Polymer preparation/characterization

M.M. Reynolds, M.C. Frost, and M.E. Meyerhoff, Nitric oxide-releasing hydrophobic polymers preparation, characterization, and potential biomedical applications. Free Radical Biol. Med. 37, 926-936... 

De Labouret, A., Thioune, O., Fessi, H., Devissaguet, J.P. and Puisieux F. (1995) Application of an original process for obtaining colloidal dispersions of some coating polymers—preparation, characterization, industrial scaling up. Drug Dev. Ind. Pharm. 21, 229-241. 

The molecules used in the study described in Fig. 2.15 were model compounds characterized by a high degree of uniformity. When branching is encountered, it is generally in a far less uniform way. As a matter of fact, traces of impurities or random chain transfer during polymer preparation may result in a small amount of unsuspected branching in samples of ostensibly linear molecules. Such adventitious branched molecules can have an effect on viscosity which far exceeds their numerical abundance. It is quite possible that anomalous experimental results may be due to such effects. 

Suspension Polymers. Methacrylate suspension polymers are characterized by thek composition and particle-size distribution. Screen analysis is the most common method for determining particle size. Melt-flow characteristics under various conditions of heat and pressure are important for polymers intended for extmsion or injection molding appHcations. Suspension polymers prepared as ion-exchange resins are characterized by thek ion-exchange capacity, density (apparent and wet), solvent sweUing, moisture holding capacity, porosity, and salt-spHtting characteristics (105). 

An unusual method for the preparation of syndiotactic polybutadiene was reported by The Goodyear Tire Rubber Co. (43) a preformed cobalt-type catalyst prepared under anhydrous conditions was found to polymerize 1,3-butadiene in an emulsion-type recipe to give syndiotactic polybutadienes of various melting points (120—190°C). These polymers were characterized by infrared spectroscopy and nuclear magnetic resonance (44—46). Both the Ube Industries catalyst mentioned previously and the Goodyear catalyst were further modified to control the molecular weight and melting point of syndio-polybutadiene by the addition of various modifiers such as alcohols, nitriles, aldehydes, ketones, ethers, and cyano compounds. 

Techniques were developed for the dilute solution characterization of polydlchlorophosphazene. The purity of the trimer has a significant effect on oligomer formation, polymerization time and polymer MW and MWD. The polymers prepared in this study have high molecular weights and broad molecular weight distributions and probably have similar, if not identical, chain structures. 

Agari, Y, Shimada, M., Ueda, A. and Nagai, S. (1996) Preparation, characterization and properties of gradient polymer blends discussion of poly(vinyl chloride)/poly (methyl methacrylate) blend films containing a wide compositional gradient phase. Macromol. Chem. Phys., 197, 2017-2033. 

The cyclotrisilazane (R = Me) produced in reaction (14) is recycled at 650°C [by reaction with MeNHo) the reverse of reaction (14)] to increase the yield of processible polymer. Physicochemical characterization of this material shows it to have a softening point at 190°C and a C Si ratio of 1 1.18. Filaments 5-18 pm in diameter can be spun at 315°C. The precursor fiber is then rendered infusible by exposure to air and transformed into a ceramic fiber by heating to 1200°C under N2- The ceramic yield is on the order of 54% although, the composition of the resulting amorphous product is not reported. The approach used by Verbeek is quite similar to that employed by Yajima et al. (13) in the pyrolytic preparation of polycarbosilane and its transformation into SiC fibers. 

The primary approach to the development of main group inorganic polymer chemistry has been in the preparation, characterization and utilization of polymers with an inorganic backbone which may, or may not, be protected by organic substituents (la). Important members of this class of materials which are discussed in this volume and elsewhere include ... 

The ligand 2,5-bis(2-pyridyl)pyrazine was used in the synthesis of a range of zinc compounds to contrast with copper coordination polymers prepared with this ligand.169 Three zinc compounds were structurally characterized, [ZnCl2L(DMF)], [Zn3(OAc)6L2], and [Zn3Cl6L3] respectively a distorted square planar monomer, a linear trimer, and a triangular arrangement of zinc centers. 

