Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Števulová, Nadežda; Estokova, Adriana; Cigasova, Julia; Schwarzova, Ivana; Kačík, František; Geffert, Anton

doi:10.1007/s10973-016-6044-z

Cited by 54 publications

(40 citation statements)

References 41 publications

(53 reference statements)

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“…Better compaction could be achieved by the improved adhesion between the hemp hurd particles and the matrix. No changes in the contents of the main cellulosic and non-cellulosic components in ultrasound-modified hemp hurds were observed [65]. In accordance with [66], lignin and wood extractives protect the fiber from mineralization phenomena.…”

Section: Resultsmentioning

confidence: 52%

Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder

et al. 2018

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This experimental study was focused on the application of a surface-modified hemphurds aggregate into composites using an alternative binder of MgO-cement. This paper presents the results of the comparative study of the parameters (chemical and physico-chemical modification, and hardening time) affecting the physical (density, thermal conductivity coefficient and water-absorption behavior) and mechanical properties (compressive strength) of the bio-aggregate-based composite. A test of the parameters of the bio-composite samples showed some differences, which were determined by the chemical and surface properties of the modified filler, and which affected the mechanisms of hardening. The bulk density values of the hemp hurd composites hardened for 28 days place this material in the lightweight category of composites. The values of water absorption and the thermal conductivity coefficient of bio-composites decreased, and the strength parameter increased with an increase in the hardening time. The lower values of compressive strength, water absorption, and thermal conductivity coefficient (except for the ethylenediaminetetraacetic-acid-treated filler) were observed in composites based on fillers chemically treated with NaOH and Ca(OH) 2 ) compared to referential composites (based on original hemp hurds). This is related to changes in the chemical composition of hemp hurds after chemical modification. The composites with ultrasound-treated hemp hurds had the greatest strengths at each hardening time. This is related to pulping the bundles of fibers and forming a larger surface area for bonding in the matrix. demand for natural fibers is growing worldwide and its price is increasing, it is still significantly lower than that of synthetic fibers; these plants need further research with respect to the opportunities for their use, and to provide novel products with improved properties. Among a wide variety of lignocellulosic material sources, a great importance is given to technical hemp (Cannabis Sativa) for its application in bio-composites. Industrial hemp is becoming a major focus of the green housing segment because of its energy-efficient cultivation, and because hemp-based composites have no negative effects on human health [5]. The excellent physical and mechanical properties of hemp, including low density, high specific stiffness and strength, biodegradability, sound absorption, low processing costs and the ecological suitability of this fast-growing, carbon-negative and non-toxic plant, predispose it for use in building materials (bio-composites) based on inorganic matrices [6], mainly for their application in the housing construction [7]. Traditional building materials, such as concrete, are increasingly being replaced with advanced composite materials in accordance with the principles of sustainability in civil engineering. One of the options involves a partial replacement of cement with active cementitious substances, such as mineral or industrial solid byproducts and wastes (metakaolin, coal and municipal s...

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Section: Resultsmentioning

confidence: 52%

Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder

et al. 2018

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“…There were some difficulties in characterizing the decomposition behavior of substances forming cellulosic fiber samples and recognizing the progress of individual degradation actions occurring during their heating as a result of the complexity of its microstructure [25]. We have encountered a similar problem in the thermal degradation studying of organic compounds present in hemp hurds samples [52]. While only slight differences were observed between the samples in DTG curves during the course of the degradation (Figs.…”

Section: Thermal Degradation Characteristicsmentioning

confidence: 99%

Characterization of Manmade and Recycled Cellulosic Fibers for Their Application in Building Materials

Števulová¹,

Hospodárová²,

Estokova³

et al. 2019

Journal of Renewable Materials

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The aim of this study was to characterize two types of cellulosic fibers obtained from bleached wood pulp and unbleached recycled waste paper with different cellulose content (from 47.4 percent up to 82 percent), to compare and to analyze the potential use of the recycled fibers for building application, such as plastering mortar. Changes in the chemical composition, cellulose crystallinity and degree of polymerization of the fibers were found. The recycled fibers of lower quality showed heterogeneity in the fiber sizes (width and length), and they had greater surface roughness in comparison to high purity wood pulp samples. The high purity fibers (cellulose content > 80.0 percent) had greater crystallinity and more homogeneous and smooth surfaces than the recycled fibers. The presence of calcite and kaolinite in all of the recycled cellulosic fibers samples was confirmed, whereas only one wood pulp sample contained calcite. The influence of the chemical composition was reflected in the fiber density values. Changes in the chemical composition and cellulose structure of the fibers affected the specific surface area, porosity and thermo physical properties of the fibers. More favorable values of thermal conductivity were reached for the recycled fibers than for the wood pulp samples. Testing the suitability of the recycled fibers with inorganic impurities originating from the paper-making processes for their use as fillers in plastering mortars (0.5 wt.% fiber content of the total weight of the filler and binder) confirmed their application by achieving a compressive strength value of 28 day-cured fiber-cement mortar required by the standard as well as by measured more favorable value of capillary water absorption coefficient.

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“…Thus, the selection of the "maximum permissible temperature" for the processing window will depend on the anticipated time that the polymer and functional filler will be in the extruder or injection molding machine barrel. The effect of time on thermal degradation at different temperatures has been well documented for wood fillers and other lingo-cellulosic fillers such as hemp and flax [4,5]. The thermal degradation of coconut shell has also been studied extensively by Macedo et al [6].…”

Section: Literature Survey 21 Maximum Allowable Processing Temperaturementioning

confidence: 99%

The Effect of Coconut Shell Powder as Functional Filler in Polypropylene during Compounding and Subsequent Molding

et al. 2019

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Fine powder produced from coconut shells (CSP) has been found to be excellent functional filler in polypropylene, significantly increasing flexural and tensile moduli, slightly increasing tensile strength, and good retention of Izod impact strength at weight percentages less than 20 %. The research presented in this paper explores the temperature processing window for coconut shell powder filled polypropylene and the change in the rheological behavior of the polypropylene due to the addition of CSP as functional filler in this processing temperature window. The reason for the simultaneous increase in flexural modulus, tensile strength, and good retention of Izod impact behavior is also investigated

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Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Cited by 54 publications

References 41 publications

Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder

Sustainable Bio-Aggregate-Based Composites Containing Hemp Hurds and Alternative Binder

Characterization of Manmade and Recycled Cellulosic Fibers for Their Application in Building Materials

The Effect of Coconut Shell Powder as Functional Filler in Polypropylene during Compounding and Subsequent Molding

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