Interfacial Polycondensation Method Research Articles

Bromine-containing copolymer polycarbonate for simultaneous thermal stability, transparency, and thin-wall flame-retardant polycarbonate

The incorporation of traditional low molecule bromine flame retardants can enhance the flame retardancy of polycarbonate (PC), yet their poor compatibility with PC impairs its transparency and mechanical properties. Here, brominated polycarbonate (B50PC) was synthesized by interfacial polycondensation method using bisphenol A, tetrabromobisphenol A, and triphosgene. The number average molecular weight (Mn) of B50PC reached 14,600, and compared to the low molecule bromine flame retardant tetrabromobisphenol A (TBBPA), its initial decomposition temperature increased by 38.7 % under air atmosphere. The PC composites containing 5 wt% B50PC achieved the V-0 rating in the UL-94 test, with LOI increased by 10.3 %. At the same time, the peak heat release rate (PHRR) was decreased by 28.6 % and the ignition time (TTI) was delayed by 21.3 %. Compared with that of samples with TBBPA, the composite with the same amount of B50PC maintained the original elongation at break of PC and the transmittance remained at 84.9 %. In summary, the composites with B50PC maintains outstanding transparency and mechanical properties while enhancing the flame retardancy. This work has developed a high molecular bromine flame retardant that combines flame retardancy and transparency, offering a strategy for expanding the application of PC in the electronics, construction, and aerospace sectors.

Double-layered hydrogels based on phase change material and pen ink for continuous and efficient solar-driven seawater desalination

A novel double-layered hydrogel based on the polyacrylamide matrix, pen ink, and phase-change microcapsules was developed to construct a hydrogel-based evaporator for efficient and continuous seawater desalination. The n-eicosane (core)@crystalline TiO2 (shell) phase-change microcapsules were fabricated through interfacial polycondensation, and the resulting phase-change microcapsules obtained a considerably high latent-heat capacity of 187 J·g−1. The upper layer of the hydrogel exhibits a high solar absorptivity of over 90 % due to the introduction of pen ink as a solar absorber, which helps the hydrogel-based evaporator to gain an excellent photothermal energy conversion capability. A high evaporation efficiency of 93.89 % was obtained for the developed hydrogel-based evaporator along with a high evaporation rate of 1.85 kg·m−2·h−1 under one-sun illumination. The phase-change microcapsules dispersed in the lower layer of the hydrogel can act as a latent heat-storage unit to store a great quantity of photothermal energy through melting phase change by the phase change material core. This imparts a consecutive evaporation capability to the developed hydrogel-based evaporator. As a result, its water production was increased by 11 % under 50-min one-sun illumination and 50-min non-illumination.

Novel Thymoquinone Nanoparticles Using Poly(ester amide) Based on L-Arginine-Targeting Pulmonary Drug Delivery.

Thymoquinone (TQ), the main active constituent of Nigella sativa, has demonstrated broad-spectrum antimicrobial, antioxidant, and anti-inflammatory effects, which suggest its potential use in secondary infections caused by COVID-19. However, clinical deployment has been hindered due to its limited aqueous solubility and poor bioavailability. Therefore, a targeted delivery system to the lungs using nanotechnology is needed to overcome limitations encountered with TQ. In this project, a novel TQ-loaded poly(ester amide) based on L-arginine nanoparticles was prepared using the interfacial polycondensation method for a dry powder inhaler targeting delivery of TQ to the lungs. The nanoparticles were characterized by FTIR and NMR to confirm the structure. Transmission electron microscopy and Zetasizer results confirmed the particle diameter of 52 nm. The high-dose formulation showed the entrapment efficiency and loading capacity values of TQ to be 99.77% and 35.56%, respectively. An XRD study proved that TQ did not change its crystallinity, which was further confirmed by the DSC study. Optimized nanoparticles were evaluated for their in vitro aerodynamic performance, which demonstrated an effective delivery of 22.7–23.7% of the nominal dose into the lower parts of the lungs. The high drug-targeting potential and efficiency demonstrates the significant role of the TQ nanoparticles for potential application in COVID-19 and other respiratory conditions.

