthesized by ionic or free radical polymerization of functional polymers or by adding functional groups to the chains of olefinic polymers. However, there is not much work on the synthesis of condensation polymers. The reason of this because the polymerization of monomers with functional groups by thermal methods is difficult and problems such as dissolution in solvent are encountered. One main approach to develop high performance plastics is based on polymer blending. The properties of different polymers are combined to result in a new material with enhanced mechanical properties1,2-PB can be performed at low or ambient temperature employing UV light or sunlight for a generation of thiyl radicals (in the absence of photoinitiator) and minimal amounts of solvent. A recent achievement in synthetic chemistry is the preparation of large, well-defined polymeric systems which carry tailored functional groups and have been shown to be critical for a range of potential applications in microelectronics and biomedical systems. Reent research in synthetic chemistry is allowed well-defined, functional materials to become ubiquitous in both academic and industrial settings. H-phosphonate and its derivatives are groups of compounds that have applications in many industrial areas such as agriculture, industry and medicine. They are used in various fields because they are used as phosphorylation agents with various substrates. Organophosphorus compounds are one of the pesticide classes, most of which are dialkyl H-phosphonates and their derivatives. They are applied in fields such as insecticide, fungicide, herbicides, bactericides and plant growth regulators.The properties of polymers are hardly affected by the incorporation of phosphorus. Diesters of H-phosphonic acid and their immediate derivatives have found a number of applications in polymer synthesis such as flame retardants, antioxidants, heat and light stabilizers, catalysts, degrading agents, and alkylating agents. They are also used as corrosion inhibitors, scale inhibitors, and lubricants (antiwear and load-carrying additives). Synthetic methods for synthesizing C-phosphonates and related compounds are of great importance in contemporary bioorganic phosphorus chemistry, as phosphorus compounds containing P-C bonds have important uses in the medical, biological and industrial fields. In this respect, H-phosphonate diesters, with their ability to act as nucleophiles, electrophiles, and P-centered free radicals, provide a plethora of mechanistic ways in which the phosphorus–carbon bond can be formed; they are unrivalled phosphorus substrates. Currently, classical methods for the formation of the P-C bond (the Michaelis – Arbuzov, the Michaelis – Becker, the Pudovik, the Abramov, and the Kabachnik – Fields reactions) and organocatalysis or transition metal catalyzed cross couplings are preferable methods. The development of new synthetic methods for synthesizing phosphorus-containing oligomers is of great importance for phosphorus chemistry, because these oligomers are used to add functional groups to polymers. It is of great importance for the synthesis and development of new polymers. Functional polymers are macromolecules that have unique properties or uses. The chemical properties of polymers with functional groups are determined by the functional group, which is largely bound to the main chain.The ability of functional polymers to form self-assemblies or supramolecular structures is a further incentive. When the formation or dissociation of the self-assemblies is triggered by chemical or physical stimuli so called“smart”materials can result. One of the most important types of addition polymerization is polymerization initiated by electrically neutral free radicals containing unpaired electrons. In this type of polymerization, unsaturated monomers give the typical chain reaction. Due to the relatively low stability of the carbon-carbon double bond, it can react particularly easily with free radicals. Chain growth reactions of unsaturated molecules are initiated by radicals or ions. It acts on an initiator monomer unit, forming an actively centered intermediate compound that can be linked with another monomer; By adding a new monomer to this intermediate compound, a larger active center compound is formed and so on, the chain grows rapidly. The free radical in the growing chain can pass to a monomer molecule, a chain transferer, or a polymer molecule. Desired controls of molecular weight can be achieved by using transfer agents in a polymerization. Growing free-radical chains may end up association or disproportionately. Controlled / living radical polymerization (CRP) was performed by Michael Szwarc and the discovery enabled the production of designable molecular structures and nanostructured morphologies, and this discovery had a huge positive impact on polymer science. In this method, the block length distribution in the copolymers obtained due to the high initiation speed and the relatively slow chain elongation (propagation) is controllable. The basic logic of these methods; The balance established between the growing chains and the passive species causes the polymerization rate to decrease and therefore the life of the growing chains increases from milliseconds to minutes or hours. Thus, it is possible to produce polymers with adjustable molecular weight and polydispersity without being affected by chain transfer processes. In photoaddition reactions, the Woodward-Hoffmann rule of conservation of orbital symmetry applies. This rule explains that when reactants are converted into products, their arbital symmetries will not change. In other words, during the adiabatic transformation of the molecular orbitals ofreactants to the molecular orbitals of products, no change in symmetry occurs. Based on this rule,photochemical reactions differ from reactions which are thermally induced. In thermally induced reactions, the contrarotatory mode is more energetically favored. But in photochemical reactions thedisrotatory mode is more favored. In most cases, this rule has been confirmed by experiment.Some of the most common photoaddition reactions involve acondensation mechanism that forms cyclic compounds, hydroperoxides, dioxetanes, and the addition of aldehydes and ketones. When a molecule absorbs UV light, it enters an excited state. The molecule in the siglet state can lose energy with a photon or heat emission and becomes triplet state or directly into the ground state. In the triplet state, the molecule may have a diradical character that undergoes chemical processes such as photoaddition/substitution reactions including hydrogen and electron abstractions, cycloadditons, isomerizations, and fragmentation. Many molecules are considered to be acceptor and operate as the singlet and triplet excited state of donors. In photoaddition reactions, a molecule funtionalized with UV light. In this thesis, we have focused phosphorylation on the structure of 1,2-Polybutadiene under UV Light. Our interest in photoinitiation polymerization to polymer functionalization. We add H-Phosphonate and Their Derivatives of 1,2-Polybutadiene. All characterization processes are made by using GPC and 1H NMR.

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