Isophthaloyl Chloride Research Articles

Exploring the potential of perovskite structured SrTiO3 ceramics nanoparticles for developing SrTiO3 ceramics-decorated advanced Super-Wettable and photocatalytic self-cleaning membrane and its applications

There is a huge potential in developing robust, highly stable, and covalently crosslinked ceramics-decorated membranes that can be efficiently used for the treatment of oil-contaminated water. Hence, the current work was focused on developing a photo-active strontium titanate (SrTiO3) perovskite ceramics decorated highly stable membrane with photocatalytic self-cleaning, superoleophobic underwater and superhydrophilic in air features. The SrTiO3 perovskite structured ceramics were decorated in the active layer of the membranes through interfacial polymerization on a polyvinylidene difluoride (PVDF) ultrafiltrationsupport. For the sake of photoactive SrTiO3 ceramics nanoparticles to take part in the interfacial polymerization, the SrTiO3 ceramics nanoparticles were functionalized with amino silane using 3-aminopropyltriethoxysilane yielding amino-functionalize-SrTiO3 (F-SrTiO3). Ethylenediamine (EDA) was used as an additional amine for ensuring the suitable cross-linking of the polyamide (PA) network where isophthaloyl chloride (IPC) was used as a crosslinker. The resultant F-SrTiO3/PA@PVDF membrane was thoroughly investigated through several membrane characterization techniques confirming the existence of all the components in the membrane structure. When applied for separating the emulsified and surfactant stabilized oil from water, the F-SrTiO3/PA@PVDF membrane showed excellent separation efficiency reaching >99 % for an emulsion of 200 ppm with a permeance of 56 L m−2 h−1 bar−1. Moreover, the membrane showed an underwater superoleophobic (θO, W = 159.9°) nature owing to the presence of amide linkages and superhydrophilic F-SrTiO3 nanoparticles. These features lowered the evidence of membrane fouling and the photocatalytic self-cleaning potential of F-SrTiO3 resulted in removing the foulants from the membrane surface with a flux recovery of 95 % while keeping the separation efficiency intact. Hence, the current approach of covalently incorporating the photocatalytic, superhydrophilic F-SrTiO3 in the membrane active layer proved to be robust and can be readily scaled up and applied in real-life filtration conditions.

Effect of surfactants on the permeation rate and selectivity of polyamide composite membranes for organic solvent nanofiltration

Solvent-resistant membranes are pivotal in industrial separations. This study aims to develop thin-film composite polyamide (TFC-PA) membranes with enhanced organic solvent nanofiltration (OSN) capabilities. Polyallylamine hydrochloride (PAAH) was used as the aqueous amine and isophthaloyl chloride (IPC) as the crosslinker to form the polyamide active layer by interfacial polymerization (IP) on a polyacrylonitrile (PAN) support. The impact of using anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) to act as phase transfer agents during IP was investigated to understand their potential for facilitating the transfer of PAAH to the organic phase for reaction with IPC. The SDS and CTAB were separately dissolved into the PAAH solutions before IP to evaluate their effects on membrane properties. Extensive characterization including SEM, EDX, AFM, Water Contact Angle, ATR-FTIR, and Solid (CP-MAS) 13C NMR revealed various chemical and structural features of the membrane. The membrane M2 (PAAH-IPC) (exhibited >98% rejection for various anionic and cationic dyes. The inclusion of SDS during interfacial polymerization led to a substantial 3-fold increase in methanol permeate flux from 31 L m−2 h−1 to 119 L m−2 h−1, at a pressure of 15 bar. Conversely, the addition of CTAB resulted in membranes with higher permeate flux but insufficient dye rejection. Moreover, after three weeks of static aging of the membranes no significant changes were detected in either permeability or solute rejection, substantiating the stability of membranes.

