Effects of the degree of hydrolysis on radiation induced reactions in the poly(vinyl alcohol)–poly(vinyl acetate) system

Gamma, E-Beam and X-ray Irradiations on PE/EVOH/PE Multilayer Film: An Industrial Point of View Regarding the Impact on Mechanical Properties

X-ray and electron-beam (E-beam) sterilization technologies were assessed to supplement gamma sterilization, the most common radiation technology used today for biopharmaceutical product sterilization. The mechanical properties of a PE/EVOH/PE film were studied using tensile tests and dynamical mechanical analysis after each irradiation technology (i.e., gamma, electron beam and X-ray irradiations). The effects of each irradiation were compared using two statistical methods. The results indicate that the three irradiation technologies induce no difference in mechanical properties in the investigated dose range for this material.

Investigations at the Product, Macromolecular, and Molecular Level of the Physical and Chemical Properties of a γ-Irradiated Multilayer EVA/EVOH/EVA Film: Comprehensive Analysis and Mechanistic Insights

Chemically and biologically safe storage of solutions for medical uses is a daily concern for industry since decades and it appeared even more dramatic during the last two years of pandemia. Biological safety is readily reached by sterilization using γ-irradiation process. However, such a type of irradiation induces the degradation and the release of chemicals able to spoil the biological solutions. Surprisingly, there are no investigations on multi-layer films combining multi-technique and multi-method approaches to unveil the events occurring during γ-irradiation. Furthermore, our investigations are focuses on properties/events occurring at product, macromolecular, and molecular levels.

Effects of microviscosity, dry electron scavenging, and protein mobility on the radiolysis of albumen hydrogel

Nanosecond pulse radiolysis experiments performed on the oxygen and nitrogen saturated thick fraction of egg white (which has an immeasurably high macroviscosity) produced a rate constant for hydrated electron reaction with oxygen equal to 1.7 × 10(10) M(-1) s(-1) at 18 °C, indicating that, due to the very low microviscosity, hydrated electrons are as mobile and reactive in the albumen hydrogel as in neat water. Also, the radiolytic yield for the hydrated electron (G-value) in the thick fraction of egg white (measured at the end of a 14 ns electron pulse) was found to be 86% of that determined in neat water, which can be attributed to the reaction of dry electrons with the protein constituents. Steady-state γ radiolysis studies on air-saturated thick and thin fraction (true solution) revealed that the immobility of egg white proteins disfavors reactions that result in molecular mass change.

pH Effects on the Complexation, Miscibility and Radiation-Induced Crosslinking in Poly(acrylic acid)-Poly(vinyl alcohol) Blends

The effect of pH on the complexation of poly(acrylic acid) with poly(vinyl alcohol) in aqueous solution, the miscibility of these polymers in the solid state and the possibility for crosslinking the blends using gamma radiation has been studied. It is demonstrated that the complexation ability of poly(vinyl alcohol) with respect to poly(acrylic acid) is relatively low in comparison with some other synthetic non-ionic polymers. The precipitation of interpolymer complexes was observed below the critical pH of complexation (pH(crit1)), which characterizes the transition between a compact hydrophobic polycomplex and an extended hydrophilic interpolymer associate. Films prepared by casting from aqueous solutions at different pH values exhibited a transition from miscibility to immiscibility at a certain critical pH, pH(crit2), above which hydrogen bonding is prevented. It is shown here that gamma radiation crosslinking of solid blends is efficient and only results in the formation of hydrogel films for blends prepared between pH(crit1) and pH(crit2). The yield of the gel fraction and the swelling properties of the films depended on the absorbed radiation dose and the polymer ratio. [Diagram: see text] SEM image of an equimolar PAA-PVA blend cast from a pH 4.6 solution.