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Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum

Trociński Adrian, Wieruszewski Marek, Kawalerczyk Jakub, Mirski Radosław

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2023

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No. 121

29--36

EN

Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum. The popularity of composites reinforced with natural fibers is constantly growing and therefore, they are a subject of many scientific works as well. An example of interesting concept is the use of hemp fibers to reinforce a gypsum matrix and therefore, presented study was aimed to determine the effect of their content on the properties of resultant composites. Moreover, the influence of setting temperature was also investigated. The scope of the research included determination of properties such as: density, setting time, bending strength, modulus of elasticity and thermal conductivity coefficient. Studies have shown that as the amount introduced fibers increases, the density of manufactured composites decreases. Furthermore, increase in the content of hemp causes a significant extension in setting time of the gypsum matrix. Based on the outcomes of mechanical properties, it was found that the optimal content of fibers is 4% and further increase in their share results in a deterioration of flexural strength characteristics. The increase in a setting temperature leads to the reduction in their bending strength and modulus of elasticity. Composites reinforced with hemp fibers demonstrate significantly improved thermal insulation properties

PL

Właściwości kompozytów włóknisto-gipsowych powstałych na bazie włókien konopi siewnej (Cannabies sativa L.) uprawianych w Polsce i gipsu naturalnego. Popularność kompozytów wzmacnianych włóknami naturalnymi nieprzerwanie rośnie, co sprawia, że są one przedmiotem wielu badań naukowych. Przykładem interesującej koncepcji jest wykorzystanie włókien konopi siewnej w celu wzmocnienia płyt gipsowych. A zatem, przeprowadzone zostały badania dotyczące wpływu ilości dodawanych włókien konopnych oraz temperatury sieciowania wzmocnionej matrycy na właściwości wytworzonych kompozytów gipsowych. Zakres przeprowadzonych eksperymentów obejmował określenie gęstości, czasu sieciowania, wytrzymałości na zginanie, modułu sprężystości oraz współczynnika przewodzenia ciepła. Badania wykazały, iż wraz ze wzrostem udziału włókien czas sieciowania matrycy znacznie się wydłuża, a gęstość otrzymywanych kompozytów maleje. Wykazano również, iż optymalną ilością wzmocnienia konopnego zapewniającą najlepsze właściwości wytrzymałościowe jest 4%, a dalsze zwiększenie jego udziału powoduje znaczne pogorszenie wytrzymałości. Ponadto zwiększenie temperatury podczas sieciowania wpływa negatywnie na charakterystykę wytrzymałościową wyprodukowanych płyt. Właściwości izolacyjne ulegały natomiast znacznej poprawie wraz z rosnącym udziałem włókien konopnych w płycie gipsowej.

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Removal of lead(II) and zinc(II) from aqueous solutions applying fibber hemp (Cannabis sativa L.)

Paliulis Dainius

Ecological Chemistry and Engineering. S

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2021

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Vol. 28, nr 2

229--239

EN

Lead and zinc are heavy metals with toxic properties. These chemical elements are found in wastewater. The article deals with the removal of lead(II) and zinc(II) ions from polluted water using adsorption. As object of researches was selected natural polymer - fibber hemp (Cannabis sativa L.). Big quantities of fibber hemp are produced as waste in textile, agricultural industry, and therefore their usage could help to solve two problems - reducing quantity of fibber hemp as waste and reducing of water pollution by heavy metals. Pb(II) and Zn(II) ions adsorption with fibber hemp was investigated for contact time, pH, and heavy metal ions concentration impact. Pb(II) and Zn(II) ions biosorption rate was highest within the first hour, with optimal their biosorption recorded at pH = 5.0. Highest lead and zinc ions removal efficiency was recorded after 240-480 min and reached 60.5 and 61.7 % respectively. This study demonstrated the applicability and effectiveness of fibber hemp in lead and zinc ions removal, which could be applied for the sewage treatment plant in small scale.

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Experimental Study on the Durability Characteristics of Several Vegetable Fiber Reinforced Concretes Exposed to Sodium Sulfate

Ziane Sami, Khelifa Mohammed-Rissel, Mezhoud Samy, Beroual Ahmed, Medaoud Saber

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 1

1--28

EN

Recently, numerous plant fibers have been investigated as a means to reinforce concrete and replace synthetic fibers, thereby producing more eco-friendly concretes. The primary concern for these studies is the durability of the fibers in the external environment. For this purpose, the current paper presents a comparison study on the physical-mechanical behavior and durability against external sulfatic attack on Alfa and Hemp fiber-reinforced concrete. To assess the effects of sulfatic attack, different types of concrete underwent two aging protocols: 1) a complete immersion in 12.5 % Sodium Sulfate (Na2SO4) solution and, 2) an accelerated aging protocol which consisted of immersion/drying in the same sulfate solution at a temperature of 60°C. The results show that the optimal amount of plant fiber is variable, depending on several parameters such as the chemical composition, mechanical characteristics, and morphology of the fiber. In addition, the results show that the use of Alfa and hemp fibers could facilitate the production of green and durable structural concretes.

