| Sažetak | Polimeri su makromolekule koji danas „grade“ većinu predmeta s kojima se čovjek susreće. Polimeri se koriste najviše za izradu ambalaže, u graditeljstvu, u automobilskoj industriji, za izradu elektronskih uređaja, igračka, namještaja, odjeće, obuće, u medicini ali i poljoprivredi i kućanstvu. Cilj ovog istraživanja bio je ispitati utjecaj alumosilikata (zeolita) kao punila na dinamiku lanaca polimera poli(dimetil-siloksana). Za ispitivanje su se koristile metode elektronske spinske rezonancije (ESR) i razlikovne pretražne kalorimetrije (DSC). Kao proba za ispitivanje elektronskom spinskom rezonancijom korišten je nitroksilni radikal 4-okso-2,2,6,6-tetrametilpiperidin-1-oksil (TEMPONE). Rezultati ispitivanja pokazuju da je pri niskim temperaturama ispod staklišta (Tg) dinamika lanaca spora što se vidi po širokim linijama spektra. Blizu staklišta pojavljuju se složeni, tzv. bimodalni spektri dok se povišenjem temperature pojavljuju uske linije karakteristične za brzo gibanje lanaca. Oblik i koncentracija zeolita također utječu na dinamiku lanaca polimera. Veće koncentracije zeolita i kubični oblik zeolita više usporavaju dinamiku lanaca od manjih koncentracija i bipiramidnog i okruglog oblika zeolita. Isto tako, istraživanjem je pokazano da je elektronska spinska rezonancija osjetljivija metoda za ispitivanje lokalne dinamike lanaca od razlikovne pretražne kalorimetrije. |
| Sažetak (engleski) | Polymers are macromolecules that today "build" most of the objects that man encounters. Polymers are mostly used for the production of packaging, in construction, in the car industry, for the manufacture of electronic devices, toys, furniture, clothing, footwear, in medicine, but also in agriculture and household. The aim of this study was to examine the influence of aluminosilicates, zeolites, as fillers on the dynamics of poly(dimethyl-siloxane) polymer chains. Investigations were performed using electron spin resonance (ESR) and differential scanning calorimetry (DSC). The nitroxide radical 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPONE) was used as a probe for electron spin resonance. Results of this study show that at low temperatures, below the glass transition temperature (Tg), the dynamics of the chains is slow, as indicated by the presence of the broad lines in ESR spectra. In the vicinity of the glass transition temperature, composite, so-called bimodal spectra appear, while increasing the temperature narrow lines appear, characteristic of fast chain motions. The shape and concentration of the zeolite also affect the dynamics of polymer chains. Higher concentrations of zeolite and the cubic shape of zeolite slow down the chain dynamics more than lower concentrations of both, bipyramidal and round forms of zeolite. Likewise, research has shown that electron spin resonance is a more sensitive method for examining local chain dynamics than differential scanning calorimetry. |
