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1

Effects of alkali solution concentration and soaking time on mechanical properties of coconut fibre

Kondo Y., Arsyad M., Ahmad A., Soenoko R., Arman A.

Archives of Materials Science and Engineering

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2023

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Vol. 124, nr 2

62--70

EN

Purpose: The study aims to determine the effect of the treatment of alkali solution concentration and soaking time on the mechanical properties of coconut fibre. Design/methodology/approach: The study consists of preparing materials and equipment, immersion of coconut fibre in an alkali solution, drying in a furnace, testing, analysis of test results, and conclusions. Materials and equipment used are coconut fibre, alkali solution, polyester matrix, distilled water, furnace, hydrolysis test, tensile test, and SEM analysis. The sample had two treatments; the first was coconut fibre, which was soaked in the sodium hydroxide solution with 5%, 10%, 15%, and 20% concentrations for 3 hours. The second treatment was coconut fibre soaked in the sodium hydroxide solution with a concentration of 20% for 1, 5, 7, 9, and 11 hours. The samples were then dried in a furnace at 90ºC for 5 hours, and then a hydrolysis test, tensile test, pull-out test, and SEM analysis were carried out. Findings: The results suggest that for immersion in an alkali solution of 20%, the highest tensile strength of coconut coir fibre was obtained in soaking for 3 hours at 280.94 N/mm2, and the highest bonding strength between coconut coir fibres with a matrix polyester was obtained at 5 hours immersion at 7.86 N/mm2. Research limitations/implications: In the given study, coconut fibre was treated by soaking it in 5%, 10%, 15%, and 20% sodium hydroxide solution. Then, a single fibre tensile test was carried out, and a pull-out test was carried out to determine the mechanical properties of coconut fibre as a required effect that had been given. Subsequent studies can be carried out with other treatments using other chemical solutions, such as hydrogen peroxide or potassium permanganate. Originality/value: The tensile strength of coconut fibre without treatment was 186.42 N/mm2, whereas after being immersed in 20% sodium hydroxide solution, the tensile strength became 280.94 N/mm2. Likewise, the shear strength of the interface between the fibre and the polyester matrix was 1.85 N/mm2 for untreated coconut fibre to 3.09 N/mm2 for coconut fibre soaked in a 20% sodium hydroxide solution. The results of the study are intended as data for the use of coconut fibre as a natural fibre-reinforced composite material, for example, as a raw material for fishing boat walls.

2

Influence of the Soaking Time on the Mechanical Properties of Coir as a Natural Composite Reinforcement

Arsyad Muhammad, Soenoko Rudy, Arman Arman

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 6 (144)

98--103

EN

This study aimed to determine the effect of the long soaking of coir in sodium hydroxide solution on its mechanical properties. The materials used, namely coir, sodium hydroxide solution, polyester matrix, catalyst, and aquades. The coir was soaked in a sodium hydroxide solution for 1, 5, 7, 9, and 11 hours. After that, coconut fibre was washed using distilled water, and then dried in an oven at 90 °C for 5 hours. Next, a single fibre tensile and pull out test was performed. Based on the results and discussion, it was concluded that immersing coconut fibre in sodium hydroxide solution for 7-hours gave the maximum tensile strength and interfacial shear strength of 223.91 N/mm2, and 9.8 N/mm2, respectively Coir as a composite reinforcement has the potential to be used for engineering material such as ceiling boards and fishing boat walls.

PL

Celem pracy było określenie wpływu długotrwałego moczenia włókna kokosowego w roztworze wodorotlenku sodu na jego właściwości mechaniczne. Zastosowane materiały, a mianowicie: kokos, roztwór wodorotlenku sodu, matryca poliestrowa i katalizator. Włókno kokosowe moczono w roztworze wodorotlenku sodu przez: 1, 5, 7, 9 i 11 godzin. Następnie włókno kokosowe przemyto wodą destylowaną i suszono w piecu w temperaturze 90 °C przez 5 godzin. Następnie przeprowadzono pojedynczą próbę rozciągania włókna. Na podstawie wyników i dyskusji stwierdzono, że zanurzenie włókna kokosowego w roztworze wodorotlenku sodu na 7 godzin dało efekt w postaci maksymalnej wytrzymałości na rozciąganie i międzyfazowej wytrzymałości na ścinanie wynoszących odpowiednio 223,91 N/mm2 i 9,8 N/mm2. Tak wzmocnione włókno kokosowe ma szansę na użycie jako zbrojenie kompozytowe i potencjał do wykorzystania w materiałach inżynieryjnych, takich jak płyty sufitowe i ściany łodzi rybackich.

3

The effect of carbonate aggregate reaction in cement concrete on long-term changes in strength due to corrosion exposition conditions

Dębska D.

Ochrona przed Korozją

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2015

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nr 5

185--189

EN

The results of a study on the impact of defined environmental exposition such as H2O, MgSO4, Na2SO4 in different temperature condition on the susceptibility to dedolomitisation processes of cement concrete with selected dolomite aggregate with specific regard to changes in long-term strength properties are presented in the paper. The impact of defined liquid environment containing different amount of calcium and magnesium ions in various temperature condition on a susceptibility to release Ca2+ and Mg2+ ions caused by chemical reaction with examined aggregate was indicated too.

PL

W artykule przedstawiono wyniki badań wpływu zdefiniowanych warunków ekspozycji korozyjnej, takich jak H2O, MgSO4, Na2SO4 i zróżnicowanej temperatury, na podatność na procesy związane z dedolomityzacją betonu cementowego z kruszywem dolomitowym. Jako cechy diagnostyczne przyjęto zmiany wytrzymałości na zginanie i ściskanie. Przedstawiono również wyniki badań wpływu środowiska ciekłego zawierającego ściśle określoną zawartość jonów wapnia i magnezu oddziałującego w różnych warunkach temperatury na reaktywność kruszywa powodującą uwalnianie jonów Ca2+ i Mg2+.

4

The impact of liquid environments containing Mg2+ and SO42- ions on the durability of cement concrete with limestone aggregates

Dębska D.

Ochrona przed Korozją

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2014

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nr 4

124--128

EN

Carbonate aggregates exposed to a liquid environment may decompose and produce bulking of calcium and magnesium hydroxides. The presence of Ca2+, Mg2+ and SO42- – ions in the corrosive environment and temperature +60ºC may influence the rate of aggregate decomposition. Limestone aggregate, however, is suspected of enhancing concrete properties under contact with aggressive sulphate medium. The paper presents the results of a study on the impact of exposure to the environment containing calcium, magnesium and sulphate(VI) ions in different temperature condition on the susceptibility of selected limestone aggregates to bulking in liquid environment in cement concrete.

PL

Kruszywa węglanowe eksponowane w środowisku ciekłym mogą ulegać zniszczeniu z wytworzeniem pęczniejących form wodorotlenku wapnia i magnezu. Obecność jonów Ca2+, Mg2+ i SO42- w środowisku korozyjnym oraz podwyższona temperatura t = +60ºC mogą mieć wpływ na stopień destrukcji tych kruszyw. Jednakże, kruszywa wapienne mogą poprawiać odporność betonu na działanie agresywnego środowiska siarczanowego. W artykule przedstawiono wyniki badań nad wpływem ekspozycji korozyjnej betonów cementowch wykonanych z wybranych kruszyw wapiennych na pęcznienie w środowisku ciekłym zawierającym jony wapnia, magnezu i siarczanu(VI) w zróżnicowanej temperaturze.

5

Eco-Friendly Soaking Process Using Tannic Acid as an Alternative Bactericide

Zengin A. C. A., Çolak S. M., Zengin G., Kiliç E.

