Maleic Anhydride Research Articles

Synthesis of a novel polymer and design of carboxylate-terminated hyperbranched PEI-incorporated PVDF membranes for efficient oil-in-water emulsion separation

Polyvinylidene fluoride (PVDF) membranes utilizing ultrafiltration (UF) and microfiltration (MF) configurations have widely been used in many separation processes, including oil/water emulsions. Recently, there have been tremendous research interests in designing PVDF membranes on their structural-property relations as well as high separation performances. Herein we report the synthesis of a novel carboxylate-terminated hyperbranched polyethylenimine (CHPEI) using a facile three-step one-pot strategy to enhance the characteristics of PVDF membranes for oil/water emulsion separation. The first step involved the production of one amide and one carboxylate functional group per maleic anhydride molecule on the outer surface of polyethylenimine (PEI). The second step involved producing two additional carboxylate groups via amine-based Michael addition of alkenes using aspartic acid dimethyl ester hydrochloride, followed by basic hydrolysis. CHPEI-n-PVDF membranes having various CHPEI contents are further fabricated by a phase-inversion process, obtaining as free-stable flat-sheet membranes. The synthesized polymer and membranes were thoroughly characterized by FTIR and 1H NMR, SEM, EDX, mapping, AFM, and contact angle analysis. The incorporation of CHPEI into PVDF positively enhanced the hydrophilicity, and the WCA was significantly reduced from 80.6° to 59.5°. The maximum permeation flux was obtained using CHPEI-3-PVDF membranes, which was 200 % more than that obtained using pristine PVDF. The CHPEI-2-PVDF membranes exhibited a rejection performance of >99 % for separating oil-in-water emulsions. The incorporation of CHPEI into PVDF significantly improved the antifouling characteristics of the membranes. After 5 h of operation in separating oil-in-water emulsions, the flux recoveries of CHPEI-2-PVDF and CHPEI-3-PVDF were found to be 92 % and 97 %, respectively. CHPEI has demonstrated a considerable positive influence in improving the PVDF membrane’s performance, making it an excellent candidate for oily wastewater treatment because of its high rejection performance and excellent flux recovery ratio.

The Conundrum of "Pair Sites" in Langmuir-Hinshelwood Reaction Kinetics in Heterogeneous Catalysis.

Understanding reaction kinetics is crucial for designing and applying heterogeneous catalytic processes in chemical and energy conversion. Here, we revisit the Langmuir-Hinshelwood (L-H) kinetic model for bimolecular surface reactions, originally formulated for metal catalysts, assuming immobile adsorbates on neighboring pair sites, with the rate varying linearly with the density of surface sites (sites per unit area); r ∝ [*]o 1. Supported metal oxide catalysts, however, offer systematic control over [*]o through variation of the active two-dimensional metal oxide loading in the submonolayer region. Various reactions catalyzed by supported metal oxides are analyzed, such as supported VO x catalysts, including methanol oxidation, oxidative dehydrogenation of propane and ethane, SO2 oxidation to SO3, propene oxidation to acrolein, n-butane oxidation to maleic anhydride, and selective catalytic reduction of nitric oxide with ammonia. The analysis reveals diverse dependencies of reaction rate on [*]o for these surface reactions, with r ∝ [*]o n , where n equals 1 for reactions with a unimolecular rate-determining step and 2 for those with a bimolecular rate-limiting step or exchange of more than 2 electrons. We propose refraining from a priori assumptions about the nature and density of surface sites or adsorbate behavior, advocating instead for data-driven elucidation of kinetics based on the density of surface sites, adsorbate coverage, etc. Additionally, recent studies on catalytic surface mechanisms have shed light on nonadjacent catalytic sites catalyzing surface reactions in contrast to the traditional requirement of adjacent/pair sites. These findings underscore the need for a more nuanced approach in modeling heterogeneous catalysis, especially supported metal oxide catalysts, encouraging reliance on experimental data over idealized assumptions that are often difficult to justify.

