Feed Molar Ratio Research Articles

Alternatif Yakıt Hidrojen Üretiminde Mezogözenekli Alüminosilikat Destekli Katalizörler

In the present study, Ni-containing mesoporous aluminosilicate (Al2(SiO2)3) supported catalysts, which are resistant to carbon formation, were developed for hydrogen production from acetic acid. Commercial aluminosilicate (Al2(SiO2)3) was used as catalyst support. Furthermore, to improve the catalyst stability, Mg, La, Ce, Ca, Ru metals, and Ni (5% by mass) were incorporated by the wet impregnation method into the catalyst supports’ structure. The synthesized catalysts were characterized to define their physical and chemical properties. N2 adsorption-desorption results reveal that the resulting isotherm behavior of all the prepared catalysts is consistent with type IV isotherm with plate-like wall structures. The catalytic activity test of the prepared catalysts was investigated at a reaction temperature of 750 C and a feed molar ratio of 1/2.5 (AA/H2O) in a packed bed continuous reactor system. Activity test results showed that catalyst composition has profound effects on product distribution. Hydrogen-rich syngas was produced over 5Ni-3Ru@Al2(SiO2)3 and 5Ni-3CeO2@Al2(SiO2)3 (about % 44 and % 46, respectively) catalysts. However, the addition of MgO over the 5Ni@Al2(SiO2)3 catalyst strongly influenced the selectivity of hydrogen. Syngas, which contains an equimolar amount of H2, and CO is a quite important feedstock for the Fischer-Tropsch process (about 35% each), was obtained with the 5Ni-3MgO@Al2(SiO2)3 catalyst.

Improvement of wettability of coal seams in water injection via co-deposition of polydopamine and polyacrylamide

Water injection into coal seams is important for dust prevention in mines. However, owing to the hydrophobicity of coal itself, the wetting effect of water injection on coal seams has yet to be enhanced. Herein, based on the hydrophobicity of coal, hydrophilic modification of the coal surface has been proposed via co-deposition of polydopamine (PDA) and polyacrylamide (PAM). Using water contact angle (WCA) test, atomic force microscope (AFM) test, X-ray photoelectron spectroscopy (XPS) characterization, and 1H nuclear magnetic resonance spectroscopy (1H NMR) measurements, the feasibility of hydrophilicity modification of coal by PDA/PAM has been investigated. The results indicate that when DA concentration is 2 mg/mL, deposition time is 45 min, and DA/PAM feeding molar ratio is 1:1, the wettability of modified coal sample clearly improves. In the water content test and dust-production test using gravity drop hammer, the modified coal exhibits good wettability and low dust production. Also, UV-Vis absorption spectroscopy and WCA results suggest that PDA/PAM coating exhibits good stability. Therefore, the modification method can effectively enhance the wetting effect of injected water on coal seam, providing a novel approach for dust prevention.

Cyanospirobifluorene-based conjugated polyelectrolytes: Synthesis and tunable nonvolatile information storage performance

Novel soluble cyanospirobifluorene-based conjugated polymers were synthesized by the Suzuki coupling copolymerization of 2′,7′-dibromo-2,7-bis(4′-cyanophenyl)-9,9′-spirobifluorene (M1), 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-dioctylfluorene (M2) and 2,7-dibromo-9,9-bis(6-bromohexyl) fluorene (M3). In an attempt to select the optimal ratio of the monomers, copolymers with different ratios of monomers were prepared via Suzuki-coupling reactions. The feed molar ratios between M1 and M3 were 1:0, 3:1, 1:1, 1:3, and 0:1 in PCSF, PCSFBF-1, PCSFBF-2, PCSFBF-3 and PFBF, respectively. The last four polymers were used to react with excessive amounts of N-methyl imidazole in the presence of acetonitrile to give polyelectrolytes PCSFF-1, PCSFF-2, PCSFF-3 and PFIF. Incorporation of the rigid cyanospirobifluorene moieties into the polymer structure could significantly improve the thermal stability of the resultant material. The as-fabricated Al/PCSF/ITO device exhibits a typical nonvolatile rewritable information storage performance, with a switch-on voltage of 1.95 V and a switch-off voltage of −3.67 V. Similarly, PCSFF-based devices also show similar information storage performance as that of PCSF-based device. The observed switch-on/off voltages are 1.77/-3.34 V for PCSFF-1; 1.57/-2.15 V for PCSFF-2; and 1.70/-2.39 V for PCSFF-3. The as-synthesized PFIF without cyanospirobifluorene unit only displays a nonvolatile WORM (write-once–read-many-times) type information storage performance, with a switch-on voltage of 1.95 V. Upon being subject to voltages, these polymers exhibited very interesting filamentary nature. This work shows a very promising strategy to tailor nonvolatile information storage performance of the polymer materials via local electrostatic fields resulted from the ionic functionalities in the resultant polymer.