Preparation and characterization of novel microencapsulated phase change materials with SiO2/FeOOH as the shell for heat energy storage and photocatalysis

A novel microencapsulated phase change material (paraffin@SiO2/FeOOH) was prepared by an interfacial polycondensation method. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) results revealed that the microcapsules were regular spherical with a diameter of 2 ∼ 5 µm. The DSC analysis results showed that the melting point and latent heat of the paraffin@SiO2/FeOOH microcapsules were 26.10 °C and 104.44 J/g, encapsulation rate of the paraffin@SiO2/FeOOH microcapsules was 49.68%. As the TGA and photo-thermal performance measurements showed, inorganic shell material not only effectively improves thermal stability of phase change microcapsules, but also exhibited a certainly photo-thermal conversion property. Additionally, the experimental results of photocatalytic degradation of MB (Methylene blue) showed that paraffin@SiO2/FeOOH microcapsules have high photocatalytic activity against organic dyes under natural light. The developed materials can be applied to the fields of residential building temperature adjustment materials and the degradation of organic pollutants.

Synthesis of Polyphosphate Polymer Employing the Bisphenol (BHBF) and the Dichloride of Phenylphosphonic (PPDC): Evaluation of the Thermal Characteristics

This work presents studies about the synthesis and thermal characterization of a new polymer synthetized from the chloride phenylphosphonic molecule containing. The interfacial polycondensation method was utilized for the synthesis at low temperature.

Preparation of Microcapsules Containing Water and Effect of Water Content on Expansion Behavior

The research work was conducted in order to establish the optimum conditions for preparing the expanded polystyrene beads without harmful substances and was aimed at the preparation of the microcapsules containing water and investigation of the effect of the water content on the expansion behavior of microcapsules. Microcapsules were prepared with the suspension polymerization method and the suspension polymerization in parallel with interfacial polycondensation method using the multiple emulsion (W/O)/W and adding a few additives. With increasing the crosslinking agent concentration in the suspension polymerization method, the water content increased from R = 5.8 wt% (CT = 0) to R = 8.2 wt% (CT = 4 wt%) and then, decreased to R = 7.5 wt% (CT = 9.0 wt%), while the expansion ratio increased from E = 1.01 (CT = 0) to E = 2.20 (CT = 4 wt%) and then, decreased to E = 1.01 (CT = 7.0 wt%). With increasing the added amount of wax in the suspension polymerization method, the water content gradually increased from R = 2.5 wt% to R = 8.0 wt%, while the expansion ratio increased from E = 1.01 to E = 1.5 and then, decreased. The water content and the expansion ratio could be increased by conducting suspension polymerization in parallel with interfacial polycondensation reaction from R = 5.0 wt % to R = 8.0 wt % and from E = 1.01 to E = 1.3, respectively. The maximum expansion ratio of E = 2.58 in this work was obtained under the conditions of crosslinking agent concentration of CT = 4.0 wt %, the added amount of wax of 3.0 g, addition of Agarose and the expansion temperature of T = 150°C.

Preparation of Microcapsules Containing Dye Aqueous Solution and Investigation of Release Feature According to Preparation Method

Microcapsules containing the dye aqueous solution were prepared with three kinds of preparation methods and the release feature of microcapsules with each preparation method was mainly investigated. As a dye tried to microencapsulate, methylene blue was adopted, because methylene blue aqueous solution was changed in color with light irradiation and utilized in order to check the degree of river pollution. Microencapsulation using multiple emulsion was performed with the suspension polymerization method, the inverse interfacial polycondensation method and the suspension polymerization in parallel with the interfacial polymerization method, respectively. The release feature of microcapsules prepared with each preparation method was estimated with the solute permeability coefficient. It was found that the release feature of dye aqueous solution was different according to the preparation method and could be delicately controlled by microencapsulating with the suspension polymerization in parallel with interfacial polycondensation reaction and forming the polyurethane shell on the surface of the dye aqueous solution droplets.

