Chemical Modification of Hemp Shives and their Characterization

Terpáková, Eva; Kidalova, Lucia; Estokova, Adriana; Cigasova, Julia; Števulová, Nadežda

doi:10.1016/j.proeng.2012.07.486

Cited by 71 publications

(25 citation statements)

References 10 publications

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“…The most serious drawback of these natural fibers is their hydrophilic nature, which causes a fragile interfacial bonding between fiber and matrix in polymer composites . Various physical impurities and the hydroxyl groups present on the fiber surface determine the fate of natural fibers as enforcement materials . Several research studies have been carried out on the surface modification and treatments of natural fibers to achieve the desired qualities .…”

Section: Natural Fibersmentioning

confidence: 99%

“…However, the mechanical performance of a composite material also depends on the orientation and nature of fibers and matrix, while the fibers‐matrix bonding plays a very important role as well . The weak bonding between fibers adversely affects the mechanical strength of fiberboard . The main setback of natural fiber composites lies in the hydrophilic nature of the natural fiber and the hydrophobic nature of the polymer matrix .…”

Section: Natural Fibersmentioning

confidence: 99%

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Natural fiber reinforced polylactic acid composites: A review

et al. 2018

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Biopolymer‐based composites have attracted the attention of researchers and industries due to their eco‐friendliness and environmental sustainability, as well as their suitability for a number of applications. Biocomposites containing natural fibers and biopolymers would be the ideal choice in the development of biodegradable materials for different applications. Polylactic acid (PLA) is an environmentally interesting biopolymer, which also has exclusive qualities, such as good transparency and processability, glossy appearance, and high rigidity, although it has some shortcomings as well, for example, its brittleness and high rate of crystallization. PLA‐based natural fiber composites are entirely bio‐based materials with promising biodegradability and mechanical properties. Several research studies have been carried out on PLA and its composites to explore their potential to substitute petroleum‐based products, but until now there is no comprehensive review with up‐to‐date research data available in the literature. The aim of this review is to highlight the trends in the research and development of PLA and PLA‐based natural fiber composites over the past few years. This review article covers current research efforts on the synthesis and biodegradation of PLA, its properties, trends, challenges and prospects in the field of PLA and its composites. PLA‐based composites are moderately abundant; and further research and development is needed for cost reduction and broader utilization. POLYM. COMPOS., 40:446–463, 2019. © 2018 Society of Plastics Engineers

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Section: Natural Fibersmentioning

confidence: 99%

Section: Natural Fibersmentioning

confidence: 99%

Natural fiber reinforced polylactic acid composites: A review

et al. 2018

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“…On the third interval the maximum percentage loss was 2.94% for M1, at around 450 • C. For the temperature range from 500 to 1000 • C there was approximately a 20% mass loss at the temperature of 767 • C. According to the scientific literature, the thermal analysis of the cement paste is characterized by the discomposure of ettrinigite at a temperature of 120-130 • C, the C-S-H gel below 150 • C, the non-hydrated gypsum at about 140 to 170 • C and CH (portlandite) between 420 and 550 • C [67]. Reference [28] presented the thermal behavior of the hemp shiv treated with CaOH 2 (lime solution) and identified two temperature ranges for the degradation, the first one around 337 • C-when the depolymerisation of hemicellulose or pectin took place-and the second one, between 377-399 • C, when the cellulose decomposition occurred.…”

Section: Thermal Analysismentioning

confidence: 99%

“…The thermal analyses of the natural hemp shiv, presented in Figure 1c, showed a total degradation of 81.20%. The hemp shiv lost 3.6% on the first temperature interval from 20-200 • C and 77.6% on the second one, from 200 and 1000 • C. Compared with References [27,28], the second temperature interval is defined by the thermal combustion of hemicellulose and cellulose. The X-ray diffraction (XRD) of the hemp shiv was presented in a previous study [19], where the higher peak was recorded at 2 θ = 22.66 • , similar to the studies of References [25,29].…”

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Experimental Investigations on the Performances of Composite Building Materials Based on Industrial Crops and Volcanic Rocks

