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Showing papers on "Polycarbonate published in 2022"


Journal ArticleDOI
01 Apr 2022
TL;DR: In this article , a comprehensive and innovative approach to assess the fire safety of flame-retardant polycarbonate composites containing potassium perfluorobutane sulfonate (PPFBS) and a silicon-based flame retardant (PSR) through combining numerous combustion parameters obtained from different measurements was proposed.
Abstract: Polycarbonate (PC) is highly attractive for applications in high-speed railways and airplanes as engineering materials, but suffers from high fire hazards with severe melting dripping during burning. To overcome the challenge, highly effective flame retardants, such as sulfonate derivatives and silicon-based compounds have been developed. Unfortunately, there is still lacking of a systematic method to evaluate the fire risk of these flame-retardant PC composites. Herein, we propose a comprehensive and innovative approach to assess the fire safety of flame-retardant PC composites containing potassium perfluorobutane sulfonate (PPFBS) and a silicon-based flame retardant (PSR) through combining numerous combustion parameters obtained from different measurements. The pyrolysis and combustion characteristics of PC/PPFBS and PC/PSR were studied in detail and revealed that PPFBS and PSR could effectively reduce the activation energy of PC. PSR is effective at reducing the heat and smoke release due to the formation of a Si–C protective layer during combustion. In contrast, PPFBS has no obvious suppression effect on smoke generation, and even shows a combustion-supporting effect under high radiation flux. Based on the analytic hierarchy process (AHP), a comprehensive evaluation model has been established to achieve an objective and comprehensive evaluation of the fire hazards of PC and its composites. This works provides a universal guidance for evaluating fire hazards of flame-retardant polymer composite.

42 citations


Journal ArticleDOI
TL;DR: In this paper , a class of seven-membered ring carbonates containing trans-cyclohexyl fused rings was used for ring-opening polymerization (ROP) with turnover frequency (TOF) up to 6 × 105 h-1 and catalyst loading down to 50 ppm.
Abstract: Monomer design plays an important role in the development of polymers with desired thermal properties and chemical recyclability. Here we prepared a class of seven-membered ring carbonates containing trans-cyclohexyl fused rings. These monomers showed excellent activity for ring-opening polymerization (ROP) with turnover frequency (TOF) up to 6 × 105 h-1 and catalyst loading down to 50 ppm, which yielded high-molecular-weight polycarbonates (Mn up to 673 kg/mol) with great thermostability (Td > 300 °C). Ultimately, the resulting polycarbonates can completely depolymerize into their corresponding cyclic dimers that can repolymerize to synthesize the starting polymers in moderate yields, demonstrating a potential route to achieve chemical recycling. Postfunctionalization of the unsaturated polycarbonate was conducted through cross-linking reaction and "click" reaction under UV irradiation.

38 citations


Journal ArticleDOI
TL;DR: In this paper , a fluorine-containing polycarbonate-based electrolyte was designed to expand the electrochemical window up to above 5 V (vs. Li/Li+ ), which exhibited an ionic conductivity of 5.02 × 10 −5 S cm −1 at room temperature.

31 citations


Journal ArticleDOI
TL;DR: In this article , a polyurethane elastomer based on polycarbonate glycol, 1,5-naphthalene diisocyanate, and 1,4-butanediol simultaneously exhibits self-repairable ability, high heat resistance, low rolling resistance, high wear resistance, and high wet-skid resistance.

21 citations



Journal ArticleDOI
TL;DR: In this paper, the fabrication of aliphatic polycarbonate (APC) coatings by electrophoretic deposition and subsequent photo-crosslinking to achieve corrosion resistance and surface biocompatibility enhancement of Mg-alloy stents was reported.

20 citations


Journal ArticleDOI
TL;DR: In this article , a series of sulfonated ionomeric fire retardants (sSEBS-M, M = Na+, Zn2+, Ce3+) were designed by sulfonating and neutralizing styrene-ethylene-butylene styrene (SEBS).

19 citations


Journal ArticleDOI
TL;DR: In this article , the fabrication of aliphatic polycarbonate (APC) coatings by electrophoretic deposition and subsequent photo-crosslinking to achieve corrosion resistance and surface biocompatibility enhancement of Mg-alloy stents was reported.

