Showing papers on "Polycarbonate published in 2011"

Highly Active Crystalline Mesoporous TiO2 Films Coated onto Polycarbonate Substrates for Self-Cleaning Applications

Abstract: SiO2 film precoating is found to be very effective for the protection of polycarbonate (PC) as a typical example for heat-sensitive substrate materials, thus preventing its photodegradation under UV light. Subsequently, transparent photoactive mesoporous TiO2 and Sachtleben Hombikat UV100 thin film coatings on SiO2/PC have been developed for self-cleaning applications. The newly prepared photocatalysts films have been compared with either a film prepared from a commercial photocatalyst (Sachtleben Hombikat UV-100), SG-TiO2, or Pilkington Glass ActivTM by the determination of their photonic efficiencies for degradation of methylene blue and the photoinduced surface wettability. The efficiency of the photocatalytic reactions was found to be about three times higher in the case of the mesoporous TiO2 films compared with films prepared from UV-100 or Pilkington Glass ActivTM. This is the first report focusing on the synthesis of mesoporous TiO2 films on polycarbonate substrates, and, to the best of our knowle...

Laser-induced breakdown spectroscopy for polymer identification

Abstract: This study aims at differentiating several organic materials, particularly polymers, by laser induced breakdown spectroscopy. The goal is to apply this technique to the fields of polymer recycling and cultural heritage conservation. We worked with some usual polymers families: polyethylene (PE), polypropylene (PP), polyoxymethylene, (POM), poly(vinyl chloride), polytetrafluoroethylene, polyoxyethylene (POE), and polyamide for the aliphatic ones, and poly(butylene terephthalate), acrylonitrile-butadiene-styrene, polystyrene, and polycarbonate for the aromatic ones. The fourth harmonic of a Nd:YAG laser (266 nm) in ambient air at atmospheric pressure was used. A careful analysis of the C(2) Swan system (0,0) band in polymers containing no C-C (POM), few C-C (POE), or aromatic C-C linkages led us to the conclusion that the C(2) signal might be native, i.e., the result of direct ablation from the sample. With use of these results, aliphatic and aromatic polymers could be differentiated. Further data treatments, such as properly chosen line ratios, principal component analysis, and partial least squares regression, were evaluated. It was shown that many polymers could be separated, including PE and PP, despite their similar chemical structures.

Plastic flame housing and method of making the same

Abstract: A flame element can comprise: a flame housing, fuel, and a medium for a flame. The flame housing is formed from a composition comprising: (a) a first polycarbonate having a LOI of greater than or equal to 25% and a glass transition temperature of greater than 170oC as measured using a differential scanning calorimetry method, wherein the first polycarbonate is derived from a monomer having the structure wherein each of A1 and A2 comprise a monocyclic divalent arylene group, and Y1 is a bridging group having one or more atoms, and wherein the structure is free of halogen atoms; 10 and (b) a second polycarbonate different than the first polycarbonate.

A Versatile Monomer for Preparing Well-Defined Functional Polycarbonates and Poly(ester−carbonates)

Abstract: Despite the increasing demands for functional degradable biomaterials, strategies for generating materials with modular compositions and well-defined functionalities from common building blocks are still lacking. Here we report an azido-functionalized cyclic carbonate monomer, AzDXO, that exhibited controlled/“living” ring-opening polymerization kinetics under the catalysis of 1,8-diazabicyclo[5.4.0]undec-7-ene. Homopolymerization of AzDXO and copolymerization of AzDXO with lactide resulted in polycarbonate and poly(ester−carbonates) with well-defined composition and narrow polydispersity. Further side-chain functionalizations of these polymers were accomplished under facile conditions via copper-catalyzed or copper-free strain-promoted azido−alkyne cyclcoaddition. This versatile monomer building block, obtainable in two steps without tedious purifications, provides a practical solution to the preparation of well-defined functional polycarbonates and poly(ester−carbonates).

