Removal Of Non-cellulosic Materials Research Articles

Removal of non-cellulosic materials from hemp fiber under ultrasonication conditions and cetyl trimethyl ammonium chloride (CTAC) catalyst

Recently, due to rising worries about global warming, pollution, and the sustainability of fossil resources, there has been a heightened interest in renewable and sustainable natural materials across different industries. Consequently, the use of renewable and sustainable natural fibers such as hemp instead of synthetic ones, such as glass and carbon has become more popular in certain composite material applications. A drawback of natural fibers including hemp is that their polar nature often leads to incompatibility at the fiber/matrix interface with nonpolar and hydrophobic matrices. This leads to weak adhesion between the fiber and matrix, resulting in reduced mechanical properties of the final composites. To enhance the performance of natural fiber composites, it is essential to modify the fibers. Non-cellulosic substances such as lignin, waxes, hemicelluloses and pectin present in the hemp fiber structure also affect the mechanical performance of composites due to poor fiber/matrix adhesion. In this study quaternary ammonium hydroxide was used in an ultrasonic-assisted pretreatment to increase the degradation rate of non-cellulosic substances in hemp fiber. Cetyl trimethyl ammonium chloride (CTAC) concentrations ranging between 1 and 8% w/w were used with a constant (10% w/w) NaOH concentration. Hemp fiber surfaces were analyzed using a scanning electron microscope (SEM). The findings revealed that ultrasonication-assisted alkali treatment effectively removed non-cellulosic substances from the fiber surface. This removal was further validated by TGA and FT-IR analysis.

Microwave-Assisted Chemical Purification and Ultrasonication for Extraction of Nano-Fibrillated Cellulose from Potato Peel Waste

Nanofibrillated cellulose was extracted from potato peel waste using a fast and green method with a simple process. To extract cellulose and eliminate non-cellulosic constituents, alkaline and hydrogen peroxide treatments were performed under microwave irradiation. The nanofibrillated cellulose was extracted from purified cellulose via TEMPO oxidation followed by ultrasonication. The TEM, FTIR, XRD, and TGA experiments were used to evaluate the structural, crystalline, and thermal properties of cellulose fiber and nanofiber. The chemical and FTIR analysis of bleached fibers indicates that almost all non-cellulosic components of biomass have been eliminated. The diameter of the extracted nanofibers is in the range of 4 to 22 nm. In terms of crystallinity, extracted nanocellulose had 70% crystallinity, compared to 17% for unprocessed lignocellulose fibers, which makes it an excellent choice for use as a reinforcement phase in biobased composites. Thermogravimetric analysis reveals that cellulose nanofibers are less thermally stable than potato peel pure cellulose, but it has a higher char content (28%) than pure cellulose (6%), which signifies that the carboxylate functionality acts as a flame retardant. The comparison between cellulose derived from microwave and conventional extraction methods confirmed that their impact on the removal of non-cellulosic materials is nearly identical.

Extraction and Characterization of Cellulosic Fibers from Jenfokie and Doby Stems: Effect of Extraction Methods on Physicochemical, Mechanical, and Thermal Properties

ABSTRACT This experimental study aims to explore natural lignocellulosic fibers from Jenfokie and Doby plants. The effect of the fiber (water-retted and non-retted) extraction methods on physical, mechanical, thermal, chemical, and crystallinity properties were experimentally investigated for fibers collected from the eastern highlands of Ethiopia. The chemical composition (cellulose, hemicellulose, lignin, extractives, etc.) was determined after different treatment processes. The tensile strength maximum of up to 72 cN/tex and 56 cN/tex, and cellulose content up to 85% and 81% were obtained for Jenfokie and Doby retted extracted fibers, respectively. There was small difference lignin extracted by Klason method and the alkaline hydrogen peroxide (APH) method. Each step-wise extracted fiber was characterized to cognize the intrinsic changes during the multi-step extraction process. The diameters were determined by Optical Microscope (OM), the removal of non-cellulosic materials by Fourier Transform Infrared (FT-IR) spectroscopy, the thermal stability (up to 375°C) by thermogravimetry (TGA), and the crystallinity index (up to 73%) by using X-ray Diffraction (XRD). An improvement in cellulose content, density, moisture absorption, tensile strength, thermal stability, and crystallinity of Jenfokie (unstudied or new) and Doby plant retted fibers would be promising for composite and textile materials.

