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1

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.

2

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.

3

Bio-based polyurethane applied as matrix of fiberglass reinforced composite

de Sousa Jr. R. R., Miranda E. A., Batalha G. F., dos Santos D. J.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 81, nr 1

5--10

EN

Purpose: of this paper was to develop and to characterize the mechanical behaviour of a structural composite obtained from a bio-based polyurethane matrix reinforced with fiberglass. Design/methodology/approach: Castor oil and Kraft lignin-containing polyol was applied for bio-based polyurethane synthesis. Structural composite was obtained by reinforcing this renewable source bio-based polymer with fiberglass mat. Polyester resin composite was also obtained for comparison, following the same process and reinforcement conditions. Mechanical characterization was carried out through uniaxial tensile, flexural strength, Izod impact tests and additionally scanning electron microscopy (MEV). Findings: Bio-based polyurethane composite was obtained and presented higher ultimate tensile strength (UTS) and equivalent impact resistance in comparison to polyester matrix composite. Research limitations/implications: Effects of Kraft lignin and fiberglass contents changing on mechanical properties might be investigated in future researches. Practical implications: Revalorization of Kraft lignin. 50 million tons of lignin are produced worldwide every year as by-product of pulp and paper manufacturing. The most part of this Kraft lignin is currently burned for energy generation. Originality/value: Results indicated the possibility of reusing this industrial wasted by-product at large scale as polymeric matrix for structural composite, in which high UTS and impact resistance are required.

4

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.

5

Wear abrasive resistance of intracorporeal prosthesis of oesophagus

Nowak A. J., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 69, nr 1

26--32

EN

Purpose: The main aim of the work is investigation of abrasive wear resistance of evaluated oesophageal prosthesis internal layer, considering its long-term exploitation possibility and extreme option of food consumed by patient after implementation. Design/methodology/approach: In the work, methodology of wear abrasive investigations of oesophageal prosthesis, made of long-fibre composite material based on medical silicon, internal surface is presented. The measurements have been done on equipment designed and made in Division of Materials Processing Technology, Management and Computer Techniques in Materials Science of Institute of Engineering Materials and Biomaterials. Findings: The volume of obtained samples mass loss have been determined from approximate calculations of wear trace to simple geometrical figure mapping this loss, ant then the volume of this figure haves been calculated. The CAD software has been used to verify approximation method, which allows to precisely determine mass loss. Research limitations/implications: Developed constructional model of modern, internal prosthesis of the human oesophagus will be used to design the manufacturing technology and to manufacture given prosthesis. Originality/value: Worked out construction 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.

6

Polymer electrolytes based on POE and Na-TFS salt for all-solid-state batteries

Martinez-Cisneros C. S., Sanchez J. Y., Levenfeld B., Varez A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 73, nr 2

72--79

EN

Purpose: Currently, electrochemical energy storage systems mostly focus on lithiumion batteries; especially in the field of portable electronics and electric transportation. Nevertheless, it is expected that the exponential growth of these markets and limited lithium resources will increase the price of lithium-based energy storage systems. To meet growing demands in terms of green and sustainable electric power storage, alternative electrochemical technologies towards post lithium-ion batteries are required. Design/methodology/approach: In the present study, polymer electrolytes based on poly(oxyethylene) (POE) and Na-TFS (NaCF3SO3) were developed to be used in solventfree batteries. Electrolytes were prepared using two methodologies: (i) a green-chemistry approach based on lyophilization combined with hot-pressing and (ii) the film-casting method. Findings: Advantages and limitations of both approaches were investigated by several characterization techniques (morphology, thermal and conductivity studies). Using lyophilization/hot-pressing, waste and chemical derivatives production is prevented (Green Chemistry approach) and uniform and porous-free films with controllable thickness and improved mechanical properties are achievable. Research limitations/implications: Further work regarding the development and application of novel polymer backbones is necessary to reach performances comparable to lithium-based polymer electrolytes in terms of electrical properties (conductivity). Originality/value: This work is in total agreement with the current need of developing alternative materials towards sustainable and environmental friendly post lithium-ion batteries. This global aspiration is supported by the recent re-emerging focus on sodium-ion batteries.

7

Surface modification of a duplex stainless steel for plastic-metal hybrid parts

Sotomayor M. E., Sanz J., Cervera A., Levenfeld B., Varez A.