Mechanical properties of injection-molded thermoplastic denture base resins

Abstract: Objective. To investigate the mechanical properties of injection-molded thermoplastic denture base resins. Material and methods. Four injection-molded thermoplastic resins (two polyamides, one polyethylene terephthalate, one polycarbonate) and, as a control, a conventional heat-polymerized polymethyl methacrylate (PMMA), were used in this study. The flexural strength at the proportional limit (FS-PL), the elastic modulus, and the Charpy impact strength of the denture base resins were measured according to International Organization for Standardization (ISO) 1567 and ISO 1567:1999/Amd 1:2003. Results. The descending order of the FS-PL was: conventional PMMA > polyethylene terephthalate, polycarbonate > two polyamides. The descending order of the elastic moduli was: conventional PMMA > polycarbonate > polyethylene terephthalate > two polyamides. The descending order of the Charpy impact strength was: polyamide (Nylon PACM12) > polycarbonate > polyamide (Nylon 12), polyethylene terephthalate > conve...

Enhanced thermal and surface properties of waterborne UV-curable polycarbonate-based polyurethane (meth)acrylate dispersion by incorporation of polydimethylsiloxane

Abstract: Hydroxy-terminated polydimethylsiloxane (PDMS) was incorporated into the soft segments of UV-curable polycarbonate-based polyurethane (meth)acrylate dispersions to improve the thermal property and surface property. 2-Hydroxymethacylate or pentaerythritol tri-acrylate was end-capped with or without PDMS to confirm the effect of the functionality of the end-capping group on the properties. Owing to the hydrophobicity of siloxane, the cured coating films containing PDMS had low surface free energy, and higher thermal degradation temperature. The functionality of the end-capping group had a slight effect on the surface and thermal properties. The UV-curing rate and final conversion depended strongly on the functionality. The glass transition temperature and the tensile strength of the cured films were increased by incorporating PDMS or increasing the functionality. Therefore, the weaknesses of waterborne UV-curable coatings can be alleviated by the incorporation of PDMS and high functionality.

Synthesis of poly(indene carbonate) from indene oxide and carbon dioxide--a polycarbonate with a rigid backbone.

Abstract: The catalytic coupling of carbon dioxide with indene oxide utilizing (salen)Co(III)-2,4-dinitrophenoxide in the presence of an onium salt is presented. X-ray structural data for indene oxide monomer as well as cis-indene carbonate display near planarity of the fused cyclopentene and benzene rings. Low temperature (0 °C) is required to selectively afford copolymer vs cyclic carbonate from the coupling reactions of CO2 and indene oxide. The produced poly(indene carbonate) samples have molecular weights of up to 7100 Da, with corresponding glass transition temperatures of up to 134 °C, the highest yet reported for polycarbonates produced from CO2/epoxides coupling. Poly(indene carbonate) is thermally stable up to 249 °C. The polymerizations are well controlled, with PDI values ≤1.3.

Some Mechanical and Thermal Properties of PC/ABS Blends

Abstract: A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young’s modulus changed gradually and monotonically with the polycarbonate content. This effect was tentatively explained as the antiplasticization of the PC which is ascribed to the chain mobility, which permits the PC chains to pack more tightly, to the secondary cross-linking between the PC chains, or to the secondary attachment of bulky side-chains to the PC, thus producing steric hindrance to the rotation of the PC main chains. The experimental values found for the impact strength were intermediate between those of the neat polymers, depending upon the dispersed rubber particles of butadiene in the matrix of SAN (Styrene-Acrylonitrile), and the dispersed PC particles which generally make the ABS more brittle. A maximum value of about 88 KJ/m2 for the impact strength was observed for the blend with 90% PC. This may be attributed to the strong polymer-polymer interactions for this particular composition. The variations in the heat deflection temperature HDT and the Vicat softening point with the blend composition were very similar, and allowed us to assume that the phase inversion between the matrices of the two polymers takes place at 50% PC. The morphology of the blends revealed by SEM observation, show a co-continuous structure.

Hydrophobic modification of polycarbonate for reproducible and stable formation of biocompatible microparticles

Abstract: We propose a simple and effective scheme for the modification of the walls of microfluidic channels fabricated in polycarbonate (PC) after the device has been bonded. The method prevents both static and dynamic wetting of PC by aqueous solutions including viscous, non-Newtonian solutions of polymers as e.g.alginate. The procedure uses dodecylamine, which readily reacts with the carbonate groups of PC to produce a hydrophobic surface. We characterize the dependence of the contact angles and homogeneity of the modified surfaces on the time, temperature, and concentration—all important parameters—of the reaction and provide optimal conditions for the process.

