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Sustainable Polymers for Additive Manufacturing
Published in Antonio Paesano, Handbook of Sustainable Polymers for Additive Manufacturing, 2022
Elastomers are polymers exhibiting rapid recovery to their approximate initial shape and dimensions after substantial deformation by an applied force and following release of that force (ASTM D1566-20). Rubbers are a type of elastomers, namely polymers that can rapidly recover from large deformations and are insoluble (but can swell) in boiling solvent, such as benzene (ASTM D1566-20). Examples of common elastomers are: isoprene rubber, fluoroelastomers, natural rubber (a polymer derived from the Hevea brasiliensis tree), neoprene, nitrile rubber, silicone, styrene-butadiene rubber, and urethane. Elastomers can be (lightly) crosslinked and left uncrosslinked: the former ones are called thermosetting or vulcanized elastomers (from the heat-driven crosslinking process called vulcanization), and the latter ones are termed thermoplastic (TP) elastomers. Examples of elastomers for AM include: BASF Ultrasint® TPU01, ESTANE® family of TP polyurethane (TPU) grades by Lubrizol varying in hardness (Lubrizol n.d.), TPU 92A (Stratasys 2021a), PUR called EPU (Carbon® Inc. 2021a), and a high performance TP called PEBA 2301 composed of polyether block amide (EOS n.d.). Sustainable elastomers for AM are also available, the TP urethane WillowFlex FX1504 (BioInspiration 2015), and ESTANE® 3D TPU F95A-030 BR ECO PL (Lubrizol n.d.).
Natural Rubber and Bio-based Thermoplastic Elastomer
Published in Abdullah Al-Mamun, Jonathan Y. Chen, Industrial Applications of Biopolymers and their Environmental Impact, 2020
A number of bio-based TPE have been applied in multiple industrial fields. A polyether-block-amide block copolymer produced by Arkema from castor oil has a hardness of 72 Shore D. It has been widely used in electronics, automotive, and sportswear. DuPont developed a renewable Hytrel RS thermoplastic elastomer using a corn sugar derivative as raw material. Hytrel RS contains up to 60% bio-based material, and has a Shore D hardness of 83. It has been widely applied in different applications, such as airbag door, energy damper, tubing boot, and hose. GLS developed two classes of bio-based TPE, which found applications in sports equipment, such as ski binding and caster wheels. OnFlex developed the BIO 5300 series compounds with good injection molding and extrusion capability. These compounds also feature high abrasion resistance, impact resistance, tensile, and tear performances. BIO 5300 can be applied in a wide range of applications, such as sports equipment, door panel skin, and interior trim.
Biodegradable Polymers in Controlled Drug Delivery Systems
Published in Munmaya K. Mishra, Applications of Encapsulation and Controlled Release, 2019
Anurakshee Verma, Prabhat Kumar, Ufana Riaz
Zeng et al. [70] prepared a block copolymer of PEG and PLA. Paclitaxel was loaded into PEG–PLA micelles, and it was found that 17.6% of paclitaxel dissolved completely in sodium salicylate solution after 5 days, while 27.6% of paclitaxel dissolved completely after 3 days. Tziveleka et al. [71] synthesized a multifunctional hyperbranched polyether polyol. and pyrene and tamoxifen were selected as model drugs for a release study. Han et al. [72] synthesized the hydrogel via esterification with chlorinated polyethylene glycol bis-carboxymethyl ether. The swelling ratio and drug release profiles of a model drug (aspirin) were also investigated, and aspirin release profiles were observed with various cross-linking ratios at 37 °C for a period of 5 h. The release kinetics showed a good fit to the zero-order model. Ortega et al. [73] developed a polyether-block-amide copolymer film with acrylic acid, which was used for the release of vancomycin. A sustained release profile was observed for 48 h.