Archives of Materials Science and Engineering

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2015

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Vol. 72, nr 2

86--93

EN

Purpose: Of this paper is the evaluation of three different surface treatments on a duplex stainless steel, in order to improve its adhesive properties on a thermoplastic like polysulfone. Design/methodology/approach: In order to improve the adhesion between stainless steel and polysulfone, shot-peening, acid (aqua regia) etching and atmospheric pressure plasma jet have been used. The topography and surface activation effects have been evaluated by means of SEM and contact angle measurements. Additionally, aging studies have been performed to evaluate the effect of storage time of parts on atmospheric plasma torch surface treatment. Finally, to test the effectiveness of the treatments, it has been carried out successfully shear strength tests by tension of adhesive assemblies previously modified with the treatments. It has been also examined rupture failures that have occurred in these assemblies. Findings: Aqua regia and plasma torch treatments have reached the optimal surface modification condition under wettability criteria. Shear strength tests demonstrated that the improved surface adhesion provided on this substrate and the polysulfone is achieved by shot-peening and acid etching treatments. Research limitations/implications: A deeper analysis varying several conditions like humidity could be suggested in order to evaluate the effectiveness of surface treatment. Originality/value: Up to now there is no any study in the literature about the comparison of different surface treatment on duplex stainless steels and the subsequent evaluation of the adhesion of a polymer like polysulfone.

8

Selected properties of plasticized PVC modified by recyclate of polylactide film

Chmielnicki B., Konieczny J., Pakieła W.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 1

10--19

EN

Purpose: The main aim of this work is to investigate mechanical properties of plasticized PVC modified by recyclate of polylactide film and influence of aging time in humidity chamber on mechanical properties. Design/methodology/approach: Static test of tensile strength was realized using the testing machine Instron TT-CM 80. Hardness was tested by hardness tester Zwick. Fractures were examined with a scanning electron microscope Zeiss Supra 25. Before the test, the sample was sprayed thin (0.05 mm) silver layer in order to ensure discharge of static electricity from the surface of the sample. PVC granules used is prepared by mixing together at 70°C: PVC 70, plasticizer – dioctyl phthalate FDO Boryszew Erg production and stabilizing lubricant composition. The final materials being studied, obtained by subjecting of the homogenizing extrusion the mixture of granules PVC and recycled PLA. Findings: The analysis of the results gives a real chance to avoid long-term retention of product made from the plastic in the landfill after the end of his exploitation.Research limitations/implications: For the blends of plasticized PVC and recycled PLA derived from films, further structural and tribological resistance examinations are planned. Practical implications: Obtained materials are characterized by satisfactory mechanical properties which make them ideal for use in the packaging industry. The effect of the addition of biodegradable recyclate postconsumer waste in the form of PLA film on plastic susceptibility to degradation under conditions of moisture was confirmed. Originality/value: The article presents selected properties of blends of plasticized PVC and recycled PLA derived from films. The content of recyclate in tested materials varied from 0% to 50%. Introduction to poly (vinyl chloride) degradable additive made it susceptible to degradation in the presence of water, which initiates the biodegradation of polylactide.

9

Toward a new approach for passive safety assessment of gymnastic equipment

Costabile G., Schwanitz S., Amodeo G., Martorelli M., Lanzotti A., Odenwald S.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 56, nr 2

59--65

EN

Purpose: Aim of the paper is to propose a new approach for the assessment of passive safety of gymnastic equipment that allows technicians to optimize the choice of protection devices. Design/methodology/approach: According to different standard procedures, EN 913 and EN 1177 with an additional control on the acceleration parameter, experimental tests on polymer foam materials were performed using cylindrical and hemispherical missiles connected to a flexible impact testing apparatus realized at Chemnitz University of Technology. Findings: Impact tests carried out using cylindrical and hemispherical missiles have shown, for the same impact energy, different acceleration peak values, always greater for hemispherical missile than cylindrical one. So considering EN 913 procedure, the severity of head impacts, in term of acceleration peak can be underestimated when a cylindrical missile is used. For this reason to correctly assess the head injuries is necessary to take into account in addition to the acceleration peak value, also HIC parameter. Research limitations/implications: The research described in the paper was carried out taking into account only the human head impacts (the most severe injuries) and not other parts of the human body. Practical implications: The new approach proposed in the paper can be useful for the choice of the protective devices to improve the passive safety of gymnastic equipment. It represents a starting point to define new standards. Originality/value: On the base of experimental tests, the authors show that the safety threshold of peak acceleration defined in the EN913 standard is poor. For this reason it is necessary to modify the current standards, in order to guarantee an adequate passive safety and to allow the technicians to optimize the choice of protection devices on the base of impact absorption properties, that are evaluated using all together the parameters: acceleration peak, drop height and Head Injury Criterion (HIC).