Tailoring thin film composite membranes for clean water production: A study on structural variations and predictive insights using machine learning

This study focuses on the fabrication of three thin film composite membranes by interfacial polymerization on polyacrylonitrile support. The objective is to explore the influence of different monomers on structural and functional features of resultant membranes for treating saline water and removing micropollutants. A new linear aliphatic amine 4A–2E was used as an aqueous monomer for the first time. Trimesoyl chloride, isophthaloyl chloride, and terephthaloyl chloride were used as organic phase crosslinkers. The resulting membranes exhibited distinctive structural features such as varied roughness and hydrophilicity, which correlated with their functional performance. The membrane roughness for 4A–2E-TPC@PAN/PET reached the highest value of Ra = 56 nm among the fabricated membranes. Moreover, permeate flux of 32, 56, and 49 L m−2 h−1 at 25 bar was measured for 4A–2E-TPC@PAN/PET, 4A–2E-IPC@PAN/PET, and 4A–2E-TMC@PAN/PET, respectively. Notably, 4A–2E-TPC@PAN/PET membrane exhibited 98% rejection of MgCl2 among the tested divalent salts. Furthermore, the membrane displayed high rejections of micropollutants, with 85% rejection for Amitriptyline. Upon chlorine exposure, the 4A–2E-TPC@PAN/PET membrane proved more resistant than both 4A–2E-IPC@PAN/PET and 4A–2E-TMC@PAN/PET membranes. Machine learning predictive insight was developed using Matérn Gaussian Process Regression model to simulate flux before and after chlorination of membranes. The results in both training and testing proved reliable predictive insight with 99% accuracy in terms of Nash Sutcliffe Efficiency. Hence, current work highlights the use of a linear amine 4A–2E and TPC crosslinker to fabricate a dense polyamide membrane and the application of ML algorithms to desalination data makes it possible to predict the membrane performance.

Fine-tuning polyamide nanofiltration membrane for ultrahigh separation selectivity of Mg2+ and Li+

The extraction of lithium resources from salt-lake brine has garnered increasing attention, and a critical challenge is to achieve an effective separation of Mg2+ and Li+. This study focuses on addressing this challenge using isophthaloyl chloride (IPC) in combination with trimesoyl chloride for completing interfacial polymerization (IP) with polyallylamine. The product is an unexpectedly highly permeable and permselective polyamide nanofiltration (NF) membrane that is effective for Mg2+/Li+ separation. Adjusting the acyl chloride density with IPC influenced the IP reaction progress, thereby yielding a polyamide layer with fine-tuned properties. Various characterization results demonstrated a significant difference in the positive chargeability between the NF membranes doped with IPC and the blank NF membrane without IPC, whereas other properties remained comparable. The optimal NF membrane prepared with a low IPC molar ratio of 33% exhibited highly positively charged and high permeability characteristics. Considering the remarkable advancements in separation performance and simplified fabrication process, a fine-tuned strategy for designing highly positively charged NF membranes holds great practical potential for the industrial development of lithium extraction from salt-lake brines.

Synthesis and characterization of aromatic copolyesters derived from bisphenol B and phenol red

AbstractA series of novel aromatic copolyesters derived from bisphenol B (BPB) and phenol red (PR) were synthesized by interfacial polymerization. The number‐ and weight‐average molecular weight (Mn and Mw) of the obtained amorphous aromatic copolyesters ranged from 1.06–1.80 × 104 to 2.01–6.17 × 104 g/mol, respectively. Density functional theory calculations showed that the reactivity of BPB was similar to that of bisphenol A. The reaction activation energy of BPB with terephthaloyl and isophthaloyl chloride (TPC and IPC) was 8.23 kcal/mol, and PR with IPC and TPC was 59.30 kcal/mol. Under the influence of the ethyl side group of BPB and the pendant group of PR, the solubility of the aromatic copolymer was improved, and the glass transition temperature (Tg) was 125.1–195.3°C, while Tmax could still be maintained above 525.72°C. The optical transmittance of the copolyesters at 450 nm (T450) was 69.29%–99.41%, and the tensile strength and Young's modulus were in the range of 46.79–58.59 MPa and 1.39–1.86 GPa respectively. All aromatic copolyesters exhibit good mechanical and processability properties and have great application potential as high‐performance plastics.

Development of Novel Phase-Change Materials Derived from Methoxy Polyethylene Glycol and Aromatic Acyl Chlorides.

