Hydrogen Nuclear Magnetic Resonance Research Articles

Synthesis and characterization of novel poly(butylene succinate)-b-poly(diethylene glycol terephthalate) multiblock copolyesters with high melting point and significantly improved mechanical property

Biodegradable poly(butylene succinate) (PBS) has extensively been studied; however, its relatively high crystallinity and poor toughness restricts its wide application. In this research, novel poly(butylene succinate)-b-poly(diethylene glycol terephthalate) (PBS-b-PDEGT) multiblock copolyesters with different mass ratios of amorphous hard PDEGT and crystallizable soft PBS segments were successfully synthesized and confirmed by hydrogen nuclear magnetic resonance. Both PBS homopolymer and PBS-b-PDEGT multiblock copolyesters displayed high thermal stability. In PBS-b-PDEGT multiblock copolyesters, PBS and PDEGT segments were partially miscible in the amorphous region. Compared with PBS homopolymer, the introduction of PDEGT segment slightly reduced the melting point of PBS-b-PDEGT multiblock copolyesters. The crystallization mechanism and crystal structure of PBS segment did not change. With the increase of the PDEGT segment content, the Young's modulus of PBS-b-PDEGT multiblock copolyesters gradually decreased, while the elongation at break remarkably increased. In brief, the synthesis of PBS-b-PDEGT multiblock copolyesters provides an efficient modification method of preparing novel PBS copolymers with still high melting point (about 110 °C) and significantly improved elongation at break (about 650% and above), which should be greatly important and helpful from a practical application viewpoint.

Synthesis and characterization of poly(p-dioxanone)-based degradable copolymers with enhanced thermal and hydrolytic stabilities

Herein, we presented a novel biodegradable copolymer via the chain extending reaction of poly(p-dioxanone)-co-poly(2-(2-hydroxyethoxy) benzoate) (PPDO-co-PDHB) prepolymer with hexamethylene diisocyanate (HDI) as a chain extender. The structures and molecular weight of PPDO-co-PDHB prepolymer and PPDO-co-PDHB-PU chain-extended copolymer are characterized via hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and viscosity test. The relationship between the molecular structures and properties of the chain-extended copolymers is established. The PPDO-co-PDHB-PU copolymers possess a better thermal stability comparing with the PPDO homopolymer. The study of mechanical properties shows that the elongation-at-break of PPDO-co-PDHB-PU is much higher than that of PPDO. The investigation of hydrolytic degradation behaviors indicates the degradation rate of PPDO can be controlled by adjusting the PDHB compositions, and proves that chain-extended copolymers exhibit an excellent hydrolytic stability being better than that of PPDO.

Antibacterial activity and inhibition against Staphylococcus aureus NorA efflux pump by ferulic acid and its esterified derivatives

Objective: To evaluate the inhibitory activity of ferulic acid and four of its esterified derivatives (methyl, ethyl, propyl, and butyl) against resistance mechanisms in Staphylococcus aureus strains. Methods: Ferulic acid derivatives were obtained by esterification with methanol, ethanol, propanol, and butanol, and then characterized by hydrogen and carbon-13 nuclear magnetic resonance analysis. The minimum inhibitory concentrations (MIC) of ferulic acid and its esterified derivatives, ethidium bromide, and norfloxacin were obtained using the microdilution test, while the efflux pump inhibition test was conducted by examining reduction in the MICs of norfloxacin and ethidium bromide. Molecular docking was also carried out using the Schrodinger Suite 2015 molecular modeling software. A three-dimensional model of NorA efflux pump was generated using I-TASSER. The best scoring model was used as a receptor for ligand-receptor docking. Results: The methyl and butyl ester derivatives did not demonstrate significant antimicrobial activity. However, a significant synergic effect was evidenced when norfloxacin was combined with the ethyl and propyl esterified derivatives. The docking study demonstrated favorable energy of interaction between ferulate derivatives and NorA, and amino acid residues TYR57, TYR58, and LEU255 were present commonly in stabilizing all complexes. The PCA analysis corroborated the docking hypothesis that the lipophilic character and hydrogen bond interactions were the most relevant characteristics involved with NorA inhibitors. The pharmacokinetic parameters of ferulic acid derivatives showed good ADMET properties, demonstrating that they can be easily absorbed and have no effect or inhibit the cytochrome P450 enzyme complex, revealing their potential as drug candidates. Conclusions: This study provides strong evidence that the molecular basis for this activity is potentially due to the NorA efflux pump.

