1,721,139 research outputs found
Polimerlerin piroliz kütle spektrometresi kullanılarak yapısal ve ısıl karakterizasyonu
No full textIn the first part of this study, the structtural and thermal characterization of electrochemically and chemically polymerized poly(paraphenylene vinylene), (PPV), have been investigated by direct pyrolysis mass spectrometry. Thermal characteristics, and degradation products of electrochemically prepared poly(paraphenylene vinylene). Pyrolysis study indicated that thermal decomposition of PPV occurs at least two steps. The first being due to the loss of supporting electrolyte present and the second being decomposition of the polymer backbone.In the second part of the study, direct insertion probe pyrolysis mass spectrometry (DIP-MS) technique was used to perform the thermal and the structural characterization of electrochemically synthesized polyaniline,PANI. The effect of dopant used (HCL, HNO3 and H2SO4) and synthesis period have been investigated. For all the samples studied, three main thermall degradation stages have been recorded; evolution of low molecular weight species, evolution of dopant based products and evolution of degradation products of polymer.M.S. - Master of Scienc
Naftoksazinlerin ve polinaftoksazinlerin ısıl özelliklerinin direkt piroliz kütle spektrometresi ile incelenmesi.
No full textIn this study, polymerization mechanisms of aromatic (C6H5 or C6F5) and alkyl (CH3, C2H5, C3H7, C6H13, C12H25 or C18H37) amine based naphthoxazine monomers (15-Na, 15Na-C1, 15Na-C2, 15Na-C3, 15Na-C6, 15Na-C12 and 15Na-C18) and thermal degradation mechanisms of polynaphthoxazines synthesized by curing the naphthoxazine monomers (P-15-Na, P-15NaF, P-15Na-C1, P-15Na-C2, P-15Na-C3, P-15Na-C6, P-15Na-C12 and P-15Na-C18) were studied by direct pyrolysis mass spectrometry. During the curing process, the evolutions of monomer and low mass aromatic or alkyl amines were detected below the curing temperature. The mass spectrometry findings indicated that the monomers were subjected to evaporation and degradation to a certain extent but also to polymerization during the curing process. It has been determined that the polymerization of aromatic amine based naphthoxazine monomer proceeded through the aniline units, either by coupling of the radicals produced by the ring opening of the side chains or by substitution to the benzene ring of aniline. However, even if no direct evidence to confirm polymerization by attack of –NCH2 groups to naphthalene ring was detected, it is not possible totally eliminate its existence. The evolution of aniline, the main thermal degradation product for this polymer was observed at relatively low temperatures indicating that thermal decomposition started by elimination of aromatic amine involving linkages. Coupling of –CH2 groups generated by loss of aniline, yielded naphthoxazines with unsaturated linkages that can recombine and form a crosslinked structure with higher thermal stability. Similarly, the polymerization of naphthoxazines based on alkyl amines followed opposing paths. The mass spectral data indicated that the coupling of alkyl amine radicals was the main polymerization pathway. Again, thermal decomposition of alkyl amine based naphthoxazines was started by loss of alkyl amines and diamines. The crosslinked structures produced by coupling of the radicals generated by lose of alkyl amines decomposed at relatively high temperatures.M.S. - Master of Scienc
Polikaprolakton Kompozitlerinin Hazırlanması ve Karakterizasyonu
Full text linkTÜBİTAK KBAG Proje15.01.2018Bu çalışmada organik düzenleyici kullanılarak modifiye edilmiş Kloisit 30B, C30B, ve Kloisit15A, C15A içeren polikaprolakton, PCL, nanokompozitleri, çeşitli miktarlarda benzendiboronik asit, BDBA, çinko borat, ZnB, ve borik asit, H3BO3 içeren polikaprolaktonkompozitleri ve hem nanokil hem de bor bileşikleri içeren PCL nanokompozitleri hem çözeltide hem de eriyikte harmanlama yöntemleri ile hazırlanmış ve örneklerin morfolojik ısıl vemekanik özellikleri saptanmıştır.In this project, nanocomposites of polycaprolactone, PCL involving organically modifiedCloisite 30B, C30B and Cloisite 15A, C15A and polycaprolactone nanocomposites involvingvarious amounts benzene diboronic acid, BDBA, zinc borate ZnB, and boric acid H 3 BO 3 andcomposites involving both nanoclays and boron compounds were prepared by solutioncasting and by melt blending techniques. Furthermore, fibers of PCL involving C30B, BDBAand both were prepared. Morphologic, therrmal and mechanical properties of these sampleswere determined. It has been determined that clay layers were separated more efficientlyand more homogenous nanocomposites were obtained when solution casting was used.The trans-esterication reactions between OH groups present in the organic modifier of C30Band BDBA and PCL caused decrease in thermal stability of PCL. Addtion of zinc borate didnot affect thermal stability noticeably. On the other hand, addition of H 3 BO 3 decreasedthermal stability. Mechanical characteristics were almost independent of the additives.Contrary to the results obtained for C30B involving composites, when C15A was used asorganically modified nanoclay no evidence for decrease in thermal stability was detected.The effect of boron compounds was similar to what was observed for nanocompositesinvolving C30B. Again decrease in thermal stability upon addition of BDBA and H 3 BO 3 wasdetected.It has been determined by TGA and DPMS analyses that the thermal properties of fibersinvolving both C30B and BDBA were not significantly affected by the presence of additives.The resuts obtained in this project indicated that the most effective way to increase thermalstability of PCL are the use of C15A and ZnB as additives
Investigation of pyrrole end capped polytetrahydrofuran graft copolymers via mass spectrometry
No full text
- …
