Naslov
ESR and NMR Study of Anisotropic Natural Rubber Material

Autori
Valić, Srećko

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

Izvornik
Proceedings of the International Conference on Polymer Processing / Yang, Weimin ; Thomas, Sabu ; Zhang Yuxia - Peking : Beijing University of Chemical Technology, 2007

Skup
International Conference on Polymer Processing (ICPP-2007)

Mjesto i datum
Peking, Kina, 18.05.2007. - 20.05.2007

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
ESR; spin probe; natural rubber; anisotropy; deuterium NMR

Sažetak
Natural rubber (NR) film with the thickness of about 1 mm was prepared by removing the liquid phase from NR latex. Two types of NR films crosslinked by γ -irradiation were investigated: (i) samples irradiated in the relaxed state and (ii) samples irradiated in the state of uniaxial deformation. The total irradiation dose was varied from 0 kGy (for nonirradiated NR) to 400 kGy and the degree of deformation, defined as λ =l/l0 (l0 and l being the lengths of relaxed and uniaxially deformed sample, respectively), was chosen to be λ =1.0 (relaxed state), λ =1.5 and λ =2.0. The amount of sol and gel phase was determined by extracting the sol component in toluene. A significant decrease in amount of the sol component was observed by increasing the irradiation dose. It has been shown that the application of deformation during the crosslinking leads to the lower crosslink density. Such an effect can be attributed to the loss of gel component induced mechanically. The ESR spectra of spin probe diffusing in NR matrix crosslinked under deformation are influenced by both, the local dynamics of the chain segments and their spacious orientation. Anisotropic segmental motions were monitored by deuterium NMR spectroscopy, using perdeuterated cyclohexane as deuterium probe. The results have shown that the crosslinking process performed under deformation makes the material anisotropic on the molecular level.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA