Analysis of cellulose nanocrystals (CNCs) with flow cytometry (original) (raw)
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Comparative Study of Extraction of Cellulose Nanocrystals (CNC) from Wood Pulp
Algerian Journal of Materials Chemistry, Vol.2 Issue 2, pp 62–69, 2019
The present work is a study on cellulose nanocrystals extracted from the wood Pulp of the joineries in order to exploit this cellulosic waste (recycling). After a bibliographic study, we selected four different extraction technics to be followed. The extracts obtained have undergone several physical and structural characterizations to evaluate the influence of the extraction method on the yield in quality and quantity of the CNCs. Fourier transform infrared spectroscopy (FT-IR) was used to highlight the evolution of the chemical composition thus confirming the elimination of extracellulosic substances during the chemical treatment of the extraction process. X-ray diffraction analysis determined the crystallinity of the CNC. According to the results of the thermogravimetric analyzes, the degradation of the CNCs occurs at a low temperature in the region of 200 ° C. The morphology of cellulose nanocrystals has been studied by optical microscopy.
ACS Appl. Mater. Interfaces , 2014
This work describes the measurement and comparison of several important properties of native cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs), such as crystallinity, morphology, aspect ratio, and surface chemistry. Measurement of the fundamental properties of seven different CNCs/CNFs, from raw material sources (bacterial, tunicate, and wood) using typical hydrolysis conditions (acid, enzymatic, mechanical, and 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation), was accomplished using a variety of measurement methods. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and 13 C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy were used to conclude that CNCs, which are rodlike in appearance, have a higher crystallinity than CNFs, which are fibrillar in appearance. CNC aspect ratio distributions were measured and ranged from 148 ± 147 for tunicate-CNCs to 23 ± 12 for wood-CNCs. Hydrophobic interactions, measured using inverse gas chromatography (IGC), were found to be an important contribution to the total surface energy of both types of cellulose. In all cases, a trace amount of naturally occurring fluorescent compounds was observed after hydrolysis. Confocal and Raman microscopy were used to confirm that the fluorescent species were unique for each cellulose source, and demonstrated that such methods can be useful for monitoring purity during CNC/CNF processing. This study reveals the broad, tunable, multidimensional material space in which CNCs and CNFs exist.
Background: Cellulose is the main constituent that forms the plant cell wall. The abundant content of cellulose makes cellulose very potential to be developed, the widely invented is the production of cellulose nanocrystals (CNC). The production of small cellulose such as micro or nano allows cellulose to have good stability and affinity, so that it can be used more effectively. The ideal utilization of cellulose nanocrystals (CNC) has spread in various sectors, such as water treatment, absorbents, cosmetic products, coatings, fillers, adhesives, nanocomposites, energy and electronics, biomedicine, drug additives, and include the manufacture of other biomaterials. Therefore, it is necessary to summarize the results of cellulose nanocrystals (CNC) from various cellulose sources, especially from agriculture and industrial waste. So that further researchers can use this as reading material so that the research can be carried out optimally and efficiently by continuing what is available. Methods: The method in this study is a systematic review by literature searches in the form of published journals, proceedings, and theses. Literature searches are carried out both manually (library) and electronically with the help of reputable journal search sites such as Science Direct, Research Gate, Google Scholar, and Scopus. The literature used focuses on English and Indonesian literature with publication years between 2010 until 2020. For journals used are Scopus and or SINTA indexed journals, with the keywords CNC, Cellulose Nanocrystals, nanocrystal cellulose isolation, cellulose nanocrystal agriculture. Results: Several studies conducted in the manufacture of CNC using strong acids such as H 2 SO4 and HCl, the summarized results found that there were differences in the results of CNC manufacturing based on cellulose sources and chemical and mechanical pretreatments. Conclusion: Production CNC for a mass production scale requires further research to obtain optimization for each type of sample and treatment.
