Research Information System
22nd International Balkan Workshop on Applied Physics and Materials Science, Constanta, Romania, 9 - 12 July 2024, vol.1, no.1, pp.86-87
Effects
of radiation on polymer materials can vary depending on many factors such as
the type of radiation, dosage, type of polymer material, and method of
application. In this study, to determine the effect of the radiation on the
polymer chain structure, the degradation characteristics of PLA (Polylactic
Acid) and ABS (Acrylonitrile Butadiene Styrene) polymers were measured after
radiation exposure. Since the treatment continues up to about 6 weeks in
radiotherapy, changes in thermo-mechanical, thermal, surface properties, and
crystal structure were investigated to examine the effect on the
characterization properties of these materials depending on the duration and
dose of radiation. Samples of materials with dimensions of 100x100x10 mm were
obtained with an injection machine and were categorized into 6 distinct groups.
The materials were placed between the
RW3 solid water phantom and the radiotherapy dose was applied to the entire
area of the materials with a Linear Accelerator (LINAC) at 6 MV energy. To evaluate
the impact of radiation dose, four groups underwent irradiation at
predetermined dose levels, while the fifth served as a control group, and the sixth
was designated for background (BG) analysis. Differential Scanning Calorimetry
(DSC) and dynamic mechanical analysis (DMA) analyses were used to determine the
thermal and thermo-mechanical properties of irradiated and non-irradiated materials.
In addition, contact angle measurement was performed to determine the
properties of the irradiated surfaces. While
the increasing amount of radiation did not affect the surface contact angle of
the ABS material, the contact angle of the PLA material was increased
significantly. There was no significant change in the melting enthalpy and
glass transition temperature of both materials. However, while the specific
heat of the ABS material decreased by 10% as the irradiation dose increased,
the increase in the specific heat of the PLA material was 62% due to its
partial crystalline structure. The glass transition temperatures of both
materials in the storage module are similar to the DSC results. While the
viscous property of ABS material improved at small amounts of radiation, this
property deteriorated at 70 Gy. With the increasing amount of radiation of the
PLA material, the cross-link density decreased and its viscous properties
worsened. During radiotherapy, the change in thermo-mechanical properties of
the biodegradable PLA material was found to be greater than ABS material.
However, both materials are suitable for radiotherapy applications.