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The Optimization of PHBV-hemp Fiber Biocomposite Manufacturing Process on the Selected Example

Frącz Wiesław Jan, Janowski Grzegorz, Bąk Łukasz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 2

127--137

EN

In this work, a modern biocomposite on the base of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) matrix commonly known as PHBV was produced in the extrusion process, containing 30% by weight of hemp fibers. The use of the above-mentioned filler allowed to reduce the producing costs of the composite material compared to pure PHBV, improving, among others, some mechanical properties of products made of this biocomposite while maintaining full biodegradation. The obtained biocomposite can be successfully used for the production of injection molded products, but its processing properties are not yet fully known and consequently it is difficult to obtain the optimal performance properties of the products. As part of this study, the process of optimization of the production process of products from the PHBV-hemp fiber biocomposite was carried out on the example of samples intended for testing in the uniaxial tensile test. By using orthogonal planes, widely used in optimization process, the required number of injection molding tests was reduced. Input data values were determined by the factorial planning method that is commonly used in designing experiments. The calculations were carried out in the Minitab 18 software. Six controlling factors were used in the analyzes, each of which was subject to changes on three levels. When selecting the range of controlling factors, it was initially assumed that for all assumed levels of variability it must be possible to fill the mold cavity completely. The orthogonal plan of the L27 type was used in the research. For the purposes of the method, an orthogonal table was built containing 27 combinations of parameters subject to optimization. Optimization was undertaken for two main criteria: shrinkage of the ,,dog-bone” samples (primary and secondary volumetric shrinkage), mechanical properties (Young's modulus, tensile strength, elongation at break). By means of Taguchi method, a significant improvement of some product mechanical properties made of biocomposite was noted and the effective reduction of the processing shrinkage was observed.

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A study of the durability of concrete reinforced with hemp fibers exposed to external Sulfatic attack

Ziane Sami, Khelifa Mohammed-Rissel, Mezhoud Samy

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 2

158--180

EN

The purpose of this paper is to study the durability of concrete reinforced with hemp fibers in the face of external Sulfatic attack. For this purpose, five types of concrete were formulated; three types of concrete reinforced with hemp fibers (HC-0.25, HC-0.5, and HC-1) at 0.25%, 0.5%, and 1 % of hemp fibers in volume, respectively. And two control concretes, being ordinary concrete (OC) and polypropylene fiber reinforced concrete (PC). To assess the sulfatic attacks, the described concrete types underwent two aging protocols: 1) a complete immersion in 12.5 % Sodium Sulfate (Na2SO4) solution, and 2) an accelerated aging protocol consisting of immersion/drying in the same sulfate solution at a temperature of 60°C. The results show that concrete reinforced with 0.25 % of hemp fibers is the optimal amount compared to control concretes in terms of physico-mechanical performance and durability under sulfate attack. This number of fibers could enable the production of green and durable structural concretes based on untreated hemp fibers.

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Wpływ chemicznej modyfikacji włókien konopnych na wybrane właściwości mechaniczne kompozytów na osnowie polipropylenowej

Pach J., Kaczmar J. W.

Polimery

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2011

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T. 56, nr 5

385-389

PL

Wytworzono kompozyty na podstawie polipropylenu, z dodatkiem włókien konopnych i kompatybilizatora (kopolimeru szczepionego polipropylenu z bezwodnikiem maleinowym, MAH-PP). Składniki kompozytów wstępnie homogenizowano na walcach, a kształtki do badań formowano metodą wtryskiwania. Włókna konopne poddawano chemicznej modyfikacji w procesie acetylowania, alkalizacji bądź obróbki bezwodnikiem maleinowym. Badano wpływ takiej modyfikacji na wybrane właściwości mechaniczne wytworzonych kompozytów (wytrzymałość na rozciąganie statyczne, wydłużenie przy zerwaniu, moduł Younga oraz udarność bez karbu wg Charpy'ego). W przypadku kompozytów z dodatkiem modyfikowanych chemicznie włókien oraz kompatybilizatora zaobserwowano wzrost wytrzymałości na rozciąganie i modułu Younga oraz spadek wydłużenia przy zerwaniu i udarności w stosunku do odpowiednich wartości czystego PP.

EN

The synthesis of composites based on polypropylene (PP) (Table 1), hemp fibers (Table 2) and a compatibilizer (polypropylene grafted with maleic anhydride -MAH-PP) has been presented. The components were initially homogenized on heated roll mills, and the shapes of the test specimens obtained by injection molding. The hemp fibers were subjected to chemical modification namely: acetylation, alkylation or treatment with maleic anhydride. The influence of such modification on selected mechanical properties of the composites (static tensile strength, elongation at break, Young's modulus, and Charpy impact strength) was studied. In the case of composites containing the chemically modified fibers and compatibilizer, an increase in tensile strength and Young's modulus while a decrease in elongation at break and impact strength in comparison with the virgin PP (Figs. 1-4).

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Ekologiczne maty dezynfekcyjne wykonane z włókna konopnego

Mańkowski J., Kubacki A., Kołodziej J.

Przemysł Chemiczny

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2008

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T. 87, nr 12

1164-1166