Wyniki wyszukiwania - Biblioteka Nauki

1

Polyurethane preparation on the base of sulfidoesterdiol-derivatives of biphenyl-bis(thioalkylenecarboxylic acids)

100%

Tarasiuk B.

Zeszyty Naukowe. Chemia / Politechnika Śląska

|

2001

|

tom z. 146

157-160

EN

New sulfidoesterdiols were obtained through condensation of biphenyl-bis(thioalkylene-carboxylic acids) with 1,4-bis(hydroxymethyl)cyclohexane. Thioacids used in the reaction were synthesized with bis(4-mercaptophenyl) and 3-bromopropionic or 4-bromobutyric acids. The obtained sulfidoesterdiols and HDI or MDI were used in the synthesis of polyurethanes. The structure of the obtained monomers and polymers was confirmed by means of elementary analysis IR spectroscopy and by magnetic proton resonance. Physico-chemical and thermal properties of the new polyurethanes were defined.

2

Polyurethane pressure-sensitive adhesives as raw materials for the manufacturing of protective films

80%

Łągiewczyk M. , Czech Z.

Polish Journal of Chemical Technology

|

2011

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tom 13

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nr 1

47-50

EN

The present paper relates to water-borne polyurethane pressure-sensitive adhesives (PU-PSA) systems for self-adhesive protective films, and methods of their preparation. The typical protective films are self-adhesive films with excellent removability. Their manufacture is a film conversion process using common materials developed for the packaging industry (PVC and polyolefins). The most often used carrier for the constructions of protective films is PE. Polyurethane PSA layers are characterized by constant low peel adhesion between 3 and 5 N/2,5 cm.

3

Investigations on the synthesis and properties of biodegradable poly(ester-carbonate-urea-urethane)s

80%

Mazurek M. M. , Rokicki G.

Polish Journal of Chemical Technology

|

2013

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tom 15

|

nr 4

80-88

EN

A new method of the synthesis of oligo(tetramethylene succinate-co-carbonate) diols using dimethyl succinate, 1,4-butanediol and tetramethylene bis(methyl carbonate) was elaborated. The resultant oligomerols (Mn = 2600- 3700) were characterized by FTIR, 1H NMR, GPC and DSC analysis. Depending on the content of carbonate units in the polymer molecules, the melting point of the crystalline phase changes significantly. The synthesis of poly(ester-carbonate-urea-urethane)s was carried out with two aliphatic diisocyanates - cyclic IPDI or linear HDI. The resultant products exhibited very good mechanical properties - tensile strength up to 60 MPa and elongation at break about 500%. Preliminary studies confirmed that the presence of ester units in the soft segments as well as lack of crystalline phase significantly enhances the biodegradability of the PUR in comparison to that of polyurethanes based on carbonate oligomers.

4

Synthesis and characterization of polyurethane-based biomaterials for orthopaedic applications

80%

Ordon K. , Pielichowska K.

Engineering of Biomaterials

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2018

|

tom Vol. 21, no. 148

112

5

Segmented block copolymers of natural rubber and 1,4-butanediol-toluene diisocyanate oligomers

80%

Gopakumar S. , Paul C. J. , Gopinathan Nair M. R.

Materials Science Poland

|

2005

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tom Vol. 23, No. 1

227--245

EN

Segmented block copolymers were synthesized from hydroxyl terminated liquid natural rubber (HTNR) and polyurethane oligomers (PU), formed from 1,4-butanediol (1,4-BDO) and toluene diisocyanate (TDI). The samples were synthesized in solution in two series by the one-step and two-step methods. They were characterized by spectral analysis, thermal analysis, etching studies, microscopy and mechanical testing. IR and NMR spectral data, along with etching studies, support the notion that a chemical reaction leads to block copolymerization. Differential scanning calorimetric (DSC) analysis showed a soft segment glass transition temperature between -62 °C and -63 °C and a hard segment glass transition temperature between 87 °C and 100 °C for different samples. This observation and two-stage thermal decomposition of the samples in thermogravimetric analysis (TGA) clearly indicate that the block copolymers are completely phase-segregated systems. The amorphous heterophase morphology of the samples is indicated by SEM, which shows well-defined beads of hard phase dispersed in a matrix. SEM results, along with the etching studies, revealed that the samples are systems consisting of block copolymers and some quantity of uncoupled polyurethane homopolymers in the form of beads. The homopolymer beads suggest that the efficiency of the chain extension in the present method of synthesis is slightly lower than expected. Tensile properties improved with the hard segment content in the samples. Low hard segment content leads to a flexible elastomer, while at the high one rigid plastics are formed. Intermediate compositions yielded rigid elastomers. Two-step samples showed slightly better properties compared to the one-step samples. This may be due to the systematic way by which the reaction progresses in two-step synthesis. The overall properties are found to be lower than that of the conventional polyurethane elastomers. This is attributed to the absence of phase mixing and the inability of the soft segments to crystallise under strain due to their short segments.