Modelling of Jatropha Oil Hydrocracking in a Trickle-Bed Reactor to Produce Green Fuel

Trickle-bed reactor (TBR) modelling to produce green fuel via hydrocracking of jatropha oil using silica-alumina-supported Ni-W catalysts was performed in this research. The objectives of this study are to obtain a TBR with good heat transfer and the optimum condition for high purities of products. A two-dimensional axisymmetric model with a diameter of 0.1 m and a length of 10 m was used as a representative of the actual TBR system. Heterogeneous phenomenological models were developed considering mass, energy, and momentum transfers. The optimisation was conducted to obtain the highest green fuel purity by varying catalyst particle diameter, inlet gas velocity, feed molar ratio, and inlet temperature. The simulation shows that a TBR with an aspect ratio of 100 has achieved a good heat transfer. The diesel purity reaches 44.22% at 420°C, kerosene purity reaches 21.39% at 500°C, and naphtha purity reaches 25.30% at 500°C. The optimum condition is reached at the catalyst diameter of 1 mm, the inlet gas velocity of 1 cm/s, the feed molar ratio of 105.5, and the inlet temperature at 500°C with the green fuel purity of 69.4%.

Ethylene and cyclohexane co-production in the fixed-bed catalytic membrane reactor: Experimental study and modeling optimization

In this study, a fixed-bed catalytic membrane reactor was used for the production of ethylene and cyclohexane from ethane and benzene. A two-dimensional non-isothermal mathematical model was used for estimating the performance of the membrane reactor. Furthermore, the effect of inlet temperature (720–1080 K), feed molar ratio (3–10) and the reactor spacetime (1–76 kgCat.s/mol) was studied on the conversion of ethane to ethylene and benzene to cyclohexane. The results of modeling showed that with the increase of inlet temperature the conversion of both (de)-hydrogenation reactions increased and the 95% of ethane conversion was achieved when the molar ratio of benzene/ethane was fixed on 3. The hydrogenation of benzene at the shell side of the catalytic membrane reactor enhanced the production of ethylene due to the exothermic nature of the hydrogenation reaction, resulting in heat conduction through the membrane and glass substrate into the tube side. The comparison between experimental data reported in literature and modeling showed that the deviation of data obtained by mathematical modeling from experimental values ranged from 15.2 to 19.8% at various spacetimes. In addition, the results of sensitivity analysis showed that the conversion of benzene and ethane is more sensitive to the inlet temperature (up to 160% change on conversion) in comparison to the other parameters including feed ratio and the reactor spacetime. Moreover, at a temperature above 1128 K, the overall performance of the catalytic membrane reactor increased significantly.

Effects of Monomer Compatibility on Sizing Performance of Chitosan-g-P(MA-co-AM)

To impart good application performance to chitosan (CS) sizes for high polyester content warp yarns, methyl acrylate (MA) and acrylamide (AM) monomers, with a variation in feed molar ratio from 1:9 to 4:6, were grafted onto the molecular chains of native CS to obtain CS- g-P(MA- co-AM) products, with similar grafting ratios through a K2S2O8-NaHSO3 redox system. Effects of monomer compatibility of MA and AM on sizing performance of the CS- g-P(MA- co-AM) for high polyester content warp were studied. Grafting MA and AM with rational compatibility onto the molecular chains of CS is an effective method to improve the application performance of CS sizes. In view of the overall performance of the CS- g-P(MA- co-AM) sizes, the appropriate feed molar ratio of MA/AM should be 3:7.

