Naslov
Orientation of the Amorphous Chains in Natural Rubber-Cloisite Nanocomposites

Autori
Didović, Mirna ; Judeinstein, Patrick ; Albouy, Pierre-Antoine ; Meera, A.P. ; Thomas, Sabu ; Valić, Srećko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
18th European Symposium on Polymer Spectroscopy - Book of Abstracts / Volovšek, Vesna ; Bistričić, Lahorioja ; Movre Šapić, Iva - Zadar, 2010, 50-50

ISBN
978-9536470-52-5

Skup
18th European Symposium on Polymer Spectroscopy

Mjesto i datum
Zadar, Hrvatska, 19.10.2010. - 22.10.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Nanocomposites; Orientation; Natural Rubber; Clay

Sažetak
Orientation of the amorphous chains in natural rubber (NR) filled with organically modified montmorillonite (Cloisite 15A) during uniaxial stretching was followed by quadrupolar NMR and compared to carbon black-filled natural rubber composites. Samples of pristine NR and nanocomposites containing 1, 3 and 5 phr of the clay Cloisite 15A were swollen with small amount of deuterated dodecane. Quadrupolar NMR gives spectra consisting of two dublets, the splitting (Δν) of which is proportional to the average of the chain orientation (in the fast motion regime) and permits determination of the local extensibility of the chains. A change of orientation of the clay during stretching was determined using small angle X-ray scattering. Wide angle X-ray scattering was used to determine critical draw ratios for the onset of crystallization (λA) and melting (λE). Similar to case of the carbon black-filled natural rubber, results show that the splitting varies linearly with the elasticity term λ2-λ-1 up to the onset of crystallization, i.e. for λ < λA, which is shifted towards lower values for filled NR. Different linear regime with a lower value of the slope is observed for λ > λA, meaning that the effect of stretching is less efficient on the orientation of the amorphous chains when stress induced crystallization (SIC) occurs ; that is in agreement with the Flory prediction that the remaining amorphous chains relax partially during SIC. It is well known that in carbon black-filled natural rubber the slope dΔν/d(λ2-λ-1) for the low deformation domain increases linearly with the content of carbon black, while our measurements indicate a different trend when clay is used as a filler (up to 5 phr). These results point towards conclusion that clay influences the orientation and strain amplification of the amorphous chains in a manner different from carbon black, implying an alternative mechanism of reinforcement.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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