Role of regulating synthetic solvents in enhancing the catalytic performance of VPO catalysts for n-butane oxidation to maleic anhydride

Vanadium phosphorus oxide (VPO) catalysts have been successfully applied in the selective oxidation of n-butane to maleic anhydride (MA). However, there is still much work to be done to enhance the n-butane conversion while maintaining a relatively high MA selectivity. Regulating the solvents in preparing VPO catalysts is an effective way to improve the catalytic performance. In this work, the correlation between the physicochemical properties of VPO catalysts and the composition of solvents was investigated by combining various characterization techniques to reveal the role of regulating synthetic solvents in enhancing the catalytic performance. Varying synthetic solvents could regulate both the synthetic mechanism and crystal growth of VOHPO4·0.5H2O. The VOHPO4·0.5H2O tended to form a nice plate-like structure in isobutanol but possessed large crystallite sizes and a low specific surface area. The introduction of n-butanol prevented the continuous growth of VOHPO4·0.5H2O, reducing the crystallite sizes and thus increasing the specific surface area. Introducing the n-butanol also optimized the catalyst surface chemical properties. The best catalyst synthesized in a solvent containing 80 % n-butanol and 20 % isobutanol enhanced the n-butane conversion from 71 % to 87 % while maintaining the MA selectivity (64 %) almost unchanged compared to the catalyst synthesized in a conventional solvent.

Innovative polymer composites based on biomedical materials

The article presents preliminary research on the influence of calcium phosphate (10-40 wt%) on the functional properties of ABS. Maleic anhydride grafted polyethylene was used as a compatibilizer (0.5 wt%). The mass flow rate, tensile properties and hardness were determined. The effect of the filler on the color change of the polymer matrix was also examined. For a composite containing 20 wt% calcium phosphate, the mechanical properties of samples obtained by 3D printing and injection molding were compared, with worse properties obtained by 3D printing. This can be explained by limited adhesion between the printed layers.

Improved thermomechanical and rheological properties of polypropylene composites with thermomechanical pulp for injection molding

AbstractMaterial extrusion and injection molding are prevalent in polymer processing, but wood fiber‐reinforced polymer composites offer eco‐friendly alternatives for industries like automotive, and aviation. Our study explores biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP). BCTMP is rich in cellulose and hemicellulose and quite hydrophilic, while PP's hydrophobic structure creates a disconnect to creating a composite of the two. Traditional methods add costly coupling agents like maleic anhydride polypropylene (MAPP) in an attempt to enhance the adhesion properties of wood‐plastic composites. However, it is worth noting that even in the presence of MAPP, PP maintains its high hydrophobicity and low surface energy, despite exhibiting considerable heterogeneity. Further complexity arises from the thermal degradation characteristics of BCTMP during the melting processing of PP. Our proposed method involves premixing via cryo and planetary ball milling. This boosts PP and BCTMP adhesion, enhancing dispersion quality and mechanical properties without needing coupling agents. Moreover, the premixing of BCTMP and PP forms a thermal buffer layer around BCTMP, minimizing its thermal degradation during processing. This process also ensures even distribution of BCTMP into PP, resulting in a 200% rise in Young's modulus with 30 wt% BCTMP without compromising ultimate tensile strength.Highlights Exploration of biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP) thorough injection molding Implementation of premixing to enhance PP/BCTMP adhesion without coupling agents Premixing reduces thermal degradation of BCTMP, enhances dispersion, and improves mechanical properties Achieving a 200% increase in Young's modulus with 30% BCTMP incorporation, while maintaining ultimate tensile strength

Hydrophilic interaction chromatographic evaluation of zwitterionic polymer grafted silica gel via multiple binding sites.

A novel zwitterionic polymer grafted silica stationary phase, Sil-PZIC, was prepared by bonding poly(ethylene maleic anhydride) molecules on the surface of silica via multiple binding sites, followed by ammonolysis of maleic anhydride through a nucleophilic substitution reaction with ethylenediamine. The stationary phase was characterized by solid-state 13C nuclear magnetic resonance, zeta potential, and elemental analysis and the results show the successful encapsulation of zwitterionic polymer on the surface of silica. The chromatographic performance of Sil-PZIC was investigated by using nucleosides and nucleic bases as test analytes The variation of retention and separation performance of these model compounds were investigated by varying the chromatographic conditions such as the components of mobile phase, salt concentration, and pH. The results show that the retention of the Sil-PZIC phase was dominated by a hydrophilic partitioning mechanism accompanied by secondary interactions such as electrostatic and hydrogen bonding. In addition, saccharides and Amadori compounds were also well separated on the Sil-PZIC, indicating that the Sil-PZIC column has potential application for separation of the polar compound.