INVESTIGATION OF QUALITY TARGET PROCESS PARAMETERS (QTPP) AND CRITICAL MATERIAL ATTRIBUTES (CMA) OF NANOCELLULOSE AS A POTENTIAL EXCIPIENT

Objective: The current work highlights the use of the Quality by Design (QbD) for optimization of Nanocellulose (NC) production from corn husk by two techniques, namely, Acid hydrolysis (AH) and High pressure homogenization (HPH).
 Methods: Characterization of NC involved Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM). For the risk assessment, QbD Software was used. According to this results 32 factorial design was applied in which two independent variables (acid concentration and time for AH whereas pressure and no of passes for HPH) and two dependent variables (particle size and yield) were selected.
 Results: FTIR showed similarity in the peaks which indicates there is no change in parent molecular structure of cellulose. TGA confirmed that the NC extracted by both the methods showed improved thermal property at onset temperature of 290 °C as compared to Avicel PH101, 270 °C. XRD results showed that the crystallinity index of the extracted nano cellulose from both the method was 83.15% which indicates transition and reorientation of corn husk into compact crystalline cellulosic structure after removal of non-cellulosic materials. TEM images indicated that the fibers were well dispersed and the treatment had reduced the size of fibers with average dimensions of 100 to 1000 nm in length. Product assay revealed that as the acid concentration and time is increased, narrow particle size is observed whereas lower number of passes and pressure resulted in a broader particle size. Studies on the variables and the experiment of NC preparation contributed a maximum yield of 77% in case of AH and 83 % in case of HPH.
 Conclusion: Evident from the results, NC prepared by QbD approach had better flow property and compatibility. Hence it is suitable for usage as an excipient in product design for variety of tailor made customized oral dosage forms in pharmaceutical industry.

Extraction and Characterisation of Cellulose Materials from Sri Lankan Agricultural Waste

Agriculture is a key sector of Sri Lankan economy today. Sri Lanka’s main food crop is rice. Rice is cultivated mainly in two seasons in the country. Rice production is the predominant form of agriculture which occupies 0.77 million hectares of the total cultivated area in Sri Lanka. Nevertheless, generation of enormous amounts of agricultural residues such as rice straw during rice production has become inevitable According to the statistics it is revealed that one ton of rice paddy produces 290 kg of rice straw. Regardless of these large amounts, rice straw is frequently abolished by open field burning by majority of farmers. However, recent researchers have reported that rice straw burning can be lethal towards human health due to the noxious emissions which cause various forms of environmental pollution. Hence, identifying the means of generating value added products by utilisation of rice straw has become a necessity today. Rice straw is a lingo cellulosic biomass which consists of biopolymers of cellulose, hemicellulose and lignin. Cellulose is the mostly abundant organic polymer on earth that can be identified as one of the most demanded advanced materials in engineering applications such as bio composites production. Therefore, developing a method to isolate cellulose from rice straw would be a convenient means of value addition to the agricultural waste. This research work is based on developing an environmentally friendly, efficient method to synthesise cellulose from rice straws of the most frequently cultivated hybrid rice variety (BG352) in Sri Lanka. BG 352 rice variety is cultivated in most of the areas in Sri Lanka today. High purity cellulose was extracted from rice straw by the removal of non-cellulosic materials. This chemical purification process consisted of dewaxing, delignification and hemicellulose and silica removal treatments. FTIR spectroscopy was used to verify the formation of pure cellulose during the extraction process. Further, morphology of extracted cellulose was studied by SEM analysis. It revealed that isolated cellulose was mostly in the form of fibers with diameters ranging from 2-8μm. This research showed that BG352 variety averagely has 16.1 wt.% wax, 38.2 wt.% lignin, 3.9% wt. hemicellulose and 12.3 wt.% silica content. Ultimately, average cellulose yield from rice straws of BG352 variety was observed as 30 wt.%. This extraction process can be used to synthesis the cellulose from Sri Lankan agricultural waste to convert it into a value added product. Keywords: Rice straw, Agricultural waste, Cellulose, Lignocellulosic, Biopolymer

Effect of mild alkali/ultrasound treatment on flax and hemp fibres: the different responses of the two substrates

Flax and hemp fibres were treated by various combinations of water/diluted alkaline solution and stirring/ultrasound, respectively. Changes in the microstructure (scanning electron microscopy) and porous structure (low-temperature nitrogen adsorption), removal of non-cellulosic materials (weight loss, FTIR), mean fibre diameter, and adhesion of the polypropylene matrix to the fibres (micro-bond test) were investigated. For both types of fibres, removal of (FTIR) was observed. The fibre diameter of hemp was decreased by several treatments, most of all by stirring in alkali and subsequent sonication in water, while the ultrasound applied in alkali solution did not change the fibre fineness. This can be attributed to the dual effect of ultra-sonication: the swelling effect of alkali combined with ultrasound energy probably served the sticking of inter-fibrillar material rather than their dissolution. Fibre diameter of flax did not change in any circumstances. The porosity of hemp in the mesopore range increased, while that of flax decreased by alkali treatment and subsequent sonication. The reason for this difference might be the dissimilar cell wall structures of the two bast fibres, the high arabinose content of the hemp, and/or the cottonisation of hemp. No treatments altered the fibre-matrix adhesion measured by pulling out the fibre from a micro-droplet of polypropylene.

