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Other Polymers (other + polymer)
Selected AbstractsApproaches to polymer selection for mascara formulationINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010Y. Loginova J. Cosmet. Sci., 60, 125,133 (March/April 2009) Synopsis The use of hair-care and hair-styling polymers in mascara formulation is well known. This paper introduces pre-formulative evaluation of film formers which are intended to be applied on eyelashes for mascara development to screen film formers more effectively. The film-forming characteristics of randomly selected hairstyling polymers were evaluated under the influence of pH, temperature, surfactant, and pigment dispersion. The selected polymers included acrylics, polyurethanes, and a pyrrolidone, all of which are used throughout the hair-care and mascara industries. An Erichsen Model 299/300 Pendulum Damping Tester was used to determine film hardness. In analyzing samples by the effect of temperature, the hardest neat polymer, a styrene-acrylate, softened 30% after heating. For most of the other polymers, the hardness was slightly lower compared to the neat polymer. The addition of pigment did not significantly influence the hardness of one acrylic copolymer and a urethane dispersion, but most of the other polymers exhibited a reduction in film hardness. Various hardnesses were observed with different surfactants and different pH's. [source] From quantum chemistry and the classical theory of polar liquids to continuum approximations in molecular mechanics calculations,INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2005Sergio A. Hassan Abstract Biological macromolecules and other polymers belong to the class of mesoscopic systems, with characteristic length scale of the order of a nanometer. Although microscopic models would be the preferred choice in theoretical calculations, their use in computer simulations becomes prohibitive for large systems or long simulation times. On the other hand, the use of purely macroscopic models in the mesoscopic domain may introduce artifacts, with effects that are difficult to assess and that may compromise the reliability of the calculations. Here is proposed an approach with the aim of minimizing the empirical nature of continuum approximations of solvent effects within the scope of molecular mechanics (MM) approximations in mesoscopic systems. Using quantum chemical methods, the potential generated by the molecular electron density is first decomposed in a multicenter-multipole expansion around predetermined centers. The monopole and dipole terms of the expansion at each site create electric fields that polarize the surrounding aqueous medium whose dielectric properties can be described by the classical theory of polar liquids. Debye's theory allows a derivation of the dielectric profiles created around isolated point charges and dipoles that can incorporate Onsager reaction field corrections. A superposition of screened Coulomb potentials obtained from this theory makes possible a simple derivation of a formal expression for the total electrostatic energy and the polar component of the solvation energy of the system. A discussion is presented on the physical meaning of the model parameters, their transferability, and their convergence to calculable quantities in the limit of simple systems. The performance of this continuum approximation in computer calculations of amino acids in the context of an atomistic force field is discussed. Applications of a continuum model based on screened Coulomb potentials in multinanosecond simulations of peptides and proteins are briefly reviewed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source] A microwave-assisted process for coating polymer and glass surfaces with semiconducting ZnO submicron particlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009Alexander Irzh Abstract A new method for coating glass slides with ZnO particles with an average size of 200 nm is proposed in the current article. The coating was performed under microwave radiation. Two main morphologies are found for the ZnO crystals that are deposited on glass slides. The first morphology is that of a very dense coating of ZnO hexagonal rods growing perpendicular to the glass surface. The second is the growth of ZnO flower-like particles. In addition to coating the glass by ZnO particles, we also report on coating other polymers [poly(methyl methacrylate) plate, polycarbonate beads, Nylon 6,6 beads, and polypropylene beads) by ZnO. The morphology obtained for ZnO coated on polymers is different from that detected for coating ZnO on glass. The unorganized coating of ZnO rods on polymers has been observed. The coated glass slides were characterized by X-ray diffraction, volumetric titration, EDS, scanning electron microscope, and optical measurements (DRS and transmittance spectroscopy). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Lewis acid,base property of P(VDF- co -HFP) measured by inverse gas chromatographyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Baoli Shi Abstract Poly (vinylidene fluoride- co -hexafluoropropylene) P(VDF- co -HFP) is an excellent material for polymer electrolytes of lithium ion battery. To enhance the lithium ion transference number, some metal oxides were often embedded into P(VDF- co -HFP). The promising mechanism for the increase in lithium ionic conductivity was Lewis acid-base theory. In this experiment, the Lewis acid,base properties of P(VDF- co -HFP) were measured by inverse gas chromatography (IGC). The Lewis acid constant Ka of P(VDF- co -HFP) is 0.254, and the base constant Kb is 1.199. Compared with other polymers characterized by IGC, P(VDF- co -HFP) is the strongest Lewis basic polymers. Except aluminum ion, lithium ion is the strongest Lewis acidic ion according to their , value of Lewis acids. Therefore, a strong Lewis acid,base interaction will exist between lithium ion and P(VDF- co -HFP). This will restrict the transference of lithium ion in P(VDF- co -HFP). To enhance the lithium ion transference by blending other metal ions into P(VDF- co -HFP), it is suggested that the preferential ions should be Al3+, Mg2+, Na+, and Ca2+ because these metal ions have relative large , values. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and properties of mesogen-jacketed liquid crystalline polymers containing bistolane mesogenJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2010Zhen Lin Zhang Abstract On the basis of the concept of mesogen-jacketed liquid crystalline polymers, a series of new methacrylate monomers, (2,5- bis[2-(4,-alkoxyphenyl) ethynyl] benzyl methacrylate (MACn, n = 4, 6, 8, 10, and 12) and 2,5- bis[2-(6,-decanoxynaphthyl) ethynyl] benzyl methacrylate (MANC10), and their polymers, PMACn (n = 4, 6, 8, 10, and 12) and PMANC10 were synthesized. The bistolane mesogen with large ,-electron conjugation were side-attached to the polymer backbone via short linkages. Various characterization techniques such as differential scanning calorimetry, wide-angle X-ray diffraction, and polarized light microscopy were used to study their mesomorphic phase behavior. The polymer PMACn with shorter flexible substituents (n = 4) forms the columnar nematic (,N) phase, but other polymers with longer flexible tails (n = 6, 8, 10, and 12) can develop into a smetic A (SA) phase instead of a ,N phase. The PMANC10 containing naphthyl can also form a well-defined SA phase. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Poly(vinyl chloride) on the way from the 19th century to the 21st centuryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004D. Braun Abstract Despite all the technical and economic problems and the public discussions on the environmental dangers and hazards of chlorine chemistry, poly(vinyl chloride) (PVC) is the second most produced plastic (with a worldwide capacity of about 31 million tons), placing after polyolefins and before styrene polymers. Presently, PVC production worldwide is growing at a rate of more than 4% per year. The application of PVC was first described in a patent in 1913, but only after 1930 did a sustained interest in PVC arise in several industrial laboratories. The most remarkable milestones in PVC history and their importance to the development of macromolecular chemistry are briefly described, and some present PVC research and industrial applications, with respect to polymerization, stabilization, bulk property modification, and chemical and material recycling of PVC waste, are discussed. Some actual selected topics include the emulsion polymerization of vinyl chloride with polymeric surfactants and controlled free-radical polymerization with nitroxyls, whereas ionic and metal organic initiators have not found any technical applications. Chemical reactions offer many possibilities for the modification of PVC, but they have been not used on a technical scale yet. Much work has been done on stabilization with nontoxic or metal-free systems. The bulk properties of PVC can be influenced by impact modification through the addition of graft copolymers or by blending with other polymers. Also presented are some problems and recent developments in PVC recycling. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 578,586, 2004 [source] Anti-Biofouling Properties of Polymers with a Carboxybetaine MoietyMACROMOLECULAR BIOSCIENCE, Issue 1 2009Susumu Tada Abstract The resistance of random copolymers of BMA and CMB against biofouling was evaluated. The amount of proteins adsorbed onto the CMB copolymers was smaller than that onto other polymers (non-ionic polymers and copolymers of ordinary ionic monomers and BMA) and decreased with an increase in the content of CMB residues. Furthermore, there was a dramatic decrease in the number of cells (platelets and fibroblasts) that adhered to the CMB copolymers compared with that to other polymers. In contrast with this, CMB copolymers were slightly perturbative to both complement and coagulation systems. However, the overall results suggest that zwitterionic moieties are effective for making polymer materials biocompatible due to their excellent anti-biofouling property. [source] Molecular Simulation Via Connectivity-altering Monte Carlo and Scale-jumping Methods: Application to Amorphous PolystyreneMACROMOLECULAR THEORY AND SIMULATIONS, Issue 7-8 2008Tim Mulder Abstract Well-equilibrated atactic-polystyrene (aPS) samples are obtained through the end-bridging Monte Carlo (EBMC) algorithm. A coarse-grained (CG) description of aPS is used; monomers are represented by two CG beads. The algorithm produces correct polymer conformations on all length scales, beyond the size of the CG beads. The code is very efficient, even though the acceptance of 0.001,0.005% is approximately 10,100 times lower than in the original EB code for PE. Systems of aPS of the order of 5000 monomers (50 chains of 100 monomers on average) can be equilibrated on all length scales within a week, in a single-processor run. The computer code is also adequate for simulations of other polymers that have the same regularity in their sequence of chemical groups and that are modeled at the same or at a coarser level of description. [source] The shock and release behavior of an aerospace-grade cured aromatic amine epoxy resinPOLYMER COMPOSITES, Issue 10 2008P.J. Hazell Knowing the dynamic behavior of polymer materials that are used in the construction of fiber-reinforced composite materials is particularly important for such materials that are subjected to impact. In this work, we have conducted a number of plate-impact experiments on a commercially important aromatic amine epoxy resin that is used in the construction of carbon fiber composite materials. The measured Hugoniot in shock velocity,particle velocity space was Us = 2.65 + 1.55 up (,0 = 1.141 g/cc), and is similar to the measured Hugoniots of other resins presented by different researchers. We have also measured the longitudinal stress in the shocked material and shown, in common with other polymers, that above a threshold stress, an increase in shear strength with impact stress is observed. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Recycling of poly(ethylene terephthalate) as polymer-polymer composites,POLYMER ENGINEERING & SCIENCE, Issue 4 2002M. Evstatiev Microfibrillar reinforced composites (MFC) comprising an isotropic matrix from a lower melting polymer reinforced by microfibrils of a higher melting polymer were manufactured under industrially relevant conditions and processed via injection molding. Low density polyethylene (LDPE) (matrix) and recycled poly(ethylene terephthalate) (PET) (reinforcing material) from bottles were melt blended (in 30/70 and 50/50 PET/LDPE wt ratio) and extruded, followed by continuous drawing, pelletizing and injection molding of dogbone samples. Samples of each stage of MFC manufacturing and processing were characterized by means of scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS), dynamic mechanical thermal analysis (DMTA), and mechanical testing. SEM and WAXS showed that the extruded blend is isotropic but becomes highly oriented after drawing, being converted into a polymer-polymer composite upon injection molding at temperatures below the melting temperature of PET. This MFC is characterized by an isotropic LDPE matrix reinforced by randomly distributed PET microfibrils, as concluded from the WAXS patterns and SEM observations. The MFC dogbone samples show impressive mechanical properties,the elastic modulus is about 10 times higher than that of LDPE and about three times higher than reinforced LDPE with glass spheres, approaching the modulus of LDPE reinforced with 30 wt% short-glass fibers (GF). The tensile strength is at least two times higher than that of LDPE or of reinforced LDPE with glass spheres, approaching that of reinforced LDPE with 30 wt% GF. The impact strength of LDPE increases by 50% after reinforcement with PET. It is concluded that: (i) the MFC approach can be applied in industrially relevant conditions using various blend partners, and (ii) the MFC concept represents an attractive alternative for recycling of PET as well as other polymers. [source] | ||||||||||