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Parametric chemistry reverse engineering biomaterial composites for additive manufacturing of bio-cement structures across scales
Published in Fernando Moreira da Silva, Helena Bártolo, Paulo Bártolo, Rita Almendra, Filipa Roseta, Henrique Amorim Almeida, Ana Cristina Lemos, Challenges for Technology Innovation: An Agenda for the Future, 2017
J. Duro-Royo, J. Van Zak, Y.J. Tai, A.S. Ling, N. Oxman
Unlike natural materials, synthetic materials generally off-gas toxic fumes; are non-biodegradable; consume large amounts of energy in manufacturing, maintenance, and disposal; have homogeneous properties across scales; and do not benefit from—or react—to the environment (Fernandez & Ingber 2012). Engineers have yet to create high-performance bio-composites with the strength and stability of traditional man-made materials (Fernandez & Ingber 2012). Bio-cement composites discussed in this paper utilize a chitosan-cellulose backbone with organ ic and inorganic additives. The synthesis of these structural biomaterials is a promising step toward large-scale digital manufacturing of economically viable, nontoxic, biocompatible, and biodegradable products and parts.
Selected Topics
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
There is an increasing emphasis on the so-called “green materials.” There are other terms often associated with the term. These other terms include renewable resource materials and natural materials. The emphasis is on the replacement of nongreen materials by these green materials. Each of these terms has slightly different meanings. The term “renewable materials” is generally employed for rapidly renewable materials that are replenished within a short time such as a year. The term “natural materials” emphasizes materials that are derived from nature. Along with these descriptions, a green material also encompasses the energy requirements, processing procedures, and recycling ability of the material.
Materials for Tissue Engineering
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
To create scaffolds that have the appropriate mechanical and biological properties, researchers have used a wide variety of materials. Synthetic polymers are frequently used because they allow the researcher to have control over the properties of the material, including strength, hydrophilicity, and charge. Natural materials are used because of their inherent bioactivity and biocompatibility. In some cases, decellularized tissues are used because they contain a host of natural materials with biocompatibility and bioactivity with specific mechanical strength and a specific architecture.
Molecularly imprinted bacterial cellulose for sustained-release delivery of quercetin
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Chutima Jantarat, Kanokkorn Attakitmongkol, Supirada Nichsapa, Pornpak Sirathanarun, Suthon Srivaro
The various approaches used in the development of drug delivery systems are aimed at achieving the highest drug efficacy and safety possible. It appears that the easiest approach to attain this goal is by controlling the rate of drug release from the delivery systems; however, this is still a big challenge with regards to practicality. Generally, slow (sustained) drug release is preferable to immediate drug release; this is because of advantages such as long-term drug action and reduced frequency of drug use [1–3]. Materials that are used to control drug release in sustained-release drug delivery systems are selected based on important factors such as drug delivery time and compatibility with human tissues. Natural materials have gained attention for this because they are biodegradable, biocompatible, and considered safer than synthetic materials. Some natural materials that are popularly used as drug carriers in delivery systems are chitosan, alginate, dextran, and gelatin [4–7]. Bacterial cellulose (BC) is a natural material that has recently gained attention as a drug carrier [8,9]. This is because it is easily produced in large quantities, has unique properties, and is cheaper compared to other natural materials.
Cyclic filtration behavior of structured cattail fiber assembly for oils removal from wastewater
Published in Environmental Technology, 2018
Shengbin Cao, Ting Dong, Guangbiao Xu, Fumei Wang
Water contamination by various pollutants is a major environmental concern today [1,2]. Among them, oil spillage attracts increasing attention, because it not only is a waste of energy, but also leads to serious environmental problems [3]. To clean and recycle the spilled oils, mechanical extraction by sorption materials is regarded as one of the most desirable choices, as they can concentrate and transform liquid oil to semi-solid or solid phase, which can then be removed from the water and recovered by mechanical extrusion or centrifugal of the sorbents [4]. At present, synthetic materials such as polypropylene and polyurethane are given priority to be applied as the sorbents because of their high oil sorption capacity, and they have been reported to absorb 100 times their weight of oil from oil–water mixtures [5–7]. The mineral inorganic products used as oil sorbents include perlite, graphite, vermiculite, zeolites, bentonites, organo clay, fly ash, sand, diatomite, etc. Most of them have poor buoyancy and oil sorption capacity. Expholiated graphite registers high oil uptake (83 g oil/g fiber), but it is fairly expensive [8]. Organic sorbents include straw, bagasse, rice husk, cotton fiber, wool, kapok fiber, populus seed fiber, milkweed, etc. [9]. Compared with synthetic products, natural materials are attractive because they are economical and easy to be collected and disposed without additional environmental hazard applied. Some products such as cotton [10], wool [11], milkweed [12], kapok [13–17] and populus seed fiber [18] are excellent oil sorbents based on their high oil uptake of over 30 g oil/g fibers. Many other natural sorbents suffer drawbacks in terms of high water uptake, which is associated with their low hydrophobicity or water-repelling ability [19]. The hydrophobic–oleophilic properties of oil sorbents are determined by factors such as the amount of surface wax, chemical constituent of the sorbent, physical configuration of the fiber such as hollow lumen and surface roughness and its porosity.
Preparation and oil absorbency of kapok-g-butyl methacrylate
Published in Environmental Technology, 2018
Jintao Wang, Yian Zheng, Aiqin Wang
As one of the most economical and efficient measures, natural vegetation such as rice straw, cotton fiber, milkweed, kapok fiber, kenaf, wool and bagasse have been used as the adsorbents for the recovery of spilled oil [3–10]. Compared with usual synthetic organic products, these natural materials have relatively lower cost and better biodegradability. Nevertheless, some natural materials are poor in oil absorbency or highly hygroscopic by nature. If they are used for the recovery of oil over water, a small amount of water can be carried into the natural absorbent. Therefore, in recent years, modification of natural vegetation with organic chemicals such as anhydrides, esters and organic acid, has been widely studied [11–14]. It is well known that most natural plants are mainly composed of cellulose, lignin and hemicellulose, wherein the hydroxyl group of cellulose is the essential part reacting with the modifier [15]. A series of properties like dimensional instability, lipophilicity and low intensity of natural vegetation can be improved by chemical modification. Acetylation is a simple, safe and effective method for increasing the hydrophobicity, mechanical properties and decay resistance of lignocellulose. The method of using acetylation to prepare a natural oil absorbent has been sparsely reported. Sun et al. [16] revealed that on acetylation of rice straw with acetic anhydride without solvent, the resulting product is so hydrophobic that it can be developed into a natural oil sorbent. Thompson et al. [17] discussed the crude oil absorptive behavior of acetylated rice husk, considering that the rapid uptake and high absorption capacity made the acetylated rice husk a very prospective alternative material for crude oil spill. In addition, raw bagasse modified with fatty acid has good affinity to oil [18]; banana trunk fibers modified with oleic acid, stearic acid, castor oil and palm oil also exhibited good sorption capacity for the studied oil [19]. Due to frequent occurrences of oil pollution, it would behoove those concerned to conduct oil sorption studies and develop a novel biodegradable sorbent by the modification of natural plants.