Cellulose, 2020
Production of nanocellulosic materials from loblolly pine (Pinus taeda) kraft pulp provides an opportunity to diversify the portfolio of traditional pulp and paper industries. In this study, pinewood was first subjected to dilute acid pre-extraction with 0.5% sulfuric acid in order to fractionate the hemicellulose, followed by kraft pulping and elemental chlorine free bleaching in order to obtain up to 97% pure cellulose fractions. CNCs (cellulose nanocrystals) were prepared by hydrolyzing the bleached kraft pulp with 64% sulfuric acid at 45°C for 30 min; the resultant unhydrolyzed solid residues were homogenized using a microfluidizer in order to produce cellulose nanofibers (CNFs). The dilute acid pre-extraction step resulted in complete hydrolysis of galactan and arabinan from pinewood, as well as in partial removal of mannan (80%) and xylan (58%). As a result of preextraction, the CNC yield and crystallinity improved by 44% and 11%, respectively, from the corresponding kraft pulps. CNCs produced from the pre-extracted materials also exhibited 16% reduction in particle size, but a 70% increase in sulfur content as well as 20% increase in zeta potential. Higher purity of kraft pulps resulted in higher exposure of cellulose crystalline domains to sulfuric acid thereby resulting in the observed changes. Thus, pulp purity was found to play a significant role in determining the quantity and
Industrial Crops and Products, 2014
The paper discusses the isolation of cellulose nanocrystals (CNC BE ) from wood resources by integrating the processing with pilot-scale bioethanol processing unit. The nanocrystals were isolated from cellulose obtained by acid pretreatment of wood chips in a bioethanol pilot-scale facility, followed by a series of chemical processes and subsequent homogenization using a lab-scale homogenizer. The isolated nanocrystals had diameters of 5-15 nm, cellulose I crystalline structure and formed a thick semi-transparent gel at low concentration (2 wt%). XPS data showed that these nanocrystals had predominantly O C O surface groups which also contributed to its high negative zeta potential. Casted CNC BE films showed excellent mechanical performance (200 MPa of strength, 16 GPa of modulus) and transparency and were also found to be cytocompatible. The developed process route resulted in high-quality nanocellulose crystals with a yield of 600 g/day.
Journal of Polymers and the Environment, 2018
Cellulose nanocrystals (CNCs) were successfully isolated by hydrochloric acid hydrolysis followed by ultrasonic homogenization of oil palm empty fruit bunches (OPEFB), which are a major form of agricultural waste in Southeast Asia. Currently sulfuric acid is mainly used in CNC preparation to achieve high dispersibility; however, we demonstrated that CNC suspensions prepared from OPEFB by hydrochloric acid hydrolysis remained stable without any sedimentation over 6 months. The obtained CNCs were fully characterized by elemental analysis, electron microscopic observation, X-ray diffraction measurement, and thermal analysis. The OPEFB-derived CNCs exhibited higher aspect ratios of 23-29 and higher thermal stability of 347-359 °C as maximum degradation temperature, as compared with those of woody CNCs prepared by sulfuric acid hydrolysis (15 and 311 °C, respectively). Although as-prepared CNCs showed comparable morphological and physicochemical properties to those prepared from oil palm biomass by other methods including sulfuric acid hydrolysis, use of hydrochloric acid and ultrasonication for hydrolysis of OPEFB was effective to yield crystalline CNCs with long-term nanodispersibility showing clear birefringence.
Optimization of the isolation of nanocrystals from microcrystalline celluloseby acid hydrolysis
Cellulose, 2006
The objective of this work was to find a rapid, high-yield process to obtain an aqueous stable colloid suspension of cellulose nanocrystals/whiskers. Large quantities are required since these whiskers are designed to be extruded into polymers in the production of nano-biocomposites. Microcrystalline cellulose (MCC), derived from Norway spruce (Picea abies), was used as the starting material. The processing parameters have been optimized by using response surface methodology. The factors that varied during the process were the concentration of MCC and sulfuric acid, the hydrolysis time and temperature, and the ultrasonic treatment time. Responses measured were the median size of the cellulose particles/whiskers and yield. The surface charge as calculated from conductometric titration, microscopic examinations (optical and transmission electron microscopy), and observation of birefringence were also investigated in order to determine the outcome (efficiency) of the process. With a sulfuric acid concentration of 63.5% (w/w), it was possible to obtain cellulose nanocrystals/whiskers with a length between 200 and 400 nm and a width less than 10 nm in approximately 2 h with a yield of 30% (of initial weight).