Synthesis of exfoliated PA66 nanocomposites via interfacial polycondensation: effect of layered silicate and silica nanoparticles

Nanocomposites of polyamide 66 (PA66) with layered silicate and silica (SiO2) nanoparticles were prepared via in situ interfacial polycondensation method. Hexamethylenediamine (HDMA) and adipoyl chloride (AdCl) were reacted in a two-phase media. Montmorillonite (NaMMT) and silica nanoparticles were added to reacting media. Preparation of PA66 and its nanocomposites were studied using Fourier transform infrared spectroscopy. Dispersion of nanoparticles was studied using X-ray diffraction and transmission electron microscopy. The results show that two structures were achieved using two kinds of nanoparticles. Silica nanoparticles were partially exfoliated, while NaMMT nanoparticles were hybrid intercalated–exfoliated in nanocomposite samples. Thermal properties of samples were investigated by differential scanning calorimetry. The results suggest that crystallinity is heterogeneous in the presence of nanoparticles. Kinetic of crystallization was studied by means of Avrami equation, based on the kinetic parameters, spherulites are produced. Results were reported for nanocomposites containing 2 and 4% of nanoparticles. Avrami equation parameter, n, shows that spherulite crystallization occured in the samples. Addition of nanoparticles decreases n first, then n increases with nanoparticle content.

Preparation and characterization of polyurea microencapsulated phase change material by interfacial polycondensation method

Phase change materials (PCMs) for heat energy storage have received an extensive attention in recent years. For heat energy storage application, a new type of polyurea (PU) microencapsulated phase change materials (MicroPCMs) were prepared by interfacial polycondensation method with isophorone diisocyanate (IPDI) and ethylene diamine (EDA) as shell monomers and paraffin as core material. The influences of monomer mass ratio, emulsifier type, emulsifier dosage and emulsifying stirring speed on MicroPCMs were investigated systemically. The morphology, chemical composition and particle size distribution of the MicroPCMs were characterized by using scanning electron microscope (SEM), fourier transform infrared (FT-IR) spectrum and laser particle size analyzer respectively. The results show that the MicroPCMs prepared under the optimal conditions have spherical shape and an average diameter of 2.42μm. The results of differential scanning calorimeter (DSC) analysis show that the phase latent heat of the MicroPCMs is 92.5J/g with 44.5% core content. The results of anti-osmosis test confirm that the MicroPCMs with the core/shell ratio of 75/25 have good compactness and stability. The microencapsulation technology developed is expected to be used in air conditioning, heating and other fields.

Thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides

A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2- methyl-1,4-benzene (BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

Synthesis and Investigation of Polyester and Poly Amide Azo Dyes (I)

The preparation of monomer dyes was carried out by formation of diazinium salt of amine compound to coupled with Ρ- toluidine, aniline to form azo dyes with function (hydroxy and amino) groups. the polymerized was carried out with different diacid chloride or modified with acroyl chloride to polymerize with methylmethacrylate (MMA) by two method solution and interfacial poly condensation methods, the prepared mono azodye, poly(ester) and poly(amide) azopolymers were characterized, by infrared spectroscopy, elemental analysis, 1H NMR, thermodynamic (TGA), thermo gravimetric (DSC) analysis and TGA. The molecular weights were measured by GPC. The synthesized polymers showed a good film forming properties.

UV Curable Self-Healing Structural Epoxy Composite Materials Interfacial Polycondensation Microencapsulation of Healing Agent and Photo-Initiator

<div>The ability of polymeric coatings to self-heal itself from mechanical damage is explored in this paper. Polymeric coatings with self-healing property is one of the important aspects in modern science. It can be used in industries such as oil industry (protection against corrosion), mechanical engineering, aircraft, etc. The polyurethane (PU) microparticles were synthesized on the basis of polypropyleneglycol (PPG) and toluene diisocyanate (TDI) with a method of interfacial polycondensation at the interface water-benzene. Further to study the surface morphology of the microcapsules with healing agent (trimethylolpropanetriacrylate–TMPTA) obtained PU was applied the method of scanning electron and atomic force microscopy. The PU microparticles hollow inside have regular spherical shape with a diameter of 5-10 µm with a dense and smooth polymerics shell. The resulting polyimide–olyurethane (PI–PU) composites have high potential to regenerate damaged surfaces not only on the surface and also in the volume of composite within several minutes.</div><div> </div>