Ethylene Hydroformylation with Carbon Dioxide Catalyzed by Ruthenium Supported on Titanate Nanotubes: Infrared Spectroscopic Evidence of Surface Species

AbstractRu nanoparticles supported on titanate nanotubes (Ru/TiNT) were catalytically active in the ethylene hydroformylation using CO2 as reactant (at atmospheric pressure and moderate temperatures) to give propanal and ethane. The rate of propanal formation at 100 °C with a molar feed ratio of 1 : 1 : 1 : 8 (CO2 : C2H4 : H2 : Ar) was 0.128 molpropanal molRu−1 h−1. Raman spectra and X‐ray diffraction data characterizing the catalyst confirmed the presence of the crystalline structure of Na2Ti3O7 for TiNT, whereas transmission electron microscopy (TEM) images evidenced its tubular morphology and the presence of finely dispersed Ru nanoparticles with an average diameter of 0.8 nm. Infrared spectra measured under reaction conditions allowed the identification of surface species that participate in the catalysis, namely CO bonded to the Ru nanoparticles, Ru‐ethyl and Ru‐acyl species and adsorbed propanal. The data show that conversion of CO2 to CO was crucial for the formation of the Ru‐acyl species, regarded as a key reaction intermediate to give propanal.

Using wide-band-gap BiOCl to greatly enhance the photocarriers separation of AgI via in-situ Ag bridge: Interfacial electron transfer route, density functional theory calculation and mechanism study

For wide-band-gap semiconductor heterojunctions such as BiOCl, the empty conduction band (CB) can act as an electron capture center to improve the separation efficiency of photocarriers, which has been considered a promising strategy for the construction of efficient composite photocatalysts. However, the interface resistance of heterojunctions immediately affects their photocatalytic activity. Herein, a well-designed AgI/Ag/BiOCl photocatalyst was constructed during the photocatalytic process, using Ag as the electron bridge to reduce interface resistance and the empty CB of BiOCl as the electron capture center, to continuously capture and shed electrons. The as-prepared AgI/Ag/BiOCl with a feeding molar ratio of Ag/Bi = 0.4 presented excellent visible light photocatalytic performance for the degradation of antibiotic tetracycline (TC) and colorless phenol, which could be mainly ascribed to the synergetic effects of a Ag bridge and the electron trapping center of BiOCl. In addition, the AgI/Ag/BiOCl also showed a desirable removal rate of TC in actual wastewater or in the presence of some electrolytes, and a logical photocatalytic mechanism was explored in detail by DFT calculations. This study illustrates the adhibition of the in-situ Ag bridge and offers a new strategy for the design of efficient catalysts for the photocatalytic elimination of organic contaminants.

Novel donor-acceptor-acceptor ternary conjugated microporous polymers with boosting forward charge separation and suppressing backward charge recombination for photocatalytic reduction of uranium (VI)

The photoreduction of soluble U(VI) to insoluble U(IV) with conjugated microporous polymers (CMPs) is a promising channel to remove uranium from radioactive wastewater efficiently. However, the rapid backward charge recombination and unsatisfactory forward charge transfer lead to undesirable photocatalytic activity of CMPs. Herein, for the first time, a series of D-A1-A2 terpolymers is developed with statistical copolymerization through adjusting the monomer feed molar ratio (FMR) for photoreduction of uranium. Compared with D-A binary copolymer, such D−A1−A2 terpolymers can inhibit charge recombination and simultaneously facilitate charge separation due to its larger dipole moment and giant built-in electric field. Therefore, the PTrSO-2 which the FMR is 0.75: 1.0: 0.75 achieves 99.5% photocatalytic U(VI) reduction efficiency within 120 min visible-light irradiation, outshining most reported photocatalysts for such applications. This work cultivates an emerging stratagem and unconventional thinking for the development of CMPs photocatalysts used in the effective treatment of radioactive wastewater.