Chitosan-based mixed matrix membranes: effect of different fillers on membrane properties and performance in hydrophilic pervaporation
Published in Chemical Engineering Communications, 2023
Wendel P. Silvestre, Jocelei Duarte, Camila Baldasso, Isabel C. Tessaro
Relative to the engineering polymers most used in the preparation of mixed matrix membranes, they depend on the feed composition and the desired separation (e.g., hydrophilic or organophilic pervaporation). Examples of polymers used to prepare pervaporation membranes are poly(vinyl alcohol), polyacrylonitrile, polyetherimide, and polyether block amide, among others. For organophilic pervaporation, the most used polymers are silicones and their derivatives, such as poly(dimethyl siloxane) – PDMS – and poly(octyl methyl siloxane) – POMS (Cheng et al. 2017; Goyal et al. 2021). Among the biopolymers commonly used in the production of mixed matrix membranes, it can be cited chitosan, cellulose and its derivatives, and other polysaccharides, such as alginate, being this kind of membrane employed both in hydrophilic and organophilic pervaporation, although the latter in a more limited scale (Noble 2011; Vatanpour et al. 2022).
A comparison of running economy across seven highly cushioned racing shoes with carbon-fibre plates
Published in Footwear Science, 2022
Dustin P. Joubert, Garrett P. Jones
Similarly, there is both a scarcity of controlled, laboratory-based research on these new shoe advancements, and it is limited almost entirely to new Nike shoes. As early as 2014, Worobets et al. showed that more compliant and resilient midsole foam made of thermoplastic polyurethane (TPU) improved RE by ∼1% compared to traditional ethylene-vinyl acetate (EVA) foam in an Adidas prototype without a carbon-fibre plate (Worobets et al., 2014). However, much of the research since has been limited to various editions of the Nike Vaporfly, which incorporates new, thicker midsole foam made of polyether block amide (PEBA) and a full-length carbon-fibre plate (Barnes & Kilding, 2019; Hébert-Losier et al., 2020; Hoogkamer et al., 2018; Hunter et al., 2019). Hoogkamer et al. (2018) found ∼4% improvements in RE in a Nike Vaporfly prototype across running speeds of 14–18 km·h−1, which was independently confirmed by Barnes and Kilding (2019). In addition to the increased longitudinal bending stiffness provided by the carbon-fibre plate in these shoes, the new midsole foam in the Nike Vaporfly was more compliant and resilient, returning more mechanical energy following compression (Hoogkamer et al., 2018). This was thought to allow for the observed improvements in RE. Along with the improvements in RE offered by the Nike Vaporfly shoes, changes in running mechanics have also been observed. Both Hoogkamer et al. (2018) and Barnes and Kilding (2019) showed an increase in stride length and slower stride rate when running at a fixed speed in the Nike Vaporfly relative to a traditional racing shoe.
Quasi-static mechanical properties of origami-inspired cellular metamaterials made by metallic 3D printing
Published in Mechanics of Advanced Materials and Structures, 2023
Kailun Huang, Jiayao Ma, Xiang Zhou, Hai Wang
With the rapid development in 3 D printing technology, OCMs made by the direct 3 D printing method have also been reported. For example, Cheung et al. [15] proposed a 3 D printed acrylic interleaved tube cellular material whose geometry is relied on the new design of deployable OCMs. Sengupta and Li [16] manufactured a unit cell prototype through the 3 D-printing method based on a thermoplastic elastomer called polyether block amide to validate the anisotropic multistability of the proposed OCMs based on the Miura-ori pattern. Zhao et al. [17] proposed a method to 3 D print origami assemblages from the photocurable resin by introducing hinge-panel elements, which was then loaded in compression test and exhibited acceptable strength and load-bearing capacity for engineering applications. Tao et al. [18] manufactured the OCMs based on the Kresling pattern by the 3 D printing method with shape memory polymer and conducted the compression tests, finding that the stress-strain curves and compression twist deformation behavior of the metamaterials can be tuned. Xiang et al. [19] manufactured uniform and graded Miura-ori nylon OCMs samples by polymer 3 D printing and then tested them under out-of-plane compression and dynamic impact. Lin et al. [20] applied a two-photon liquid photoresist to fabricate the zipper/aligned OCMs specimens by 3 D printing and studied their mechanical properties using in situ SEM experimentation. By inserting origami folds into square honeycombs, Townsend et al. [21] fabricated OCMs specimens made of thermoplastic polyurethane by 3 D printing and tested them under compression, finding that the OCMs have an adjustable buckling behavior and an out-of-plane energy absorption ability. Moreover, Song et al. [22–24] manufactured octet-truss cellular materials, cuttlebone-like lattices, and gradient composite lattices by a stereolithography 3 D printing method and achieved their mechanical behaviors by in situ compressive tests.