Chemistry, functionality, and coating performance of biobased copolycarbonates from 1,4:3,6-dianhydrohexitols

Abstract: Biobased polycarbonates were synthesized from 1,4:3,6-dianhydro-D-glucitol, 1,4:3,6-dianhydro-L-iditol, and 1,4:3,6-dianhydro-D-mannitol as the principal diols, using different types of carbonyl sources. The (co)polycarbonates resulting from polycondensation reactions in solution using triphosgene consisted of several types of polymer chains with respect to chain topology (e.g., linear or cyclic chains) and end-group structure (e.g., hydroxyl, chloroformate or alkyl chloride end-groups). The introduction of flexible comonomers seemed to increase the amount of cyclic structures in the product mixtures. The melt polymerization of diphenyl carbonate with 1,4:3,6-dianhydrohexitols required high reaction temperatures and led to almost exclusively hydroxy-functional poly(1,4:3,6-dianhydrohexitol carbonate)s. Copolymerizing the 1,4:3,6-dianhydrohexitols with 1,3-propanediol and diphenyl carbonate at high temperature resulted in the partial loss of 1,3-propanediol. On the other hand, by melt polycondensation of 1,4:3,6-dianhydrohexitol-based bis(phenyl carbonate) monomers in combination with primary diols and/or triols, the insertion of the primary alcohols could be achieved in a more controlled way. OH-functional materials were prepared, having suitable molecular weights, Tg values, thermal stability, and melt viscosity profiles for (powder) coating applications. These functional biobased (co)polycarbonates were cured with polyisocyanate curing agents, resulting in colorless to pale yellow transparent, glossy coatings with good mechanical performance and solvent resistance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Fabrication of nanostructured polycarbonate/poly(methyl methacrylate) blends with improved optical and mechanical properties by high-shear processing

Abstract: The structure and properties of polycarbonate (PC)/ poly(methyl methacrylate) (PMMA) blends fabricated using a high-shear extruder at different shear rates were investigated. It was found that the morphologies of the blends were greatly dependent on the shear rate exerted during melt processing. High-shear processing leads to a nanostructured PC/PMMA blend, in which PMMA domains with a size of less than 50 nm are homogeneously dispersed in the PC matrix. The prepared nanostructured blends exhibit not only excellent optical properties with a transmittance of more than 90% in the visible region but also a higher modulus than pure PC. In contrast, the PMMA domain size ranges from submicron to micrometer for the same blends processed at a low-shear rate. These blends are opaque and display much lower elongation at break compared with the blends processed at a high-shear rate. POLYM. ENG. SCI., 51:1437–1445, 2011. a 2011 Society of Plastics Engineers

Polymer Materials: Macroscopic Properties and Molecular Interpretations

Abstract: PREFACE. LIST OF SYMBOLS. Introduction to Polymer Materials. PART I. 1 The Four Classes of Polymer Materials. 2 The Macromolecular Chain in the Amorphous Bulk Polymer: Static and Dynamic Properties. 3 The Glass Transition. 4 Secondary Relaxations in Amorphous Polymers. 5 Entanglements in Bulk Un-Cross-Linked Polymers. 6 Semicrystalline Polymers. PART II. 7 Elastic and Hyperelastic Behaviors. 8 Linear Viscoelastic Behavior. 9 Anelastic and Viscoplastic Behaviors. 10 Damage and Fracture of Solid Polymers. PART III. 11 Mechanical Properties of Poly(Methyl Methacrylate) and Some of Its Random Copolymers. 12 Mechanical Properties of Bisphenol-A Polycarbonate. 13 Mechanical Properties of Epoxy Resins. 14 Polyethylene and Ethylene-a-olefi n Copolymers. 15 High-Modulus Thermoplastic Polymers. PART IV. 16 Mechanical Tests for Studying Impact Behavior. 17 High-Impact Polystyrene. 18 Toughened Poly(Methyl Methacrylate). 19 Toughened Aliphatic Polyamides. 20 Toughened Epoxy Resins. PART V. 21 Chemically Cross-Linked Elastomers. 22 Reinforcement of Elastomers by Fillers. 23 Thermoplastic Elastomers. Appendix: Problems. INDEX.

