Synthesis of Poly (Citric Acid-Co-Glycerol) and Its Application as an Inhibitor of CaCO3 Deposition

This investigation determined a feasible route to prepare hyperbranched polyesters involving citric acid (CA) and glycerol (GLC) monomers (CA-co-GLC) using a thermal polycondensation method. The synthesized copolymer was characterized using Fourier transform infrared spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The ability of CA-co-GLC to inhibit deposition of inorganic scales such as calcium carbonate was investigated under varying temperature and pH medium. The evaluation of inhibition efficiency (IE) was conducted using the static scale inhibition method. The mechanism of the inhibitor’s action was investigated via growth solution analysis, measurement conductivity, and analysis of CaCO3 using FT-IR and scanning electron microscopy. The results obtained showed that the CA-co-GLC had good IE at an elevated temperature reaching 75% at 100 °C, pH 7.5, and 10 ppm copolymer dose. Using the same dose, the IE reached 66% at 50 °C and pH 10. The CA-co-GLC did not chelate Ca2+ in water, but led to a change in polymorphism, making it brittle and able to slip easily from the surface. Its action principally prevented the adhesion of calcium carbonate onto the surface.

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Synthesis of a Cationic Polyacrylamide under UV Initiation and Its Flocculation in Estrone Removal

International Journal of Polymer Science ◽

10.1155/2018/8230965 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Jiaoxia Sun ◽

Xiqin Ma ◽

Xiang Li ◽

Jianxin Fan ◽

Qingkong Chen ◽

...

Keyword(s):

Ammonium Chloride ◽

Removal Rate ◽

Phenyl Group ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Floc Size ◽

Cationic Polyacrylamide ◽

H Nmr ◽

Ft Ir ◽

Dsc Analyses

A ternary cationic polyacrylamide (CPAM) with the hydrophobic characteristic was prepared through ultraviolet- (UV-) initiated polymerization technique for the estrone (E1) environmental estrogen separation and removal. The monomers of acrylamide (AM), acryloyloxyethyl-trimethyl ammonium chloride (DAC), and acryloyloxyethyl dimethylbenzyl ammonium chloride (AODBAC) were used to synthesize the ternary copolymer (PADA). Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectroscopy (1H NMR), thermogravimetry/differential scanning calorimetry (TG/DSC), and scanning electron microscopy (SEM) were employed to characterize the structure, thermal decomposition property, and morphology of the polymers, respectively. FT-IR and 1H NMR results indicated the successful formation of the polymers. Besides, with the introduction of hydrophobic groups (phenyl group), an irregular and porous surface morphology and a favorable thermal stability of the PADA were observed by SEM and TG/DSC analyses, respectively. At the optimal condition (pH = 7, flocculant dosage = 4.0 mg/L and E1 concentration = 0.75 mg/L), an excellent E1 flocculation performance (E1 removal rate: 90.1%, floc size: 18.3 μm, and flocculation kinetics: 22.69×10-4 s−1) was acquired by using the efficient flocculant PADA-3 (cationic degree = 40%, and intrinsic viscosity = 6.30 dL·g−1). The zeta potential and floc size analyses were used to analyze the possible flocculation mechanism for the E1 removal. Results indicated that the charge neutralization, adsorption, and birding effects were dominant in the E1 removal progress.

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Performance of N,O-Carboxymethyl Chitosan as Corrosion and Scale Inhibitors in CO2 Saturated Brine Solution

Indonesian Journal of Chemistry ◽

10.22146/ijc.64255 ◽

2021 ◽

Vol 21 (4) ◽

pp. 954

Author(s):

Muhamad Jalil Baari ◽

Bunbun Bundjali ◽

Deana Wahyuningrum

Keyword(s):