6

Synthesis of antibacterial polyurethane film and its properties

80%

Lin Z. , Yunyun L. , Bin C. , Yu C.

Polish Journal of Chemical Technology

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2020

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tom Vol. 22, nr 2

50--55

EN

Polyurethane (PU) is a polymer widely used in the biomedical field with excellent mechanical properties and good biocompatibility. However, it usually exhibits poor antibacterial properties for practical applications. Efforts are needed to improve the antibacterial activities of PU films for broader application prospect and added application values. In the present work, two PU films, TDI-P(E-co-T) and TDI-N-100-P(E-co-T), were prepared. Silver nanoparticles (AgNPs) were composited into the TDI-N-100-P(E-co-T) film for better mechanical properties and antibacterial activities, and resultant PU/AgNPs composite film was systematically characterized and studied. The as-prepared PU/AgNPs composite film exhibits much better antibacterial properties than the traditional PU membrane, exhibiting broader application prospect.

7

Selected aspects of polyurethane processes

80%

Król P. , Król B. , Pilch-Pitera B.

Polish Journal of Chemical Technology

|

2003

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tom Vol. 5, nr 3

84-87

EN

Polyurethanes - plastics synthesised in the reactions of diisocyanates and polyols, known for nearly 60 years, are still in wide demand for the production of rigid and flexible foamed materials for the automotive industry, refrigerating engineering and civil engineering; cast or thermoplastic elastomers to be further processed in RIM methods, with the monolithic or microcellular structures; adhesives, binders, and protective coatings for concrete, steel, wood and glass surfaces, applicable either as paints with minimum content of volatile organic solvents, or - more recently - as environmentally compatible aqueous dispersions or emulsions. The paper presents the latest trends in the development of those processes, providing abundant references, and finally asks the question whether our domestic industry is in the position to compete in that sector of the market, and whether the presently available resources of raw materials for those processes are satisfactorily modern.

8

Izolacja w płynie

80%

Papiński J. , Żabski L.

Izolacje

|

2011

|

tom R. 16, nr 2

44-46

PL

Konieczność izolowania budynków nie tylko wynika z potrzeby oszczędzania energii, lecz także wymuszana jest dążeniem do poprawy warunków życia. W przeszłości izolacja przede wszystkim chroniła przed chłodem, teraz coraz częściej ma zapewnić również ochronę przed przegrzewaniem.

9

Siły i stereometria warstwy wierzchniej poliuretanu po różnych obróbkach skrawaniem

80%

Wójcik R. , Wlazło J.

Mechanik

|

2015

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tom R. 88, nr 8-9CD2

742--754

PL

Wśród materiałów stosowanych w przemyśle oprócz stopów tytanu i niklu, uznawanych za trudno-skrawalne, istnieje grupa materiałów, które również sprawiają duże problemy podczas obróbki – należą do niej poliuretany. Artykuł poświęcono obróbce poliuretanu, który znajduje zastosowanie w różnych układach tribologicznych. Przedstawiono wybrane procesy obróbki skrawaniem, w tym omówiono siły składowe skrawania oraz parametry chropowatości. Pokazano kształty wiórów powstających podczas obróbki.

EN

Among the materials used in the industry, apart from titanium and nickel alloys, considered to be difficult to machine, there is a group of materials which cause much problems in machining as well – it includes polyurethanes. The article covers the machining of polyurethane used in various tribological systems. Assorted machining processes were presented, including discussion of components of the cutting force and roughness parameters. The shapes of chips generated during the machining were shown.

10

Fabrication of novel material with athrombogenic potential: Immobilization of peptides on polyurethane surface

80%

Ziętek P. , Butruk B. , Ciach T.

