A well-defined poly (n-butyl acrylate) (PBA) homopolymer was prepared by activators generated by electron transfer (AGET) ATRP at 90°C in N, N -dimethylformamide using ferric chloride hexahydrate (FeCl3.6H2O) /succinic acid (SA) as a catalyst and ethyl 2-bromoisobutyrate as an initiator. Ascorbic acid was selected as a reducing agent. The kinetic results showed that a linear increase of molecular weights of polymers with monomer conversion and a relatively narrow polydispersity (<1.25), when the conversion is beyond 40%, is an indication of a polymerization controlled by AGET ATRP of n-butyl acrylate (nBA). That is to say, (FeCl3.6H2O) /SA catalyst complex is demonstrated to be highly efficient for the AGET ATRP of nBA. The effects of different molar ratios of [FeCl3.6H2O] / [SA] and the concentration of ascorbic acid on polymerization rate were investigated. The maximum polymerization rate was obtained at molar ratio of [FeCl3.6H2O] / [SA] =1:2 and gave the best control of molecular weight and the distribution of polymer molecular weight. The polymerization reaction rate decreased when the higher or lower molar ratio of [FeCl3.6H2O] / [SA] was employed.The polymerization rate increased with higher content of ascorbic acid. The effects of different solvents on the polymerization were investigated. The experimental results showed that the polymerization rate was faster in polar solvent (such as DMF) than that in non-polar solvent (such as benzene). The obtained polymers had higher molecular weights with narrow distribution of molecular weight in DMF than that in benzene.Moreover, the obtained PBA was used as a macroinitiator in the chain extension experiment via AGET ATRP. The molecular weight of polymer increased after chain extension experiment.The chain extension experiment confirmed the living character of the polymerization system. The resultant PBA was characterized by 1H NMR, FTIR and gel permeation chromatography.

Poly (styrene-co-butyl acrylate) /clay nanocomposites were synthesized via in situ atom transfer radical polymerization using activators generated by electron transfer in the presence of a montmorillonite ion-exchanged with mixed surfactants of dodecyl trimethyl ammonium bromide and vinyl trimethyl ammonium chloride. The living nature of polymerization is confirmed by occurrence of narrow molecular weight distribution of the nanocomposites in which copolymers with polydispersity index of about 1.13-1.15 were obtained. Partial exfoliation of clay layers in the copolymer matrix was demonstrated by XRD patterns and further studies of TEM images. Thermogravimetric analysis (TGA) results demonstrated a slight increase in the thermal stability of nanocomposites in comparison with the neat copolymer. DSC results indicated a decrease in the glass transition temperature (Tg) of nanocomposites by the addition of clay content which are attributed to low molecular weights of the copolymers and weaker interactions between polymer chains. The chemical structure and composition of copolymers was identified by 1H NMR analysis.

Introduction: The dose distribution in the tumor bed and the neighboring tissue is an important issue in intraoperative radiation therapy (IORT). In the current study, a new software tool was developed to calculate and visualize the 2D and 3D dose distributions of the electron beams from the light intraoperative accelerator (LIAC) and validate the software through experimental measurements. Methods: The Monte Carlo code ‘ GATE’ was used to simulate the LIAC. Percentage depth dose curves (PDD) and transverse dose profiles (TDP) were calculated for all nominal energies in the water phantom, for the reference applicator. Results: The dose distribution was defined in the form of isodose curves in the water phantom to study the volumetric and superficial changes of absorbed dose. There weren’ t significant differences between calculated and measured PDD curves and TDPs. R100, R50, R90, Rp, and Ds values obtained from simulation were in good agreement with measurement. The maximum relative error was 8. 6% which was related to R100, due to the absence of charged particle equilibrium in the surface. As expected, the least error was related to R50; making it the most common parameter in electron dosimetry. Conclusions: The developed software is a basis to assess the dosimetric characteristics of all applicators and energy levels of the LIAC accelerator by calculating the 2D and 3D dose distribution during a proper calculation time. It can perform as a treatment planning system for IORT to calculate the absorbed dose of the clinical target volume and adjacent normal tissues which is not directly possible.

The copolymerization of methyl acrylate (MA) and glycidyl methacrylate (GMA) with 1-hexene was carried out using activator regenerator by electron transfer atom transfer radical polymerization (ARGET ATRP) employing Cu(0)/CuBr2 as a catalyst, pentamethyl diethylenetriamine (PMDETA) as a ligand, and ethyl 2-bromoisopropionate (EBriP) as the initiator, all at a reaction temperature of 70°C. This process resulted in the production of viscous and transparent copolymers, namely poly (methyl acrylate-co-1-hexene) or PMH and poly (glycidyl methacrylate-co- 1-hexene) or PGMH. For the MA/1-Hex copolymer, conversion rates ranged from a maximum of 31 wt.% to a minimum of 12 wt.%, while the GMA/1-hexene copolymer exhibited conversion rates ranging from a maximum of 42 wt.% to a minimum of 12 wt.%. It was observed that increasing the amount of 1-hexene during the synthesis led to a higher incorporation of 1-hexene content in both the MA and GMA polymer backbones, with a maximum of 15 wt.% and 18 wt.% of 1-hexene being incorporated into PMH and PGMH, respectively. The incorporation of 1-hexene was confirmed through Nuclear Magnetic Resonance (NMR) studies, including 1H, 13C, and DEPT 135 studies. Additionally, the copolymer PMH and PGMH exhibited monomodal molecular weight distribution curves when evaluated using the size exclusion chromatography (SEC) high-performance liquid chromatography (HPLC) technique, with polydispersity values in the range of 1.19-1.37 and 1.07-1.11, respectively. These findings indicate that the copolymerization process was well-controlled and followed a radical polymerization mechanism.