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Bionanocomposites
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
Archita Gupta, Padmini Padmanabhan, Sneha Singh
Cellulose is an abundant agro-based polymer and the main constituent of the cell wall of a plant. This polysaccharide polymer contains liner chains of sugar molecules, making it a robust natural polymer with varying properties depending on the chain length and the degree of polymerization (Reddy et al. 2012 and Averous 2004). Cellulose fibers are a commonly available, eco-friendly, inexpensive, recyclable material and require less energy-intensive manufacturing processes. The fabrication of nanofibers of cellulose through nano reinforcement leads to the development of two cellulose types, which are microfibrils and whiskers (Oksman et al. 2016 and De Azeredo 2009). Esterifying with respective acids and anhydride leads to the synthesis of thermoplastic cellulose, namely. propionate, cellulose acetate butyrate, and cellulose acetate (Reddy et al. 2012 and Averous 2004). For plasticization of cellulose, cotton and wood are used as raw materials and then esterified by different additives. The plasticizers used in the synthesis of plastic cellulose are commonly utilized but pose severe health issues, such as eye irritation and liver cancer; they have recently been replaced by citrate-based materials (De Azeredo 2009).
Ingredients for Elastomer- Based Composite Materials: Requirements and Ecological Concerns
Published in Nikolay Dishovsky, Mihail Mihaylov, Elastomer-Based Composite Materials, 2018
Nikolay Dishovsky, Mihail Mihaylov
Cellulose is the most abundant natural polymer. Commercial cellulose fibers are commonly produced from cotton and wood. Native cellulose is amorphous and crystalline in nature. Crystalline cellulose includes microcrystalline and nano-crystalline cellulose and can thus be derived from the native cellulose fibers. As crystalline cellulose has high strength and high stiffness, it has a great potential to be used as a reinforcing material in the rubber matrix.
Natural Nanomaterials
Published in M. H. Fulekar, Bhawana Pathak, Environmental Nanotechnology, 2017
Cellulose is a water-insoluble compound, which is commonly found in the cell walls of plant, mainly in the stalk, stem, branches and woody parts. Cellulose fibre is a formed component of plant cell walls. Cellulose is found in plants known as microfibril where its network forms a strong bonding structure in the cell wall. Cellulosic nanomaterials are produced by single-celled organisms such as algae and bacteria as well as by plants. Plant cellulose and bacterial cellulose have similar chemical structure but different physical and chemical properties (Mohammad et al., 2014). Certain strains of Acetobacter xylinum bacteria produce fine cellulose fibrils with a diameter of 3–8 nm and a length of 50–80 nm. A. xylinum bacterial cellulose can be pressed and dried into sheets with remarkable mechanical strength; the Young's modulus is as high as >15 GPa across the plane of the sheet. The high Young's modulus has been attributed to the unique supermolecular nanostructure in which fibrils of biological origin are preserved and bound tightly by hydrogen bonds. A team of scientists and engineers led by Sony in Japan have studied the mechanical properties of cellulose sheets and use the material in a commercial speakerphone. Because of their strength, stability and optical transparency, these fibres have also been used in reinforcement material in flexible displays for television, personal computers and portable phones developed in Japan by NTT, Mitsubishi and others (Hornyak et al., 2008).
Intensification of cellulosic fiber drying through fundamental insights and process modeling
Published in Drying Technology, 2020
Sabyasachi Mondal, Suvankar Dutta, Puja Agarwala, Vishvas Nimbalkar, Sunil S. Dhumal
Cellulose fibers, such as cotton and man-made fibers (viscose, lyocell, modal), impart varied texture and comfortability to the garment and fashion industry.[1–3] Cotton scarcity coupled with increased per capita consumption of the final fabric pushed man-made cellulosic fiber growth in the recent past. Commercially, all man-made cellulosic staple fibers get regenerated in a spin bath followed by cutting, fiber web or mat formation, washing, bleaching, and squeezing operation. Finally, drying of fiber mat takes place on a conveyor dryer[4–6] to achieve desired moisture content (10.5–11.5% on dry basis) in the final product with steam consumption ∼1 ton/ton of fiber production. Specific energy consumption reduction is always a target for all production units to reduce the operating cost. However, maintaining the fiber quality (like: precise control over moisture variation) always a priority for all fiber production units to meet customer requirements.
Medical textiles
Published in Textile Progress, 2020
Viscose rayon and its associated industry is the oldest of the existing man-made fibre businesses (slightly older and more extensive than that of cuprammonium rayon) with roots stretching back to the late 19th century. A fibre made from regenerated cellulose, the starting material is purified wood pulp from spruce or eucalyptus trees, but it can also be produced from parts of other plants with a high cellular cellulose content such as soy plant stems, bamboo and sugar cane; when used, these other cellulose sources are often mentioned in the promotional literature presumably with the purpose of making the resulting viscose rayon products sound more acceptable. In fact the process, once the cellulose fibre pulp has been prepared, is the same as for wood pulp from trees. As for wood pulp, the original pulp is purified to remove lignin and undesirable colourants then temporarily chemically modified into sodium cellulose xanthate to render it soluble in sodium hydroxide solution prior to spinning; the syrupy so-called viscose solution is extruded into an acidic coagulating bath (wet-spun) to regenerate the cellulose and yield continuous filaments of viscose rayon. The filaments are then drawn and washed before winding, and depending upon the method of manufacture and extent of drawing, different physical and mechanical properties can be provided to the resulting fibre [94].
A linearisation approach to the stochastic dynamic capacitated lotsizing problem with sequence-dependent changeovers
Published in International Journal of Production Research, 2020
Niels De Smet, Stefan Minner, El-Houssaine Aghezzaf, Bram Desmet
The case we study involves a production planning problem at a paper mill where 24 types of coreboard are to be scheduled and produced. The production process can be seen as a serial production line with three different steps. In the first step, cellulose fibres are extracted from waste paper and mixed with water and chemicals to create pulp. In the second step, the pulp is fed into the paper-making machine which creates large rolls of coreboard. In the last step, the slitting process, the large rolls of coreboard are cut to the desired diameter and width. In terms of scheduling, the second step is the bottleneck in this production process. It drives the production rate of the system, therefore the entire production process is modelled as a single-machine production process.