Challenges of Modern Technology

|

2012

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tom Vol. 3, no. 1

38--41

EN

Presented study was undertaken to fabricate a hemocompatible material that could be a potential candidate for use in fabrication of blood-contacting devices, e.g. circulatory support devices, vessel grafts, heart valves. The final material could be used as a scaffold for endothelial cell growth and initiate in situ endothelialisation. The newest and most promising strategy in material endothelialization involves introduction of short peptide sequences that can selectively address one particular type of cell adhesion receptors and promote cell adhesion. Thus, the aim of work was to elaborate a method of immobilizing peptides specific for integrins onto polymer substrate.

11

Polyurethanes used in the endoprosthesis of joints

80%

Domańska A. , Boczkowska A. , Izydorzak M. , Jaegermann Z. , Kurzydłowski K.

Polish Journal of Chemical Technology

|

2010

|

tom 12

|

nr 3

10-14

EN

The aim of the studies presented in this paper was the selection of the polyurethanes synthesized from different substrates in order to obtain i) ceramic - biodegradable polymer composite and ii) polyurethane resistant to abrasive wear. The polyurethanes were obtained from the crystalline prepolymers extended by water, because it may have a beneficial effect on the toxicity of the material. The properties of PUs were investigated using infrared spectroscopy, thermogravimetry, differential scanning calorimetry and scanning electron microscopy. In all the tested polyurethanes the peak from the reactive -NCO groups was not observed, which indicates that all the substrates are fully reacted. Such polyurethanes are characterized by interesting properties with the perspective use as components of ceramic-polymer joints endoprosthesis. The designed endoprosthesis should fulfill at least three functions: load bearing function (ceramic core), fastening and stabilizing endoprosthesis to the bone (composite ceramics - biodegradable polymer) and tribologic function allowing mating with parts of the prosthesis (polyurethane layer resistant to abrasive wear).

12

Synthesis of polyurethanes by exchange reaction between bis(hydroksyethyloxycarbonylimino)alkanes and diols

80%

Piotrowska A. , Rokicki G.

Zeszyty Naukowe. Chemia / Politechnika Śląska

|

2001

|

tom z. 146

87-90

PL

Przedstawiono badania nad syntezą poliuretanów alifatycznych na drodze polikondensacji węglanu etylenu, diamin alifatycznych i dioli zawierających więcej niż 4 atomy węgla w cząsteczce. Struktura chemiczna poliuretanów otrzymanych tą metodą została zbadana za pomocą spektroskopii (1H, 13C NMR, FTIR) oraz spektrometrii masowej MALDI-TOF. Przedyskutowano mechanizm tworzenia się ugrupowań uretanowych mocznikowych.

13

Injectable bone substitutes based on polyurethane and β-TCP

80%

Szczepańczyk P. , Pielichowska K. , Chłopek J.

Engineering of Biomaterials

|

2014

|

tom Vol. 17, no. 128-129

90--91

14

Cell outer membrane mimetic surface as a material with improved hemocompatibility

80%

Trzaskowski M. , Butruk B. , Ciach T.

Challenges of Modern Technology

|

2011

|

tom Vol. 2, no. 4

7--10

EN

The phenomenon of blood coagulation on the surfaces of implantable devices such as artifi cial blood vessels, valves or hearts is the major problem that has to be taken into consideration during the construction of such devices. Since the main factor that has an infl uence on clotting of blood is the surface of the material the device is made of, numerous attempts has already been undertaken to modify surfaces of existing materials in order to provide necessary protection against clot formation, very often by coating the materials with bio-active substances. The aim of presented study was to create a coating of phosphatidylcholine that would mimic natural cell outer membrane on the surface of polyurethane — a material already in use in construction of cardiovascular implants. The obtained coated materials have been evaluated with the use of FT-IR/ATR spectroscopy. The change in contact angle of modifi ed material was also investigated. Finally in vitro cytotoxicity tests were performed in order to examine biocompatibility of obtained material.

15

The preliminary studies of a structure and electrospinning of new polyurethanes based on synthetic atactic poly[(R, S)-3-hydroxybutyrate]

80%

Sajkiewicz P. , Brzeska J. , Denis P. , Sikorska W. , Kowalczuk M. , Rutkowska M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2014

|

tom Vol. 62, nr 1

55--60

EN

Novel polyurethanes based on synthetic, atactic poly[(R, S)-3-hydroxybutyrate] (a-PHB) and polycaprolactone (PCL) or polyoxytetramethylene (PTMG) diols were synthesized. It was shown that the presence of a-PHB within soft segments reduces crystallinity of PUR. Because of the low melting temperature for polyurethanes with PCL in soft segments, at this stage of work, electrospinning was limited to polyurethanes containing PTMG and a-PHB. Polyurethane containing 80% of PTMG and 20% of a-PHB was electrospun at various parameters from hexafluoro-2-propanole solution, resulting in formation of fibers with the average diameter ca. 2 μm. The fiber diameter decreased with decreasing polymer concentration in a solution and was practically insensitive to the needle-collector distance in the applied range of distances.