Bimetallic Mn-Cu oxide catalysts for toluene oxidation: Synergistic effect and catalytic mechanism

A series of Mn-Cu composite oxides with different Mn/Cu molar ratios were synthesized via a facile ethanol-redox precipitation method and investigated for the oxidation of toluene. Among as-synthesized MnxCuy catalysts, Mn5Cu1 showed the most excellent toluene catalytic activity at a weight hourly space velocity (WHSV) of 30000 mL∙g−1∙h−1, with 90 % conversion achieved at 212 °C. Furthermore, the Mn5Cu1 catalyst exhibited exceptional thermal stability over a 12-hour period at 215 °C, along with outstanding resistance to H2O in the range of 5 vol% to 40 vol%. As characterized by XRD, BET, XPS, EPR, H2-TPR, and O2-TPD, it was found that Mn5Cu1 possessed a unique three-phase coexisting structure, large specific surface area (57 m2·g−1), plentiful oxygen vacancies, excellent redox capacity, and strong mobility of oxygen, which were attributable to the synergistic effect between Mn and Cu. This strong synergy between Mn and Cu is the underlying reason for the strong catalytic activity of Mn5Cu1. Moreover, toluene-TPD and TPSR results indicated that appropriate Cu loading was favorable for the adsorption and activation of toluene. The potential reaction pathway for toluene oxidation was presented based on in situ DRIFTS characterization. Maleic anhydride was the critical reaction intermediate species.

On The Crystallinity Of Eco Bioplastics Packaging Using DSC Techniques

The aim of this study is to examine Eco Bioplastics Packaging containing LDPE/CS. Effects content concentration of corn stalk and inclusion compatibilizer on the crystallinity and morphology of Eco Bioplastics Packaging biocomposites. It was found that the by using similar filler loading, compatibilized Eco Bioplastics Packaging has revealed higher enthalpy and crystallinity of Eco Bioplastics Packaging with MAPE. Additionally, the addition of MAPE improved the interfacial interaction between corn stalk and LDPE biocomposites, as confirmed by SEM analysis. Keywords: Corn Stalk Powder (CSP), Maleic Anhydride Polyethylene (MAPE), Light Density Polyethylene (LDPE)

Synthesis and Characterization of 1,3-Oxazepindion Derivatives via Diformylbenzene Imines as Precursors

In this paper, 1,3-oxazepindione derivatives [D] and [E] were prepared by reacting Schiff bases di Azomethine [A], [B], and [C] with maleic anhydride and succinic anhydride in the presence of dried benzene as a solvent. Schiff bases di Azomethine [A], [B], and [C] were prepared by reacting Terephthalaldehyde, Isophthalaldehyde, or o-Phthalaldehyde with 5 drops of glacial acetic acid as a catalyst and halo-aniline derivatives in absolute ethanol as a solvent. The prepared compounds were diagnosed and confirmed by using infrared and nuclear magnetic resonance spectroscopies. All the reactions of the prepared compounds were monitored by TLC.

Karakterisasi Komposit Polimer dengan Matriks Polistirena dan Bahan Pengisi dari Berbagai Limbah Pabrik Kelapa Sawit

The first stage of this research was to make polystyrene grafted with maleic anhydride for making the couping agent with other filling compound. In the second stage, the polystyrene matrix grafted with maleic anhydride was combined with filler material derived from palm oil mill waste using the dry mixing method with an internal mixer. Among several variables tested, the optimum composition of the polymer composite was found to be Polystyrene grafted with maleic anhydride: sludge: boiler ash in a ratio of 60:25:15. This composition exhibited a Young's modulus of 856.752 MPa, a tensile strength of 6.057 MPa, and an elongation at break of 0.775%. Differential Scanning Calorimetry (DSC) testing revealed a glass transition temperature of 403.22°C, a crystallization temperature of 426.39°C, and a cross-linking indication temperature of 478.64°C. Scanning Electron Microscopy (SEM) tests showed an even distribution of the material. Fourier-transform infrared (FT-IR) spectroscopy indicated a decrease in absorption peaks at 3024.94 cm⁻¹ and 3025.15 cm⁻¹, while the polystyrene characteristics at the wave number 1600.57 cm⁻¹ appeared sharper. The sound absorption test results met the ISO 11654:1997 standard for the rating level of sound absorption coefficient in materials, achieving Class D and C sound absorption with an αₙₓ value ranging from 0.328 to 0.793.

