Showing papers on "Polycarbonate published in 2016"

Bio-based polycarbonate as synthetic toolbox

Abstract: Completely bio-based poly(limonene carbonate) is a thermoplastic polymer, which can be synthesized by copolymerization of limonene oxide (derived from limonene, which is found in orange peel) and CO2. Poly(limonene carbonate) has one double bond per repeating unit that can be exploited for further chemical modifications. These chemical modifications allow the tuning of the properties of the aliphatic polycarbonate in nearly any direction. Here we show synthetic routes to demonstrate that poly(limonene carbonate) is the perfect green platform polymer, from which many functional materials can be derived. The relevant examples presented in this study are the transformation from an engineering thermoplastic into a rubber, addition of permanent antibacterial activity, hydrophilization and even pH-dependent water solubility of the polycarbonate. Finally, we show a synthetic route to yield the completely saturated counterpart that exhibits improved heat processability due to lower reactivity.

Ion transport in polycarbonate based solid polymer electrolytes: experimental and computational investigations.

Abstract: Among the alternative host materials for solid polymer electrolytes (SPEs), polycarbonates have recently shown promising functionality in all-solid-state lithium batteries from ambient to elevated temperatures. While the computational and experimental investigations of ion conduction in conventional polyethers have been extensive, the ion transport in polycarbonates has been much less studied. The present work investigates the ionic transport behavior in SPEs based on poly(trimethylene carbonate) (PTMC) and its co-polymer with epsilon-caprolactone (CL) via both experimental and computational approaches. FTIR spectra indicated a preferential local coordination between Li+ and ester carbonyl oxygen atoms in the P(TMC20CL80) co-polymer SPE. Diffusion NMR revealed that the co-polymer SPE also displays higher ion mobilities than PTMC. For both systems, locally oriented polymer domains, a few hundred nanometers in size and with limited connections between them, were inferred from the NMR spin relaxation and diffusion data. Potentiostatic polarization experiments revealed notably higher cationic transference numbers in the polycarbonate based SPEs as compared to conventional polyether based SPEs. In addition, MD simulations provided atomic-scale insight into the structure-dynamics properties, including confirmation of a preferential Li+-carbonyl oxygen atom coordination, with a preference in coordination to the ester based monomers. A coupling of the Li-ion dynamics to the polymer chain dynamics was indicated by both simulations and experiments.

A Novel Single-Ion-Conducting Polymer Electrolyte Derived from CO2-Based Multifunctional Polycarbonate

Abstract: This work demonstrates the facile and efficient synthesis of a novel environmentally friendly CO2-based multifunctional polycarbonate single-ion-conducting polymer electrolyte with good electrochemistry performance. The terpolymerizations of CO2, propylene epoxide (PO), and allyl glycidyl ether (AGE) catalyzed by zinc glutarate (ZnGA) were performed to generate poly(propylene carbonate allyl glycidyl ether) (PPCAGE) with various alkene groups contents which can undergo clickable reaction. The obtained terpolymers exhibit an alternating polycarbonate structure confirmed by 1H NMR spectra and an amorphous microstructure with glass transition temperatures (Tg) lower than 11.0 °C evidenced by differential scanning calorimetry analysis. The terpolymers were further functionalized with 3-mercaptopropionic acid via efficient thiol–ene click reaction, followed by reacting with lithium hydroxide, to afford single-ion-conducting polymer electrolytes with different lithium contents. The all-solid-state polymer elect...

Chemoselective alternating copolymerization of limonene dioxide and carbon dioxide:a new highly functional aliphatic epoxy polycarbonate

Abstract: The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg) up to 135 °C. These polycarbonates can be efficiently modified by thiols or carboxylic acids in combination with lithium hydroxide or tetrabutylphosphonium bromide as catalysts, respectively, without destruction of the main chain. Moreover, polycarbonates bearing pendent cyclic carbonates can be quantitatively prepared by CO2 insertion catalyzed by lithium bromide.