Inhibition Efficiency ◽

Electrochemical Impedance ◽

Chloroacetic Acid ◽

Carboxymethyl Chitosan ◽

Scale Formation ◽

Water Soluble ◽

Complexing Agent ◽

Dissolved Gas ◽

Scale Inhibition ◽

Ft Ir

The presence of salts and dissolved gas like CO2 that is carried with natural gas and crude oil along the pipeline is the main reason for corrosion and scale formation. These problems are usually resolved separately by corrosion inhibitors and scale inhibitors or acidification. Meanwhile, utilizing a compound to resolve both corrosion and scale formation has an advantage in the economic side and working time. N,O-carboxymethyl chitosan or N,O-CMCs is one of the chitosan's derivates. It is water-soluble and has different functional groups. Those properties support its capability as a complexing agent on corrosion and scale inhibitors. Synthesis of N,O-CMCs was carried out by chemical reactions between chitosan and chloroacetic acid under alkaline circumstances. N,O-CMCs product was characterized using FT-IR and 1H-NMR spectroscopy. The inhibition efficiency was analyzed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The measurements showed that the highest efficiency of corrosion inhibition reached 63.54% when the concentration and temperature were 30 ppm and 35 °C, respectively. N,O-CMCs was classified as a mixed-type inhibitor. The adsorption mechanism of the inhibitor followed Langmuir adsorption isotherm. The static scale inhibition test informed that the optimum inhibition efficiency of N,O-CMCs reached 60.00%.

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DSC, FT-IR, NIR, NIR-PCA and NIR-ANOVA for determination of chemical stability of diuretic drugs: impact of excipients

Open Chemistry ◽

10.1515/chem-2018-0014 ◽

2018 ◽

Vol 16 (1) ◽

pp. 116-132 ◽

Cited By ~ 2

Author(s):

Anna Gumieniczek ◽

Hanna Trębacz ◽

Łukasz Komsta ◽

Agnieszka Atras ◽

Beata Jopa ◽

...

Keyword(s):

High Temperature ◽

Citric Acid ◽

Principal Component ◽

Magnesium Stearate ◽

Scanning Calorimetry ◽

Diuretic Drugs ◽

Temperature And Humidity ◽

Ft Ir ◽

Selection Of

AbstractIt is well known that drugs can directly react with excipients. In addition, excipients can be a source of impurities that either directly react with drugs or catalyze their degradation. Thus, binary mixtures of three diuretics, torasemide, furosemide and amiloride with different excipients,i.e. citric acid anhydrous, povidone K25 (PVP), magnesium stearate (Mg stearate), lactose, D-mannitol, glycine, calcium hydrogen phosphate anhydrous (CaHPO4) and starch, were examined to detect interactions. High temperature and humidity or UV/VIS irradiation were applied as stressing conditions. Differential scanning calorimetry (DSC), FT-IR and NIR were used to adequately collect information. In addition, chemometric assessments of NIR signals with principal component analysis (PCA) and ANOVA were applied.Between the excipients examined, lactose and starch did not show any interactions while citric acid, PVP, Mg stearate and glycine were peculiarly operative. Some of these interactions were shown without any stress, while others were caused or accelerated by high temperature and humidity, and less by UV/VIS light. Based on these results, potential mechanisms for the observed interactions were proposed Finally, we conclude that selection of appropriate excipients for torasemide, furosemide and amiloride is an important question to minimize their degradation processes, especially when new types of formulations are being manufactured.

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Development of Pelubiprofen Tromethamine with Improved Gastrointestinal Safety and Absorption

Pharmaceutics ◽

10.3390/pharmaceutics13050745 ◽

2021 ◽

Vol 13 (5) ◽

pp. 745

Author(s):

Ji Yeon Park ◽

Dong Ho Oh ◽

Sang-Wook Park ◽

Bo Ram Chae ◽

Chul Woo Kim ◽

...

Keyword(s):

Plasma Concentration ◽

Water Soluble ◽

Resonance Spectroscopy ◽

Maximum Plasma ◽

Scanning Calorimetry ◽

Time Curve ◽

Nmr Spectrum ◽

Gastrointestinal Safety ◽

Ft Ir

Pelubiprofen (PEL), which is a commercialized non-steroidal anti-inflammatory drug (NSAID), is associated with the risk of gastrointestinal (GI) adverse events following long-term exposure and has poor water-soluble properties. Here, a new pelubiprofen tromethamine (PEL-T) with improved solubility, permeability, GI safety, and absorption, compared to PEL, has been developed. The nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR) results confirmed that the PEL-T was well formed. The powder of PEL-T showed the presence of additional 6H protons at δ 3.66–3.61 in the 1H NMR spectrum, and shifted the sharp endothermic peaks at 129 °C in DSC, and the spectrum of distinct absorption peaks in FT-IR. In addition, compared with PEL, PEL-T showed a significantly improved solubility in various media and an increased permeability coefficient (Kp) in Caco-2 cells. Furthermore, compared to PEL oral administration, PEL-T was found to significantly reduce the damaged area in an acute gastric damage rat model. The pharmacokinetic study of the PEL-T powder showed higher maximum plasma concentration (Cmax) and area under the plasma concentration–time curve from 0 h to the last time point (AUCt) than those of the PEL powder. Taken together, our data suggest that PEL-T is a recommendable candidate with enhanced gastrointestinal safety and better absorption compared with commercial PEL.