Optimization of malic anhydrate concentration in manufacturing PP-g-MA compatibilizer on test percent of grafting degree

The difference in polarity means that two or more materials cannot react, a connecting material such as a compatibilizer is needed to react between polar and non-polar materials. This research aims to determine the effect of maleic anhydride (MA) concentration on the process of grafting MA onto polypropylene (PP) chains with the help of benzoyl peroxide (BPO) as an initiator. The method used to mix these two materials uses the blending method using an internal mixer instrument and testing the percent degree of grafting using the titration method with three repetitions of the test.The research results showed that the highest percent grafting degree occurred at a concentration of 86% PP, 11% MA, and 3% BPO, with a value of 10.28%. The Spectroscopy Fourier Transform Infrared (FTIR) analysis of Polypropylene grafted maleic anhydride (PP-g-MA) showed the presence of new peaks at wavenumbers 1707cm-1 and 1162 cm-1.Increasing the concentration of maleic anhydride had no effect on increasing the percent degree of grafting.

Studies on adsorptive dehydration of pasteurised milk by filled polymeric IPN hydrogel

ABSTRACT Adsorptive dehydration utilising polymeric hydrogels presents an effective technique for removing excess water from pasteurised milk. This study investigated three Interpenetrating Polymeric Network (IPN) hydrogels comprising Polyvinyl Alcohol (PVOH) and Hydroxyethyl Cellulose (HEC) at mass ratios of 90:10, 70:30 and 50:50, respectively, with Maleic Anhydride (MAn) as a cross-linker at concentrations of 2% 4%, and 8% based on total polymer weight. It was observed that the rate of dehydration increased with higher HEC content in the hydrogels. However, the stability decreased due to changes in the structural alignment of polymer chains and weak cross-linking. Among the tested hydrogels, the one with a composition of 70:30 for PVOH and HEC, respectively, cross-linked with 8% MAn (0.096gm), exhibited the best adsorption (569% Swelling) with minimal changes in pH (<10%) and conductivity (<10%) and was, therefore, selected for further study. This selected hydrogel composition was further enhanced by incorporating a hydrophilic nanofiller (Bentonite) at proportions of 2%, 4% and 6% based on total polymer weight during hydrogel synthesis. The hydrogel with 4% nanofiller (0.081 gm) showed the best results in terms of swelling and stability although the 6% filled hydrogel exhibited superior swelling but lower stability. Finally, the dehydration process was optimised using Type 1 fuzzy logic (T1FL), achieving an R2 value of 95.13%.

HEMP FIBER REINFORCED SUSTAINABLE “GREEN” COMPOSITE PRODUCTION WITH EPOXIDIZED SOYBEAN OIL

Due to the rising environmental concerns, industry branches are pushed to research and invest sustainable materials and technologies. In this context, this study aimed to combine a sustainable fiber and matrix material to produce green composite. For this purpose, epoxidized soybean oil and hemp fiber were utilized for composite production. Sebacic acid and maleic anhydride were used as hardeners. Histidine and glycerol were applied as accelerator and starter, respectively. Mechanical performance of the composites was evaluated by tensile and impact tests. Hemp fiber reinforcement resulted in improvement on tensile properties, up to 2.6 MPa tensile strength and 11.7 kJ/m2 impact strength. Thermal properties were determined by TGA and DSC analyses. The changes in molecular level after curing was traced with FTIR measurements and surface morphology was monitored with SEM imaging.

Equilibrium Moisture Mediated Esterification Reaction to Achieve Over 100% Lignocellulosic Nanofibrils Yield.

