engleski

Response of some poly(ethylene‐terephtalate) based nanocomposites to various radiation types

The radiation response of polymers and (nano)composites depends on polymer matrix structure and radiation type. The overall outcome can be cross-linking and/or degradation [1]. The addition of (nano)fillers is expected to increase radiation stability of polymers [2]. Poly(ethylene-terephthalate), PET is widely used thermoplastic polymer with excellent engineering properties. Unlike its photostability the stability of PET to gamma- radiation is relatively high. The aim of this work was to assess how the addition of selected nanofillers influenced stability of PET to those types of radiation. Two PET nanocomposites based on 150 μm PET film, one containing 1% of nano-diamonds and the other containing combination of 1% of nano-diamonds and 0.5% graphene nanoplatelets [3] were studied in comparison to corresponding pure PET film and to another PET film, 12 μm thick, biaxially oriented to better distinguish structural changes if any. A part of the samples was gamma-irradiated in ambient conditions at 60Co γ-irradiation facility of Laboratory for Radiation Chemistry and Dosimetry, Ruđer Bošković Institute (RBI) in Zagreb, Croatia to doses of order of MGy. Other samples were exposed to UV irradiation of 254 nm also in ambient conditions. The samples were characterized by thermal analysis and FTIR spectroscopy. The addition of nanopartilces did not produce significant changes to non- irradiated PET except that graphene shifted its crystallization temperature to higher values. On the other hand nanoparticles influenced response of PET to both types of radiation and it varied depending on the nanocomposite composition. All samples were relatively stable to gamma-radiation below 1 MGy and retained their mechanical properties. At higher gamma- dose of 2 MGy only biaxially oriented 12 μm thick PET film remained unaffected while all 150 μm films became brittle and cracked easily. Graphene and nanodiamond containing nanocomposite was somewhat less resistant to gamma-radiation than the one with nano-diamonds only or pure PET that had similar stability. Nanodiamonds slightly increased stability of PET to photodegradation while additional graphene reduced stability below that of pure PET film.

PET nanocomposites ; gamma-irradiation ; UV-irradiation ; DSC ; FTIR

nije evidentirano