Process Intensification of Methane Production via Catalytic Hydrogenation in the Presence of Ni-CeO2/Cr2O3 Using a Micro-Channel Reactor

A slight amount of Cr2O3 segregation in 40 wt% NiO/Ce0.5Cr0.5O2 was presented at the surface. The best catalytic performance towards the reaction was achieved at 74% of CO2 conversion and 100% CH4 selectivity at 310 °C, the reactant (H2/CO2) feed molar ratio was 4, and the WHSV was 56,500 mlN·h−1·g−1cat. The mechanistic pathway was proposed through carbonates and formates as a mediator during CO2 and H2 interaction. Activation energy was estimated at 4.85 kJ/mol, when the orders of the reaction were ranging from 0.33 to 1.07 for nth-order, and 0.40 to 0.53 for mth-order.

Coke-resistance enhancement of mesoporous γ-Al2O3 and MgO-supported Ni-based catalysts for sustainable hydrogen generation via steam reforming of acetic acid

Highly ordered mesoporous γ-Al2O3 particles and MgO materials were synthesized by evaporation induced self-assembly (EISA) and template-free hydrothermal co-precipitation routes, respectively. Ni, Ni–MgO, and Ni–La2O3-containing catalysts were prepared using a wet-impregnation method. The synthesized catalysts were characterized by N2 adsorption–desorption, XRD, SEM-EDS, DRIFTS, XPS, TGA-DTA, and Raman spectroscopy analysis. The mesoporous γ-Al2O3 catalyst support exhibited a high surface area of 245 m2/g and average pore volume of 0.481 cm3/g. The DRIFTS results indicate the existence of large Lewis's acid regions in the pure γ-Al2O3 and metal-containing catalysts. Catalytic activity tests of pure materials and metal-containing catalysts were carried out at the reaction temperature of 750 °C and a feed molar ratio of AA/H2O/Ar:1/2.5/2 over 3 h. Complete conversion of acetic acid and 81.75% hydrogen selectivity were obtained over the catalyst 5Ni@γ-Al2O3. The temperature and feed molar ratio had a noticeable impact on H2 selectivity and acetic acid conversion. Increasing the water proportion in the feed composition from 2.5 to 10 considerably improved the catalytic activity by increasing hydrogen selectivity from 81.75% to 91%. Although the Ni-based γ-Al2O3-supported catalysts exhibited higher activity performance compared to the Ni-based MgO-supported catalysts, they were not as resistant to coke formation as were MgO-supported catalysts. The introduction of MgO and La2O3 into the Ni@γ-Al2O3 and Ni@MgO catalysts' structures played a significant role in lowering the carbon formation (from 37.15% to 17.6%–12.44% and 12.17%, respectively) and improving the thermal stability of the catalysts by decreasing the agglomeration of acidic sites and reinforcing the adsorption of CO2 on the catalysts' surfaces. Therefore, coke deposition was reduced, and catalyst lifetime was improved.

Production of Biodiesel from Waste Cooking Oil by Transesterification Process using Heterogeneous Catalyst

Non-renewable diesel from fossil has been considered as potentially carcinogenic with serious harmful effect to human health and to the environment. This study aimed to produce a renewable diesel –biodiesel- via transesterification of waste cooking oil (WCO), investigated and determined the most suitable amongst various types of heterogenous catalysts (viz a viz KOH/CaCO3, KOH/CaO and KOH/K2CO3). The chemical and physical characterisation of the biodiesel was been carried out. Among the catalysts investigated, KOH/CaCO3 catalyst showed the best catalytic performance in terms of % yield and better fuel quality in density, acid value, viscosity and free fatty acid. The reason for this performance may be due to its most basic characteristic than the others. As a result, this catalyst was selected for the optimisation study. At the optimum reaction conditions of 10 wt% catalyst loading and 1:10 oil to methanol feed mole ratio, triglycerides conversion was highest, 98.12%. The characterisation results shows that the parameters tested (i.e. density, viscosity, acid value and free fatty acid) meet the strict requirements of the biodiesel standard and therefore, the produced fuel can be used in place of the petrol diesel.