Anti-Fog Layer Deposition onto Polymer Materials: A Multi-Step Approach

Abstract: A coating with anti-fog properties was developed for a polycarbonate (PC) substrate using a multi-step process. A silicon-containing multilayer was first deposited by atmospheric pressure Townsend discharge (APTD) using hexamethyldisiloxane (HMDSO) precursor to ensure cohesion between the coating and the PC and to protect the polymer against dissolution in solvents during subsequent spin-coating processes. The multilayer was also developed in a nitrogen environment in order to provide amino groups on the surface, which allowed for the subsequent covalent bonding of the anti-fog layer. This anti-fog layer was made of a spin-coated (poly(ethylene-maleic anhydride) (PEMA) layer, used as a linking arm, followed by a spin-coated poly(vinyl alcohol) (PVA) layer, for its anti-fog properties. Surface analyses (XPS, FTIR, and AFM) confirmed that the silicon-containing multilayer was successfully deposited with a good control obtained for each step. The anti-fog coating, also tested with promising results, displayed a negligible loss of optical transmission across the visible spectrum.

Novel biodegradable block copolymers of poly(ethylene glycol) (PEG) and cationic polycarbonate: effects of peg configuration on gene delivery.

Abstract: A novel amine-functionalized polycarbonate was synthesized and its excellent gene transfection ability in vitro is demonstrated. In the framework of adapting the cationic polycarbonate for in vivo gene delivery applications, here the design and synthesis of biodegradable block copolymers of poly(ethylene glycol) (PEG) and amine-functionalized polycarbonate with a well-defined molecular architecture and molecular weight is achieved by metal-free organocatalytic ring-opening polymerization. Copolymers in triblock cationic polycarbonate-block-PEG-block-cationic polycarbonate and diblock PEG-block-cationic polycarbonate configurations, in comparison with a non-PEGylated cationic polycarbonate control, are investigated for their influence on key aspects of gene delivery. Among the polymers with similar molecular weights and N content, the triblock copolymer exhibit more favorable physicochemical (i.e., DNA binding, size, zeta-potential, and in vitro stability) and biological (i.e., cellular uptake and luciferase reporter gene expression) properties. Importantly, the various cationic polycarbonate/DNA complexes are biocompatible, inducing minimal cytotoxicities and hemolysis. These results suggest that the triblock copolymer is a more useful architecture in future cationic polymer designs for successful systemic therapeutic applications.

Solution-processed nanostructured benzoporphyrin with polycarbonate binder for photovoltaics.

Abstract: Figure 1 . (a) Chemical transformation of BP precursor (CP) to benzoporphyrin (BP) during annealing; (b) standard BP OPV device; (c) TGA analysis of PC and CP; (d) schematic of processing method used to form fi lms of BP for morphology analysis. Organic photovoltaics (OPV) based on bulk heterojunctions (BHJs) have effi ciencies above 7% [ 1 , 2 ] and can be processed from solution at potentially low cost. [ 3 ] BHJs comprise a blend of an electron donor and an electron acceptor in a phase separated morphology that provides a large interfacial area for photogeneration of electron-hole pairs. [ 4 ] The highest performance OPVs currently comprise blends of semiconducting polymers and fullerenes, such as [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM). [ 4 ] Despite their performance in BHJs, semiconducting polymers often take many complicated steps to synthesize and may be diffi cult to purify. [ 5 , 6 ]

Multiple activation of ion track etched polycarbonate for the electroless synthesis of metal nanotubes

Abstract: In our study, we examined the formation of thin films of silver nanoparticles on polycarbonate and the influence of the silver loading on the electroless synthesis of metal nanotubes. Control of the silver film thickness occurred by consecutive dipping of the polymer template in tin(II) and silver(I) solutions. The deposition progress was studied using UV-Vis spectroscopy. The reaction mechanism relies on the adsorption of reactive ions on the polymer template as well as on the silver nanoparticles. The initial catalytic activity of silver-covered ion track etched polycarbonate is an important governing factor for the electroless synthesis of metal nanotubes with desired thickness and shape. Therefore, the presented method allows specific template preparation according to given synthetic demands. High aspect ratio copper, gold, and platinum nanotubes were produced by the combination of sufficiently activated templates with optimized electroless plating procedures.