10

Simulation diagnostics of the polyester-glass pipes degradation process; experimental basis

Szymiczek M., Wróbel G., Rojek M., Czapla T.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 59, nr 1

37--47

EN

Purpose: In the work is described the method that enables identification of controller of simulation procedures which ensures compliance of experimental research results of changes in material physical characteristics with the characteristics of the numerical model. Design/methodology/approach: The work presents the method of diagnostic assessment of residual strength of composite pipes produced with the use of the method of winding glass fibre impregnated by chemically setting polyester resin, subjected to fatigue load in condition of pulsating fluid pressure. Findings: The basis of assessment is the correlation of residual strength with the acoustic characteristics of composite coating of the researched pipes. Research limitations/implications: The parameters of simulation procedures which are of key importance for correctness of diagnosis were determined on the basis of results of non-destructive and destructive testing of pipe material samples, subjected to the load in conditions corresponding the working ones. Practical implications: The diagnostic tool is the simulation program of degradation process of composite material with set structure, which enables investigating the changes in material characteristics for any operating load program. Originality/value: The paper presents a new approach to diagnostic processes of destruction aging-fatigue for the purpose of assessing the residual strength of composite pipes using computer simulation methods.

11

Evaluation of selected properties of PA6-copper/graphite composite

Konieczny J., Chmielnicki B., Tomiczek A.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 60, nr 1

23--30

EN

Purpose: The aim of this study was to investigate the possibility of improving the tribological properties and thermal conductivity of composites with structural modification of polyamides by the additions of copper and graphite. Design/methodology/approach: The study involved testing polyamide composites containing metallic powder. As the matrix was used polyamide 6 Tarnamid 27 Natural produced by Azoty Tarnów, which strengthened copper, graphite or molybdenum disulfide with varying participation in the composite. Taken tensile test, Brinell hardness, thermal conductivity and the tribological wear resistance. Analyzed the influence of the type of dopant and the participation of the studied property. Findings: The study showed the desirability of the use of graphite and copper as fillers polyamide. The resulting composites are characterized by satisfactory mechanical properties and thermal conductivity. Applied fillers also showed a positive effect on the value of the coefficient of friction wear him down much. Research limitations/implications: No synergistic effect of fillers on the properties of a ternary mixture polyamide-graphite-copper property in all test. Tribological wear for this material was significantly higher than for the binary mixtures of polyamide-graphite and polyamide-copper. According to the literature, composite reinforced with graphite and copper should have a best tribological properties, far in excess of other subjects. Low wear resistance of this material disqualify applications on the nodes friction. Practical implications: The results obtained newly developed composites, combined with the relatively low price of graphite and copper as compared with the price of molybdenum sulfide II may be reasons to use them as analogues of commercial mixtures of PA with MoS2. Originality/value: The results are original and valuable cognitive nature. They bring a new and expanded information about the effects of fillers on mechanical and physical properties. Unique data on tribological wear resistance depends on the type and amount of filler.

12

Thermal conductivity of the epoxy resin filled by low melting point alloy

Wierzbicki Ł., Pusz A.