Thermal and mechanical properties of polymer networks prepared by the thiol-ene reaction of a vanillin/acetone condensate and its related compounds

• Vanillin and benzaldehyde condensates with acetone were cured with a tetrathiol, S4P. • A diallylated vanillin/acetone condensate (DADVAT) was cured with S4P. • Radical-initiated photo/thermal cure and thermal cure using Et 3 N were investigated. • Photo/thermal dual cured DADVAT/S4P 1/1 exhibited excellent physical properties. • The thiol-ene reaction of the enone/thiol groups was promoted by the basic catalyst. A new bio-based diallyl compound, DADVAT, was synthesized by the allylation of 2,5-bis(4-hydroxy-3-methoxybenzylidene)acetone (DVAT), which had been prepared by the cross-aldol condensation of vanillin and acetone. The radical-initiated photothermal thiol–ene reactions of DADVAT/pentaerythritol tetrakis(3-mercaptopropionate) (S4P) at feed molar ratios of 1/1 and 2/1, DVAT/S4P, and trans,trans -dibenzylidene acetone (DBAT)/S4P at a molar ratio of 2/1 produced bio-based polymer networks (ptDADVAT-S4P-11, ptDADVAT-S4P-21, ptDVAT-S4P-21, and ptDBAT-S4P-21). The thermal and mechanical properties of the dual cured polymer networks were compared with those of thermally cured products (tbDADVAT-S4P-21 and tbDBAT-S4P-21) at a molar ratio of 2/1 using triethylamine as a basic catalyst for the nucleophilic thiol–ene reaction. ptDADVAT-S4P-11 displayed excellent thermal and mechanical properties compared to the other cured products. tbDADVAT-S4P-21 and tbDBAT-S4P-21 exhibited better thermal and mechanical properties than ptDADVAT-S4P-21 and ptDBAT-S4P-21, respectively, because the thiol–ene reaction of the enone and thiol groups is promoted by the basic catalyst rather than the radical initiators.

Temperature and pH-responsive in situ hydrogels of gelatin derivatives to prevent the reoccurrence of brain tumor

Glioblastoma multiforme (GBM) is a grade IV malignant brain tumor with a median survival time of approximately 12–16 months. Because of its highly aggressive and heterogeneous nature it is very difficult to remove by surgical resection. Herein we have reported dual stimuli-responsive and biodegradable in situ hydrogels of oligosulfamethazine-grafted gelatin and loaded with anticancer drug paclitaxel (PTX) for preventing the progress of Glioblastoma. The oligosulfamethazine (OSM) introduced to the gelatin backbone for the formation of definite and stable in situ hydrogel. The hydrogels transformed from a sol to a gel state upon changes in stimuli. pH and temperature and retained a distinct shape after subcutaneous administration in BALB/c mice. The viscosity of the sol state hydrogels was tuned by varying the feed molar ratio between gelatin and OSM. The porosity of the hydrogels was confirmed to be lower in higher degree OSM by SEM. Sustained release of PTX from hydrogels in physiological environments (pH 7.4) was further retarded up to 63% in 9th days in tumor environments (pH 6.5). While the empty hydrogels were non-toxic in cultured cells, the hydrogels loaded with PTX showed antitumor efficacy in orthotopic-GBM xenograft mice. Collectively, the gelatin-OSM formed porous hydrogels and released the cargo in a sustained manner in tumor environments efficiently suppressing the progress of GBM. Thus, gelatin-OSM hydrogels are a potential candidate for the direct delivery of therapeutics to the local areas in brain diseases.

