Page 21 - PR 2014 2016 03 Applications of Ionizing Radiations

Applications of Ionizing Radiations | Progress Report 63

was analyzed using high performance liquid characteristics as high impact and high ten-
chromatography (HPLC) in order to investigate sile stress were increased by irradiation pro-
chemical phase diffusion of bisphenol A (BPA). cess with absorbed doses between 50 kGy
EPR results showed strong singlet attributed to and 100 kGy from gamma and electron beam
phenoxyl radical, which decays within 40 days. sources.
UV spectra presented increase in relative absor-
bance at 400-450nm with increasing radiation
absorbed dose. Ionizing radiation caused green-
ness of original clear PC samples. On the other
hand, glass transition temperature decreased
1% (5K) for maximum applied radiation dose.
Similarly, small decrease on carboxyl group
-1
peak at 1770 cm was observed by FTIR. No de-
tectable change on crystallinity was observed
by WAXD. HPLC with fluorescence detector
can be employed to analyze chemical phase Figure 31. Injected HDPE samples: 1) virgin; 2) Recycled (20 times by
extrusion); 3) , 4), 5) and 6) composites with EPDM rubber in distinct
diffusion of BPA in saline solution at ppb con- concentrations respectively 1% and 5 % nonthermal treated, 5 %
thermal treated (composites with virgin and 20 x recycled HDPE).
centration. For sterilization absorbed dose, no
significant changes on studied properties was
observed, that way it can be recommended to Ionizing Irradiation Applied to
use PC instead of borosilicate glass column in Modification of Polymer Substrate
99 Mo/ 99m Tc generator. from Biological Molecules

Olefinic polymers were modified by irradia-
tion process. Biological molecules as chitosan
were incorporated to the original polymeric
matrix and gave specific characteristics such
as antibacterial activity, capture of metal ions
and bio-material suitability for medical appli-
cations. The new polymeric material was also
developed with irradiation processes where
natural chitosan (from Brazilian coast alien
species Charybdis helleeri crabs) was used to
modify the base polymer.
Figure 30. Mo/ 99m Tc generator columns: a) borosilicate
99
type 1 glass; b) polycarbonate PC.

Recycling Polymers by
Irradiation Process Figure 32. Chitosan
from Charybdis
helleeri crabs.
High density polyethylene (HDPE) and eth-
ylene-propylene-diene monomer rubber
(EPDMR) were recycled to obtain blends and
composites for several applications. Some