Archives of Environmental Protection

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2014

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Vol. 40, no. 1

3--12

EN

Eco-friendly leather processes based on the usage of natural products have become a potentially attractive issue for leather industry during the last few decades. Synthetic protective chemicals like bactericides used in most soaking process are known as hazardous substances and cause tannery effluents with high concentrations of Chemical Oxygen Demand (COD). In the present study, the effect of tannic acid on microorganisms, skin, wool and effluent were investigated in order to demonstrate the applicability of tannic acid in soaking process instead of commonly used bactericides. The bacterial load (cfu/ml), COD and Nitrogen Content (N) of the soaking effluents and Total Kjeldahl Nitrogen (TKN) content of skins and wools were investigated. Application of 0.5 and 1 wt% tannic acid concentrations was more effective than commercial bactericide, while comparable results were achieved by 0.1 and 0.3 wt% tannic acid. The application of tannic acid for soaking process resulted in lower COD and N values of effluents. The results show that tannic acid has the potential to be an alternative, eco-friendly bactericide for leather industry by reducing the pollution of leather soaking process.

6

A model of agglomerate formation during bed wetting in the process of disc granulation

Obraniak A., Gluba T.

Chemical and Process Engineering

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2012

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Vol. 33, nr 1

153-165

EN

This paper presents a method for quantitative assessment of the mechanisms of nucleation and granules growth by layering in the process of bed wetting during periodic disc granulation. This study included two initial, consecutive stages of a process with defined time courses. The first phase was a time period, in which only formation of new nuclei took place, while in the second stage simultaneous nucleation and growth of granules as a result of sticking raw material grains to preexisting nuclei occurred. Different kinds of binding liquid were used for bed wetting in each phase. In the first phase, an aqueous solution of dye was used, and pure distilled water in the second stage. The contribution of particular mechanisms to the formation of agglomerates at different time points within the second phase of the process was determined in this study. To do that the results of bed granulometric analysis, mass balance of size fractions and the analysis of contents of a marker (dye) delivered to the bed with the binding liquid during the first phase in agglomerates were used. To assess the concentration of the dye in different size fractions of the batch, spectrophotometric analysis was utilised. The study was performed using UV-VIS JASCO V-630 spectrophotometer equipped with an integrating sphere. The sieve analysis, spectrophotometric studies and mass balance were used to determine changes in the weight of the dye containing nuclei and of the nuclei containing no dye. The aforementioned analyses were also used to assess changes in the weight of formed granules and of raw material particles attached to nuclei during simultaneous nucleation and growth of granules.

7

Zmiany zdolności i energii kiełkowania ziarna jęczmienia browarniczego w wyniku moczenia w różnych warunkach ciśnieniowych

Rydzak L., Bożek W.

Inżynieria Rolnicza

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2007

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R. 11, nr 5 (93)

375-382

PL

W pracy podjęto próbę oceny wpływu zabiegu wstępnego moczenia ziarna jęczmienia browarnego w podciśnieniu na jego zdolność i energię kiełkowania. Ziarno nawilżano w systemie zalewowym w komorze próżniowej, w ciśnieniu 5 i 100 kPa (ciśnienie atmosferyczne) i w temperaturach wody od 15 do 50°C. Czas kontaktu ziarna i czynnika nawilżającego wynosił od 0,5 do 10min. Badano udział procentowy ilości ziaren skiełkowanych w poddawanej słodowaniu masie ziarna, wyznaczając energię i zdolność kiełkowania. Stwierdzono istotne zależności zdolności i energii kiełkowania po procesie od ciśnienia w komorze nawilżacza. Ponadto stwierdzono znaczące różnice w budowie morfologicznej nasion kiełkujących po wstępnym moczeniu w ciśnieniu atmosferycznym i w podciśnieniu 5 kPa.

EN

The paper is an attempt to assess the effect of presoaking of brewer's barley grain under vacuum conditions on its sprouting capability and energy. The grain was soaked in the filling system in the vacuum chamber, under pressure of 5 and 100kPa (atmospheric pressure) and at water temperatures from 15 to 50°C. The time of grain and soaking medium contact ranged from 0,5 to 10min. The percentage share of number of sprouted grains in grain mass put to malting, was analyzed by setting the sprouting energy and capability. The tests demonstrated significant dependencies of sprouting capability and energy after the pressure process in the humidifier chamber. The tests additionally revealed significant differences in morphological structure of sprouting seeds after presoaking under atmospheric pressure and in vacuum of 5 kPa.