Enhanced production of butyl acetate via methanol-extracting transesterification membrane reactors using organosilica membrane: Experiment and modeling

Experimentation and numeric calculation were focused on n-butyl acetate (BA) production from Methyl acetate (MA) and n-butanol (BuOH) via Membrane reactor to extract methanol (MeOH) through 1,2-bis(triethoxysilyl)acetylene(BTESA)-derived organosilica membranes. A batch reactor (BR) model was formulated using Damköhler number (Da) and Permeation number (θ) similarly to plug flow reactor. Simulation on the effect of Da, θ, permeance ratio of MeOH (αi) and MA/BuOH feed molar ratio (δ) showed that a α > 20 and a θ > 10 are required to achieve a high BA yield. BTESA membranes showed high performance for MeOH removal from the mixtures with various types of organic solvents such as various esters, alcohols, Toluene, and ketone. Two types of BTESA membranes: high-flux (M−1) and high-selectivity (M−2), which showed MeOH flux of 4.2 kg/(m2 h) and 2.6 kg/(m2 h), and separation factor of 3100 and 9200, respectively, for MeOH/BA mixtures (MeOH 10 wt%, 50°C), were used for the transesterification membrane reactor. Batch-type membrane reactor performances were evaluated experimentally using M−1 and M−2 membranes. At MA/BuOH feed molar ratio, δ , of 2, extraction of MeOH increased the BA yield reached as high as 95.4%, which was higher than that of equilibrium (60%). Experimental results agreed with numeric calculations without fitting parameters.

Study on the Intensification of Reaction Kinetics and Reactive Distillation for the Esterification of N-Butyl Acetate Using [HSO3-BMIM][HSO4] as a High-Efficiency Ionic Liquid Catalyst

An ionic liquid (IL) catalyst 1-sulfobutyl-3-methylimidazolium hydrogen sulfate, [HSO3-BMIM][HSO4], was used to produce n-butyl acetate (BuAc) via esterification. A novel modified nonideal homogeneous kinetic model was developed by self-catalysis theory. A new reactive distillation (RD) process using [HSO3-BMIM][HSO4] to produce BuAc was intensified using Aspen simulation taking advantage of phase splitting to increase the ester purity. Various design parameters like reactant feed location, reflux ratio, reactant feed molar ratio, flow ratio of products to materials, and condenser pressure were optimized. Fitting results indicated that modified models presented exact prediction results for the [HSO3-BMIM][HSO4]-catalyzed esterification compared with the unmodified model because the former introduced a revisional term for the self-catalysis of HAc, which revealed the mechanism of self-catalysis and interaction between ILs and reactants. The BuAc purity was increased from 91.05 to 95.02 wt % by the RD process intensification. [HSO3-BMIM][HSO4] showed a higher acid conversion (75%) than commercial ILs and resins. The ester yield was higher when using [HSO3-BMIM][HSO4] as the catalyst than resin A (80.89 wt %) in the intensified RD process. This research provides a novel modified method for the kinetic model in the IL-catalyzed reaction where the modified model exhibited a high accuracy and is useful for improving the production efficiency and controlling the catalyst dosage in the chemical engineering process design. The intensified RD process shows a flexible design for IL application, which is helpful for designing industrial scale-up.

One-pot preparation of thermosensitive polylactic acid materials by modifying with N-Isopropyl acrylamide

Polylactic acid (PLA) is highly attractive polyester in biomedical application, and its thermosensitive materials can achieve multiple functions due to their being sensitive to the temperature. In this work, based on lactic acid (LA), maleic anhydride (MAH), and N-isopropyl acrylamide (NIPAM), a thermosensitive modifier, the thermosensitive PLA material PLAMN is directly synthesized via one-pot preparation of melt polymerization and radical polymerization. The molecular structure, thermosensitive characteristics, and micellization behavior of the serial PLAMNs with different molar feed ratios are well characterized with FTIR, 1H NMR, GPC, DLS, TEM and other characterization techniques. The results show that, as anticipated, the obtained products have the ability to self-assemble. The specific physical and chemical properties can be controllable by the molar feed ratio n(LA)/n(MAH)/n(NIPAM). When the ratio is 20/1/7, the obtained PLAMN7 has the minimum critical micelle concentration (only 4.17 mg L−1), and its critical phase transition temperature is 30.6 °C. This new synthetic strategy can effectively simplify the preparation of the thermosensitive PLA polymeric material, which is beneficial to realize the loading of the hydrophobic drugs.