In this research, novel, organic, solid-liquid phase-change materials (PCMs) derived from methoxy polyethylene glycol (MPEG) and aromatic acyl chlorides (ACs) were prepared through a condensation reaction. The MPEGs were used as phase-change functional chains with different molecular weights (350, 550, 750, 2000, and 5000 g/mol). The aromatic ACs, terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC), were employed as bulky linker cores. Solubility tests demonstrated that this family of PCMs is soluble in protic polar solvents such as H2O and MeOH, and insoluble in nonpolar solvents such as n-hexane. Fourier-ransform infrared spectroscopy (FT-IR UATR) and nuclear magnetic resonance (1H, 13C, DEPT 135°, COSY, HMQC, and HMBC NMR) were used to confirm the bonding of MPEG chains to ACs. The crystalline morphology of the synthesized materials was examined using polarized optical microscopy (POM), revealing the formation of spherulites with Maltese-cross-extinction patterns. Furthermore, it was confirmed that PCMs with higher molecular weights were crystalline at room temperature and exhibited an increased average spherulite size compared to their precursors. Thermal stability tests conducted through thermogravimetric analysis (TGA) indicated decomposition temperatures close to 400 °C for all PCMs. The phase-change properties were characterized by differential scanning calorimetry (DSC), revealing that the novel PCMs melted and crystallized between -23.7 and 60.2 °C and -39.9 and 45.9 °C, respectively. Moreover, the heat absorbed and released by the PCMs ranged from 57.9 to 198.8 J/g and 48.6 to 195.6 J/g, respectively. Additionally, the PCMs exhibited thermal stability after undergoing thermal cycles of melting-crystallization, indicating that energy absorption and release occurred at nearly constant temperatures. This study presents a new family of high-performance organic PCMs and demonstrates that the orientation of substituent groups in the phenylene ring influences supercooling, transition temperatures, and thermal energy storage capacity depending on the MPEG molecular weight.

Study on the synthesis of soluble copolymer polyarylate from asymmetric bisphenol A derivative (2,2‐bis(4‐hydroxyphenyl)butane/9,9‐bis(4‐hydroxyphenyl)fluorene) monomer

AbstractA series of polyarylates composed of different bisphenol monomers were synthesized by interfacial polymerization using 9,9‐bis(4‐hydroxyphenyl)fluorene (BHPF), 2,2‐bis(4‐hydroxyphenyl)butane (BPB), terephthaloyl chloride (TPC), and isophthaloyl chloride (IPC) as raw materials. The DFT calculations showed that the energy required for the reaction of BHPF with TPC/IPC was between 15.82 and 16.04 Kcal/mol, which was higher than the energy required for the reaction of BPB with TPC/IPC of 8.05–8.40 Kcal/mol. The solubility test showed that the solubility of BHPF‐BPB‐type polyarylate was better than that of BPB‐type polyarylate in various organic solvents withTgranging from 199.3 to 215.0°C, indicating that the solubility was improved while increasing theTgof the products. The weight loss (T5%) and maximum weight loss (Tmax) of BHPF‐BPB‐type polyarylates under N2atmosphere ranged from 464.6–489.4°C and 521.7–534.6°C, indicating good thermal stability. The tensile strength of the BHPF‐BPB‐type polyarylates ranged from 53.21 to 61.23 MPa, Young's modulus ranged from 1479.66 to 1867.23 MPa and elongation at break ranged from 19.5% to 30.1%. The mechanical property test showed that the BHPF‐BPB‐type polyarylates have high tensile strength. These characteristics indicate that BHPF‐BPB‐type polyarylates have a very broad potential for application in engineering plastics.

A novel bisphenol A‐free polyarylates synthesis strategy: 4,4′‐sulfobisphenol/2,2‐bis(4‐hydroxyphenyl)butane co‐polyarylate prepared by interfacial polymerization

AbstractA series of bisphenols, 4,4′‐sulfobisphenol (BPS)/2,2‐bis(4‐hydroxyphenyl)butane (BPB) co‐polyarylates with amorphous structures were synthesized from two BPS and BPB, and two different structures of benzoyl chloride monomers. The results of DFT calculations showed that the reaction activation energy of BPB with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) was 8.05–8.40 Kcal/mol. The reaction activation energy of BPS with IPC and TPC was 38.73–39.09 Kcal/mol. GPC test results were consistent with theoretical calculations with BPS content from 0% to 15% resulting in a copolymer Mn of 22,000–11,600 and a Mw of 46,100–34,800. The intrinsic viscosity of co‐polyarylates ranged from 0.55 to 0.71 dL/g. The glass transition temperature (Tg) and 5% thermal weight loss of the co‐polyarylates were 179.3–205.4 °C and 461.4–487.8 °C, respectively. Improved solubility of co‐polyarylates in polar solvents. At the same time, the introduction of BPS did not result in any loss of mechanical properties, with Young's modulus in the range of 1444.32–1870.45 MPa, elongation at break in the range of 23.7%–30.8%, and tensile strength in the range of 52.21–59.38 MPa.