Extraction and characterization of holocellulose fibers by microwave‐assisted selective liquefaction of bamboo

ABSTRACTMicrowave‐assisted selective liquefaction was proposed and used as a novel method for the isolation of holocellulose fibers. The results showed that the bamboo lignin component and extractives were almost completely removed by using a liquefaction process at 120 °C for 9 min, and the residual lignin and extractives in the solid residue were as low as 0.65% and 0.49%, respectively. Increasing the reaction temperature or time could decrease the solid yield, but they can also enhance the removal of lignin and extractives from bamboo particles and increase the holocellulose content in the solid residue. The absorbance bands that characterized functional groups of lignin on the Fourier transform infrared spectra of the solid residue weakened or disappeared. The solid residue showed high crystallinity, indicating the removal of noncellulosic material. Small cracks were observed on the SEM images of the residue, which indicated that the fibers from liquefaction may be susceptible to chemical access or enzyme attack. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43394.

Characterization of Adhesion Surface of Cellulosic Fibers Extracted from Agro Wastes

The adhesion characteristics of agro waste–derived fibers are examined in this study. Fibers obtained from groundnut shell, coconut shell, rice husk, palm fruit bunch, and palm fruit stalk are subjected to a combination of batch treatments in two distinctive ways. These batch fiber treatments involve mechanical defibrillation, steam explosion, acid hydrolysis, alkaline hydrolysis, and enzymatic hydrolysis. Topography, mean surface roughness, maximum surface roughness, skewness, and morphology of the resulting fibers are characterized using the atomic force microscopy and scanning electron microscopy. Results show that the treatments are effective in removal of noncellulosic materials and smoothening of fiber surface. This phenomenon would results in improvement in wettability between fiber and matrix in polymer composite applications. Palm fruit–derived fibers are found to retain a greater portion of noncellulosic materials compared to others. This is attributed to the high amorphous content of palm fruit with very low crystalline portion compared to others.

Novel and Efficient Method to Reduce the Jute Fibre Prickle Problem

College of Textiles, DongHua University, Shanghai, 201620, P. R. China E-mail: wdyu@dhu.edu.cn Abstract The physical especially bending properties of jute fibres treated with dimethyl sulphoxide (DMSO) were studied in this work. To the knowledge of these authors, the influence of DMSO treatment on the prickle properties of jute fibres has not been investigated earlier. The results of the investigation indicate that 8 hours of DMSO treatment at 80 °C leads to a decrease in the equivalent bending modulus of up to 38.3%. This decrease was due to the swelling of fibrils and the removal of non-cellulosic materials. It is significant to improve the wear behaviour of jute fabrics. Suitable chemical treatment not only slenderised the jute fibres, but also removed the wax dramatically.

Evaluation of liquid ammonia treatment on surface characteristics of hemp fiber

In this study, we investigated the effects of liquid ammonia treatment on the surface characteristics of hemp fibers. We determined the elemental composition, morphological structure, roughness, and wettability of fiber surface using techniques such as electron spectroscopy for chemical analysis, scanning electron microscopy, atomic force microscopy, and contact angle measurements. The lignin coverage on the hemp surface was calculated from the O/C ratio and the C1 content. The results show that lignin removal from the fiber surface was significantly greater than that from the fiber bulk. After the treatment, the O/C ratio of hemp fibers increased, and cellulose was exposed. The proportion of O2 species that contributed to formation of hydrogen bonds increased; this further increased the number of hydrophilic groups in the hemp fibers, improving the fiber wettability. The liquid ammonia treatment did not change the large dislocation structures in hemp fibers, but the removal of noncellulosic materials from the fiber surface increased the roughness of the fiber surface.

Enhancement of tensile strength of lignocellulosic jute fibers by alkali-steam treatment

The physico-chemical properties of jute fibers treated with alkali (NaOH) solution have been investigated in this study. The treatments were applied under ambient and elevated temperatures and high pressure steaming conditions. To the knowledge of these authors the influence of alkali-steam treatment on the uniaxial tensile strength of natural ligno-cellulosic fibers, such as jute, has not been investigated earlier. The results from this investigation indicate that a 30 min dipping of the fibers in 0.5% alkali solution followed by 30 min alkali-steam treatment leads to an increase in the tensile strength of up to 65%. The increase appears to be due to fiber separation and removal of non-cellulosic materials, which, in turn, resulted in an increased crystallinity.