Crosslinking Poly(ε-caprolactone) with benzoyl peroxide by thermal method for making radiotherapy masks

External radiotherapy is a major method of treating cancer. For just hitting the cancer cells by emitting rays, masks are used to stabilize the patient's body in the right position during the radiotherapy, so that the rays are not emitted to the healthy tissues of the patient's body. Due to the unique properties of these masks, suitable polymeric materials must be used to produce them, which has initially been investigated using a variety of thermoplastic polymers.

 In the following, polycaprolactone is proposed as the main material for making the mask. Due to its low tensile strength, this material alone is not suitable for the intended use. Therefore, the material was cured with different percentages of benzoyl peroxide (BPO) to increase tensile strength by crosslinking of the polymer. The properties of the cured samples were investigated using the tests of gel content, shape memory, unidirectional tensile strength and, DSC diagrams.

With increasing BPO, the percentage of gel content and shape memory of the cured samples increased. All cured samples had a high percentage of shape recovery, the highest of which belonged to samples containing 2 and 3% by weight of BPO. By Examining the tensile strength test diagrams, it was observed that by increasing the amount of BPO from 0.5 to 2% by weight in the cured samples, the tensile strength at the breaking point increased to 10 MPa. Shape recovery and tensile strength at the breaking point were 94% and 10 MPa for both cured polycaprolactone samples with 2% by weight of BPO and the Orfit mask, which were very similar in this respect. Finally, a mixture of PCL with 2% by weight of BPO is proposed to make a radiotherapy mask.