What copolymer of ethylene and vinyl acetate can nanofibers be made of?
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Nanofiber Nanofibers are fibers with diameters in the nanometer range. Nanofibers can be generated from different polymers and hence have different physical properties and application potentials. Examples of natural polymers include collagen, cellulose, silk fibroin, keratin, gelatin and polysaccharides such as chitosan and alginate. Examples of synthetic polymers include poly(lactic acid) (PLA), polycaprolactone (PCL), polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(ethylene-co-vinylacetate) (PEVA). Polymer chains are connected via covalent bonds. The diameters of nanofibers depend on the type of polymer used and the method of production. All polymer nanofibers are unique for their large surface area-to-volume ratio, high porosity, appreciable mechanical strength, and flexibility in functionalization compared to their microfiber counterparts.
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Ethylene-vinyl acetate Ethylene-vinyl acetate (EVA), also known as poly (ethylene-vinyl acetate) (PEVA), is the copolymer of ethylene and vinyl acetate. The weight percent vinyl acetate usually varies from 10 to 40%, with the remainder being ethylene.
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PEDOT:PSS PEDOT:PSS or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate is a polymer mixture of two ionomers. One component in this mixture is made up of sodium polystyrene sulfonate which is a sulfonated polystyrene. Part of the sulfonyl groups are deprotonated and carry a negative charge. The other component poly(3,4-ethylenedioxythiophene) or PEDOT is a conjugated polymer and carries positive charges and is based on polythiophene. Together the charged macromolecules form a macromolecular salt.
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Linear low-density polyethylene Linear low-density polyethylene (LLDPE) is a substantially linear polymer (polyethylene), with significant numbers of short branches, commonly made by copolymerization of ethylene with longer-chain olefins. Linear low-density polyethylene differs structurally from conventional low-density polyethylene (LDPE) because of the absence of long chain branching. The linearity of LLDPE results from the different manufacturing processes of LLDPE and LDPE. In general, LLDPE is produced at lower temperatures and pressures by copolymerization of ethylene and such higher alpha-olefins as butene, hexene, or octene. The copolymerization process produces an LLDPE polymer that has a narrower molecular weight distribution than conventional LDPE and in combination with the linear structure, significantly different rheological properties.
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Poly(hydridocarbyne) Poly(hydridocarbyne) (PHC) is one of a class of carbon-based random network polymers primarily composed of tetrahedrally hybridized carbon atoms, each having one hydride substituent, exhibiting the generic formula [HC]n. PHC is made from bromoform, a liquid halocarbon that is commercially manufactured from methane. At room temperature, poly(hydridocarbyne) is a dark brown powder. It can be easily dissolved in a number of solvents (tetrahydrofuran, ether, toluene etc.), forming a colloidal suspension that is clear and non-viscous, which may then be deposited as a film or coating on various substrates. Upon thermolysis in argon at atmospheric pressure and temperatures of 110 °C to 1000 °C, decomposition of poly(hydridocarbyne) results in hexagonal diamond (Lonsdaleite).
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Polyglycolide Polyglycolide or poly(glycolic acid) (PGA), also spelled as polyglycolic acid, is a biodegradable, thermoplastic polymer and the simplest linear, aliphatic polyester. It can be prepared starting from glycolic acid by means of polycondensation or ring-opening polymerization. PGA has been known since 1954 as a tough fiber-forming polymer. Owing to its hydrolytic instability, however, its use has initially been limited. Currently polyglycolide and its copolymers (poly(lactic-"co"-glycolic acid) with lactic acid, poly(glycolide-"co"-caprolactone) with ε-caprolactone and poly (glycolide-"co"-trimethylene carbonate) with trimethylene carbonate) are widely used as a material for the synthesis of absorbable sutures and are being evaluated in the biomedical field.
