Hemp Fiber Reinforced Geopolymer Composites: Effects of NaOH Concentration on Fiber Pre-Treatment Process

2020 ◽  
Vol 841 ◽  
pp. 166-170
Author(s):  
Phattharachai Maichin ◽  
Teewara Suwan ◽  
Peerapong Jitsangiam ◽  
Prinya Chindaprasirt

High demand for using parts of natural materials, e.g., cores, fibers or leaves, as alternative additives are being increased. The main reasons are that natural materials can be served as renewable and eco-friendly choices such a sustainable development. Nevertheless, some limitations of applying those natural products, such as biodegradation, UV degradation, or weak bonding, are raised and need to be modified before further handling. One of the modification techniques for bio-based materials is chemical treatment by using alkaline solution (alkalization). Treatment process allows the plant's fiber to have fewer impurities as well as to increase the bonding on its contacting surface area. This research focuses on (i) effects of NaOH solution concentration on the pre-treatment properties of hemp fibers and (ii) self-treatment behavior of hemp fiber in geopolymer composites. The results show that the concentration of NaOH solution directly affected the pre-treatment process of hemp fiber as higher concentration from 1, 3, 5, 8, 10 to 12 Molar provided more vanishing level of fiber impurities, indicated by Contact Angle (CA) measurement and Fourier Transform Infrared (FT-IR) Spectroscopy analysis. With the concept of alkaline treatment, the self-treatment process was therefore applied for hemp fiber incorporated in alkaline-activated geopolymer matrix. The results illustrate the self-treatment behavior of hemp fiber in geopolymer composites, which could improve the final performances of the hardened products without conventional pre-treatment process.

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 511 ◽  
Author(s):  
Eyerusalem A. Taye ◽  
Judith A. Roether ◽  
Dirk W. Schubert ◽  
Daniel T. Redda ◽  
Aldo R. Boccaccini

Novel hemp fiber reinforced geopolymer composites were fabricated. The matrix was a new geopolymer based on a mixture of red mud and fly ash. Chopped, randomly oriented hemp fibers were used as reinforcement. The mechanical properties of the geopolymer composite, such as diametral tensile (DTS) (or Brazilian tensile) strength and compressive strength (CS), were measured. The geopolymer composites reinforced with 9 vol.% and 3 vol.% hemp fiber yielded average DTS values of 5.5 MPa and average CS values of 40 MPa. Scanning electron microscopy (SEM) studies were carried out to evaluate the microstructure and fracture surfaces of the composites. The results indicated that the addition of hemp fiber is a promising approach to improve the mechanical strength as well as to modify the failure mechanism of the geopolymer, which changed from brittle to “pseudo-ductile”.


2007 ◽  
Vol 352 ◽  
pp. 297-300
Author(s):  
Toshikazu Akahori ◽  
Mitsuo Niinomi ◽  
Masaaki Nakai

Titanium and its alloys have been widely used as biomaterials for hard tissue replacements because of their excellent mechanical properties and biocompatibility. However, the bonding between their surfaces and bone is not enough after implantation. The bioactive surface modification such as a hydroxyapatite (HAp) coating on their surfaces has been investigated. Recently, a simple method for forming HAp layer on the surfaces of titanium and its alloys has been developed. This method is called as alkaline treatment process. In this method, HAp deposits on the surfaces of titanium and its alloys by dipping into simulated body fluid (SBF) after an alkaline solution treatment that is followed by a baking treatment (alkaline treatment). This process is applicable to newly developed beta-type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) for biomedical applications achieving bioactive HAp modification. In this study, the morphology of the HAp layer formed on the surface of TNTZ was investigated after various alkaline treatments followed by dipping in SBF. The formability of HAp on the surface of TNTZ was then discussed. The formability of HAp on TNTZ is much lower than that of commercially pure Ti, Ti-6Al-4V ELI and Ti-15Mo-5Zr-3Al alloys, which are representative metallic biomaterials. The formability of HAp on TNTZ is improved by increasing the amount of Na in the sodium titanate gels formed during an alkaline solution treatment where the NaOH concentrations and the dipping time are over 5 M and 172.8 ks, respectively. The formability of HAp on TNTZ is considerably improved by dipping in a 5 M NaOH solution for 172.8 ks. This condition for alkaline solution treatment process is the most suitable for TNTZ.


2021 ◽  
Vol 03 (02) ◽  
pp. 130-134
Author(s):  
N. Khatun ◽  
M. Misbahuddin ◽  
D. Biswas ◽  
U. Roy

Rubber (Hevea brasiliensis) wood (stem and branch) chips were pulped to produce hardboard for industrial use. Hardboards were made by thermo mechanical (steaming) and chemo mechanical processes for making hardboard to assess their suitability. In the thermo mechanical process, chips under 7.03 kg/cm2 and 10.55 kg/cm2 digester pressure each for 30, 60 and 90 minutes. In the chemo mechanical (chemical pre-treatment) process, chips were soaked in 1, 2, 3% NaOH solution under atmospheric pressure at 24 hours soaking time. Hardboards were tested to determine their modulus of rupture and water resistance properties. Results showed that chemically treated boards are stronger than steam softening boards. The boards made from rubber branches are much stronger than rubber stems.


2021 ◽  
pp. 004051752110003
Author(s):  
Ruoying Zhu ◽  
Ye Yu ◽  
Wenfang Yang ◽  
Jin Zhao ◽  
Guigang Shi ◽  
...  