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Green anionic polymerization of vinyl acetate using Maghnite-Na+ (Algerian MMT): synthesis characterization and reactional mechanism

Discover Chemical Engineering ◽

10.1007/s43938-021-00005-8 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Badia Imene Cherifi ◽

Mohammed Belbachir ◽

Abdelkader Rahmouni

Keyword(s):

Vinyl Acetate ◽

Polymerization Reaction ◽

Resonance Spectroscopy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

H Nmr ◽

Simple Filtration ◽

Renewable Material ◽

Ft Ir ◽

C Nmr

AbstractIn this work, the green polymerization of vinyl acetate is carried out by a new method which consists in the use of clay called Maghnite-Na+ as an ecological catalyst, non-toxic, inexpensive and recyclable by simple filtration. X-ray diffraction (XRD) showed that Maghnite-Na+ is successfully obtained after cationic treatment (sodium) on raw Maghnite. It is an effective alternative to replace toxic catalysts such as benzoyl peroxide (BPO) and Azobisisobutyronitrile (AIBN) which are mostly used during the synthesis of polyvinyl acetate (PVAc) making the polymerization reaction less problematic for the environment. The synthesis reaction is less energetic by the use of recycled polyurethane as container for the reaction mixture and which is considered as a renewable material and a good thermal insulator which maintains the temperature at 0 °C for 6 h. The reaction in bulk is also preferred to avoid the use of a solvent and therefore to stay in the context of green chemistry. In these conditions, the structure of obtained polymer is established by Nuclear Magnetic Resonance Spectroscopy 1H NMR and 13C NMR. Infrared spectroscopy (FT-IR) is also used to confirm the structure of PVAc. Thermogravimetric analysis (TGA) showed that it is thermally stable and it starts to degrade from 330 °C while Differential Scanning calorimetry (DSC) shows that this polymer has a glass transition temperature (Tg = 50 °C). The composition in PVAc/Maghnite-Na+ (7 wt% of catalyst) is the most tensile resistant with a force of 182 N and a maximum stress of 73.16 MPa, the most flexible (E = 955 MPa) and the most ductile (εr = 768%).

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Synthesis and Nonisothermal Crystallization Kinetics of Poly(Butylene Terephthalate-co-Tetramethylene Ether Glycol) Copolyesters

Polymers ◽

10.3390/polym12091897 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1897 ◽

Cited By ~ 1

Author(s):

Hsu-I Mao ◽

Chin-Wen Chen ◽

Syang-Peng Rwei

Keyword(s):

Crystallization Rate ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Nonisothermal Crystallization ◽

Excellent Thermal Stability ◽

Butylene Terephthalate ◽

Melt Polymerization ◽

Ft Ir ◽

Nonisothermal Crystallization Kinetics ◽

Kinetics Of

Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents.

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Synthesis of Eugenol-Based Silicon-Containing Benzoxazines and Their Applications as Bio-Based Organic Coatings

Coatings ◽

10.3390/coatings8030088 ◽

2018 ◽

Vol 8 (3) ◽

pp. 88 ◽

Cited By ~ 19

Author(s):

Jinyue Dai ◽

Shimin Yang ◽

Na Teng ◽

Yuan Liu ◽

Xiaoqing Liu ◽

...

Keyword(s):

Thermal Stability ◽

Moisture Absorption ◽

High Hardness ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Good Thermal Stability ◽

Chemical Structures ◽

Ring Opening Reaction ◽

Ft Ir ◽

Excellent Adhesion

In this work, several bio-based main-chain type benzoxazine oligomers (MCBO) were synthesized from eugenol derivatives via polycondensation reaction with paraformaldehyde and different diamine. Afterwards, their chemical structures were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance Spectroscopy (1H-NMR). The curing reaction was monitored by Differential Scanning Calorimetry (DSC) and FT-IR. The polybenzoxazine films were prepared via thermal ring-opening reaction of benzoxazine groups without solvent, and their thermodynamic properties, thermal stability, and coating properties were investigated in detail. Results indicated that the cured films exhibited good thermal stability and mechanical properties, showing 10% thermal weight loss (Td10%) temperature as high as 408 °C and modulus at a room temperature of 2100 MPa as well as the glass transition temperature of 123 °C. In addition, the related coatings exhibited high hardness, excellent adhesion, good flexibility, low moisture absorption, and outstanding solvent resistance.