Archives of Materials Science and Engineering

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2013

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Vol. 61, nr 1

22--29

EN

Purpose: The aim of the work was to determine the effectiveness of the modification of epoxy resin’s thermal conductivity by Wood’s alloy particles addition. Design/methodology/approach: The manufacturing method of thermosetting polymer matrix composite materials reinforced with the Wood’s alloy particles was searched. Firstly, the mixing conditions were differentiated to obtain good dispersion of the reinforcement in polymeric matrix. The thermal conductivity coefficient of composites has been investigated by using of the quasi-static test. Findings: The suggested method of thermal conductivity measurement allows to avoid the procedure of solving complicated equations. The developed measuring device enables the measurements of thermal conductivity of polymer composites in a form of a beam of 4x20X120 mm dimension. The results of the thermal conductivity tests and their analysis are presented. Research limitations/implications: The presented research was limited to composites in the form of small samples. The developed technology of this type of composites’ preparation is limited to small volumes because of the sedimentation process. The second limitation results from the necessity of matching the shape of the test specimen to the size of the cooler and heater on the device for measuring thermal conductivity. Practical implications: Materials with low melting point alloy content show many possible applications. First of all, these are the materials of higher thermal conductivity and electrical conductivity than the standard polymeric materials. Originality/value: The preparation method of thermosetting polymer matrix composite materials reinforced with the Wood’s alloy particles fabricating method was developed. Composites with good thermal properties were obtained. The obtained results confirm the utility of the applied investigation methods in the thermal analysis of polymer composites.

13

Finite Element Method application for modelling of internal oesophageal prosthesis

Nowak A., Dobrzański L. A., Rybczyński R., Mech R.

Archives of Materials Science and Engineering

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2013

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Vol. 64, nr 2

198--204

EN

Purpose: The general topic of this paper is the computer simulation with the use of finite element method for determining the internal stresses in the internal oesophageal prosthesis based on long-fibre composite material. Design/methodology/approach: Modelling of stresses in the internal oesophageal prosthesis was performed with the help of finite element method in ANSYS environment. Application of Finite Element Method was discussed and essential advantages resulting from application of it are pointed Findings: The presented model meets the initial criteria, which gives ground to the assumption about its usability for determining the stresses in the internal oesophageal prosthesis, employing the finite element method using the ANSYS program. The computer simulation results correlate with the experimental results. Research limitations/implications: Applied Finite Element Method enables modelling of stresses and deformations arises in composite material in the conditions representing real experimental investigations as well as condition similar to those prevailing in human body after prosthesis implementation. Originality/value: Developed simulation simplifies and reduces cost of optimization of the internal oesophageal prosthesis properties by simulation of this properties without necessity of additional laboratory investigations.

14

Mechanical and physical properties investigation of polyurethane material obtained from renewable natural source

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

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 54, nr 2

211--217

EN

Purpose: The purpose of this paper is to investigate the influence of different polyol/diisocyanate ratios on the mechanical and physical behaviours of polyurethane based polymers. Design/methodology/approach: Castor oil was mixed, as polyol, to diisocyanate in order to obtain polyurethane based polymers. Besides the ideal stoichiometry, polyol/ diisiocyanate ratio, ratios with excess/ lack of diisocyanates were provided. The mechanical behaviour was investigated by uniaxial tests. Differential Scanning Calorimetry (DSC) and Thermo gravimetric Analysis (TGA) were used to investigate the thermal behaviour. The various polymeric structures, obtained by the different ratios, were analysed and compared by Infrared Spectroscopy (IR). Findings: Mechanical performance was increased proportionally to contend of diisocyanate. High levels of diisocyanate have generated elongation decreasing and CO2 formation during curing, damaging mechanical behaviour due to bubble presence. Analytical experiments have showed important changes on: polymeric structures, glass transition temperatures and behaviour at elevated temperatures. Research limitations/implications: Free acid and water contend were not taken into consideration by defining the ideal stoichiometry. The investigated formulations cannot be direct applied on practical applications; fillers and additives must be added to them, which were not taken in consideration. Practical implications: The obtained results can support development of adhesives, engineering polymers and polymeric matrix for structural composites. Stabling the relation between component ratios to their behaviours is possible to define optimal performance ranges and to avoid excess of diisocyanate on polymers. Originality/value: Deep investigation of PU based material, obtained from renewable natural source (castor oil). The results can orientate development of materials for industrial applications and researches using other oils as polyol.

15

The preparation of aramid fibres in silicone based composite materials

Dobrzański L. A., Nowak A. J., Pusz A., Górniak M.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 45, nr 2

125--131

EN

Purpose: The evaluation of modified aramid fibres - Kevlar - as reinforcement in silicon materials used in medicine. Design/methodology/approach: Samples of laminated material based on modified aramid fibres and medical silicone were made by a method of manual formation of laminates that is impregnation of reinforcement with matrix to hardening silicone process using hardening methods connected with heat. Created material was observed on Scanning Electron Microscopy manufactured by Zeiss. Findings: The results show that the modification of aramid fibres has a positive influence on adhesion of silicon material to aramid fibres and strengthening of tested samples. Research limitations/implications: Carried out investigations show that the problem with modification of aramid fibres is very important in having proper percentage of intensifier in developed material used for medical purposes. Originality/value: Taking the specific properties of material into account it seems that modification of aramid fibres would be useful in medicine. However, application of aramid fibres as reinforcing phase of polymer medical materials requires many additional investigations which are already planned and will soon be done in Institute of Engineering Materials and Biomaterials at Silesian University of Technology.

