Premises of creation of Internet portal designed to provide access to participants of educational and scientific process for the joint creation, consolidation, concentration and rapid spreading of educational and scientific information resources in its own depository are considered. CMS-based portal content management systems’ potentiality is investigated. Architecture for Internet portal of MES of Ukraine’s information resources is offered.

Створення порталу інформаційно-довідкових ресурсів міністерства освіти і науки україни

Unperturbed dimensions of stereoregular polymers.- Reinforcement of rubber by carbon black.- Transformations of phenolic antioxidants and the role of their products in the long-term properties of polyolefins.

Properties of polymers

PLA composites: From production to properties

The replacement of current petroleum-based plastics with sustainable alternatives is a crucial but formidable challenge for the modern society. Catalysis presents an enabling tool to facilitate the development of sustainable polymers. This review provides a system-level analysis of sustainable polymers and outlines key criteria with respect to the feedstocks the polymers are derived from, the manner in which the polymers are generated, and the end-of-use options. Specifically, we define sustainable polymers as a class of materials that are derived from renewable feedstocks and exhibit closed-loop life cycles. Among potential candidates, aliphatic polyesters and polycarbonates are promising materials due to their renewable resources and excellent biodegradability. The development of renewable monomers, the versatile synthetic routes to convert these monomers to polyesters and polycarbonate, and the different end-of-use options for these polymers are critically reviewed, with a focus on recent advances in c...

Catalysis as an Enabling Science for Sustainable Polymers

https://digital.csic.es/bitstream/10261/192179/1/10.1016_j.progpolymsci.2013.05.010.pdf

Multifunctional nanostructured PLA materials for packaging and tissue engineering

Purpose: The main purpose of this paper is the analysis of the most common methods for the calculation of the surface free energy (SFE) of solids, utilising the results of the contact angle measurements. The calculation deals also with the SFE at the interface, especially that at the surface of polymers and polymeric materials. The survey has been meant to ease the understanding of physical processes occurring at the solid-liquid interface and to help to find proper measuring methods with respect to various physical systems. Design/methodology/approach: The presented analysis has been based on the papers of the fundamental nature as well as on the specialised literature reports. The results of the experimental and theoretical studies of the author of this article are also considered. Findings: Different assumptions have been made in the individual methods for calculating the SFE of polymeric materials. Thus, the SFE values for a given material, obtained by various methods and with use of different measuring liquids, are not consistent. The method for the calculation of the SFE of porous or granulated materials, powders, and fibres, in which the Washburn equation is utilised, is very useful in practice. Currently, there is no appropriate alternative to this method. Research limitations/implications: The method for calculating the SFE with use of the equation of state requires further investigation, both experimental and theoretical. Further studies on the phenomena associated with penetration of the measuring liquids into the bulk of an examined material and on the relevant changes concerning this material, including the changes in its SFE, have also to be carried out. Practical implications: The presented results of the investigations may be applied in optimisation of the current and derivation of the new methods for calculating the SFE of solids and liquids, including mainly the SFE of polymers in the solid state. Originality/value: Because of differences in the assumptions made in most of the methods for the SFE calculation and of differences in the interactions between the individual measuring liquids and the examined material, the SFE values for various polymer materials may be compared with one another only when the contact angle measurements have been made using the same measuring liquids and when the SFE calculations have been performed by the same method.

Marian Żenkiewicz

Papers

Methods for the calculation of surface free energy of solids

Characterisation of multi-extruded poly(lactic acid)

Comparative study on the surface free energy of a solid calculated by different methods

Permeability of polylactide nanocomposite films for water vapour, oxygen and carbon dioxide

Influence of some crosslinking agents on thermal and mechanical properties of electron beam irradiated polylactide