STİREN-ALKİLMETAKRİLAT KOPOLİMERLERİNİN FİZİKSEL VE TERMODİNAMİK ÖZELLİKLERİNİN İNCELENMESİ

Abstract

Doktora Tezi STİREN-ALKİLMETAKRİLAT KOPOLİMERLERİNİN FİZİKSEL VE TERMODİNAMİK ÖZELLİKLERİNİN İNCELENMESİ Aslışah ACIKSES Fırat Üniversitesi Fen Bilimleri Enstitüsü Kimya Anabilim Dalı 1 996, Sayfa: 1 02 Bu çalışmada 5 farklı zamanda, radikalik yolla, 6û°C'de başlatıcı olarak Benzoiî Peroksit kullanılarak Stiren-Alkilmetakrilat kopolimerleri sentezlerdi. Elde edilen kopolımerlerın İR, i H-NMR ve ' 3C-NMR spektrumlan alınarak yapı tayini yapıldı. Elde edilen polimerlerin % verimleri, limit viskozite katsayısı ve kn Huggins sabitleri bulundu. Homo ve kopolımerlerın yoğunlukları tıtrasyon, şişme yöntemiyle çözünürlük parametreleri bulundu. KopoîirnerinTGA ile termal özellikleri ve bozunmaya ait Ea (aktivasyon enerjileri) belirlendi. DSC ile Homo ve kopolimerlerin camsı geçiş sıcaklıkları, 6PC ile molekUl alırlıktan belirlendi. Ayrıca ınversgaz kromatografisi tekniği kullanılarak (çözücü olmayan prob-polimer) sistemleri ni n bazı tizi ksel ve ter modi nami k özelli kleri i ncelendi. Bu amaçla Chromosorb W üzerine kaplanan kopolimerler, bakır kolon içine doldurularak değişik sıcaklıklarda problar enjekte edildi ve spesifik alıkonma hacimleri tayin cuildi. (1/T;lnVg) grafiklerinden camsı geçiş sıcaklıkları tayin edildi. Poîı (ST-ko-MMA), Poli (ST-ko-EliA) ve Poli (ST-ko-BMA) polimerleri için camsı geçiş sıcaklıkları sırasıyla 97, 78 ve 69°C olarak bulundu. Camsı geçiş sıcaklıkları altındaki sıcaklıklarda kopolimerler üzerinde probların absorpsıyon ısılarının hidrokarbonlarda n-hekzan < n-heptan < n-oktan < n-dekan, alkollerde metil alkolIV SUMMARY PhD Thesis IMYESTSGATIOH OF THERMODINAMIC AND PHYSICAL PROPERTIES OF STYREHE ALKYLMETHACRYLATE COPOLYMERS Aslisah ACIKSES Fırat University Graduate School of Natural and Applied Seiencies Department of Chemistry 1996, Page: 102 In this vork, styrene-alkylmethacrylate copolymers vere synthesised using benzoyl peroxide üs initiator at 6Q°C by the fr&Q radical polymerization at five different durations. The structures cf copolymers vere determined by IR, ^H-NMR, l^c-fJMR tecniques. % yields, limiting viscosity coefficients and k\\ Huggins constants of polymers were obtained. Also the densities and solubility parameters of homo and copolymers were found. The thermal properties and activation energies (Ea) of copolymers were determined by TGA. The glass transition temperatures and molecular weights of homo and copolymers were determined by DSC and GPC respectively. Also some physical and thermodiynamic properties of (polymer- probe) systems were investigated by using inverse gas chromatography (IGC) technique. In this purpose, copolymers vere coated on to the chromosorb W, which were packed within copper column, and then the probes vers injected at different temperatures and the specific retention volumes were determined.v. The yl*53 transition temper «ttüre3 vere determined by the plot of In v^ againts 1 /T. The glass transition temperatures of Poly (ST-ko-MMA), Poly (ST-ko-EMA) and Poly (ST-ko- BfiA) were found as 97, 78 and 69°C, respectively. The heats of the adsorption of probes on the copolymers at the temperatures below the glass transition temperature were found to be increasing for hydrocarbons (n-hexane < n- heptane < n-octane) for alcohols (methyl alcohol < ethyl alcohol < propyl alcohol < buthyl alcohol < pentiji alcohol), for amins (ethyl amine < propyl amine < buthyl amine). The heats of adsorhtion ot alcohols were observed higher than those of hydrocarbons and amines. i'ne values of the molar heats itlf, the free entalpies &6f and the entropies ASf for the sorption vers rtetermi tied for every probe over the glass transition temperature. Furthermore, weignt traction activity coefficients (&1 / wj)~ Flory-Huggins interactions parameters X, partial moiar heats aH^ and partial rnolar free energies aGj of probes were calculated for the infinite dilute solutions. These values were in good aggreement with the date found in (polymer- nonsoivent) systems. The solubity parameters §2 of copolymers were determined by means of values of th« Flory Huggins interactions parameters. It was observed that the solubility parameters of polymers wa3 decreased with increasing temperature. Keg Word : Inverse Gas Chromatography, Weight Fraction Activeity Coefficients, Flory- Huggin3 Interactions Parameters, Solubity Parameters, Partial Molar Free Energies, Partial Molar Heats, Glass Transition Temperatures, Limit Viscosity Coefficient.