A Theoretical Analysis on a Multi-Bed Pervaporation Membrane Reactor during Levulinic Acid Esterification Using the Computational Fluid Dynamic Method.

Pervaporation is a peculiar membrane separation process, which is considered for integration with a variety of reactions in promising new applications. Pervaporation membrane reactors have some specific uses in sustainable chemistry, such as the esterification processes. This theoretical study based on the computational fluid dynamics method aims to evaluate the performance of a multi-bed pervaporation membrane reactor (including poly (vinyl alcohol) membrane) to produce ethyl levulinate as a significant fuel additive, coming from the esterification of levulinic acid. For comparison, an equivalent multi-bed traditional reactor is also studied at the same operating conditions of the aforementioned pervaporation membrane reactor. A computational fluid dynamics model was developed and validated by experimental literature data. The effects of reaction temperature, catalyst loading, feed molar ratio, and feed flow rate on the reactor’s performance in terms of levulinic acid conversion and water removal were hence studied. The simulations indicated that the multi-bed pervaporation membrane reactor results to be the best solution over the multi-bed traditional reactor, presenting the best simulation results at 343 K, 2 bar, catalyst loading 8.6 g, feed flow rate 7 mm3/s, and feed molar ratio 3 with levulinic acid conversion equal to 95.3% and 91.1% water removal.

Synthesis and unique characteristics of biobased high Tg copolyesters with improved performance properties for flexible electronics and packaging applications

The synthesis and characterization of two series of biobased novel poly(1,4-cyclohexylenedimethylene terephthalate-co-1,4-cyclohexylene dimethylene 2,6-naphthalenedicarboxylate) copolyesters containing isosorbide (ISB) content (PCITN) ranging from 0 to 11 mol% relative to the total diol amount was carried out in this study. The Novel PCITN was containing 2,6-naphthalenedicarboxylic acid (NDA) content ranging from 0 to 100 mol% relative to the total diacid amount. The synthesized PCITN were thoroughly characterized for their actual chemical composition, molecular weight, thermal properties, thermal stability, dimensional stability, transmittance (%), and birefringence. All the copolyesters showed the characteristics of random copolyesters and their composition and thermal properties could be controlled by the molar feed ratio of diol and diacid moieties. Results indicate that ISB significantly improves the glass transition temperature (Tg) of resultant copolyesters. It was also found that synthesized copolyesters have a high Tg and wide processing window compared to conventional homopolyesters. Exceptional performance properties: such as high Tg, Tm, high thermal stability, dimensional stability, good moisture barrier, good transmittance, and low birefringence of fabricated PCI6TN70 film, make it suitable for versatile industrial applications especially for biomedical, packaging, and optical applications.

Rational integration of defense and repair synergy on PEEK osteoimplants via biomimetic peptide clicking strategy

Polyetheretherketone (PEEK) has been widely used as orthopedic and dental materials due to excellent mechanical and physicochemical tolerance. However, its biological inertness, poor osteoinduction, and weak antibacterial activity make the clinical applications in a dilemma. Inspired by the mussel adhesion mechanism, here we reported a biomimetic surface strategy for rational integration and optimization of anti-infectivity and osteo-inductivity onto PEEK surfaces using a mussel foot proteins (Mfps)-mimic peptide with clickable azido terminal. The peptide enables mussel-like adhesion on PEEK biomaterial surfaces, leaving azido groups for the further steps of biofunctionalizations. In this study, antimicrobial peptide (AMP) and osteogenic growth peptide (OGP) were bioorthogonally clicked on the azido-modified PEEK biomaterials to obtain a dual-effect of host defense and tissue repair. Since bioorthogonal clicking allows precise collocation between AMP and OGP through changing their feeding molar ratios, an optimal PEEK surface was finally obtained in this research, which could long-term inhibit bacterial growth, stabilize bone homeostasis and facilitate interfacial bone regeneration. In a word, this upgraded mussel surface strategy proposed in this study is promising for the surface bioengineering of inert medical implants, in particular, achieving rational integration of multiple biofunctions to match clinical requirements.