Allyl Ethers as Combined Plasticizing and Crosslinkable Side Groups in Polycarbonate-Based Polymer Electrolytes for Solid-State Li Batteries

Abstract: Allyl ether-functional polycarbonates, synthesized by organocatalytic ring-opening polymerization of the six-membered cyclic carbonate monomer 2-allyloxymethyl-2-ethyltrimethylene carbonate, were used to prepare non-polyether polymer electrolytes. UV-crosslinking of the allyl side groups provided mechanically stable electrolytes with improved molecular flexibility—Tg below −20 °C—and higher ionic conductivity—up to 4.3 × 10−7 S/cm at 25 °C and 5.2 × 10−6 S/cm at 60 °C—due to the plasticizing properties of the allyl ether side groups. The electrolyte function was additionally demonstrated in thin-film Li battery cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2128–2135

Solution blending preparation of polycarbonate/graphene composite: boosting the mechanical and electrical properties

Abstract: We report on the preparation of polycarbonate-based graphene (PC/G) composites, by using a simple and scalable solution blending method to disperse single- (SLG) and few-layer (FLG) graphene flakes, prepared by liquid phase exfoliation (LPE), in the polymer matrix. A solvent-exchange process is carried out to re-disperse the exfoliated SLG/FLG flakes in an environmentally friendly solvent, i.e. 1,3-dioxolane, which is also used to dissolve the polycarbonate pellets, thus facilitating the mixing of the polymer dispersion with the SLG/FLG flakes. The loading of SLG/FLG flakes improves the mechanical and thermal properties, as well as the electrical conductivity of the polymer, reaching a +26% improvement of the elastic modulus at 1 wt% loading, and an electrical conductivity 10−3 S m−1 at 10 wt% with a percolation threshold achieved at 0.55 vol%. The as-prepared PC/G composite with the aforementioned reinforced properties can be a promising material for 3D printing-based applications.

Characterization of Environmental Dust in the Dammam Area and Mud After-Effects on Bisphenol-A Polycarbonate Sheets.

Abstract: Owing to recent climate changes, dust storms are increasingly common, particularly in the Middle East region. Dust accumulation and subsequent mud formation on solid surfaces in humid environments typically have adverse effects on surface properties such as optical transmittance, surface texture and microhardness. This is usually because the mud, which contains alkaline and ionic species, adheres strongly to the surface, often through chemical bonds and is therefore difficult to remove. In this study, environmental dust and the after-effects of mud formed on a polycarbonate sheet, which is commonly used as a protective glass in photovoltaic cells. Ionic compounds (OH−) are shown to significantly affect the optical, mechanical and textural characteristics of the polycarbonate surface and to increase the adhesion work required to remove the dry mud from the polycarbonate surface upon drying. Such ability to modify characteristics of the polycarbonate surface could address the dust/mud-related limitations of superhydrophobic surfaces.

Oxyalkylation of Condensed Tannin with Propylene Carbonate as an Alternative to Propylene Oxide

Abstract: Propylene carbonate (PC) was used as an alternative to the hazardous propylene oxide (PO) for the oxypropylation of condensed tannins from Acacia mearnsii. The influence of the catalyst, temperature and stoichiometry was evaluated in detail. All the synthesized polymers were characterized by 1H and 31P NMR, FTIR, and size exclusion chromatography. Polyether chains were successfully grafted on all hydroxyl groups. In addition to the ether linkages, some carbonate linkages were also formed. This can cause some chain coupling reactions, through condensation and/or transesterification reactions, which ultimately increase the molar mass and reduce the OH content of the final products. The use of K2CO3 as catalyst rather than hydroxides (KOH or NaOH) and a high temperature of reaction (170 °C) were found to strongly reduce this phenomenon. Using 10–40 equiv of PC per OH in tannins, polyether/polycarbonate chains of 2–6 units in average were grafted, containing less than 25% of carbonate units. The synthesized p...

Efficient Flame Retardant Thin Films Synthesized by Atmospheric Pressure PECVD through the High Co-deposition Rate of Hexamethyldisiloxane and Triethylphosphate on Polycarbonate and Polyamide-6 Substrates.

Abstract: An innovative approach to produce high-performance and halogen-free flame-retardant thin films at atmospheric pressure is reported. PDMS-based coatings with embedded dopant-rich polyphosphates are elaborated thanks to a straightforward approach, using an atmospheric pressure dielectric barrier discharge (AP-DBD). Deposition conditions have been tailored to elaborate various thin films that can match the fire performance requirements. Morphology, chemical composition, and structure are investigated, and results show that the coatings performances are increased by taking advantage of the synergistic effect of P and Si flame retardant compounds. More specifically, this study relates the possibility to obtain flame retardant properties on PolyCarbonate and PolyAmide-6 thanks to their covering by a 5 μm thick coating, i.e. very thin films for this field of application, yet quite substantial for plasma processes. Hence, this approach enables deposition of flame retardant coatings onto different polymer substrat...