Structure of thin film polymer/nanoparticle systems: polystyrene (PS) coated-Au nanoparticle/tetramethyl bisphenol-A polycarbonate mixtures (TMPC)

Abstract: The morphologies of thin film blends of polystyrene (PS)-brush coated Au nanoparticles with tetramethyl bisphenol-A polycarbonate (TMPC) were investigated. Our results reveal that entropic effects, associated with the brush/host chain interactions, nanoparticle diameter, D, and asymmetries in monomer sizes of the host and grafted chains, can play a more important role than the favorable PS/TMPC enthalpic interactions toward determining the phase miscibility of the system. A diagram of states is constructed to show the phase separated and dispersed regimes as a function of D, N, the degree of polymerization of the grafted chains, and P, the degree of polymerization of the host chains, at a constant grafting density. These results have important implications on the design of brush coated nanoparticle/homopolymer mixtures for various applications.

Method of manufacturing polycarbonate/polyester alloy

Abstract: The invention discloses a preparation method of polycarbonate/polyester alloy. Glycidyl methacrylate grafted ethylene-octylene multipolymer/organic modified needle-shaped aedelforsite composite toughener, i.e. a technology of simultaneously using organic/inorganic rigid particle toughener is adopted; the glycidyl methacrylate grafted ethylene-octylene multipolymer, organic modified needle-shaped aedelforsite, polycarbonate and polyester are melted and mixed in a double-screw extruder, to obtain high-performance alloy material. The prepared polycarbonate/polyester alloy has excellent integrated mechanical properties and size stability, the notched impact strength reaches 1200J/m, the tensile strength reaches 67MPa, the elongation at break reaches 250 percent, the flexural strength is up to98MPa, the flexural modulus reaches 2750MPa, and the thermal deformation temperature in high load (1.82MPa) is up to 105 DEG C. Therefore, the prepared polycarbonate/polyester alloy can be applied incars, and to outer decorations, household electrical appliances, IT and the like industrial products.

High heat polycarbonate and siloxane copolycarbonate blends that provide ductile high heat options for flame retardant applications

Abstract: Polycarbonate blend compositions are provided. In particular, polycarbonate blend compositions having a combination of a high heat polycarbonate, a polycarbonate polysiloxane copolymer, an anti-drip agentcomprising a perfluorinatedpolyolefin, and a flame retardant additive.

Preparation and Characterization of Heterogeneous Cation Exchange Membranes Based on S-Poly Vinyl Chloride and Polycarbonate

Abstract: This research deals with the preparation of heterogeneous cation exchange membranes by solution-casting techniques using S-polyvinylchloride (S-PVC) and polycarbonate (PC) as binders, cation exchange resin powder as functional groups agent, and tetrahydrofuran as solvent. The effects of polymer binder type and resin ratio loading on morphological, electrochemical, and mechanical properties of prepared membranes were studied and evaluated. Scanning electron microscopy and scanning optical microscopy were used for the membranes structure investigation. Images showed that increase of resin loading in casting solution resulted in a highly uniform phase forming. Moreover resin particles were distributed more uniformly in polycarbonate membranes compared to the polyvinylchloride ones. The water content, surface hydrophilicity, ion exchange capacity, ion concentration, permselectivity, membrane potential, surface charge density, transport number, ionic permeability, flux of ions, and current efficiency were enha...

Polycarbonate resin composition and molded article

Abstract: Provided a polycarbonate resin composition excellent in flame resistance, impact resistance, and color fastness. A polycarbonate resin composition containing, per 100 parts by mass of polycarbonate resin (A), 0.001 to 30 parts by mass of flame retardant (B), 0.001 to 1 part by mass of fluoropolymer (C), and 0.5 to 10 parts by mass of graft copolymer (D) obtainable by graft-copolymerizing a diene-based rubber with a (meth)acrylate ester compound, the graft copolymer (D) having (i) a sulfur content of 100 to 1500 ppm, and (ii) an average particle size of 70 to 240 nm.