Wyniki wyszukiwania - BazTech

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Lignin-based polyurethane and epoxy adhesives: a short review

dos Santos D.J., Tavares L.B., Gouveia J.R., Batalha G.F.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 2

56--63

EN

Purpose: of this paper was to review and summarize significant papers related to the development and characterization of lignin-containing adhesives: polyurethane and epoxy types. In the last decades, several efforts have been dedicated on the development of renewable raw materials for polymer synthesis, mainly due to petroleum depletion and sustainability. In this context, lignin emerged as a potential candidate to substitute fossil-based raw materials in adhesive synthesis and formulations. Design/methodology/approach: Recent and other relevant papers were reviewed, aiming to identify the main advantages and limitations involved in lignin incorporation into epoxy and polyurethane adhesives formulations. First, effects of unmodified lignin addition were presented. Afterwards, the main lignin chemical modification methods were presented and discussed, based on thermomechanical results. Findings: Incorporation of unmodified lignin usually is limited to 30 %wt., otherwise mechanical properties are drastically affected as consequence of poor lignin solubility and excessive brittleness. Lignin chemical modification can be used to increase the reactivity of hydroxyl groups and/or add new moieties in its molecular structure, improving solubility and thermomechanical properties of cured adhesives. Practical implications: In the last years, some industrial plants started to operate and produce technical grade lignin at industrial scale, with reproducible properties and controlled molecular structure. Therefore, increasing efforts have been dedicated from researchers and chemists to develop lignin-based technologies, in which this work can directly contribute with. Originality/value: As consequence of the high content of phenol groups in its molecular structure, lignin was mostly applied on the development of phenolic resins applied as wood adhesives. For the first time in the literature, this work summarizes the advances related to synthesis and characterization of polyurethane and epoxy, applied as adhesives. Results can support the development and application of biobased, as well as contribute to the revalorization of this valuable and readily available biomass.

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Stan potencjału intelektualnego i bazy chemikaliów platformowych do produkcji tworzyw inżynieryjnych w Polsce. Czy utrzymamy się w światowym peletonie?

Kijeński J., Kijeńska M., Rejewski P.

Polimery

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2017

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T. 62, nr 5

380--387

PL

W opinii ekspertów tworzywa inżynieryjne i agrochemikalia stanowią jedyne branże, w których europejski przemysł chemiczny może skutecznie konkurować na rynku globalnym. Polskie spółki sektora Wielkiej Syntezy Chemicznej od lat nie wykazują wysokomarżowego rozwoju down-stream. W pracy przeprowadzono ocenę możliwości rozwoju obszaru chemikaliów inżynieryjnych w Polsce, z uwzględnieniem trendów światowych, kompetencji i tradycji polskich firm oraz zaplecza badawczego, a także niedomagań obszaru wytwórczego chemikaliów platformowych.

EN

In the opinion of experts, engineering polymers and agrochemicals are the only fields, in which the European chemical industry can successfully compete in the global market. Polish companies which are grouped in the Great Chemical Synthesis sector have not shown any high gain development down-stream for years. An analysis of the potentials for growth in the field of engineering chemicals in Poland, taking into consideration global trends, the competence and tradition of Polish companies and their R&D base as well as the shortcomings of the production sector of platform chemicals have been presented.

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Geometrical structure investigation of the surface of internal oesophagus prosthesis

Nowak A. J., Dobrzański L. A.

Archives of Materials Science and Engineering

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2017

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Vol. 83, nr 2

79--85

EN

Purpose: The aim of the work was roughness investigation of the surface of developed oesophageal prosthesis before and after texturing, to estimate its influence on future application of prosthesis. Design/methodology/approach: Linear, mechanical contact-measurement method and, for verification, optical profile measurement in confocal microscope were used in the work. Findings: The roughness investigation of the surface of developed oesophageal prosthesis before and after texturing was necessary to estimate its influence on future application of prosthesis. Research limitations/implications: The results of investigations of prosthesis of the human oesophagus internal and external surface roughness will be used to design the manufacturing technology and to manufacture given prosthesis. Originality/value: Investigation of geometrical structure of internal and external surface of internal oesophageal prosthesis is the part of the research project realized by authors, that will result in cognitive, constructional and technological effects, but first of all, it will enable the real help very sick people.

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Preparation and structure of the electro-deposited Ni-Mo alloys with polymers

Karolus M., Niedbała J., Rówiński E., Łągiewka E., Budniok A.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 16, nr 1-2

25--29

EN

Purpose: The aim of the paper is presentation the process of forming the Ni-Mo electrodeposited layers with polypyrrole, polytiophne and polyethylene. Design/methodology/approach: There are three ways of polymeriztion and layer depositon. Findings: In case of polytiophen + Ni-Mo – there is observed process of electropolymerization and Ni-Mo electrodeposition in the cathodic process. In case of polypyrrole + Ni-Mo – there is observed two-step process: electropolymerization in the anodic process and Ni-Mo electrodeposition in the cathodic process. So the composite is forming when the electrodes have worked alternately as the anode and as the cathode. In case of polyethylene + Ni-Mo – there is observed process of Ni-Mo electrodeposition with grains of polyethylene in the cathodic process. From structural analyses by X-ray diffraction it was noticed that the solid solution of Mo in Ni is forming. The unit cell parameters of solid solution are slightly changing with the incerasing of molybdenum contents in the alloy from the value 3.57 to 3.61 Å. In case of all polymers, the crystallite size calculated basing on the Williamson-Hall theory is about 5-6 nanometers. Practical implications: The codeposition of alloys with polymers or polymerisation with alloys codeposition has created new opportunities in the preparation of novel composite materials. Conductive polymers have been investigated for use as the electrode materials for a number of applications including rechargeable batteries, electrochemical sensors etc. Electrochemical method described in this paper is unique in that it can be used for processing ceramics, polymers, metals, composites and hybrid materials. Originality/value: Using the electopolymerization and electrodeposition processes in preparation of the composites.