The influence of fluorine terminal group and flexible spacers on properties of the liquid crystal dimers

ABSTRACT Two series of symmetric LC dimers with the same rigid group and different fluorine terminal group (F and F3C) have been synthesised by varying the length of flexible spacers, termed 1 F series (1 F-4, 1 F-6, 1 F-8) and 3 F series (3 F-4, 3 F-6, 3 F-8). Chemical structures and LC properties of the six symmetric LC dimers were characterised by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectrometer (1H NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and polarised optical microscopy (POM). The 1 F series dimers only show nematic phase. While for 3 F series, smectic phase appeared, and with the increase of flexible spacers, the smectic phase is dominant. For the formation of smectic phase of 3 F series, the larger intermolecular transverse force coming from CF3 may be the driving force, and the long flexible spacer makes it possible. The melting temperatures of the 1 F series and 3 F series gradually decrease as the length of the flexible spacer increases, respectively, indicating that molecular rigidity has a greater influence on the melting temperatures. The melting temperatures of the 3 F series dimers decrease faster, which may attribute to the influence of CF3 on the conformation of the dimers.

Evaluation of a new green synthesized surfactant from linseeds - chemical EOR implications from sandstone petroleum reservoirs

Surfactants are materials with different applications in industries. The development of surfactants and the reduction in their associated harmful effects are among the most crucial matters that must be taken into account to increase their efficiency. Surfactants are widely employed in chemical enhanced oil recovery, yet sometimes these materials are not environmentally friendly and economically affordable. Hence, the natural surfactants were introduced to address this issue. However, they show poor efficiency in the main mechanisms of oil recovery enhancement, including wettability alteration and interfacial tension reduction. Herein, a new anionic surfactant was synthesized from the natural base material (linseeds) revealing high efficiency in chemical enhanced oil recovery. In addition, esterification and sulfonation methods were applied to conduct the synthesis process. Following the conduction of the synthesis process, the synthesized surfactant was characterized by the use of Fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (HNMR), and thermogravimetric analysis (TGA) to ensure the accuracy of the synthesis process and the appropriate thermal stability. The solution properties of the surfactant synthesized from linseeds, abbreviated as PELS, were analyzed through pH and the electrical conductivity at different concentrations. It must be regarded that micellar behavior is an essential parameter for each surfactant normally analyzed with surface tension (ST) and interfacial tension (IFT) respectively expressing 96% (28.97 to 0.99) and 59% (74.5 to 28) optimization. The fact that all of these experiments indicate the value of 1500 ppm as the critical micelles concentration must be taken into consideration. The wettability alteration was analyzed through a contact angle experiment on the sandstone surface showing a 58% optimization once the contact angle reduced to 54.5° in the water-wet zone. Owing to the presence of salt in the reservoir condition, NaCl was utilized as a sample to analyze the ion effect on the PELS performance. Meanwhile, it demonstrated good compatibility, especially in IFT reduction, reducing the IFT value from 0.99 in CMC point to 0.26 mn/m in the presence of NaCl ions. Several other surfactant properties, such as foamability, emulsion stability, and salt compatibility were analyzed for chemical enhanced oil recovery purposes. The adsorption of surfactant molecules on the rock surface reduces the surfactant efficiency and is of significant importance. This issue was evaluated and the pertinent results were compared with common models of isotherm absorption. Ultimately, the results of core flooding experiments using sandstone sample illustrated a 7.9% increase in the recovery factor and the required relative permeability charts were plotted via JBN method.