Cellulose, 2015
Cellulose nanocrystals (CNC) have recently received much attention in the global scientific community for their unique mechanical and optical properties. Here, we conducted the first detailed exploration of the basic properties of CNC, such as morphology, crystallinity, degree of sulfation and yield, as a function of production condition variables. The rapid cellulose depolymerization and sulfation reactions under concentrated acid concentrations of around 60 wt% resulted in a very narrow operating window for CNC production. We found that CNC yields as high as 70 wt% from a bleached eucalyptus kraft pulp with glucan content of 78 wt% can be achieved under a tight range of reaction conditions and that a weighted average length of over 200 nm and sulfur content (a measure of CNC surface charge) between 3 and 10 mg/g can be produced. This study provided critical knowledge for the production of CNC with characteristics tailored for different specific applications, significant to commercialization. Keywords Cellulose nanocrystals (CNC) Á Crystallinity Á Crystal length and morphology Á Surface charge Á CNC yield optimization Á Concentrated acid hydrolysis This work was conducted on official government time of Zhu, Hirth, Baez, and Agarwal and while Chen and Wang were visiting students at the USDA Forest Products Lab.
Cellulose
Cellulose nanocrystals (CNCs) were isolated for the first time from pine cones (PC) by alkali and bleaching treatments and subsequent sulfuric acid hydrolysis (64%) at 45°C. The influence of the hydrolytic reaction time (30, 45, and 90 min) on the yield, chemical composition and structure, and thermal stability of CNCs was evaluated. The removal of non-cellulosic constituents during the alkaline and bleaching treatment resulted in high pure cellulosic fibres. The isolation of CNCs from these cellulosic fibres at different reaction times was verified by the nano-dimensions of the individual crystals (\ 3 and \ 335 nm of average diameter and length, respectively). The highest yield (15%) and the optimum CNCs properties in terms of aspect ratio, thermal stability and crystallinity were obtained for an extraction time of 45 min. PC appeared to be a new promising source of cellulose fibres and CNCs with potential to be applied as reinforcement in composites and for food-packaging.
2023
Extraction of cellulose nanocrystals (CNCs) from agro-residues has received much attention, not only for their unique properties supporting a wide range of potential applications, but also their limited risk to global climate change. This research was conducted to assess Nile roses (Eichhornia crassipes) fibers as a natural biomass to extract CNCs through an acid hydrolysis approach. Nile roses fibers (NRFs) were initially subjected to alkaline (pulping) and bleaching pretreatments. Microcrystalline cellulose (MCC) was used as control in comparison to Nile rose based samples. All samples underwent acid hydrolysis process at a mild temperature (45 • C). The impact of extraction durations ranging from 5 to 30 min on the morphology structure and crystallinity index of the prepared CNCs was investigated. The prepared CNCs were subjected to various characterization techniques, namely: X-ray diffraction (XRD), FT-IR analysis, Transmission electron microscopy (TEM), and X-ray Photoelectron spectroscopy (XPS). The outcomes obtained by XRD showed that the crystallinity index increased as the duration of acid hydrolysis was prolonged up to 10 min, and then decreased, indicating optimal conditions for the dissolution of amorphous zones of cellulose before eroding the crystallized domains. These data were confirmed by FT-IR spectroscopy. However, a minor effect of hydrolysis duration on the degree of crystallinity was noticed for MCC based samples. TEM images illustrated that a spherical morphology of CNCs was formed as a result of 30 min acid hydrolysis, highlighting the optimal 20 min acid hydrolysis to obtain a fibrillar structure. The XPS study demonstrated that the main constituents of extracted CNCs were carbon and oxygen.