16

The concept of preparation of oesophageal prosthesis based on long-fibre composite materiał

Dobrzański L.A., Nowak A. J., Błażejewski W., Rybczyński R.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 46, nr 1

18--24

EN

Purpose: In the work, there was investigated the possibility of an application of long-fibrous composite material as a based material for prototype of oesophageal prosthesis (tubular element) with the use of so called arms, using coiling, plaiting and winding techniques. Design/methodology/approach: Coiling, plaiting and winding techniques were used. As a reinforcement, aramid fibres bound with different types of so called silicone rubbers. Selection of winding parameters has been made in order to fabrication of prosthesis with appropriate mechanical parameters. Findings: Technological tests have given promising results. In the summary, comments and technological remarks are described. For prototype of prosthesis manufacturing, components, which in the form of composite materials are characterized by biocompatibility, have been used, that is medical silicone and aramid fibres. Research limitations/implications: The pilot investigation of fabricated prototypes of internal oesophageal prosthesis show that it is necessary to change the fabrication technology onto dry winding followed by closing obtained reinforcement in a mould and saturation with silicone. The idea is to get better silicone content and connected with it better elasticity and tightness of the prosthesis. Originality/value: Accepted method of winding is the most effective due to fabrication of prototypes of internal oesophageal prosthesis in laboratory. In industry, probably the better method will be plaiting, e.g.: as in the case of high-pressure hose of applied hydraulics.

17

Photoalignment - an alternative aligning technique for Liquid Crystal Displays

Chrzanowski M. M., Zieliński J., Olifierczuk M, Kędzierski J., Nowinowski-Kruszelnicki E.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 48, nr 1

7--13

EN

Purpose: The main aim of this work is to present our investigation in the field of photoalignment. In this work we introduce useful photoalignment techniques and discuss in detail the results of photocrosslinking and photodegradation in photosensitive polymer materials. Design/methodology/approach: We describe the new procedure investigated in our laboratory for the following materials: HD-4100, HD-4110 and HD-8820 (DuPont Microsystems) as well as the characteristics obtained for the thin polyimide layers: optical homogeneity, thickness, surface tension. Findings: Polyimide layers obtained on the glass/ITO substrates which were irradiated using linearly polarised ultraviolet light show the aligning properties for liquid crystal layers. The proposed new technology is fairly fine to obtain 2-3 cm2 layers. Research limitations/implications: The liquid crystal material alignment quality is not perfect, but the works are still in progress. In the next step we will try to use silan-derivative adhesion promoters to lower the aligning layers thickness. This solution will probably also have a big influence on the aligning layers homogeneity. Practical implications: We discuss an alternative technique of the rubbing method for composition of liquid crystal displays. Liquid crystal displays are widely used for many industrial and commercial applications. Multimedia and graphics and medical-imaging systems require top quality images. Such an image can be obtained under the condition of good liquid crystal alignment. Rubbing is a method conventionally used for these purposes. Unfortunately this technique has some disadvantages that are particularly visible in new generation displays. The usage of photodephiniable materials opens the route to obtain an appropriate molecular tilt and controlled anchoring energy as well as preparing layers that are suitable to providing diversified optical axes in one liquid crystal cell. Originality/value: Agents investigated in the paper hasn’t been used as the alignment materials in liquid crystal cells preparation so far. The used technology as well as HD-4100, HD-8820 and HD-4110 materials are suitable as the alternative substances for common used aligning chemical substances and technologies.

