The first plastic (Celluloid) and the first artificial fiber(Rayon) were produced from .The first truly synthetic plastic was bakelite, developed by LeoBaekland between 1905 and 1914. The synthesis of bakelite startswith the reaction between formaldehyde (H2CO) andphenol (C6H5OH) to form a mixture of ortho-and para-substituted phenols. At temperatures above100C, these phenols condense to form a polymer in which thearomatic rings are bridged by either -CH2OCH2-or -CH2- linkages. The cross-linking in this polymeris so extensive that it is a thermoset plastic. Once it isformed, any attempt to change the shape of this plastic is doomedto failure.
A series of copolymers based on CPD and p-CPH were synthesized and the physicochemical properties compared as a function of polymer composition. The polymers described herein were prepared via melt-condensation polymerization methods as previously detailed . An outline of the CPD:p-CPH poly(anhydride-ester) (10) synthesis, starting from the relevant diacids (6 and 7) is outlined in .
Synthesis and solubility of linear poly(tetrafluoroethylene-co ..
N2 - Herein we review the environmentally friendly synthesis of fluorinated polymers in supercritical carbon dioxide (scCO2). Historically, many high-performance fluorinated materials are commercially synthesized in aqueous media using fluorinated surfactants or in non-aqueous conditions using fluorinated solvents. Our group has pioneered both the homogeneous and heterogeneous polymerization of fluorinated monomers in scCO2. This review includes discussions on the synthesis of main-chain and side-chain fluoropolymers conducted via a chain-growth or continuous process. Specific materials consist of acrylate- and styrene-based systems, poly(vinyl ether)s, tetrafluoroethylene- and vinylidenefluoride-based, as well as novel fluorinated elastomers and thermoplastics.
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Weight-average molecular weights (Mw) were determined by gel permeation chromatography (GPC) on a Perkin-Elmer liquid chromatography system consisting of a Series 200 refractive index detector, a Series 200 LC pump, and an ISS 200 advanced sample processor. A Dell OptiPlex GX110 computer running Perkin-Elmer TurboChrom 4 software was used for data collection and processing, and to automate the analysis via Perkin-Elmer Nelson 900 Series Interface and 600 Series Link. Polymers were dissolved in methylene chloride (5mg/mL) and filtered through 0.45μm poly(tetrafluoroethylene) (PTFE) syringe filters (Whatman, Clifton, NJ) before elution. Samples were resolved on a Jordi divinylbenzene mixed-bed GPC column (7.8×300mm) (Alltech Associates, Deerfield, IL) at 25°C, with methylene chloride as eluent at a flow rate of 0.5mL/min. Molecular weights were calibrated relative to narrow molecular weight polystyrene standards (Poly-sciences, Dorval, Canada).
A recent progress in thin film composite membrane: A review
N. Aumuswan, Sang-Ho Ye, W.R. Wagner and M.W. Urban, “Covalent Attachment of Multilayers on Poly(tetrafluoroethylene) Surfaces,” , 2011, 27 (17), 11106–11110.
Applied Sciences | An Open Access Journal from MDPI
Diacids 6 and 7 were synthesized as previously reported [,]. CPD (6) and p-CPH (7) were separately stirred in excess acetic anhydride at room temperature and reflux temperature, respectively. Monomers (8 and 9) were obtained as white solids. Various molar ratios of the two solids, 8 and 9, (9:1, 7:3, 6:4, 5:5, 4:6, 3:7, 1:9) were melt-polymerized to yield the corresponding CPD:p-CPH copolymers (10). Melt-condensation polymerization was performed using a modular apparatus in conjunction with an overhead mechanical stirrer, the polymerization was deemed complete upon solidification.