Facile fabrication of silicon carbide decorated ceramic membrane, engineered with selective surface wettability for highly efficient separation of oil-in-water emulsions

The separation of oil in water and water in oil emulsions using the ceramic membranes with selective oil and water wettability has proven to be cost effective, less cumbersome and more efficient, compared to the conventional methods. In this work, a silicon carbide having hexagonal crystal structure (H-SiC) based ceramic membrane, exhibiting in-air superhydrophilicity and underwater superoleophobicity was fabricated for water passing oil-water emulsion separation. Initially silicon dioxide (SiO2) was grown on the surface of H-SiC by thermal process to enhance the hydrophilicity, and further enhancement of hydrophilicity was introduced by amino-functionalizing H-SiC/SiO2 using N1-(3-trimethoxysilylpropyl)diethylenetriamine (N-TMS-DETA). The amino-functionalized H-SiC/SiO2 particles were deposited on porous alumina support surface and crosslinked via interfacial polymerization (IP) using Isophthaloyl chloride (IPC) cross-linker and ethylenediamine (EDA) to fabricate functional PA/H-SiC/SiO2@Alumina ceramic membrane for oil/water emuslion separation. The morphological, structural, elemental characterizations using FT-IR, XRD, FE-SEM, EDS, elemental mapping, and the wettability of PA/H-SiC/SiO2@Alumina ceramic membarne were carried out. The characterization results revealed the perfect deposition of functionalized H-SiC/SiO2 on alumina support surface, and the contact angles of PA/H-SiC/SiO2@Alumina ceramic membrane surface in air-surface-water (θWA), and oil-surface-water (θOW) interfaces were 0° and ∼159.7° respectively. When PA/H-SiC/SiO2@Alumina ceramic membrane was used for the oil-water emulsion separation using dead-end filtration cell, an impressive separation efficiency of > 99% with a flux of around 312 L∙m−2∙h−1 was observed. The system was tested for the separation efficiency at different transmembrane pressures, oil concentration of oil-water emulsion, and the long term stabilty of the PA/H-SiC/SiO2@Alumina ceramic membrane.

Highly Efficient and Solvent-Free Purification Technique and Model Study of Layer Melt Crystallization

Developing a green and sustainable technique seems necessary when facing an increase in the environmental burden. Layer melt crystallization (LMC) is recognized as an environmentally friendly separation technique because of its lower energy consumption and chemical waste emission. For the first time, this study applied LMC to prepare the high-purity isophthaloyl chloride (IPC), which is an important chemical intermediate in the synthesis of fibers. Under the optimal trajectory, the purity of IPC could improve from 97.811 to 99.381%, which reached the standard of subsequent production. Meanwhile, theoretical models were established and combined with the experimental results to visualize the crystallization and sweating processes. The fractal porosity model was used to describe the crystal layer structure, in which the pore structure could provide the adsorption sites for inclusion components and channels for the melt flow. Crystallization and sweating process kinetics models were established to explore the crystal layer growth and sweating melt flow characteristics. The distribution coefficient and the impurity removal rate were used to describe the separation efficiency. The interfacial solute distribution factor and the mass transfer coefficient were used to explore the solute and impurity distribution rules. The mechanisms of the mass flow were revealed. Finally, four different crystallizer structures were designed to intensify the heat and mass transfer, which significantly improved the separation efficiency.

Highly heat-resistant NF membrane modified by quinoxaline diamines for Li+ extraction from the brine

The Functional layers with excellent heat-resistence nanofiltration (HRN) property were designed by fixing thermal stabilized quinoxaline diamines (QHDA) on poly (m-phenyleneisophthalamide) (PMIA) substrate through interfacial polymerization. QHDA was used as aqueous monomer while cinnamoyl chloride (CNC), isophthaloyl chloride (IPC) and trimesoyl chloride (TMC) were served as organic monomers to realize the immobilization of thermally stable N heterocycles. The experimental results stated clearly that the compact package reaction of QHDA with TMC lead a raise of thermal stability and salts rejection at high temperature stream. With the optimal TMC and 0.5 wt.% QHDA, the as-developed membrane achieved the excellent NF performance and thermal stability. The rejection of MgSO4 reached to 94.6 % at 30 °C and hardly decrease at 90 °C. The reduction in rejection was satisfactory at high temperatures. The functional layer still showed highly stability after 10 h long-term operation at 90 °C with only 2.8 % reduction in MgSO4 rejection. Besides, the excellent Mg2+ and poor Li+ rejection made this membrane have huge potential in the application of extracting Li+ from brine. The separation factor of Mg2+-Li+ at high temperature was satisfactory. Over all, this study offered a prospect technology to exploit heat-resistant membranes for extraction lithium at high temperature.