Fabrication of poly(t-butyl betaine carboxylate)-based nanoparticles and study on their in vivo biosecurity

The purpose of this article was to fabricate the novel poly(t-butyl betaine carboxylate)-S-S-poly (1, 3-dioxan-2-one) nanoparticles (PCB-tBU-S-S-PDI NPs) and study their in vivo biosecurity. The poly(t-butyl betaine carboxylate) (PCB-tBU) segment was conjugated to the poly(1, 3-dioxan-2-one)(PDI) moity with a disulfide bond to obtain the copolymer PCB-tBU-S-S-PDI. Hydrogen nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR) spectra were applied to study the structure of PCB-tBU-S-S-PDI. The cargo-free NPs were administrated to Sprague-Dawley (SD) rats by intraperitoneal injection every 3 days for 30 days. Then, the blood routine examination, blood biochemistry, and histologic slides of rat’s organs were carried out to monitor the in vivo biosecurity of cargo-free PCB-tBU-S-S-PDI NPs. 1H NMR and FTIR spectra confirmed the successfully synthesis of PCB-tBU-S-S-PDI. The cargo-free NPs showed spherical morphology with an average of 139.8 ± 0.26 nm. The results of blood biochemistry and blood routine examination suggested that the cargo-free PCB-tBU-S-S-PDI NPs did not show any influence on the liver and renal functions of treated rats. Significantly, the physiological slides of treated rat’s organs did not show any physiological and pathological changes. These phenomena suggested that the PCB-tBU-S-S-PDI NPs had good biosecurity, and it could be used as a vehicle for antineoplastic drug delivery.

Covalence and π-electron delocalization influence on hydrogen bonds in proton transfer process of o-hydroxy aryl Schiff bases: A combined NMR and QTAIM analysis.

Within the framework of the density functional theory approach, we studied the relationship between the chemical nature of intramolecular hydrogen bonds (HBs) and nuclear magnetic resonance (NMR) parameters, J-couplings and 1H-chemical shifts [δ(1H)], of the atoms involved in such bonds in o-hydroxyaryl Schiff bases during the proton transfer process. For the first time, the shape of the dependence of the degree of covalence in HBs on 1J(N-H), 1J(O-H), 2hJ(O-N), and δ(1H) during the proton transfer process in o-hydroxyaryl Schiff bases was analyzed. Parameters obtained from Bader's theory of atoms in molecules were used to assess the dependence of covalent character in HBs with both the NMR properties. The influence of π-electronic delocalization on 2hJ(N-O) under the proton transfer process was investigated. 2hJ(O-N) in a Mannich base was also studied in order to compare the results with an unsaturated system. In addition, substituent effects on the phenolic ring were investigated. Our results indicate that the covalent character of HBs on both sides of the transition state undergoes a smooth exponential increase as the δ(1H) moves downfield. The degree of covalence of the N⋯H (O⋯H) bond increases linearly as 1J(N-H) (1J(O-H)) becomes more negative, even after reaching the transition state. Non-vanishing values of spin dipolar (SD) and paramagnetic spin orbital terms of 2hJ(O-N) show that π-electronic delocalization has a non-negligible effect on tautomeric equilibrium and gives evidence of the presence of the resonance assisted HB.Variation of the SD term of 2hJ(O-N) follows a similar pattern as the change in the para-delocalization aromaticity index of the chelate ring.

Novel Difolate Targeting Nano-Level Ultrasound Contrast Agent for Therapy of Breast Cancer Tumor Cells

ABSTRACTA new type of difolate targeting nano-level ultrasound contrast agent ((folate molecule, FOL)2-TUAs) was prepared, so as to investigate its targeted binding effect with human breast cancer mammary carcinoma cells (MCF-7) in vitro. L-2-aminoadipic acid (L-2-AD) as a branch unit was inserted at the hydroxyl end of distearoyl phosphatidylethanolamine (DISP)-PEG2000-COOH to construct a tree structure. At this time, the free hydroxyl group in the distearoyl phosphatidylethanolamine (DISP)-PEG2000-COOH structure modified the FOL with the help of N-Hydroxysuccinimide/N,N'-dicyclohexylcarbodiimide (NHS/DCC). Each 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DISP-PEG2000) connected two FOLs to generate difolate targeted nanomaterials. Nano laser particle size (PS) and Zeta potential analyzer (ZPA) were applied to analyze the physical characteristics of the material such as PS and dispersion, and the enhanced development effect in vitro was detected by the ultrasonic diagnostic instrument. Besides, the targeted binding ability of the contrast agent based on this material to folate receptor (FR) overexpressing MCF-7 cells was analyzed by flow cytometry (FCM) and fluorescence microscope. In the experiment, hydrogen-1 nuclear magnetic resonance (1H NMR) demonstrated that (FOL)2-TUAs was successfully synthesized. The surface of this material was round and uniformly distributed without aggregation. According to the relative number of FOL molecules, non-targeted nano-agent (U-TUA), monofolate targeted nano-agent (FOL-TUA), and difolate targeted nano-agent ((FOL)2-TUA) were obtained. The in vitro imaging showed that different materials exhibited enhanced imaging effects in ultrasonic diagnostic equipment. FCM and fluorescence microscopy both indicated that the difolate TUA could achieve a good binding to MCF-7 cells. Most of the nano-agents were attached to the cell membrane, surrounded by red fluorophore, namely increasing the FOL content of DISP-PEG2000 chain could enhance the targeted binding ability of tumor cells.

