Polivinilpirolidan kopolimerlerinin fizikokimyasal özellikleri
Başlık çevirisi mevcut değil.
- Tez No: 46124
- Danışmanlar: PROF.DR. A. SEZAİ SARAÇ
- Tez Türü: Yüksek Lisans
- Konular: Kimya, Chemistry
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1995
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 33
Özet
ÖZET Fonksiyonel grup içeren polimerler fonksiyonel grubun yapısına bağlı olarak polimerlerin elektrolitik özelliklerinin araştırılmasına ve polimerlerin metallerle komp¬ leks oluşturmasının incelenmesine olanak sağlar. Metal iyonlarının sentetik polieleketrolitlerin fizyolojik aktifligine etki etmesi, polimer metal kompleksinin önemini arttırmıştır. Polimer metal kompleksleri ilaç aktif maddelerinde kullanılmaktadır. Bunlara ek olarak polimer metal kompleksleri, doğal polimerlerin yapılarının aydınlatılmasında ve spesifik etkinliğinin belirlenmesinde model olarak kullanılmaktadır. Polimerlerin metallerle kompleks oluşturma olayının incelenmesi yanında polimerlerin içerdiği fonksiyonel gruba bağlı olarak, elektrolitik iletkenliğinin araştırılması önemlidir. Bu çalışmada polimer metal komplekslerinin sentezi için molekül ağırlığı 40.000 olan polivinilpirolidon, molekül ağırlığı 240.000 olan poliakrilik asit ve molekül ağırlığı 80.000 olan poli(vinilpirolidon-akrilik asit) ko- polimeri ile Cu iyonu arasındaki pH=7'deki kompleks oluşu¬ mu incelenmiştir. Bakır ile 250 nm ve 300 nm'deki spektrofotometrik sonuçlar bakır ile poli(vinilpirolidon-akrilikasit) kopolimer arasındaki kompleks oluşumunu bakır-poliakrilik asit, bakır-polivinil pirolidon arasındaki kompleks oluşumunun daha yüksek olduğunu göstermiştir. Ayrıca çeşitli molekül ağırlığına sahip olan polivinilpirolidonun, molekül ağırlığı 240.000 olan poliakrilik asit ve molekül ağırlığı 80.000 olan poli(vinilpirolidon- akrilik asit) kopolimerinin sulu çözeltilerinin iletkenlikleri konsantrasyona bağlı olarak ölçülmüş ve molar iletkenlikleri hesaplanarak bu polimerlerin çözeltilerinin iletkenlik-konsantrasyonlarının arasındaki ilişkisinin Onsager ve Osuald seyrelme bağıntısına uyup uymadığı araştırılmıştır.
Özet (Çeviri)
PHYSICO CHEMICAL PROPERTIES OF POLYVINYLPYRROLIDONE, POLYACRYLICACID AND THEIR COPOLYMER SUMMARY The N-winylamide, are polymerized readily by free- radical initiators. The preferred free-radical catalysts are azobisiobutyronitrile and hydrogen peroxide. Peroxi des such as benzoly peroxide or lauroyl peroxide are not effecient catalysts for polymerization; they apparently take part with the monomer in a redox reaction that destrays catalyst of a faster rate thon that of polymeri zation. Since the vinylamides are hydrolyzed under acid conditions, polymerizations are best done at neutral or basic pH in water. NH, OH H2D2> 2H0“ H HO* + CH2 = CH> HO - CH2 - C. 0 Ü DT-) v H0-CH”- C. + nCH“ = CH» HO - CH”- C- 4CH--CH}.-CH^-CH* c Z 2 c. n-l c 0 It can be seen that N-winylpyrrolidone sould copoly- merize“well with many of the vinyl monomers. The proper ties of the copolymer vary with the monomer rations Increasing the N-vinypyrrolidone content increases the hydrophilic character and also the adhesiveness in the copolimers. Surface -active properties usually increase with increasing vinyl pyrrolidone content. VIThe homopolymer of N-vinyl-2-pyprolidone iş readily soluble in water and many organic solvents. Polyvinyl^.'- pyrrolidone is hygroscopic, the equilibrium mater content being equal to approximately one thind the relative humidity. P\JP powder is relatively stable when stored under ordinary conditions. Aqueous PUP when protected from molds is stable for extended periods. One of the most unusual properties of polyvinyl* '??. pyrrolidone is its great tendency to form complexes with many different substances. It forms such a tight complex with iodine that the iodine cannot be extracted with chloroform and there is no appreciable vapor pressure of iodine above the complex. The complex, however, retains the excellent germicidal properties of the iodine but with a greatly reduced toxicity and staining tendency. Insoluble complexes are formed on addition of polybasic acids such as poly (^acrylic acid), tannic acid, or the copolymer of methyl vinyl ether and maleic acid to polyvinylpyrrolidone in aqueous solution. Although these products are insoluble in water, alcohol, or acetone, the reaction can be reversed by neutralizing the polyacid with base. This phenomenon is thought to be a hydrogen bonding effect of the polyvinylpyrrolidone, much as is observed in proteins. In addition to iodine and polyacids, polyvinylpyrro lidone complexes with certain toxins, durgs, and toxic chemicals to reduce their toxicity. Many phenols such as resorcinol or pyrogallol precipitate polyvinylpyrroli done from aqueous solution, although they will redissolve upon the addition of more water. Some dyes also strongly complex with polyvinylpyrrolidone and are the basis of the use of polyvinylpyrrolidone as a dye-stripping agent. Polyvinylpyrrolidone is very soluble in water, bBing limited in a practical sense only by the