Lignocellulosic nanofibrils (LCNFs) isolation is recognized as an efficient strategy for maximizing biomass utilization. Nevertheless, achieving a 100% yield presents a formidable challenge. Here, an esterification strategy mediated by the equilibrium moisture in biomass is proposed for LCNFs preparation without the use of catalysts, resulting in a yield exceeding 100%. Different from anhydrous chemical thermomechanical pulp (CTMP0%), the presence of moisture (moisture content of 7wt%, denoted as CTMP7%) introduces a notably distinct process for the pretreatment of CTMP, comprising the initial disintegration and the post-esterification steps. The maleic acid, generated through maleic anhydride (MA) hydrolysis, degrades the recalcitrant lignin-carbohydrate complex (LCC) structures, resulting in esterified CTMP7% (E-CTMP7%). The highly grafted esters compensate for the mass loss resulting from the partial removal of hydrolyzed lignin and hemicellulose, ensuring a high yield. Following microfluidization, favorable LCNF7% with a high yield (114.4 ± 3.0%) and a high charge content (1.74 ± 0.09mmolg-1) can be easily produced, surpassing most previous records for LCNFs. Additionally, LCNF7% presented highly processability for filaments, films, and 3D honeycomb structures preparation. These findings provide valuable insights and guidance for achieving a high yield in the isolation of LCNFs from biomass through the mediation of equilibrium moisture.

An insight into the mechanical and morphological properties of palm oil plasticized high density polyethylene-chitosan composites

An experimental analysis of the mechanical properties of maleic anhydride compatibilized high density polyethylene-chitosan composites plasticized with palm oil were investigated. The effect of chitosan as filler (0, 2.5, 5, 7.5 and 10 wt%) on the mechanical properties of the injection moulded samples and its comparison with the corresponding palm oil plasticized with the optimised composite system has been performed. The mechanical properties of the melt mixed composites were studied and compared. An increase of 11.3 % in tensile strength, 9.4% in impact strength and 44.4 % increase in Young's modulus for 5 wt% chitosan loaded composite system was obtained when compared with the neat HDPE system. Furthermore, the addition of 5 wt% palm oil to the optimised system increased its impact strength to 102 kJ/m2 when compared to the neat high density polyethylene system without chitosan. The improved compatibility between high density polyethylene and chitosan has been further confirmed through the morphological analysis. Finite element analysis of the tensile properties showed comparable values with the experimental values within acceptable error limits. This study led to the development of a bio-based material having better mechanical performance which can be used in bone-tissue engineering applications.

Synthesis and analysis of (2z)-4-(4-methylanilino)-4-oxobut-2-enoic acid

The paper identified the structure of synthesised maleic acid monoamide by physical methods of analysis. The authors have determined the solubility of maleic acid monoamide in organic solvents with different properties and dielectric constant values. The paper describes the solvent ratio allowing the analysis with the best metrological properties. The reaction between p-toluidine and maleic anhydride to form (2z)-4-(methylanilino)-4-oxobut-2-enoic acid proceeds with high yield; mass fraction of the main substance is 94.23±0.69 %.

Environmentally-friendly solvent pulping and grafting strategies for better foamability of poly(lactic acid)/agricultural waste biocomposites

In this study, the foamability of poly (lactic acid) (PLA) through a continuous extrusion process was enhanced by using an agricultural waste, environmentally friendly pulping methods, and reactive compatibilization of the lignocellulosic filler with matrix in the extrusion flow field. Both applied solvent-pulping methods by using chemicals with low safety and toxicity risks were considerably successful in purifying the micron-sized cellulosic fibers of rice straw (RS). The interface of PLA matrix with RS pulp fibers was modified by applying reactive compatibilizers containing maleic anhydride (MA) and epoxy functional groups. Both compatibilizers had the ability to simultaneously react with the hydroxyl groups of RS pulp fibers and end groups of PLA chains during the melt-compounding process. As a result of RS pulping and PLA/RS pulp compatibilizing reactions, the processability of PLA in an extrusion foaming process was substantially enhanced, in a way that the void fraction and cell density of PLA foam increased more than seven and two times, respectively. The extruded lightweight all-green biocomposite foams can be applied in construction and packaging applications.