A novel ratiometric fluorescent chemosensor for detecting malononitrile and application assisted with smartphone

Malononitrile can be transformed into hypertoxic hydrogen cyanide which induces severely jeopardizes to human beings and environment. However, an effective detection technology for malononitrile was still lacking, which means that it is necessary to develop new sensitive analysis technology for malononitrile. Here in, a high sensitive fluorescent probe NQBS for detecting malononitrile was designed and synthesized from the derivative of natural product nopinone. NQBS could selectively recognize malononitrile from 26 kinds of competitive compounds in N, N-dimethylformamide (DMF) solution. The detection limit of NQBS for malononitrile was calculated to be 1.96 μM at the concentration range of 0–25 μM. In addition, the sensing mechanism of NQBS towards malononitrile was proved with high resolution mass spectrometer (HRMS), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), and density functional theory (DFT) calculation analysis as Knoevenagel condensation process and intramolecular cyclization reaction. With the assistance of smartphone and color recognition software, NQBS was well applied in the on-site recognition of malononitrile in real time by analyzing the change trend of the red–greenblue (RGB) value of the NQBS solution.

A novel method for the functionalization of graphene oxide with polyimidazole for highly efficient adsorptive removal of organic dyes

Graphene oxide (GO) and its related composites have been extensively studied for various applications due to their unique two-dimensional structure and promising performance. In this study, we reported for the first time that polyimidazole-modified GO composites (abbreviated as PILGO) could be successfully fabricated through the combination of thiol-ene click and Radziszewski reactions. Functionalized GO composites were characterized by a series of techniques, such as nuclear magnetic resonance hydrogen spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis, and the adsorption behaviour of these PILGO composites towards Congo red (CR, an anionic dye) was investigated in detail. We demonstrated that the adsorption capacity of PILGO was significantly improved as compared with that of pristine GO. The maximum uptake performance of PILGO was up to 191.9 mg g−1 with a near-saturation state achieved in the first 5 min. The adsorption equilibrium data were better fitted through the pseudo-second-order model, while the adsorption isotherm data were better correlated with the Freundlich and Tempkin models. The adsorption affinity between CR and PILGO was positively related to the solution pH. The adsorption mechanism between CR molecules and composite material was further put forward, and it included electrostatic attraction, π-π stacking and hydrogen bond interactions. Competitive adsorption and cycling experiments further demonstrated that PILGO composites can be used as clean, efficient and novel adsorbents in wastewater treatment.

Antioxidant stress and anticancer activity of peptide‑chelated selenium invitro.

The association between selenium and peptide in gastric cancer is an important research topic. The present study reported the facile synthesis of anticancer bioactive peptide (ACBP)-functionalized selenium (ACBP-S-Se) particles with enhanced anticancer activities and a detailed mechanistic evaluation of their ability to regulate oxidative stress in vitro. Structural and chemical characterizations were revealed by ultraviolet absorption, Fourier transform infrared, X-ray photoelectron, nuclear magnetic resonance carbon and hydrogen, energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectrometry, as well as scanning electron microscopy. Sulfhydrylation modifications of ACBP were achieved with Sacetylmercaptosuccinic anhydride via chemical absorption. After the polypeptide was modified by sulfhydrylation, the ACBP chain was linked to sulfhydryl groups by amide bonds to form the ACBP-chelated selenium complex. Two gastric cancer cell lines (MKN-45 and MKN-74 cells) demonstrated high susceptibility to ACBP-S-Se particles and displayed significantly decreased proliferation ability following treatment. The results suggested that the bioactive peptide-chelated selenium particles effectively inhibited the proliferation of MKN-45 and MKN-74 cells in vitro. The genes encoding CDK inhibitor 1A (CDKN1A), cyclin B1, thioredoxin (TXN) and mitogen-activated protein kinase kinase kinase 5 are associated with regulation of oxidative stress, while CDKN1A and TXN protect cells by decreasing oxidative stress and promoting cell growth arrest. Therefore, ACBP-S-Se may be an ideal chemotherapeutic candidate for human cancer, especially gastric cancer.