Toughening modification of polycarbonate/poly(butylene terephthalate) blends achieved by simultaneous addition of elastomer particles and carbon nanotubes

Abstract: Small quantities of maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MAH) copolymer and carbon nanotubes (CNTs) were introduced into polycarbonate (PC)/poly(butylene terephthalate) (PBT) blends. The results demonstrated that simultaneously adding SEBS-g-MAH and CNTs greatly enhanced the fracture toughness of the samples and the impact strength increased with increasing CNT content. The morphologies, the dispersion of CNTs, the relaxation behaviors and the crystallization behaviors of samples were systematically investigated. SEBS-g-MAH formed the dispersed particles in the system. The particle diameter was decreased in the blend composites. CNTs exhibited homogeneous dispersion in the blend composites and they also formed a percolated network structure at relatively high content. The transesterification between PC and PBT components was suppressed by SEBS-g-MAH, and the crystallization ability of the PBT component was greatly enhanced. The toughening mechanisms were mainly related to the suppressed transesterification, the decreased elastomer particle size, and the formation of a CNT network structure.

Polycarbonate all-solid-state polymer electrolyte, all-solid-state secondary lithium battery made of same and preparation and application thereof

Abstract: The invention relates to solid-state electrolytes, in particular to a polycarbonate all-solid-state polymer electrolyte, an all-solid-state secondary lithium battery made of the same and preparation and application thereof. The all-solid-state polymer electrolyte is prepared from polycarbonate macromolecules, lithium salt and a porous supporting material; the thickness is 20-800 micrometers, the mechanical strength is 10-80 MPa, the room temperature ion conductivity is 2*10 S/cm-1*10 S/cm, and the electrochemical window is higher than 4V. The all-solid-state polymer electrolyte is easy to prepare and form, good in mechanical property, high in ion conductivity and wide in electrochemical window; meanwhile, the solid-state electrolyte effectively inhibits growth of negative electrode lithium dendrites and improves interface stability and long circulation performance.

Structure and tensile properties evaluation of samples produced by Fused Deposition Modeling

Abstract: Abstract This paper presents the result of a study evaluating the influence of alternative path generation strategy on structure and some mechanical properties of parts produced by Fused Deposition Modeling (FDM) technology. Several scientific investigations focused on resolving issues in FDM parts by modifying a path generation strategy to optimize its mechanical properties. In this study, an alternative strategy was proposed with the intention of minimizing internal voids and, thus, to improve mechanical properties. Polycarbonate samples made by this alternative path generation strategy were subjected to tensile strength test and metro-tomography structure evaluation. The results reveal that the structure observed on build models differs from a structure expected from path generation predicted by software Insight 9.1. This difference affected the tensile strength of samples.

Polycarbonate resin composition

Abstract: PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition which is excellent in flowability and suppresses reduction in impact resistance caused by high-temperature working.SOLUTION: There is provided a polycarbonate resin composition containing a polycarbonate resin (a) and sucrose aromatic monocarboxylic acid ester (b), where 1-30 pts.mass of the sucrose aromatic monocarboxylic acid ester (b) is preferably used with respect to 100 pts.mass of the polycarbonate resin (a), and the sucrose aromatic monocarboxylic acid ester (b) preferably has an average number of ester groups of 2.5-7.9.SELECTED DRAWING: None

Aliphatic polycarbonate-based thermoplastic polyurethane elastomers containing diphenyl sulfide units

Abstract: New thermoplastic polyurethane elastomers (TPUs) were obtained by a one-step melt polyaddition from 30, 45 and 60 mol% aliphatic polycarbonate diol of M n = 2000 g mol−1 (Desmophen® C2200, Bayer), 1,1′-methanediylbis(4-isocyanatocyclohexane) (HMDI) or 1,6-diisocyanatohexane (HDI) and 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol (acting as a chain extender). The TPUs were examined by FTIR, UV–Vis, atomic force microscopy, X-ray diffraction analysis, differential scanning calorimetry, thermogravimetry (TG) and TG–FTIR. Moreover, their Shore A/D hardness, tensile, adhesive and optical properties were determined. The obtained TPUs were transparent or opaque high molar mass materials, showing amorphous or partially crystalline structures. The HDI-based TPUs exhibited lower glass-transition temperatures than those based on HMDI (from −35 to −31 °C vs. from −20 to 1 °C) as well as a higher degree of microphase separation. The TPUs were stable up to 262–272 °C, taking into account the temperature of 1 % mass loss, with somewhat higher values shown by those from HDI. They decomposed in two stages. The main volatile products of the hard-segment decomposition were carbon dioxide, water and carbonyl sulfide, while aliphatic ethers, aldehydes and unsaturated alcohols, as well as carbon dioxide, originated from the soft-segment decomposition. The synthesized TPUs, with hardness in the range of 80–90°Sh A, possessed a good tensile strength (33.0–38.7 MPa), similar to that of the commercial biodurable medical grade TPU ChronoFlex® AL 80A (37.9 MPa), prepared from aliphatic polycarbonate diol, HMDI and butane-1,4-diol.

