Study of Coffee Grounds Oil Action in PVC Matrix Exposed to Gamma Radiation: Comparison of Systems in Film and Specimen Forms

<div><p>The poly (vinyl chloride), PVC, undergoes changes in its physicochemical properties when it is exposed to gamma radiation. Thus, the radiolytic stabilization of PVC is one way for obtain a material with radiation resistance. In this work, we studied the coffee grounds oil as PVC radiolytic protection in two systems forms: PVC film and PVC specimen. The systems were irradiated at sterilization dose of medical devices and viscosity measurements were performed. According to viscosity assays of PVC films, there was a 67% protection in polymer matrix promoted by the oil. On the other hand, the mean viscosity molar mass (Mv) of PVC specimens increased about 13%, indicating predominance of crosslinking effect, however samples containing the oil showed no Mv significant changes. Therefore, the oil can be considered a PVC radio stabilizing substance and open a way for use of sustainable additive in PVC industry.</p></div

ZnS Nanocrystals as an Additive for Gamma-Irradiated Poly (Vinyl Chloride)

<div><p>Zinc sulfide (ZnS) was synthesized by sonochemical method and nanoparticles with crystallite size around 2 nm were obtained. PVC containing ZnS nanoparticles at concentrations of 0.10; 0.30; 0.50; 0.7 and 1.00 wt% were gamma irradiated (60Co) at room temperature in air. No appreciable decrease in PVC Viscosity-Average Molar Mass (Mv) was observed for samples containing 0.7 wt% of ZnS nanocrystals. It was demonstrated that the addition of ZnS nanocrystals imparted molecular protection to the polymer matrix while improving flexibility, by decreasing the Young Modulus of PVC films. These results suggest the use of sonochemically synthesized ZnS nanocrystals as a new additive for radiation-grade PVC materials.</p></div

ZnS Nanocrystals as an Additive for Gamma-Irradiated Poly (Vinyl Chloride)

<div><p>Zinc sulfide (ZnS) was synthesized by sonochemical method and nanoparticles with crystallite size around 2 nm were obtained. PVC containing ZnS nanoparticles at concentrations of 0.10; 0.30; 0.50; 0.7 and 1.00 wt% were gamma irradiated (60Co) at room temperature in air. No appreciable decrease in PVC Viscosity-Average Molar Mass (Mv) was observed for samples containing 0.7 wt% of ZnS nanocrystals. It was demonstrated that the addition of ZnS nanocrystals imparted molecular protection to the polymer matrix while improving flexibility, by decreasing the Young Modulus of PVC films. These results suggest the use of sonochemically synthesized ZnS nanocrystals as a new additive for radiation-grade PVC materials.</p></div