Metabolic Profile Changes in Mangalarga Marchador Horses Subjected to A Hypercaloric Diet Evaluated by Proton NMR Spectroscopy

The incidence of equine metabolic syndrome, a condition that results in endocrinopathic laminitis, is increasing worldwide. Although it is well known that the development of this syndrome depends on imbalances in energy metabolism and genetic traits, its pathophysiology remains unclear. Hydrogen nuclear magnetic resonance (1H NMR) is a powerful tool used to compare metabolic profiles and to discriminate metabolites in living beings. The aim was to apply this technology to detect blood biomarkers candidates in horses that were previously demonstrated to developed metabolic changes when subjected to induced obesity. Nine Mangalarga Marchador horses received a hypercaloric diet for 5 months and serum metabolomic analysis was performed before, during, and after the diet period. The 1H NMR results were subjected to multivariate analysis and NMR analysis allowed to identify six compounds (alanine, threonine, choline, α-glucose, β-glucose, and creatinine), and observe the increasing choline level over the assessment period in four animals. A hypercaloric diet altered the metabolic profile of horses, with an individual bias in the time at which these changes occurred. This study is the first to describe metabolomic compounds in Mangalarga Marchador horses subjected to a hypercaloric diet rich in non-structural carbohydrates.

Simple pyrolysis of polystyrene into valuable chemicals

Abstract Overuse of polymer products has led to severe environmental problems, which are threatening survival of creatures on earth. It is urgent to tackle enormous polymer wastes with proper cycling methods. Pyrolysis of polymers into high-value chemicals and fuels is displaying great potential to address the white pollution issue. In this study, we focus on chemical recycling of polystyrene, an important polymer in our everyday life, into valuable chemicals through simple pyrolysis strategy under nitrogen protection. It is found that yield of liquid product from polystyrene pyrolysis achieves as high as 76.24%, and there exists single component in the liquid product, which has been identified as styrene through hydrogen nuclear magnetic resonance spectra. Moreover, we propose monomer dissociation mechanism to explain the pyrolysis process of polystyrene based on the structure of polystyrene and experimental results.

Research on a new cationic polyacrylamide (CPAM) with a cationic microblock structure and its enhanced effect on sludge condition and dewatering.

Flocculation is one of the commonly used sludge conditioning methods in water supply plants, which can improve the sludge dewatering performance by reducing the specific resistance of sludge (SRF), decreasing the amount of sludge, and finally lowering the transportation cost and subsequent disposal cost of sludge. Therefore, it is particularly important to develop new and efficient flocculants. In this paper, the template copolymer of acryloxy trimethylammonium chloride (DAC) and acrylamide (AM) was successfully synthesized by microwave-template copolymerization (MV-TP) using sodium polyacrylate (NaPAA) as template. The template copolymer was analyzed by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), and scanning electron microscopy (SEM). It was found that this template copolymer had obvious cationic microblock structure. In addition, the test results of association constant (KM) and polymerization kinetics showed that the MW-TP was assigned to free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP). It confirmed the formation of cation fragment structure again. Due to its dense positive charges in this new cationic microblock structure, it greatly improved the functions of electric neutralization, electrical patching, and adsorption bridging. The cationic fragment structure in the template copolymer could help to generate large and dense floc structure and form stable drainage channels. Under external pressure, these large and compact floc structures had greater compressive resistance, which avoided deformation and blockage of drainage channels and voids. It was beneficial to reduce SRF and evidently enhanced sludge dewatering performance.

Synthesis and Characterization of Block Copolymers of Poly(silylene diethynylbenzen) and Poly(silylene dipropargyl aryl ether).

Poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl propane) copolymer (ABA-A), poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl ether) copolymer (ABA-O), and a contrast poly(silylene diethynylbenzene) with equivalent polymerization degree were synthesized through Grignard reactions. The structures and properties of the copolymers were investigated via hydrogen nuclear magnetic resonance, Fourier transform infrared spectroscopy, Haake torque rheometer, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis and mechanical tests. The results show that the block copolymers possess comprehensive properties, especially good processability and good mechanical properties. The processing windows of these copolymers are wider than 58 °C. The flexural strength of the cured ABA-A copolymer reaches as high as 40.2 MPa. The degradation temperatures at 5% weight loss (Td5) of the cured copolymers in nitrogen are all above 560 °C.

The preparation and characterization of chemically deuterium incorporated cotton fibers

Preparation of deuterium incorporated cellulose is a vital tool to investigate cellulose internal structure and to expand the application fields of cellulose materials. In this study, cellulosic cotton fibers with anti-rehydration (exchange-resistant) deuterium incorporated in cellulose were prepared by chemical hydrogen–deuterium exchange treatment. The chemical hydrogen–deuterium exchange process, along with exchange time, were characterized by nuclear magnetic resonance hydrogen spectroscopy (1H-NMR). The anti-rehydration deuterium incorporation was determined by Fourier Transform infrared spectroscopy (FTIR) and Stable Isotope Ratio Mass Spectrometer (IRSM). The effect of the deuterium hydroxyl substitution on cotton fiber’s spectral data, microstructure, crystalline information, degree of polymerization, as well as it’s thermogravimetric analysis (charcoalization and combustion) are explored. Analysis of the chemical exchange process indicated that the hydrogen–deuterium exchange occurred preferentially in the amorphous cellulose component over the first several minutes. Deuterium exchange in the anti-rehydration crystalline phase took several hours. Increasing the treatment time, enhanced exchange-resistant deuterium incorporation to as high as about 60% of the cotton fibers’ cellulose hydroxyl groups was achieved. The characterization of FTIR, Fourier transform Raman (FT-Raman), and near-infrared spectra (NIR) all exhibited the deuterium spectral isotope effect on cellulose hydroxl groups. While, apart from the effect of reaction temperature, deuterium incorporation isotope effect did not affect the cellulose microstructure, crystalline index and the degree of polymerization properties. Furthermore, the thermogravimetric analysis of deuterated cotton fibers under N2 and air atmosphere were both altered due to the thermodynamic isotope effect. These observations revealed the hydrogen–deuterium exchange treatment process and impacts on cellulose fiber properties, which helped us to better understand the cellulose internal structure and may facilitate the potential utilization of deuterated cellulosic materials.

Synthesis of novel polycarbonate‐based thermoplastic polyurethane elastomers compatibilizers with octadecyl side chains and their application in PC/PP blends

AbstractWith the aim to improve the compatibility of polycarbonate (PC)/polypropylene (PP) blends, a novel aromatic polycarbonate diol (PCDL) was synthesized by the transesterification reaction, then a series of polycarbonate‐based thermoplastic polyurethane elastomers compatibilizers (TPU‐Gx) with octadecyl side chains were successfully prepared by introducing different content of PCDL and glyceryl monostearate (2,3‐Dihydroxypropyl octadecenoate; GMS). The structures of synthesized products were confirmed by Fourier transform infrared spectroscopy and Nuclear magnetic resonance hydrogen spectroscopy. Thermogravimetry results showed that all TPU‐Gx had good thermal stability. The effects of TPU‐Gx on the compatibilization of PC/PP blends were investigated in the aspect of morphology, mechanical, thermal, and rheological properties. The results showed that all TPU‐Gx could enhance the interfacial adhesion between PC/PP and improve the mechanical properties of PC/PP blends. Among them, the addition of TPU‐G1.5 containing 6.0 wt% PCDL and 1.5 wt% GMS made PC/PP/TPU‐G1.5 blends show the highest impact strength, which increased by 54.1% when compared with that of pure PC/PP blends.

