Preparation of Thermoplastic X-ray Masks for Medical Applications

Abstract

The objective of this thesis was to study the appropriate polymer for preparation of thermoplasticmasks for medical applications. The commercial thermoplastic mask was characterized by Fouriertransform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The resultsindicated that the type of polymer being used is polycaprolactone. The tensile strength, hardness andimpact strength of the commercial thermoplastic mask were 17.35 MPa, 51.40 D Scale and 9 10-3J/(mm)2, respectively. The polymers used for preparing the masks in this study were polycaprolactone(PCL), poly(vinyl chloride) (PVC) and polycarbonate (PC). The PVC compound was prepared by mixingon a two roll mill using di-2-ethylhexyl phthalate (DEHP) as a plasticizer. The concentration of DEHP wasvaried from 8 to 25 phr. From the results, it was found that the optimum PVC compound is that obtainedby using 18-25 phr of DEHP. The PC compound was prepared in twin-screw extruder using trioctyltrimellitate (TOTM) as a plasticizer. The concentration of TOTM was varied from 20 to 80 phr. From theresults, it was found that the optimum PC compound is that obtained by using 75-80 phr of TOTM.Finally, the PCL compound was prepared in twin-screw extruder using 25 phr of high density polyethylene(HDPE), 73 phr of PCL, 2 phr of triallyl cyanurate as a crosslink enhance and 2 phr of Irganox 1010antioxidant gave the optimum PCL compound.

Keywords : Radiotherapy / Head and Neck Cancer / Thermoplastic Masks / Polycaprolactone