18 citations



Journal ArticleDOI
TL;DR: In this article , a homogeneous dinuclear methyl zinc catalyst ((BDI-ZnMe)2) was used to rapidly copolymerize meso-CHO and CO2 into poly(cyclohexene carbonate) (PCHC) with an unprecedentedly cyclic structure.
Abstract: It is highly desirable to reduce the environmental pollution related to the disposal of end-of-life plastics. Polycarbonates derived from the copolymerization of CO2 and epoxides have attracted much attention since they can enable CO2-fixation and furnish biorenewable and degradable polymeric materials. So far, only linear CO2-based polycarbonates have been reported and typically degraded to cyclic carbonates. Here we synthesize a homogeneous dinuclear methyl zinc catalyst ((BDI-ZnMe)2, 1) to rapidly copolymerize meso-CHO and CO2 into poly(cyclohexene carbonate) (PCHC) with an unprecedentedly cyclic structure. Moreover, in the presence of trace amounts of water, a heterogeneous multi-nuclear zinc catalyst ((BDI-(ZnMe2·xH2O))n, 2) is prepared and shows up to 99% selectivity towards the degradation of PCHC back to meso-CHO and CO2. This strategy not only achieves the first case of cyclic CO2-based polycarbonate but also realizes the complete chemical recycling of PCHC back to its monomers, representing closed-loop recycling of CO2-based polycarbonates.

17 citations


Journal ArticleDOI
TL;DR: A rare charring behavior was found during the combustion of polycarbonate (PC) composites containing polyborosiloxane (PBS), in which a highly intumescent char layer with core-shell structure was formed as discussed by the authors .

Journal ArticleDOI
TL;DR: In this article, an environmentally sound method for valorization of plastic waste is suggested, where pyrolysis of polycarbonate-containing plastic waste such as automotive headlight housing (AHH) was carried out using CO2 as a co-reactant.

Journal ArticleDOI
TL;DR: In this article , an environmentally sound method for valorization of plastic waste is suggested, where pyrolysis of polycarbonate-containing plastic waste such as automotive headlight housing (AHH) was carried out using CO2 as a co-reactant.


Journal ArticleDOI
01 May 2022-Polymer
TL;DR: In this article , a porous polycarbonate blend monolith with hierarchical micro-nano structure using fluorine-free and low-cost material via a simple thermally induced phase separation is successfully prepared.

Journal ArticleDOI
TL;DR: In this article , a shadow mask is used to cover the contacts of WS 2 photodetectors and the contacts are then deposited by thermal evaporation through shadow mask.
Abstract: Abstract We present a low-cost and easy-to-implement technique to fabricate large-area WS 2 photodetector devices onto transparent and flexible polycarbonate substrates. The method relies on the deposition of large-area (in the cm scale) thin films (~30 nm thick) of WS 2 by a recently introduced abrasion-induced method. Interdigitated electrical contacts are then deposited by thermal evaporation through a shadow mask. The photodetectors present well-balanced performances with an good trade-off between responsivity (up to 144 mA/W at a source-drain voltage of 10 V and illumination power of 1 μW) and response time (down to ~70 µs) and a detectivity value of 10 8 Jones. We found that the devices perform very reversibly upon several illumination and straining cycles and we found a moderate device-to-device variation.


Journal ArticleDOI
G Yeo1
TL;DR: In this paper , the mechanism of the AC electronic conduction loss is studied for high-temperature polycarbonate (HTPC)/poly(vinylidene fluoride) (PVDF) MLFs with either HTPC or PVDF skin layers.

Journal ArticleDOI
TL;DR: In this paper , the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries.
Abstract: Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 °C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 °C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