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Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation

Materials ◽

10.3390/ma12020229 ◽

2019 ◽

Vol 12 (2) ◽

pp. 229 ◽

Cited By ~ 5

Author(s):

Blanca Lorenzo-Veiga ◽

Hakon Sigurdsson ◽

Thorsteinn Loftsson

Keyword(s):

1H Nmr ◽

Self Assembly ◽

Topical Administration ◽

Water Soluble ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Nmr Studies ◽

Water Soluble Polymers ◽

1H Nuclear Magnetic Resonance ◽

Ft Ir

The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was confirmed by DSC, FT-IR and 1H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 µm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.

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P(N-Phenylmaleimide-Alt-Styrene) Introduced with 4-Carboxyl and Its Effect on the Heat Deflection Temperature of Nylon 6

Materials ◽

10.3390/ma11112330 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2330 ◽

Cited By ~ 4

Author(s):

Yufei Liu ◽

Min He ◽

Daohai Zhang ◽

Qian Zhao ◽

Yang Li ◽

...

Keyword(s):

Dynamic Viscosity ◽

Gel Permeation Chromatography ◽

Nylon 6 ◽

Mechanical Analysis ◽

Radical Copolymerization ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Free Radical Copolymerization ◽

Ft Ir ◽

Heat Deflection Temperature

P(N-phenylmaleimide-alt-styrene) (P(NPMI-alt-St)) and P(N-(4-carboxyphenyl)maleimide-alt-styrene) (P(CPMI-alt-St)) were designed and synthesized via free radical copolymerization. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to confirm the structure of P(NPMI-alt-St) and P(CPMI-alt-St). Next, the effect of P(CPMI-alt-St) on the heat deflection temperature (HDT) of nylon 6 was studied. In comparison to the PA6/P(NPMI-alt-St) blend, with the addition of 10 wt %, the HDT value of the PA6/P(CPMI-alt-St) blend increased by 15.7 °C, and the glass transition temperature (Tg) by Dynamic mechanical analysis (DMA) increased 2.3 °C. According to the analysis of DMA, dynamic viscosity, and the SEM of PA6 and its blends, P(CPMI-alt-St) promoted its compatibility with PA6, and promoted the storage modulus and dynamic viscosity of the blends. Thus, the introduction of 4-carboxyl can significantly improve the effect of P(CPMI-alt-St) on the heat resistance modification of nylon 6.

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Synthesis of Highly Thermally Stable Daidzein-Based Main-Chain-Type Benzoxazine Resins

Polymers ◽

10.3390/polym11081341 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1341 ◽

Cited By ~ 3

Author(s):

Mengchao Han ◽

Sijia You ◽

Yuting Wang ◽

Kan Zhang ◽

Shengfu Yang

Keyword(s):

Thermal Stability ◽

Main Chain ◽

Gel Permeation Chromatography ◽

Polymerization Process ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Molecular Weights ◽

Potential Applications ◽

Ft Ir ◽

Chain Type

In recent years, main-chain-type benzoxazine resins have been extensively investigated due to their excellent comprehensive properties for many potential applications. In this work, two new types of main-chain benzoxazine polymers were synthesized from daidzein, aromatic/aliphatic diamine, and paraformaldehyde. Unlike the approaches used synthesizing traditional main-chain-type benzoxazine polymers, the precursors derived from daidzein can undergo a further cross-linking polymerization in addition to the ring-opening polymerization of the oxazine ring. The structures of the new polymers were then studied by 1H nuclear magnetic resonance spectroscopy (NMR) and Fourier-transform infrared spectroscopy (FT-IR), and the molecular weights were determined by using gel permeation chromatography (GPC). We also monitored the polymerization process by differential scanning calorimetry (DSC) and in situ FT-IR. In addition, the thermal stability and flame-retardant properties of the resulting polybenzoxazines were investigated using TGA and microscale combustion calorimeter (MCC). The polybenzoxazines obtained in this study exhibited a very high thermal stability and low flammability, with a Tg value greater than 400 °C, and a heat release capacity (HRC) value lower than 30 J/(g K).

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