Novel high performance poly(sulfone-ether-amide-imide)s

A novel sulfone ether amide diamine was prepared through a two-step synthetic route. At first, 3,3′-((sulfonyl bis(1,4-phenylene))bis(oxy))dianiline was prepared from nucleophilic aromatic substitution reaction of 3-aminophenol with 4,4′-dichlorodiphenyl sulfone in the presence of K2CO3. In the second step, the reaction of this compound with isophthaloyl chloride resulted in the preparation of a unique aromatic diamine containing amide, ether, and sulfone groups. Then three different kinds of poly(sulfone-ether-amide-imide)s were prepared via polycondensation reaction of the synthesized diamine with different dianhydrides including pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, and hexafluoroisopropylidene diphthalic anhydride. The structures of synthesized precursors, monomer, and prepared polymers were characterized using elemental analysis, 1H-NMR and FT-IR spectroscopy methods. Inherent viscosity, molecular weight, thermal behavior and stability, flame retardancy, and solubility of polymers were studied. As the polymers showed high thermal stability and also improved solubility, they can be used as heat and fire resistant materials.

A method to quantify composition, purity, and cross-link density of the active polyamide layer in reverse osmosis composite membranes using 13C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy

A method for harvesting and purifying the thin polyamide (PA) active layer from thin-film composite (TFC) reverse osmosis (RO) membranes was developed, enabling quantitative nuclear magnetic resonance (NMR) measurements of the composition and cross-linking in the PA layer that can be directly related to membrane performance. Using our chemical separation process, we report on four trimesoyl chloride (TMC)/isophthaloyl chloride (IPC)/ m -phenylene diamine (MPD)-based TFC membranes in which the cross-link density was intentionally reduced by replacing trifunctional cross-linking TMC monomers with their linear IPC difunctional analog. While the NMR results show a two-fold decrease in cross-linking that causes a 30% increase in salt passage, the addition of the difunctional analog leads to increased polar amine groups that reduce water permeance due to tighter binding of water in the PA membrane. Our results demonstrate that 13 C cross polarization magic angle spinning (CPMAS) is a powerful method for quantitatively monitoring the purity, cross-linking, and chemical composition in PA membranes and will be an essential tool in ascertaining atomistic models of PA structure. • A method for purifying the polyamide layer from TFC RO membranes was developed. • 13 C CPMAS quantifies composition and crosslinking in harvested polyamide TFC RO films. • Crosslinking is controlled by IPC/TMC ratio. • With a two-fold decrease in crosslinking, a 30% increase in salt passage. • With a two-fold increase of amine content, a 30% decrease in water permeance.

Effects of Polyamide Chemistry on Solution Permeance in Molecular Layer-By-Layer Desalination Membranes

We present a series of polyamide membranes synthesized via molecular layer-by-layer (mLbL) deposition using a combination of two acid chlorides, trimesoyl chloride (TMC) and isophthaloyl chloride (IPC), and one of two diamines, m-phenylenediamine (MPD) or 3,5-diaminobenzoic acid (BA). These monomer combinations permit comparison of the conventional reverse osmosis chemistry, TMC combined with MPD, against a variant with a higher concentration of polar acid groups, TMC combined with BA, and a variant with reduced cross-link density via the addition of a linear monomer, a 50%/50% mixture by mass fraction of TMC and IPC combined with MPD. Water permeance, NaCl rejection, and water swelling are compared across the series. Although efficient NaCl rejection appears to be dependent on the formation of a sufficiently cross-linked polyamide network, we find that water permeance is more strongly controlled by the concentration of hydrophilic moieties in the membrane than by the cross-link density. The enhanced permeance in polar membranes is associated both with increased membrane swelling and with elevated water mobility.