Journal ArticleDOI
TL;DR: In this paper , Probabilistic material flow analysis (PMFA) was used to quantify flows from production in 45 product categories to their end-of-life in Europe and Switzerland.
Abstract: Detailed knowledge about polymer flows through the anthroposphere and into the environment is information essential to the better management of plastics. Currently, only limited knowledge about specific polymer flows is available. This work aimed to model those flows for five polymers: polyurethane (PUR), acrylonitrile butadiene styrene (ABS), polyamide (PA), polycarbonate (PC) and polymethyl methacrylate (PMMA). Probabilistic material flow analysis (PMFA) was used to quantify flows from production in 45 product categories to their end-of-life in Europe and Switzerland. We then considered 40 release pathways for macro- and microplastic flows to assess polymer release into Switzerland's environment. PMFA results showed considerable variations between the polymers considered because their flows through the anthroposphere are determined by their different uses. Total macro- and microplastic emissions into Switzerland's environment in 2018 were estimated at masses of 208±76 t for PA, 179±98 t for PUR, 79±26 t for PC, 36±23 t for PMMA and 25±6 t for ABS. Relative to Switzerland's total production and imports, this amounted to total releases of 0.23% of PA, 0.07% of PUR, 0.16% of PC, 0.32% of PMMA and 0.14% of ABS. Contributions as released microplastics ranged from 18% of PMMA to 75% of ABS. These results showed that the amounts of the polymers considered released into the environment were much smaller than previously assumed in simpler release estimates, and they may be more realistic for countries with well-functioning waste treatment systems.

Journal ArticleDOI
TL;DR: In this paper , the effect of size print path (raster angle and build orientation) and print sequence on the mechanical properties of polycarbonate (PC) and polypropylene (PP) was investigated.
Abstract: Print conditions for thermoplastics by filament-based material extrusion (MatEx) are commonly optimized to maximize the elastic modulus. However, these optimizations tend to ignore the impact of thermal history that depends on the specimen size and print path selection. Here, we investigate the effect of size print path (raster angle and build orientation) and print sequence on the mechanical properties of polycarbonate (PC) and polypropylene (PP). Examination of parallel and series printing of flat (XY) and stand-on (YZ) orientation of Type V specimens demonstrated that to observe statistical differences in the mechanical response that the interlayer time between printed roads should be approximately 5 s or less. The print time for a single layer in XY orientation is much longer than that for a single layer in YZ orientation, so print sequence only impacts the mechanical response in the YZ orientation. However, the specimen size and raster angle did influence the mechanical properties in XY orientation due to the differences in thermal history associated with intralayer time between adjacent roads. Moreover, all of these effects are significantly larger when printing PC than PP. These differences between PP and PC are mostly attributed to the mechanism of interface consolidation (crystallization vs. glass formation), which changes the requirements for a strong interface between roads (crystals vs. entanglements). These results illustrate how the print times dictated by the print path layout impact observed mechanical properties. This work also demonstrated that the options available in some standards developed for traditional manufacturing will change the quantitative results when applied to 3D printed parts.

Journal ArticleDOI
TL;DR: Based on the chemical selectivity of heterometallic Salen-Co-Mn complexes of different valences, an electrochemically switchable strategy was developed for the copolymerization of lactide (LA), CO2 & epoxides as discussed by the authors .
Abstract: Electrochemical redox-control is an emerging strategy for the regulation of polymerization process without the addition of external oxidants and reductants, which enables the control over composition, microstructure and properties of the polymer products. In this paper, based on the chemical selectivity of heterometallic Salen-Co-Mn complexes of different valences, an electrochemically switchable strategy was developed for the copolymerization of lactide (LA), CO2 & epoxides. The switchable redox reactions endowed this system with the capability to easily synthesize a multi-block copolymer of polylactide (PLA) and polycarbonate (PC). Moreover, the multi-block copolymer could be further modified by introducing various monomers with different microstructures and functional groups.

Journal ArticleDOI
TL;DR: In this paper , a polycarbonate (PC) polymer is melt extruded together with titanium carbide (TiC) nano powder for the development of advanced nanocomposite materials in material extrusion (MEX) 3D printing.
Abstract: Herein, a polycarbonate (PC) polymer is melt extruded together with titanium carbide (TiC) nano powder for the development of advanced nanocomposite materials in material extrusion (MEX) 3D printing. Raw material for the 3D printing process was prepared in filament form with a thermomechanical extrusion process and specimens were built to be tested according to international standards. A thorough mechanical characterization testing course (tensile, flexural, impact, microhardness, and dynamic mechanical analysis-DMA) was conducted on the 3D printed specimens. The effect of the ceramic filler loading was also investigated. The nanocomposites’ thermal and stoichiometric properties were investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy-dispersive X-ray spectroscopy (EDS), and Raman respectively. The specimens’ 3D printing morphology, quality, and fracture mechanism were investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively. The results depicted that the addition of the filler decidedly enhances the mechanical response of the virgin polymer, without compromising properties such as its processability or its thermal stability. The highest improvement of 41.9% was reported for the 2 wt.% filler loading, making the nanocomposite suitable for applications requiring a high mechanical response in 3D printing, in which the matrix material cannot meet the design requirements.