Hemp fiber has excellent performance as a renewable fiber material. It is of great significance to study more efficient, energy-saving and environmentally friendly pre-treatment methods of hemp textiles. A novel hemp fiber scouring method based on electrochemical techniques was presented in the research. A type of water solution with high and stable oxidative potential due to in-situ- generated oxidative components was produced by the proposed electrical method, and was applied to scouring treatment of raw hemp fibers by just soaking the fibers in it. Hemp fibers with different treatments were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction, and residual gum rate, lignin content and whiteness of the samples were tested. Experiment results show that electrochemical scouring has a similar degumming effect of hemp fibers compared with traditional chemical scouring, with a better lignin removal and whiteness, implying an effective and short process method of hemp textiles pre-treatment with low impact on the environment.


Author(s):  
I. Baltiņa ◽  
Z. Zamuška ◽  
V. Stramkale ◽  
G. Strazds

Each year more and more people focus on healthy, ecological and environmental-friendly living. Environmentally friendly lifestyle doesn’t mean that we are using only natural products, but attention is pointed to the manufacturing and production process also. The rapid development of recycled and biodegradable products causes expanding usage of hemp fibers both in household and technical textiles. The analysis of hemp cultivation and usage trends in the world and Europe shows that hemp cultivation and processing in Latvia has good perspectives. Product quality is influenced by raw materials. In this case it is hemp fiber descriptive characteristics. Hemp fibers are natural fibers and their properties varies according to plant growing regional climatic conditions, amount of manure, plant density, harvesting time and pre-treatment technological processes. There are studied the influence of above mentioned factors on chemical composition, geometrical and physical properties of the Latvian hemp fiber both local and foreign cultivars. The work was carried out in cooperation between Riga Technical University, Textile Technology and Design Institute and the Agriculture Science Centre of Latgale.


1986 ◽  
Vol 18 (9) ◽  
pp. 163-173
Author(s):  
R. Boll ◽  
R. Kayser

The Braunschweig wastewater land treatment system as the largest in Western Germany serves a population of about 270.000 and has an annual flow of around 22 Mio m3. The whole treatment process consists of three main components : a pre-treatment plant as an activated sludge process, a sprinkler irrigation area of 3.000 ha of farmland and an old sewage farm of 200 ha with surface flooding. This paper briefly summarizes the experiences with management and operation of the system, the treatment results with reference to environmental impact, development of agriculture and some financial aspects.


2018 ◽  
Vol 2018 (4) ◽  
pp. 103-117
Author(s):  
Bipin Pathak ◽  
Ahmed Al-Omari ◽  
Scott Smith ◽  
Nicholas Passarelli ◽  
Ryu Suzuki ◽  
...  

2021 ◽  
pp. 004051752110277
Author(s):  
Qilu Cui ◽  
Jiawei Li ◽  
Chongwen Yu

In this paper, the extraction process of flavonoids from hemp fibers was studied. Response surface methodology (RSM) analysis of the extraction parameters indicated that optimized results would be ethanol concentration 76 vol.%, bath ratio 1:50, and reaction time 139 min; therefore, an optimal extraction rate of flavonoids of 0.2275% can be obtained. The chemical structure, surface morphology and element composition of flavonoid extracts were analyzed. The test results indicated that hemp extract contains flavonoids, which can be used to extract flavonoids from hemp fiber, so as to comprehensively develop hemp fiber and reduce the discharge of waste liquid in the traditional degumming process.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Anita Ejiro Nwaefuna ◽  
Karl Rumbold ◽  
Teun Boekhout ◽  
Nerve Zhou

AbstractBioethanol from abundant and inexpensive agricultural and industrial wastes possesses the potential to reduce greenhouse gas emissions. Bioethanol as renewable fuel addresses elevated production costs, as well as food security concerns. Although technical advancements in simultaneous saccharification and fermentation have reduced the cost of production, one major drawback of this technology is that the pre-treatment process creates environmental stressors inhibitory to fermentative yeasts subsequently reducing bioethanol productivity. Robust fermentative yeasts with extreme stress tolerance remain limited. This review presents the potential of dung beetles from pristine and unexplored environments as an attractive source of extremophilic bioethanolic yeasts. Dung beetles survive on a recalcitrant lignocellulose-rich diet suggesting the presence of symbiotic yeasts with a cellulolytic potential. Dung beetles inhabiting extreme stress environments have the potential to harbour yeasts with the ability to withstand inhibitory environmental stresses typically associated with bioethanol production. The review further discusses established methods used to isolate bioethanolic yeasts, from dung beetles.


2013 ◽  
Vol 559 ◽  
pp. 13-18 ◽  
Author(s):  
Anna Borisova ◽  
Skaidrīte Reihmane

Successful results of textile materials finishing process in order to gain desired properties to the fabric according to customers’ demands mainly depend on properly-carried pre-treatment stages. The present study covers twill weave cotton/polyester fabric’s modification in alkaline medium at different temperatures and treatment durations through exhaustion (hot and cold treatment) and pad-steam process. An influence of the reduction agent addition was ascertained. Weight loss, water absorbency, vertical wicking, dye uptake, colour measurements, surface morphology and psysicomechanical characteristics were determined. Samples and recommendations of optimal alkaline treatment technologies are developed.


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