Exploring a novel family of poly(amide-imide)s as promising cationic sorbents for water remediation

A new monomer 5-(5-(chlorocarbonyl)-1,3-dioxoisoindolin-2-yl) isophthaloyl chloride was synthesized and subsequently condensed with a variety of diamines yielding a novel family of poly(amide-imide)s (PAIs), which were exploited as potential cationic sorbents for water treatment. The synthesized monomer and all PAIs were characterized using Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analyses. High thermal stability and molar masses of the whole PAIs family were determined using thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). Decomposition temperatures and char yields were found to be in the range 422-600 °C and 2–57% respectively. X-ray diffraction (XRD) patterns revealed the crystalline nature of PAIs family with few exceptions. PAI-2 was found to be the best contender with 99% optimum adsorption capacity for both Cd(II) and Pb(II) cations at optimal conditions. Adsorption capacities have been improved till 700 and 800 mg/g for Cd and Pb respectively for 100 ppm feed concentration, which depicted the efficiency of adsorbent. Adsorption data of all PAIs fitted well to Langmuir as compared to Freundlich, Temkin and Dubinin-Radushkevich adsorption models and exhibited favorable monolayer adsorption mechanism. The relative uptake of cations by PAIs followed the preferential trend Fe(II) > Pb(II) > Cd(II) > Cu(II) in a mixture of metal ions.

Synthesis and characterization of novel poly(urethane-amide)s with enhanced thermal stability

The aim of the present study was to design and synthesis a novel monomer to produce polyurethanes with improved thermal stability as well as good solubility. Herein, N1,N3-bis(5-hydroxynaphthalene-1-yl) isophthalamide was synthesized by the nucleophilic reaction of 5-amino-1-naphthol and isophthaloyl chloride. Afterward, the synthesized diol was reacted with various diisocyanates such as toluene diisocyanate and methylene diphenyl diisocyanate to attain novel poly(urethane-amide)s via condensation reaction. The chemical structure of the monomer and the resulting polymers were thoroughly investigated and approved via spectroscopic techniques and elemental analysis. Also, physical properties of the prepared polymers like thermal characteristics, molecular weight, solubility, and viscosity together with their structure-property relationship were evaluated. The obtained results showed improved thermal stability of the synthesized poly(urethane-amide)s compared to other common polyurethanes. Also, the results indicated that the higher the aromatic groups in the polymer chain, the higher the thermal stability and glass transition temperature. Presence of bulky naphthyl groups from another side, improve their solubility as well. The synthesized poly(urethane-amide)s with remarkable thermal stability and solubility might open up new possibilities for a wide range of applications in various industries such as transportation, aerospace, electronics, appliances, and so on.

Novel Polyelectrolytes Obtained by Direct Alkylation and Ion Replacement of a New Aromatic Polyamide Copolymer Bearing Pyridinyl Pendant Groups.

The following work shows, for the first time, the synthesis and characterization of a new family of polyelectrolytes, along with their preliminary assessments in terms of desalin water treatment. These materials fall into the category of aromatic co-polyamides, which are obtained by the direct condensation of monomers 4,4′-oxydianiline (ODA), isophthaloyl chloride, and 3,5-diamino-N-(pyridin-4-ylmethyl)benzamide (PyMDA). Thereby, the charged nature exhibited by these materials was achieved through the quaternization of PyMDA moieties using linear iodoalkanes of different lengths (CnI with n = 1, 2, 4, and 6). After completing the quaternization process, polyelectrolytes were subjected to a one-step anion substitution process, where iodide counterions were replaced by bis(trifluoromethane)sulfonamide entities. For all the obtained materials, solubility tests were carried out, showing that those alkylated with methyl and ethyl chains exhibit high solubility in rutinary aprotic polar solvents, while those containing n-butyl and n-hexyl units resulted in the formation of insoluble gels. Due to the above, the latest were discarded from this study early on. The structural characterization of the initial neutral co-polyamide was carried out by means of infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H, 13C-NMR), and size-exclusion chromatography (SEC), while the structure of methylated and ethylated polyelectrolytes was successfully confirmed through FT-IR, 1H, 13C, and 19F-NMR. Additionally, the thermal behavior of these materials was analyzed in terms of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), showing thermal degradation temperatures above 300 °C and glass transition temperatures (Tg) above 200 °C, resulting in polymers with outstanding thermal properties for water treatment applications. On the other hand, through the solvent-casting method, both neutral and charged polymers were found to be easily prepared into films, exhibiting a remarkably flexibility. The mechanical properties of the films were analyzed using the traction test, from which tensile strength values ranging between 83.5 and 87.9 Mpa, along with Young’s modulus values between 2.4 and 2.5 Gpa were obtained. Moreover, through contact angle measurements and absorption analysis by immersion, polyelectrolytes showed important changes in terms of affinity against polar and polar substances (water, n-heptane, and benzene), exhibiting a higher rejection regarding the neutral polymer. Finally, as a preliminary test against the seepage of saline waters, thin polymer films (from 11.4 to 17.1 µm) were deposited on top of commercial filter discs and tested as filters of saline solutions ([NaCl] = 1000 and 2000 ppm). These tests revealed a decrease of the salt concentration in the obtained filtrates, with retention values ranging between 6.2 and 20.3%, depending on the concentration of the former solution and the polymer used.