The organoboron polymer complex was prepared as follows. First, poly(organoboron halide)55 was prepared according to the reported method, by hydroboration polymerization between 1,7-octadiene and the monobromoborane dimethylsuffide complex. The polymer obtained was then reacted with half an equivalent of methanol and 1-methylimidazole to give the corresponding copolymer efficiently (scheme 4). The structure of the polymer was characterized by H- and UB-NMR spectra. 

Table III. Conditions for Polymer Preparation and Sample Characterization"...

A given sample of polymer is characterized by a distribution of molecular weights arising from the interaction of the network of reactions shown in equation 9.3.17 (and possibly equation 9.3.18), and the mixing processes taking place in the reactor in which the polymer sample was prepared. 

Carrado, K.A. (2000) Synthetic organo-and polymer-days preparation, characterization and materials applications. Applied Clay Science, 17, 1-23. 

H. Kong, R Luo, C. Gao, and D. Yan, Polyelectrolyte-functionalized multiwalled carbon nanotubes preparation, characterization and layer-by-layer self-assembly. Polymer 46, 2472—2485 (2005). 

Catalyst efficiency, estimated by polymer yield, eliminated several of the potential CSAs due to their inhibition of polymerization. For those combinations that produced a sufficient amount of polymer for characterization, the molecular weights and molecular weight distributions of the polyethylene samples were then compared to control polymers prepared with no added CS A. A reduction in the Mn in combination with a narrowing of the MJMn indicated a hit for chain shuttling behavior. 

Lu, P. et al., Polymer-protected Ni/Pd bimetallic nano-clusters preparation, characterization and catalysis for Hydrogenation of Nitrobenzene, J. Phys. Chem. B, 103, 9673, 1999. 

The synthesis of well-defined LCB polymers have progressed considerably beyond the original star polymers prepared by anionic polymerization between 1970 and 1980. Characterization of these new polymers has often been limited to NMR and SEC analysis. The physical properties of these polymers in dilute solution and in the bulk merit attention, especially in the case of completely new architectures such as the dendritic polymers. Many other branched polymers have been prepared, e.g. rigid polymers like nylon [123], polyimide [124] poly(aspartite) [125] and branched poly(thiophene) [126], There seems to be ample room for further development via the use of dendrimers and hyperbran-... 

El Sherbiny IM, Lins RJ, Abdel-Bary EM, Harding DRK (2005) Preparation, characterization, swelling and in vitro drug release behaviour of poly [N-acryloylglycine-chitosan interpoly-meric pH and thermally-responsive hydrogels. European Polymer Journal 41 2584-2591. 

Polymer Preparation and Characterization. Bisphenol A-polysulfones of different molecular weight and sulfonated to various degrees have been prepared. In addition, the commercial Bis A-PSF has been sulfonated to various D.S. values and neutralized with sodium or potassium counter-ions. The... 

Polymer Preparation and Characterization. The results of the measurements to determine D.S. are shown in Table II. The data illustrate that the D.S. determined by the three methods are in reasonable agreement. For convenience, in the remainder of this paper the D.S. as determined by NMR will be used for reference... 

Our results on the preparation, characterization, and potential applications of different mono- and disaccharides as monomers in polymer chemistry are discussed in the present report. 

Whitcombe MJ, Rodriguez ME, Villar P, Vulfson EN. A new method for the introduction of recognition site functionality into polymers prepared by molecular imprinting synthesis and characterization of pol3mieric receptors for cholesterol. J Am Chem Soc 1995 117 7105-7111. 

Intercalation of polyaniline between MoS2 layers produced nanoscale molecular composites with unusual charge transport properties [119]. Recent advances in the preparation, characterization, and utilization of conducting polymers intercalated into layered solids were surveyed [120],... 

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