No abstract available

No abstract available

No abstract available

No abstract available

[en] The reported investigations were focused on the elucidation of the most important factors influencing radiation-induced grafting, particularly on studying the relationship between layer structure formed via copolymerization and content of monomers in the initial solution. Sorption capacity of the prepared by radiation grafting adsorber was evaluated by gamma radiometer using ¹⁵²Eu³⁺ as a marker monitoring depletion of the radioisotope from the feed solution. When two monomers, AAc and AAm, contributed in the formation of grafted layer, their input into copolymerization was not proportional to their concentrations in the feed solution. It was confirmed that grafting of the monomers shows synergetic effect as the yield of copolymerization exceeds degree of grafting achieved for the individual components. - Highlights: • Two monomers were copolymerized on polypropylene filter by radiation grafting. • Grafting has changed thermal characteristic of polypropylene matrix. • Contribution of monomers in the grafted layer was determined by IR spectroscopy

No abstract available

[en] Complete text of publication follows. Polymeric biomaterials might be exposed to ionising radiation in order to improve their properties or to carry out sterilization that may also contribute in changes of the macroscopic features. It is generally known that irradiation affects physicochemical and mechanical properties of polymers leading usually to crosslinking and/or degradation. Crosslinking transforms a linear polymer into a tree dimensional network in resulting improvement of mechanical properties. The decrease in molecular weight is a consequence of degradation and leads to deterioration of polymer properties. A proportion between both processes determines final effect. Polyurethanes are a well-known class of polymers with the characteristic -NH-CO-O- linkage in the chain. They are block copolymers, which physicochemical properties may be modified by changing the ratio between soft and hard segments. Type and proportions between segments determine the character of polymer and consequently their industrial utility. Polyurethanes are known as radiation stable materials but their behaviour upon the exposure to ionising radiation is strongly dependent on their chemical and physical structure. Segmented polyurethanes have found application in medicine as biomaterials due to good biocompatibility, hydrolytic and oxidative biostability, excellent mechanical properties and good processibility. They are used for production of scaffolds in tissue engineering and for manufacturing medical devices, such as vascular grafts, artificial hearts, catheters and mammary implants. The aim of this study was to characterize influence of ionizing radiation on the selected physicochemical properties of polyurethanes. Samples of polyurethanes were investigated before and after irradiation by EPR, DSC, TG, gas chromatography, measurement of dynamic contact angle and mechanical properties. On a basis of the study we found that radiation sterilization has not significant influence on physicochemical properties of segmented polyurethanes and two parallel, competitive processes: crosslinking and chain scission were observed.

No abstract available

No abstract available

[en] This work investigated the effects induced in natural lignocellulosic material caused by irradiation with electron beam. The thermal properties of investigated samples of willow were tested using thermogravimetric analysis (TG). Irradiation of willow biomass samples with doses from 100 to 900 kGy resulted in degradation of its structure observed as decrease of degradation temperature. (author)