Segmented-Block Poly(ether amide)s Containing Flexible Polydisperse Polyethyleneoxide Sequences and Rigid Aromatic Amide Moieties.

We describe the synthesis and characterization of three novel aromatic diamines containing oxyethylene sequences of different lengths. These diamines were polymerized using the low-temperature solution polycondensation method with isophthaloyl chloride (IPC), terepthaloyl chloride (TPC), [1,1’-biphenyl]-4,4’-dicarbonyl dichloride (BDC), and 4,4′-oxybis(benzoyl chloride) (OBE), obtaining twelve poly(ether amide)s with short segments of polydisperse polyethyleneoxide (PEO) sequences in the polymer backbone. These polymers show reasonably high molecular mass materials (Mw > 12,000), and the relationship between their structure and properties has been carefully studied. Compared with conventional polyamides containing monodisperse PEO sequences, the polydispersity of the PEO segments within the structural units exerts a significant influence on the crystallinity, flexibility, solubility, and the thermal properties of the polymers. For instance, the all-para oriented polyamides (TPCP-A), with an average number of 8.2 ethylenoxide units per structural unit can be transformed conventionally (Tm = 259 °C) in comparison with thermally untransformable polymer with 2 ethylenoxide units (Tm = 425 °C).

Synthesis and thermal degradable property of novel tertiary ester‐containing four‐functional epoxy resin

AbstractA kind of four‐functional epoxy resin containing tertiary ester groups (FETE) was designed and synthesized by two‐step reaction: first, the nucleophilic substitution reaction between linalool and isophthaloyl chloride, and then epoxidation. The chemical structure of obtained product was determined by infrared (IR) spectroscopy and nuclear magnetic resonance spectroscopy. Unlike traditional thermosetting epoxy resins, the cured FETE could degrade rapidly at low temperature (200–300°C). Dynamic mechanical analysis analysis showed that through copolymerization of FETE with (4,5‐epoxycyclohexane‐1,2‐dicarboxylic acid diglycidyl ester) epoxy resin (TDE‐85), the glass transition temperature (Tg) of copolymer system could be adjusted in the range of 136–179°C; FETE had good miscibility with TDE‐85. The thermal degradation behavior of the copolymer system was studied by theoretical calculation, thermogravimetric (TG), and TG coupled with FTIR analysis, the results showed the thermal decomposition performance of the copolymer system could be adjusted in the range of 200–400°C. The tertiary ester groups in FETE were easy to thermally degrade and caused the network skeleton of the copolymer system to collapse. The FETE would have good prospects in reworkable electronic packaging, recycling or degradable epoxy resin area.

Synthesis of the hyper-branched polyamides and their effective utilization in adsorption and equilibrium isothermal study for cadmium ion uptake

This report deals with the simple development of a method for the uptake of cadmium ions by polymer adsorbent from the main sources of cadmium like water. The monomer is synthesized by reacting 2,4,6-trichloro-1,3,5-triazine with N(4-aminophenyl)acetamide. The adsorbents synthesis is completed by reacting a synthesized monomer with 1,3,5-tribenzoylchloride, terephthaloyl chloride, and isophthaloyl chloride. The as-synthesized polymer exhibits high molecular mass with narrow molecular weight distribution and good thermal stability. The metal ion adsorption study is established by using atomic absorption spectroscopy at optimized parameters, showing excellent adsorption capacity of polymer adsorbent. Further, the isothermal equilibrium adsorption study reveals the monolayer adoption of the metal ion by the Langmuir model with experimental and theoretical parameters, optimized by the linear regression analysis using the curve fitting tool in MATLAB software.