Development of microstructure-rheological and electrical properties relationship in PS/POE/HNTs blend nanocomposites using machine learning

Halloysite nanotubes (HNTs) and polypropylene-grafted maleic anhydride (PP-g-MA) were studied for their effects in blends of polystyrene (PS) and polyolefin elastomer (POE). The method used to prepare PS/POE blends (90/10 and 80/20 wt/wt) containing 1, 3, and 5 phr HNTs with or without PP-g-MA (a compatibilizer) was melt blending. Structural and morphological studies using X-ray diffraction analysis (XRD), scanning electron microscopy assisted energy dispersive X-ray spectroscopy (SEM-EDS), and transmission electron microscopy (TEM) confirmed a matrix-droplet morphology and the sample containing compatibilizer has better microstructure than the other formulations. The presence of both PP-g-MA and HNTs together has been discovered to improve the viscoelastic properties of the solid, as evidenced by increased storage modulus and complex viscosity. A notable change occurred in the rheological behavior of the PS/POE blends containing 5 phr of PP-g-MA and HNTs. The dependence of zero-shear viscosity on HNTs loading (0–5 phr) was approximated as a polynomial curve by fitting the experimental data with the Carreau-Yasuda model. Computational fluid dynamics (CFD) simulations were also used to study the effects of HNTs loading on changes in fluid flow patterns and shear rates. The calculated effective viscosities at a given shear rate (0.05 1/s) were in qualitative agreement with the experimental results. Moreover, we utilized various machine-learning techniques to predict the complex viscosity of PS/POE blends and their nanocomposites. The results showed that Extreme Gradient Boosting (XGBoost) outperformed other predictive models based on evaluation metrics. Four-point probe measurements found that the samples containing 5 phr HNT had the lowest conductivities due to the presence of aggregated structures. However, the homogeneous distribution of HNT led to a sudden rise in conductivity in the samples containing 5 phr of PP-g-MA. Computer modeling results of samples with uniform and non-uniform HNT distributions showed that the conductivity decreased with HNT loading and decreased considerably compared to the uniform distribution.

Effect of Different Compatibilizers on the Properties of Green Low-Density Polyethylene Composites Reinforced with Bambusa Vulgaris Bamboo Fibers.

Low-density green polyethylene (LDGPE) composites reinforced with 5 wt% of bamboo fiber and 3 wt% of a compatibilizing agent (polyethylene grafted with maleic anhydride and tannin) were processed through extrusion and injection molding. Bamboo fiber, Bambusa Vulgaris, was characterized using Fourier-transform infrared spectroscopy (FTIR). The molded specimens were analyzed for their thermal, mechanical, and morphological properties. The estimated concentration was chosen to provide the best mechanical strength to the material studied. FTIR analysis of the fibers revealed the presence of groups characteristic of bamboo fiber and tannin. Differential scanning calorimetry revealed that both compatibilizing agents increased the matrix's degree of crystallinity. However, scanning electron microscopy (SEM) showed that, despite the presence of compatibilizing agents, there was no significant improvement in adhesion between the bamboo fibers and LDGPE.

Investigation of synergistic effects incorporating esterified lignin and guar gum composite aerogel for sustained oil spill cleanup

The recently developed aerogel demonstrates a high capacity for pollutant absorption, making it an environmentally friendly option for oily water treatment. In an effort to reduce the adverse effects of the black liquor accumulation in the pulp industry, this study focused on utilizing the mentioned abundant bio-resource lignin, which can be applied to various high-value applications such as 3D porous materials for oil spill cleanup. Lignin, precipitated from the black liquor, was esterified using maleic anhydride as the esterifying reagent to enhance the hydrophobicity. Then, the composite aerogel fabricated from esterified lignin and guar gum (GG) was successfully prepared through the facile freeze-drying, using glutaraldehyde (GA) as the cross-linker. The resulting aerogel exhibited high porosity values exceeding 95%, low density (27.4 mg/cm3), and an impressive absorption capacity of 32.5 g/g for sunflower oil. These results demonstrate the potential of black liquor utilization as a bio-waste source of lignin and highlight the cost-effective guar gum-esterified lignin composite aerogel, which exhibits remarkable oil absorption capabilities and environmental sustainability promotion.