Elucidation of the structure, spectroscopic techniques and quantum chemical investigations on nonlinear optical material 2‑hydroxy-5-methylbenzaldehyde

First and second order hyperpolarizabilities of, 2‑hydroxy-5-methylbenzaldehyde (HMB) and its related three molecules 2, 6‑hydroxy-3-methyl acetophenone (HMA), 5-ethyl-2-hydroxybenzaldehyde (HBA) and 2, 6-Dihydroxy-4-methyl benzaldehyde (DMB) were calculated by employing MP2 (Moller-Plesset) method. The vibrational behavior of the title molecule was extracted by using Fourier transform infrared, Fourier transform-Raman analysis. The UltraViolet-visible spectrum recorded and analyzed using ethanol solvent, reveals the optical and electronic transition properties. Hydrogen and carbon nuclear magnetic resonance spectra were also recorded. Kurtz and Perry powder technique was utilized to examine the second harmonic generation effectiveness. The third-order nonlinear optical performances and optical limiting threshold are investigated by Z-scan techniques. The experimental results of SHG and Z-scan strongly proved the NLO behavior of the HMB molecule. The optical limiting value is 19.64 Jcm−2 indicating that the HMB molecule could be a promising candidate for optical limiting materials. Potential energy surface scanning has been performed to discover the stability of the molecules which leads to the nonlinear optical activity. The geometry optimization has been performed to analyze the nonlinear optical active site with bonding features. Natural bond orbital analysis, Hirshfeld surface analysis, density of energy states, Frontier molecular orbital analysis, molecular electrostatic potential, Fukui function and global reactivity descriptor have also been carried out to verify the nonlinear optical activity. The natures of intramolecular hydrogen bonds are analyzed using QTAIM and RDG analysis.

Synthesis and Characterization of Biodiesel from Tofu Dregs Oil through Esterification and Transesterification Irradiated by Microwave

Biodiesel has become an alternative energy source that continues to be developed. In this research, biodiesel synthesis from tofu dregs oil has been carried out through two stages of the reaction, namely the esterification stage using H2SO4 catalyst to reduce the content of FFA (Free Fatty Acid) and the transesterification stage using KOH catalyst to produce biodiesel. The esterification reaction using 2% H2SO4 catalyst was carried out by microwave heating at power variation of the microwave power 150, 300, 450, 600, 800 Watt with a reaction time of 10 minutes. The transesterification reaction was carried out with variations in microwave power of 150, 300, 450, 600, 800 watts and variations of the reaction time of 5, 10,15,20, and 25 minutes. Biodiesel products were characterized using Gas Chromatography-Mass Spectroscopy (GC-MS), Hydrogen-1 Nuclear Magnetic Resonance (1H-NMR) spectrometer, and feasibility test with the American Standard for Testing Material (ASTM). The characterization results showed that tofu dregs oil biodiesel has been successfully synthesized. The optimum biodiesel was achieved at 600 Watt microwave power with a reaction time of 20 minutes at 92%. The formation of biodiesel is evidenced by several methyl ester peaks, namely methyl oleate (59.98%), methyl linolenic (28.13%), methyl palmitate (8.54%), and methyl stearate (2.32%). Based on the results of ASTM biodiesel tofu dregs oil has met SNI-04-7182-2006 standards, namely the specific density parameter 60/60 ° F (0.87 g/cm3), kinematic viscosity at 40 ° C (4.3 mm2/s), pour point (8 °C), flash point (202 °C) and cloud point (7 )° C for biodiesel.

Tunable plasticization of sustainable ethyl cellulose toward thermoplastic elastomers through ATRP grafting

Thermoplastic elastomers (TPEs) derived from sustainable cellulose and its derivatives have attracted a great deal of attention, because of their abundance, renewable nature, rigid backbone and good mechanical properties. To fabricate TPEs with tunable performance, a series of sustainable ethyl cellulose (EC)-grafted poly(methyl methacrylate (MMA)) (EC-g-P(MMA)) and poly(MMA-co-butyl methacrylate (BMA)) (EC-g-P(MMA-co-BMA)) were fabricated by way of atom-transfer radical polymerization (ATRP). By tuning the molar ratio of MMA/BMA in the copolymer side chains, tunable performance of TPEs with tunable glass transition temperatures (118–47.8°C) was achieved. The chemical structures of EC-bromide and EC graft copolymers were identifiable by Fourier transform infrared spectroscopy and hydrogen-1 (1H) nuclear magnetic resonance spectroscopy. The EC graft copolymers exhibited a higher molecular weight and good thermal stability and mechanical properties. These results suggested that these tunable-performance copolymers with a sustainable cellulose backbone and an acrylate side chain were potential candidates for service as TPEs in some applications.