16

Investigations on the synthesis and properties of biodegradable poly(ester-carbonate-urea-urethane)s

80%

Mazurek M. M. , Rokicki G.

Polish Journal of Chemical Technology

|

2013

|

tom Vol. 15, nr 4

80-88

EN

A new method of the synthesis of oligo(tetramethylene succinate-co-carbonate) diols using dimethyl succinate, 1,4-butanediol and tetramethylene bis(methyl carbonate) was elaborated. The resultant oligomerols (Mn = 2600- 3700) were characterized by FTIR, 1H NMR, GPC and DSC analysis. Depending on the content of carbonate units in the polymer molecules, the melting point of the crystalline phase changes significantly. The synthesis of poly(ester-carbonate-urea-urethane)s was carried out with two aliphatic diisocyanates - cyclic IPDI or linear HDI. The resultant products exhibited very good mechanical properties - tensile strength up to 60 MPa and elongation at break about 500%. Preliminary studies confirmed that the presence of ester units in the soft segments as well as lack of crystalline phase significantly enhances the biodegradability of the PUR in comparison to that of polyurethanes based on carbonate oligomers.

17

Structure-property relationship of shape memory polyurethanes

80%

Kim B. K.

Applied Mechanics and Engineering

|

1999

|

tom Vol. 4, no spec.

435-439

EN

Shape memory behavior of segmented polyurethanes and their ionomers has been determined in terms of various structural parameters including soft segment type and content, hard segment type and content, ionomer content, and extent of phase separation.

18

Tribological properties of multilayered vacuum coating

80%

Rogachou A. , Popov A. , Piliptsov D. , Yarmolenko M. , Rogachev A. , Fedosenko N.

Journal of Automation Mobile Robotics and Intelligent Systems

|

2009

|

tom Vol. 3, No. 4

115-117

EN

The results of studies show the deposition conditions of the titanium-nitride based coatings and their structure influence on the tribological characteristics of the dry friction and in the diesel fuel. Tribological characteristics of multilayered systems on the basis of diamond-like coatings (DLC) have been studied. The deposition of the systems onto small-size cutting tools is found efficient for improving their service characteristics. When depositing the coatings to the cutting tool surface the microrelief of edges is not distorted and the service life increases 1.3 - 1.5 times. The morphology and tribological behaviour of composite and multi-layer polymer coatings based on polytetrafluoroethylene (PTFE) and polyurethane (PU) are studied after deposition by means the method of electron beam dispersion. It is shown possibility to produce fine-film systems based on polyurethane with polytetrafluoroethylene as filler that possess high tribological performance.

19

Initial in vivo biocompatybility evaluation of biomaterials used in the new biomimetic heart valve

80%

Gonsior M. , Zawidlak-Węgrzyńska B. , Janiczak K. , Gonsior D. , Kustosz R. , Major R. , Lackner J.

Engineering of Biomaterials

|

2018

|

tom Vol. 21, no. 148

81

20

Studies on utilization of rye slops in production of rigid polyurethene-polyisocyanurate foams

80%

Czupryński B. , Sadowska J.

Polish Journal of Applied Chemistry

|

2000

|

tom Vol. 44, nr 2-3

173-180

EN

A rye slop (92.2% of H2O and 7.8% of dry mass), a by-product in the process of making high wines, were added as a filler (5-30 % by weight in relation to total weight of polyisocyanurate and oligomerol) to PUR-PIR foam composition (Table 3). Apparent density, compressive strength, friability, oxygen index, combustion residue, dimensional stability at 120°C, softening point and TGA thermograms were determined for the seven foams prepared (Figs. 1-5). Foams characterized by reduced brittleness, slightly reduced oxygen index, retention and softening temperature and slightly increased compressive strength in relation to the standard foam (with no rye slop added) were obtained when rye slops were added in amounts from 5% to 30% by weight. IR spectra confirmed the presence of bands characteristic for isocyanurate and urethane groups.