Experimental analysis and theoretical modeling of the mechanical behavior of short glass fiber and short carbon fiber reinforced polycarbonate hybrid composites

Abstract: In this research, polycarbonate (PC) composites with short glass fiber (SGF) and short carbon fiber (SCF) hybrid fiber reinforcements were compounded by single screw extruder and specimens were prepared by injection molding machine. This article aims to investigate the mechanical properties of PC hybrid composites, by means of the experimental and the theoretical methods. The composites were subjected to tensile test. Experimental results showed the improvements in tensile strength and modulus by increasing the SCF content of the hybrid composite. The theoretical tensile strength was predicted based on Kelly–Tyson model and rule of hybrid mixture. Kelly–Tyson model showed to be a good approximation to predict the tensile strength of composite. When the SCF was replaced by milled carbon fiber (MCF) to form a PC/SGF/MCF hybrid system, poorer mechanical properties are reported due to the weaker interfacial adhesion between MCF and PC, as proven by the scanning electron microscopy. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

Octadecylsilane/Nylon-6 composite as a thin-film microextraction sorbent for the determination of bisphenol A in water samples

Abstract: We report on the fabrication of a thin-film composite for the extraction of bisphenol A from aqueous solutions. Nylon-6, C18 particles, and polyethylene glycol were used to prepare the thin film sorbent. Bisphenol A was used as a model compound to evaluate the extraction efficiency of the sorbent. High-performance liquid chromatography with UV detection was used for the analysis. The extraction yield of the sorbent was compared with other thin films fabricated using different sorbents including nanoclay, LiChrolut EN, and multiwalled carbon nanotubes. Experimental parameters affecting the extraction performance (extraction time, desorption condition, sample stirring, and ionic strength of the sample solution) were investigated. The detection limit and the dynamic range of the method were 0.05 and 0.15–50 μg/L, respectively. The relative standard deviation of the method at two concentration levels (0.5 and 20 μg/L) was less than 7.2%. Finally, a polycarbonate baby bottle, river water, and wastewater samples were analyzed by the method.

Experimental and numerical evaluation of transparent bulletproof material for enhanced impact-energy absorption using strengthened-glass/polymer composite

Abstract: The ballistic impact resistance of glass/polymer composites was evaluated in relation to application in high-performance and lightweight bulletproof materials by using a strengthened soda-lime silicate glass An effective strengthened-glass fabrication method was developed, which involves combined reinforcement incorporating ion exchange using dispersed concentrated potassium nitrate powder, followed by quenching at 15 K/s The static compression test of the strengthened glass was approximately 37 times greater than that of the parent glass The elastic modulus of the strengthened glass through the dynamic compression tests increased from 587 to 729 GPa as compared to the parent glass at a strain rate of 1042/s As a result, we confirmed that the strengthened glass exhibits anisotropic behavior and high impact resistance In addition, the fracture behavior of tested specimens from the finite element simulation appeared in good agreement with the experimental results By laminating the two strengthened-glass samples with two continuous polycarbonate sheets at the back, we achieved a ballistic limit velocity of 8929 m/s and reduced the thickness of the bulletproof materials from 2883 to 1815 mm

Solvent-induced crystallization of a polycarbonate surface and texture copying by polydimethylsiloxane for improved surface hydrophobicity

Abstract: The influence of the immersion period on the crystallization of polycarbonate (PC) was investigated, and the resulting texture configurations of the crystal structures were reconstructed with polydimethylsiloxane (PDMS). Analytical tools, including optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, the sessile drop technique, Fourier transform infrared spectroscopy, microtribometry, and ultraviolet–visible spectrophotometry, were used to characterize crystallized PC and PDMS surfaces. We found that the crystallized PC surface possessed microsize/nanosize spherulites, voids, and fibrils, and the increasing immersion period increased the texture height and spherulite concentration at the surface. The residual stress in the crystallized PC wafer was compressive, and it was on the order of 230 MPa. The friction coefficient of the crystallized PC surface remained lower than that of the as-received PC wafer, and the increase in the immersion period lowered the friction coefficient. The crystallized PC surface demonstrated superhydrophobic characteristics, and the maximum contact angle occurred with 6 min of immersion. The PDMS exactly reconstructed the texture of the crystallized PC surface, except those of the nanofibrils and subnanofibrils. The droplet contact angle attained a higher values for the PDMS replicated surfaces than for those corresponding to the crystallized PC wafer. VC 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43467.