2020

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Interdisciplinary and sustainability represent the main characteristics of this paper due to the fact that this research is offering a connection between two main areas-agronomy and construction, by using hemp shiv for the design of new building materials, which can increase the sustainability level of the building industry. For this reason, the main scope of this study is based on the investigation of a new category of composite building materials-lightweight mortars based on hemp shiv, volcanic rocks and white cement-which contribute to a positive environmental impact and help to increase indoor comfort. A complex report was carried out on two segments. The first one is focused upon the characteristics of the raw materials from the composition of the new materials, while the second segment presents a detailed analysis of these composites including morphological and chemical investigation, pyrolytic and fire behavior, compression and flexural strengths, and acoustic and thermal characteristics. The proposed recipes have as a variable volcanic rocks, while the hemp and the binder maintain their volumes and properties. The results were analyzed according to the influence of volcanic rocks on the new composites.Crystals 2020, 10, 102 2 of 21 consideration in the construction sector. There is a significant number of studies on hemp shiv with lime, which is a composite material named hempcrete [12][13][14], but there are only few studies that concern hemp shiv with cement [15][16][17][18][19].Due to the fact that hemp shiv presents poor fire resistance, a new approach can be made with volcanic rocks, which are natural products with higher fire resistance [20]. These materials are usually found in the composition of mortars used in the rehabilitation process of the walls, because of their increased mechanical resistances [21]. They also present sound and thermal properties, as well as a low density, which will help the workability of the mortar. Durable and with higher strength properties for structural application [20], volcanic rocks are low cost materials [22] that also present fire retarding properties for steel structures [23].Therefore, the purpose of this paper is to analyze the impact of the volcanic rocks when these are incorporated in hemp-cement composite materials used as interior mortars. These building materials are developed to be suitable not only for eco-friendly construction but also in regular buildings made from concrete, steel, and so forth, where they can increase indoor comfort. Materials and Methods Raw MaterialsThe composition of the new materials is designed to increase indoor comfort by developing new types of lightweight mortars, obtained as prefabricated plates. In order to understand the characteristics of the new composites, hemp shiv, natural and treated; volcanic rocks, perlite and vermiculite; and binders, white cement and hydrated lime, were analyzed. Hemp ShivThe hemp shiv used for the new composites was received from HempFlax Romania (Pianu De Jos, Alba, Romania). The chemical stru...

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“…At the same time, it is shown that shives ( Fig. 1(B)), woody core particles of hemp stems, can be used in different fields, such as livestock bedding [1], horticultural mulch [2], chemical absorbents [3] and industrial insulating building materials [4] demonstrating excellent properties. By now, it is important to investigate a new processing technology that will broaden application areas, as well as improve efficiency of the usage of the shives comprising 80% of the plant biomass.…”

Section: Introductionmentioning

confidence: 99%

Extraction of highly purified microfibrils from the renewable resources by using green technology

Putnina¹,

Kukle²,

Grāvītis³

2013

Energetika

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The main task in preparing hemp shives for further processing is to remove noncellulosic substances without usage of strong chemical treatments applying the steam explosion (SE) auto-hydrolysis process. The results indicate that the SE has significant effects on lignin removal and distribution of hemp shives. Effects of pre-treatment temperature and duration on characteristics of the steam exploded shives are studied by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Key words: hemp shives, steam explosion, lignin, biomass IntroductIonThe synthetic man-made fibres can be replaced by the micro-and nano-scale cellulosic fibres obtained by green technologies. Eco-efficient green chemistry and industrial ecology are the guidelines for the development of next-generation materials, processes and products.Hemp (Cannabis sativa) ( Fig. 1 (A)) suitable for the Latvian climate is one of the fastest growing plants with a potential in a number of industrial areas. Hemp fibres obtained from straw can be used effectively in many applications, whereas shives are considered as an invalid part and are often combusted to get cheap fuel. At the same time, it is shown that shives ( Fig. 1(B)), woody core particles of hemp stems, can be used in different fields, such as livestock bedding [1], horticultural mulch [2], chemical absorbents [3] and industrial insulating building materials [4] demonstrating excellent properties. By now, it is important to investigate a new processing technology that will broaden application areas, as well as improve efficiency of the usage of the shives comprising 80% of the plant biomass.Several methods generally based on successive chemical [7,8] and mechanical [9] treatments are used to extract highly purified micro-fibrils from the plant cell wall. The steam explosion (SE) auto-hydrolysis is currently comprehensively studied as a promising green pre-treatment tech- 21Extraction of highly purified microfibrils from the renewable resources by using green technology nology [10] to obtain micro-fibrils of cellulose and also to remove lignin from the cellulose. Removal of lignin after SE makes the cellulose accessible for further processing, for example, by electro-spinning -a novel process of forcing a suspension by electric field through a spinneret to obtain superfine fibres.Effective usage of SE for treatment of the shives could provide lignin-free cellulose micro-fibrils. This could provide new application areas for shives where they could not be possible to use by now. MethodoloGyHemp shives of the local variety 'Purini' grown on the experimental fields of the Latgalian Agriculture Research Center LLZC (Latvia, Vilani District) were used as lignocellulosic biomass. Laboratory-type steam explosion equipment was used to make steam explosion treatment experiments [16].After steam explosion treatment, within a split second, the biomass is decompressed (exploded) to one atmosphere. Empirically, the so-called severity parameter or the reaction ordinate R 0 can be exp...

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Chemical Modification of Hemp Shives and their Characterization

Cited by 71 publications

References 10 publications

Natural fiber reinforced polylactic acid composites: A review

Natural fiber reinforced polylactic acid composites: A review

Experimental Investigations on the Performances of Composite Building Materials Based on Industrial Crops and Volcanic Rocks

Extraction of highly purified microfibrils from the renewable resources by using green technology

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