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Cigarette filter A cigarette filter is a component of a cigarette, along with cigarette paper, capsules and adhesives. The filter may be made from cellulose acetate fibre, paper or activated charcoal (either as a cavity filter or embedded into the cellulose acetate). Macroporous phenol-formaldehyde resins and asbestos have also been used in cigarette filters. The acetate and paper modify the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption). Filters can reduce "tar" and nicotine smoke yields up to 50%, with a greater removal rate for other classes of compounds (e.g., phenols), but are ineffective in filtering toxins such as carbon monoxide. Most factory-made cigarettes are equipped with a filter; those who roll their own can buy them from a tobacconist.
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Polyvinyl acetate Poly(vinyl acetate) (PVA, PVAc, poly(ethenyl ethanoate): commonly referred to as wood glue, white glue, carpenter's glue, school glue, Elmer's glue in the US, or PVA glue) is an aliphatic rubbery synthetic polymer with the formula (CHO). It belongs to the polyvinyl esters family, with the general formula -[RCOOCHCH]-. It is a type of thermoplastic.
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Ultrasuede Ultrasuede is the trade name for a synthetic microfiber fabric invented in 1970 by Dr. Miyoshi Okamoto, a scientist working for Toray Industries. In Japan it is sold under the brand name Ecsaine. It's an ultra-microfiber. It is often described as an artificial substitute for suede leather. The fabric is multifunctional: it is used in fashion, interior decorating, automotive and other vehicle upholstery, and industrial applications, such as protective fabric for electronic equipment. It is also a very popular fabric in the manufacture of footbags (also known as hacky sacks) and juggling balls. Other manufacturers such as Sensuede and Majilite also produce similar product lines of synthetic microfiber suede construction.
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Phillips catalyst The Phillips catalyst, or the Phillips supported chromium catalyst, is the catalyst used to produce approximately half of the world's polyethylene. A heterogeneous catalyst, it consists of a chromium oxide supported on silica gel. Polyethylene, the most abundant synthetic polymer, is produced industrially by the polymerization of ethylene:
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Polythiazyl Polythiazyl (polymeric sulfur nitride), (SN), is an electrically conductive, gold- or bronze-colored polymer with metallic luster. It was the first conductive inorganic polymer discovered and was also found to be a superconductor at very low temperatures (below 0.26 K). It is a fibrous solid, described as "lustrous golden on the faces and dark blue-black", depending on the orientation of the sample. It is air stable and insoluble in all solvents.
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Phenolic paper Phenolic paper is a material often used to make printed circuit board substrates (the flat board to which the components and traces are attached). It is a very tough board made of wood fibre and phenolic polymers. It is most commonly brown in colour, and is a fibre reinforced plastic. These PCB materials are known as FR-1 and FR-2 – FR-1 is rated to 130°C, FR-2 is rated to 105°C.
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Polyethylene naphthalate Polyethylene naphthalate (poly(ethylene 2,6-naphthalate or PEN) is a polyester with good barrier properties (even better than Polyethylene terephthalate). Because it provides a very good oxygen barrier, it is particularly well-suited for bottling beverages that are susceptible to oxidation, such as beer. It is also used in making high performance sailcloth. It also has been found to show supreme scintillation properties and is expected to replace classic plastic scintillators.
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Window film Window film is a thin laminate film that can be installed to the interior or exterior of glass surfaces in automobiles and boats and also to the interior or exterior of glass in homes and buildings. It is usually made from Polyethylene Terephthalate (PET), a thermoplastic polymer resin of the polyester family, due to its clarity, tensile strength, dimensional stability, and ability to accept a variety of surface-applied or embedded treatments.
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EPDM rubber EPDM rubber (ethylene propylene diene monomer (M-class) rubber), a type of synthetic rubber, is an elastomer characterized by a wide range of applications. The "M" refers to its classification in ASTM standard D-1418; the "M" class includes rubbers having a saturated chain of the polymethylene type. Dienes currently used in the manufacture of EPDM rubbers are dicyclopentadiene (DCPD), ethylidene norbornene (ENB), and vinyl norbornene (VNB). EPDM rubber is closely related to ethylene propylene rubber: ethylene propylene rubber is a copolymer of ethylene and propylene, whereas EPDM rubber is a terpolymer of ethylene, propylene, and a diene-component.