Journal ArticleDOI
TL;DR: In this paper , block polymers designed to address these issues combine ionic conductivity, electrochemical stability, and suitable elastomeric mechanical properties, including adhesion, where the soft “B” block is poly(ethylene oxide) (PEO), and the hard “A) block is a CO2-derived polycarbonate, poly(4-vinyl cyclohexene oxide carbonate), which provides mechanical rigidity and enhances oxidative stability.
Abstract: Polymers designed with a specific combination of electrochemical, mechanical, and chemical properties could help overcome challenges limiting practical all-solid-state batteries for high-performance next-generation energy storage devices. In composite cathodes, comprising active cathode material, inorganic solid electrolyte, and carbon, battery longevity is limited by active particle volume changes occurring on charge/discharge. To overcome this, impractical high pressures are applied to maintain interfacial contact. Herein, block polymers designed to address these issues combine ionic conductivity, electrochemical stability, and suitable elastomeric mechanical properties, including adhesion. The block polymers have “hard-soft-hard”, ABA, block structures, where the soft “B” block is poly(ethylene oxide) (PEO), known to promote ionic conductivity, and the hard “A” block is a CO2-derived polycarbonate, poly(4-vinyl cyclohexene oxide carbonate), which provides mechanical rigidity and enhances oxidative stability. ABA block polymers featuring controllable PEO and polycarbonate lengths are straightforwardly prepared using hydroxyl telechelic PEO as a macroinitiator for CO2/epoxide ring-opening copolymerization and a well-controlled Mg(II)Co(II) catalyst. The influence of block polymer composition upon electrochemical and mechanical properties is investigated, with phosphonic acid functionalities being installed in the polycarbonate domains for adhesive properties. Three lead polymer materials are identified; these materials show an ambient ionic conductivity of 10 –4 S cm–1, lithium-ion transport (tLi+ 0.3–0.62), oxidative stability (>4 V vs Li+/Li), and elastomeric or plastomer properties (G′ 0.1–67 MPa). The best block polymers are used in composite cathodes with LiNi0.8Mn0.1Co0.1O2 active material and Li6PS5Cl solid electrolyte–the resulting solid-state batteries demonstrate greater capacity retention than equivalent cells featuring no polymer or commercial polyelectrolytes.

Journal ArticleDOI
TL;DR: In this article , a carbonate linkages reinforcement approach was proposed to improve the thermal and fire safety of polycarbonate (PC) compounds, which achieved an increase in T1% of 32 °C and 41 °C under nitrogen and air, along with a reduction of 49.4% and 19.3% for peak heat release rate and total heat release.
Abstract: To tailor the enhancement strategies for polymers according to structure, inspired by the concept of “Cannikin's Law”, this work proposes and exemplifies a novel strategy for reinforcing the carbonate linkages to simultaneously improve the thermal and fire safety of polycarbonate (PC). Herein, we introduce MIL-53(Al) to functionalize black phosphorus ([email protected]) via a simple method of hydrothermal. As expected, the incorporation of [email protected] (1.0 wt%) in PC, resulted in an increase in T1% of 32 °C and 41 °C under nitrogen and air respectively, along with the reduction of 49.4% and 19.3% for peak heat release rate and total heat release. Moreover, PC/[email protected] passed the V-0 rating of UL-94 with a high limiting oxygen index (LOI) value of 30.5%, which achieved the dual purpose of simultaneously enhancing the thermal stability and flame retardancy of PC. In addition, the addition of flame retardants had no effect on the tensile strength of the PC. These results demonstrate the high flame retardant efficiency of [email protected] at ultra-low addition levels. Moreover, these results also illustrate the forward-looking nature of the strategy of tailoring flame retardants to the properties of the substrate. This work combines the advantages of black phosphorus (BP) and Mental organic frameworks (MOFs) materials. The carbonate linkages reinforcement approach provides a viable, new, and scalable idea for polyester compounds' thermal and fire safety properties.

