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Influence of surface treatment on the wetting process of jute fibres with thermosetting polyester resin

Bogdan-Włodek A., Kozioł M., Myalski J.

Polish Journal of Chemical Technology

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2012

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Vol. 14, nr 1

21-27

EN

The aim of this study is the evaluation of the effect of chemical treatment of jute fibres on their permeability with polyester resin and determination of optimal treatment parameters. Unmodified jute fabric by LENTEX, Poland and polyester resin ESTROMAL 14 were used in the experiments. NaOH and KOH water solutions (various concentration - from 1 to 15% - and treatment duration - from 0.5 to 6h), vinyl acetate, methanol, toluene diizocyanate were used for the treatment. Determination of the effect of the chemical treatment on fiber-resin interaction was made in: infiltration of resin into reinforcement structure tests and fabric absorbability tests. Three criteria: time of penetration of resin into the reinforcing fabric, fabric absorbability and the area of a part of the specimen cross-section penetrated with the resin were taken into account. The fabrics treated with 1-5% - long-time and 15% short-time NaOH and KOH water solutions showed the best results within the tested criteria. These results do not correspondent directly with the mechanical properties of cured composites manufactured on the base of the treated fabrics. Alkali- and organic treatments significantly improve the mechanical performance of natural fibres reinforced composites, but organic treatments (methanol, toluene diisocyanate) gives better improvement in mechanical properties in comparison with the alkali-treatments. The measurement methods applied in the study may be generally useful in the evaluation of the effect of chemical treatment of natural fibres on their wettability with the liquid matrix.

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Porównawcza ocena testów penetracji wody w papier. Część 2. Nowa metodologia testowania wnikania wody w strukturę papieru

Skowroński J. W.

Przegląd Papierniczy

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2010

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R. 66, nr 7

393-398

PL

W pierwszej części niniejszego artykułu (2) wyjaśniono złożoność penetracji wody w strukturę papieru, rozważając takie podstawowe zjawiska, jak: zwilżanie powierzchni włókna, rozprzestrzenianie się wody w porach papieru oraz wewnątrz włókien (pęcznienie). Część druga przedstawia trzy nowe techniki pomiaru wnikania wody w papier, pozwalające na rozróżnienie wnikania w pory papieru od wnikania w pory włókna, oraz pomiar równomierności wnikania wody.

EN

This is part 2 of a series on testing water penetration into paper. Part one (2) outlines the scientific basis of water penetration into paper, interpretation and suitability of presently used tests. Part two will discuss three novel testing techniques allowing to distinguish paper pore penetration from fiber pore penetration and to determine the penetration uniformity.

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Porównawcza ocena testów penetracji wody w papier. Część 1. Charakterystyka zjawiska i konwencjonalne metody pomiarowe

Skowroński J. W.

Przegląd Papierniczy

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2010

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R. 66, nr 5

271-277

PL

Wyjaśniono złożoność penetracji wody w strukturę papieru w oparciu o takie podstawowe zjawiska, jak zwilżanie powierzchni włókna, rozprzestrzenianie się zwilżania, wnikanie nawilżającej wody w pory papieru oraz do wnętrza włókien (pęcznienie). Stanowiło to podstawę do oceny użyteczności powszechnie używanych testów pomiarowych, takich jak kąt zwilżania, test Herculesa (HST) oraz test Bristowa. Podano charakterystykę tych testów i uzasadniono ich ograniczone możliwości precyzyjnego i całościowego interpretowania wnikania wody w papier.

EN

This is part 1 of a series on testing water penetration into paper. The subject at hand is very complex and not completely understood. Part one outlines the scientific basis of water penetration into paper, interpretation and suitability of presently used tests.

4

Oddziaływanie strumienia kropel i powietrza na powierzchnię ciała stałego

Zapałowicz Z.

Prace Naukowe Politechniki Szczecińskiej. Katedra Techniki Cieplnej

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2007

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Nr 592 (9)

3-204

PL

W niniejszej rozprawie skoncentrowano się przede wszystkim na analizie procesu oddziaływania strumienia kropel z powierzchnią ciała stałego w zakresie temperatur powierzchni ścianki niższych od temperatury nasycenia cieczy lub bliskich jej. Na podstawie literatury, uzupełnionej wynikami badań doświadczalnych, dokonano szczegółowej analizy procesu rozlewania się i odparowania kropli cieczy z powierzchni ciała stałego do "nieruchomego" powietrza atmosferycznego. W pracy opisano także szczegółowo proces rozlewania się i odparowania kropli cieczy z powierzchni ciała stałego, gdy układ kropla-ścianka omywany jest strumieniem powietrza.

EN

The work presents hydrodynamic and thermal processes that occur during the contact of a droplet stream and air with the solid body. The above processes are applied in technologies of coating surfaces of solid bodies with various substances, as well as in processes of cooling the heated surfaces of products and installations. The work consists of 9 chapters, literature on the subject, and annex. Chapter 1 contains a brief characteristic of two-phase flows, as well as aims and scope of the work, Chapter 2 presents methods of droplet formation, and physical mechanisms due to separation of droplets on the surface of solid body. Chapter 3 deals with mathematical description of the two-phase flow consisting of droplets and mixture of air and vapor. Chapter 4 is the basic part of work. The chapter deals with conditions of reaction between droplets and environment. Depending on the dynamics of droplet's dropping and of initial surface temperature, classification of behavior of particular droplets after their contact with the surface of solid body has been made. The chapter deals with physical mechanisms that are responsible for the processes of droplet*s spreading and evaporating. It gives a detailed presentation of droplet's evaporation process in conditions when surface is wetted by droplet. It has been proposed to divide the whole process into phases. Characteristic parameters describing the droplet*s spreading process (wetting angles, wetting coefficients) have been defined. The chapter shows the mathematical description of the droplet's spreading process on the surface of solid body. and it presents the own model of the phenomenon of spreading of a single droplet. The model has been compared with simplified models of the other authors. The chapter deals also with the effect of parameters of humid air on the process of wetting the surface of a solid body by droplet, and it presents the own model of the phenomenon. The model refers to the effect of microscopic phenomena on the process of droplet's spreading on the surface. The scope of this part of the work covers also the phenomenon of convective motion of liquid in the droplet and on its free surface. The main phase of droplet evaporation has been divided into sub-phases, depending on presence of the borderline between flow structures on the free surface of droplet. Chapter 5 presents the discussion on thermal exchange between the stream of air with droplets and the surface of solid body. Theoretical models of the phenomenon of evaporation of a single droplet present on the surface with temperature lower than the bubble point of the liquid are given a detailed presentation in the chapter, as well as the own model of the phenomenon of evaporation of a single droplet with relation to the spreading coefficient. Chapter 6 gives information about the working stands, methods, and results of experimental research carried out by author. The research concerns determination of effect of characteristic parameters on phenomena of spreading and evaporation of a single droplet. The chapter gives also the analysis of effect of the velocity of air stream in the channel on the droplefs evaporation time, and analysis of conditions of its movement on the surface. The work gives the comparison of obtained results of own experimental research with calculation results obtained from theoretical models (Chapter 7). Chapters 8 and 9 contain recapitulation conclusions. The work is closed with literature on the subject and with annex which refers to methodology of map plotting for presence of droplet structure and liquid film on the surface.