18

Experimental study of influence factors on compression stress relaxation of ACM

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

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 46, nr 1

33--39

EN

Purpose: Purpose: of this paper is to investigate the influence of electron beam (EB) radiation, temperature and deformation on the compression stress relaxation behavior of UV curing polyacrylate rubber (ACM). Design/methodology/approach: ACM plugs were obtained by UV radiation curing. Some samples were post cured by EB dose of 250 kGy, providing two material conditions. The plugs were submitted to compression stress relaxation experiments (CSR) for 5.000 min on two temperature levels, 23°C and 90°C, and deformation levels of 10% and 15%. Results were analyzed using 2k Factorial Design, quantifying the influence of these factors on the maintained compression force. Findings: The results have shown an increase in the maintained compression force, respectively a decrease in the compression stress relaxation, for all EB irradiated ACM specimens along the entire measured period of time. The increase of the three analyzed factors has caused an increase of the maintained compression force. Through the 2k Factorial Design was possible to find out the deformation as the most relevant influence factor, followed by irradiation, as second influence factor and temperature. Research limitations/implications: ACM molecular structures were not physical-chemically investigated. Therefore, possible molecular structural changes, caused by EB radiation, were not described. Practical implications: Decreasing of compression stress relaxation implicates on increasing working life of sealing components made from the studied material, besides the improvement of sealing capacity of these components, even under reduced deformation conditions. Originality/value: The use of EB radiation as successful method to decrease compression stress relaxation of UV curing ACM rubber, has opened opportunities to industrial applications. Thus, provide knowledge about influence factors on ACM relaxation behavior.

19

Application of feature method to the modelling of composite structural elements

Beier A., Majzner M.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 45, nr 1

30--38

EN

Purpose: The paper describes the use of object-oriented methods in modelling and analysis of components made of fibre-based composites. Defined and specified the method for creating fibre primitives. An algorithm for the design of composite structures using object-oriented methods. Design/methodology/approach: The basic tool is an algorithm to build fibre facilities. Material properties can be found in the previously created databases of material objects. The whole is linked to the relevant formulas and diagrams. Findings: The basis for the introduction of object-oriented method was to systematize the processes of modelling and analysis of composite materials. Application issue features possible to determine the final form of composite structure. Research limitations/implications: Research direction is to create tools to support the work of the constructor during the construction of composite components. Material created a database of individual components of laminates, allows to build optimal in terms of established criteria of composite elements. Practical implications: The practical aspect of using object-oriented method is to use it to define the structure of the laminates. At the modelling stage it is possible to perform the parameterization formula of each phase of the composite. This recipe is especially important during the manufacture of composites. Originality/value: The paper presents a new approach to modelling of composites by defining a new elementary objects forming the basis for during the composite design process. Algorithms used in the work are particularly important for designers of new technical components made on the basis of fibre composites.

20

Rheometric research of polypropylene Licocene PP2602 melts

Mandzyuk I., Romanuke V.

Archives of Materials Science and Engineering

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2011

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Vol. 50, nr 1

31-35

EN

Purpose: To comprehend and ascertain reasons of the transition into the non-Newtonian viscosity zone for the melted polypropylene material, depending upon the number of recycling series. Design/methodology/approach: There were carried researches on rheological features of the primary material of the melted polypropylene Licocene PP2602, subjected to be processed repeatedly in as many series as needed, using the Brookfield viscometer CAP2000+ within the temperature range 130-200şC and the shear rate range 166-3000 s–1. Findings: There were obtained dependence of polypropylene melt viscosity against the shear rate at fixed temperatures, and dependence of polypropylene melt shear stress against the shear rate at fixed temperatures with the non-Newtonian viscosity transient zone shifting into the zone of greater shear rate values as the temperature increases. Also there was obtained dependence of the shear stress critical value on the number of recycling series, where the corresponding critical shear rate value grows as this number increases. This may be applied for predetermining the state of the repeatedly processed polymer material. Research limitations/implications: The found rheometric regularities reflect behaviour for a homologous series of the polymer, but most probably they are generic for all polyolefines, what should be investigated and ascertained subsequently. Practical implications: On the ground of the ascertained temperature-rate dependences of the polypropylene melt flow, there has appeared a possibility to gain a quantitative response about the secondary low-density-polyethylene material state, what allows selecting strategically the way of controlling this material properties, and that let develop new composites of those recycled materials for manufacturing footwear at enterprise “Vzuteks” (Khmelnytskyy). Originality/value: The present paper states that processing the polymer materials repeatedly influences directly on their rheological parameters, increasing, particularly, the melt shear rate critical value.