Journal ArticleDOI
TL;DR: In this paper , a facile approach was reported towards the incorporation of limonene into an epoxy-functionalized polycarbonate and its crosslinking with a polyamine curing agent to obtain a thermoset material.
Abstract: Biobased epoxy-derived raw materials will be essential for future coating and adhesive designs in industry. Here, a facile approach is reported towards the incorporation of limonene into an epoxy-functionalized polycarbonate and its crosslinking with a polyamine curing agent to obtain a thermoset material. For the first time, a solvent-borne adhesive with excellent film-forming, mechanical and adhesion strength properties is described.

Journal ArticleDOI
TL;DR: In this paper , the authors present a vision for realizing a circular polymer economy for polycarbonate materials, from the chemical recycling of widely used BPA-A-polycarbonates to the novel aliphatic polycarbonates from renewable resources.
Abstract: The extensive use of commodity polymer materials has led to the depletion of natural resources and caused the undesirable problem of plastic pollution. In this context, the design of novel polymeric structures with unique recyclability characteristics from renewable resources and the recycling of real-life plastic wastes are critical to address the problems associated with the increasing demand for plastics. Chemical degradation of wastes through polymerization–depolymerization followed by re-polymerization has already emerged as a long-term strategy toward the attainment of completely sustainable cycles. Bisphenol-A-polycarbonates (BPA–PC) exhibit high thermal resistance, excellent mechanical properties, and high optical transparency, which make them suitable materials for commodity and engineering plastics. This review presents our vision for realizing a circular polymer economy for polycarbonate materials—from the chemical recycling of widely used BPA–PCs to the novel aliphatic polycarbonates from renewable resources.

Journal ArticleDOI
TL;DR: In this article , two phenylacetate end-capping oligoesters from recycled bisphenol A (RBPA) were successfully applied as epoxy-curing agents.
Abstract: We prepared two phenylacetate end-capping oligoesters from recycled bisphenol A (RBPA), which is obtained from a phase-transfer agent-assisted basic degradation of waste polycarbonate (WPC). The two oligoesters were successfully applied as epoxy-curing agents. The curing of oligoesters with epoxy is based on the chemistry of a 4-dimethylaminopyridine (DMAP)-catalyzed model reaction of phenyl benzoate and glycidyl phenyl ether. Mechanical and thermal properties of oligoesters/epoxy-cured thermosets were investigated and discussed. Glass transition temperatures (Tg), the coefficient of thermal expansions (CTE), thermal decomposition temperatures (Td5%), and tensile strengths of four thermosets are, respectively, in the ranges of 140 to 180 °C, 37 to 72 ppm/°C, 396 to 431 °C, and 49 to 73 MPa. We also prepared carbon fiber composites (CFRPs) by using oligoester/epoxy resin, which could be effectively degraded to phenoxy resin using a catalyst-free aminolysis technique, and undamaged carbon fibers could be recycled without sacrificing mechanical strength or chemical composition. Processes such as recycling of WPC into bisphenol A-based oligoesters as epoxy-curing agents and degrading the epoxy thermosets and CFRPs into useful chemicals have been achieved.

Journal ArticleDOI
TL;DR: In this article , a dopant-free hole-transporting materials (HTM) and interface modification are two effective approaches for developing sustainable perovskite solar cells (PSCs).

Journal ArticleDOI
TL;DR: In this article , the first example of discrete metal-mediated poly(bisphenol A carbonate) (BPA•PC) methanolysis being appreciably active at room temperature was reported.
Abstract: Abstract ZnII‐complexes bearing half‐salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal‐mediated poly(bisphenol A carbonate) (BPA‐PC) methanolysis being appreciably active at room temperature. Indeed, Zn(2)2 and Zn(2)Et achieved complete BPA‐PC consumption within 12–18 mins in 2‐Me‐THF, noting high bisphenol A (BPA) yields (SBPA =85–91 %) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28±0.040 and 0.47±0.049 min−1 respectively at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly(ester‐amide)s (PEAs), based on a terephthalamide monomer derived from bottle‐grade poly(ethylene terephthalate) (PET), which exhibited excellent thermal properties.