viscosity of the resulting solutions at high concentration. There is no change in viscosity over the pH range of 1-10, although it increases in concentrated hydrochloric acid. Polyvinylpyrrolidone can be cast from a number of solvents such as methanol, water, or butyrolactone to give on drying clear, hard, and glossy films. Water acts as a plasticizer when not completely removed or if taken up by absorption from the air. Compatible resins such as Vllcarboxymethylcellulose, cellulose acetate, or shellac can be used to decrease the hygrascopicity. Polyvinyl-”pyrrolidone has been found to be compatible with many natural and synthetic resins as well as w5 th many inor ganic salts. The open-chain N-vinyl amide polymers are soluble in water and in some organic solvents, eg. alcohols and chlorohydrocarbons. Colorless hard films are obtained from such solutions. Polyvinylpyrrolidone forms molecular complexes with many other substances and by such action may be a detoxifying agent. Pharmacological action may be enhanced and duration prolonged for certain antibiotics, durgs, and anesthetics by complexing with polyvinylpyrrolidone. Polyacrylic Acid, Linear polymers of acrylic and methacrylic acids may be prepared by the general metods used with other vinyl monomers, ie nCH“ = CHCDOH initiator> - -CH,- CH-CH^-CH2 2, 2, CDOH CODH Polymerization in aqueous solution at concentrations of 25 % or less is convenient. Polymerization of more concentrated solutions or of undiluted monomer is not recommended because the high heat of polymerization makes polymerization difficult to control and produces insoluble polymer. The polymerization of undiluted monomer is hazardous. Polymerization in Aqueous solution. Aqueous solutions of acrylic and methacrylic acids can be polymerized in the presence of a peroxydisulf ate initiator at 90-1 00Dc. When acrylic acid is used the polymerizate remains homogeneous. Polymerization is also possible in range D-10 C with vxiia redox initiator, activated by a feu hundredths of a percent of ferric ion. The use of redox initiators, especially at low temperatures, requires efficient purging of solvent and apparatus with nitrogen or other inert gas to remove molecular oxygen, which inactivates the initiator. The polymers can be used as aqueous solutions or they can be dried to flaky white solids. It is advisable to allow at least 5 % moisture to remain in the dried polymer to facilitate re-solution. Preparations which dissolve instantaneously can be made by f reeze-drying. Tacticity, during polymerization, successive monomer units became incorporated in a polymer chain with confi gurations that are the same or opposite to the configura tions of the preceding monomer units. In:polymers made by free-radical polymerization, the distribution of these conf igurations-the tacticity-depends on the monomer, the temperature of polymerization, and the solvent. When polyacrylic acid and polymethacrylic acid are dried under conditions which are mild enough to prevent crosslinking these polymers are extremely soluble in water even when their molecular weights are one million of greater. However, if the polymers are rigorously dried, especially at elevated temperatures, their solubility is greatly reduced. In this work, for synthesis of polymer metal complexes (PMC), each polymer (polyvinylpyrrolidone which has 40.000 molecular weight, polyacrylic acid having 240.000 molecu lar weight, poly(vinylpyrrolidone-acyrilic acid) copolymer having B0. 000 molecular weight) was dissolved neutral water (pH=7) and CuSO,. 5H”0 was dissolved in water in acidic medium (pH=*4) and tnan the solution of CuSO,.5H20 was added polymer solution by magnetic stirring at 20DC.than pH of solution mixture was adjusted to about 7. Spectrophotometry properties at 250 nm. and 300 nm. were measured. From obtained results with increasing of Cu2 :?. concentrations which were adding to each polymer, the velocity of the complex formation increased linearly. However the velocity of complex formation between poly( vinilypyrrolidone-acrylic acid) and Cuz ion is higher that the velocity of complex formation between polyacrylic acid and Cuz:ion, between polyvinylpyrrolidone and Cuz ion. m IX2+ The relation between the increase of Cu concentra tion adding to polymer and absorbance values measured at 250 nm. and 300 nm. is shown as follows. (Table 1). 2+ Table 1. Slopes Obtained From Cu Concentration Absor bance Figures for different Polymers The conductivities of polymer solution depending on dilution were measuredat 20 C,. The cell constant of platinium electrode was 1 cm". Specific and molar conductivities were calculated by using following equations. X = KL A = 1000X L : Conductivity of polymer solution (ohm ) K : Cell constant (cro~ ) 1. X : Specific conductivity (ohm~ cm~ ) C : Molar concentration of polymer solution (mole/1) A : Molar conductivity (ohm cm' M ' ) The reaction between the dilution of polymer solution and their conductivities was investigated.
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