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Polyvinyl chloride acetate Polyvinyl chloride acetate (PVCA) is a thermoplastic copolymer of vinyl chloride and vinyl acetate. It is used in the manufacture of electrical insulation, of protective coverings (including garments), and of credit cards and swipe cards.
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Conservation and restoration of vinyl discs The conservation and restoration of vinyl discs refers to the preventive measures taken to defend against damage and slow degradation, and to maintain fidelity of singles, 12" singles, EP, LP in 45 or 33⅓ rpm disc recordings. LPs are most often in the 12” format, although very early vinyl recordings were 10”. Vinyl LP preservation is generally considered separate from conservation, which refers to the repair and stabilization of individual discs. Commonly practiced in major sound archives and research libraries that house large collections of audio recordings, it is also frequently followed by audiophiles and home record collectors. Because vinyl—a virtually unbreakable light plastic made up of polyvinyl chloride acetate copolymer, or PVC—is considered the most stable of analog recording media, it is seen as less a concern for deterioration than earlier sound recordings made from more fragile materials such as acetate, vulcanite, or shellac. This hardly means that vinyl recordings are infallible, however, and research—both expert and evidential—has shown that the way in which discs are handled and cared for can have a profound effect on their longevity. Though some 45s (7”s) are also made from vinyl, many of them are actually polystyrene—a more fragile medium that is prone to fracturing from internal stress. Still, many of the recommendations for the care of vinyl LPs can be applied to 45s.
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End-group End groups are an important aspect of polymer synthesis and characterization. In polymer chemistry, end groups are functionalities or constitutional units that are at the extremity of a macromolecule or oligomer (IUPAC). In polymer synthesis, like condensation polymerization and free-radical types of polymerization, end-groups are commonly used and can be analyzed for example by nuclear magnetic resonance (NMR) to determine the average length of the polymer. Other methods for characterization of polymers where end-groups are used are mass spectrometry and vibrational spectrometry, like infrared and Raman spectrometry. Not only are these groups important for the analysis of the polymer, but they are also useful for grafting to and from a polymer chain to create a new copolymer. One example of an end group is in the polymer poly(ethylene glycol) diacrylate where the end-groups are circled.
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Wet nanotechnology Wet nanotechnology (also known as wet nanotech) involves working up to large masses from small ones.
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Polyethylene 2,5-furandicarboxylate Polyethylene 2,5-furandicarboxylate, also named poly(ethylene 2,5-furandicarboxylate), polyethylene furanoate and poly(ethylene furanoate) and generally abbreviated as PEF, is a polymer that can be produced by polycondensation of 2,5-furandicarboxylic acid (FDCA) and monoethylene glycol (MEG). As an aromatic polyester from ethylene glycol it is a chemical analogue of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). PEF has been described in (patent) literature since 1951, but has gained renewed attention since the US department of energy proclaimed its building block, FDCA, as a potential bio-based replacement for purified terephthalic acid (PTA) in 2004.
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Nano manufacturing Nano manufacturing is both the production of nanoscaled materials, which can be powders or fluids, and the manufacturing of parts "bottom up" from nanoscaled materials or "top down" in smallest steps for high precision, used in several technologies such as laser ablation, etching and others. Nanomanufacturing differs from molecular manufacturing, which is the manufacture of complex, nanoscale structures by means of nonbiological mechanosynthesis (and subsequent assembly).
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Low molecular-mass organic gelators Low molecular-mass organic gelators (LMOGs) are a relatively new and dynamic soft materials capable of numerous possible applications; LMOGs are the monomeric sub-unit which form self-assembled fibrillar networks (SAFINs) that entrap solvent between the strands. SAFINs arise from the formation of strong non-covalent interactions between LMOG monomeric sub-units. As SAFINs are forming, the long fibers become intertwined and trap solvent molecules. Once solvent molecules are entrapped within the network, they are immobilized by surface tension effects. The stability of a gel is dependent on the equilibrium between the assembled network and the dissolved gelators. One characteristic of an LMOG, that demonstrates its stability, is its ability to contain an organic solvent at the boiling point of that solvent due to extensive solvent-fibrillar interactions.