Interfacial polycondensation method used in the synthesis of polymers containing phosphorus in the main chain

Abstract Polyphosphoesters gained importance especially due to their use as flame retardants and as biocompatible and biodegradable materials for medicine and in the pharmaceutical industry. This paper presents the results obtained by our research group in the synthesis of polyphosphoesters by interfacial polycondensation. This reaction is rapid and irreversible polymerization at the interface between a phase containing one difunctional intermediate and another phase containing a complementary difunctional reactant. Different methods like liquid–liquid, vapor–liquid or solid<uni-2013;liquid were used in the synthesis of polyphosphates of polyphosphonates using aliphatic/aromatic phosphoric/phosphonic dichlorides and different diols. Aqueous NaOH, or tripotasium phosphate were used as bases. In almost all cases a catalyst is not needed.

Main-chain sulphur containing water soluble poly(N-isopropylacrylamide-co-N,N′-dimethylacrylamide sulphide) copolymers via interfacial polycondensation

Here, we report the first synthesis of water soluble poly(N-isopropylacrylamide-co-N,N′-dimethylacrylamide sulfide) copolymers via conventional interfacial polycondensation method using phase transfer catalyst (PTC). The effect of various kinds of PTC having different aliphatic chain length and counter ion were employed to examine the kinetics of polysulfide polymer formation. The reactivity ratios, determined employing extended Kelene–Tüdös method using feed composition obtained from 1H NMR analysis, suggest that N-isopropylacrylamide (NIPAM) is more reactive than N,N′-dimethylacrylamide (DMA) in both mono- and di-sulfide polymers. Thermal transition behavior investigated by differential scanning calorimetry (DSC) demonstrated that as the sulphur rank of the sulfide main chain linkages increased, the flexibility of the polymers increased reflected by lower glass transition temperature (Tg) values. The thermal degradation behavior and the major degradation products have been characterized by thermogravimetric analysis (TGA) and electron-impact mass spectroscopy (EI-MS), respectively. Both the studies reveal that the degradation takes place due to weak-link scission of the polymeric main chain. Solubility in water and in most of the common organic solvents even after the sulphur rank increased from 1 to 2 in the main chain, is expected to render potential applications in biological field as well as in industry for these interesting new class of polymers.

Production of Self-Healing PI Polymeric Films with Encapsulated TMPTA in PU Microparticles

The ability of polymeric coatings to self-heal from mechanical damage is explored in this paper. Polymeric coatings with self-healing property isoneof the important aspects in science. It can be used in industries such as oil industry (protect against corrosion), mechanical engineering, aircraft, etc. The PU microparticles were synthesized on the basis of PPG and TDI with a method of interfacial polycondensation at the interface water-benzene. Further to study the surface morphology of the microcapsules with healing agent (TMPTA) obtained PU was applied the method of scanning electron and atomic force microscopy. The PU microparticles hollow inside have regular spherical shape with a diameter of 5-10 μm with a dense and smooth polymeric shell. The resulting polyimide – polyurethane (PI – PU) composites have high potential to regenerate damaged surfaces not only on the surface and also in the volume of composite.

Interfacial Polycondensation Synthesis of Optically Sensitive Polyurea Microcapsule

TMPTA prepolymer resin and photoinitiators of ITX/TPO had been encapsulated in core-shell structured microcapsules as optical responding ingredients based on interfacial polycondensation method, and polyurea structured microcapsule shell had been formed on the sheared O/W interface. The synthesized microcapsule had regular core-shell structure with the diameter of about 0.455 μm and shell thickness of about 40 nm. UV-visible absorption spectra indicated that the encapsulated ITX and TPO photoinitiators could efficiently absorb UV irradiation. Under exposure, the C=C bonds absorbance of the microencapsulated TMPTA decreased rapidly and then nearly unchanged during further exposure after 30 s. This implied that the optical response was achieved by C=C bond cleavage of TMPTA monomer initiated by the photoinitiator radicals, to form network polymers in microcapsules. The relative crosslinking rate was about 50%. Due to core polymer formation, the thermal phase change temperature of exposed microcapsules was narrowed and ranged from 105 to 205°C, compared with that from 125 to 260°C of unexposed microcapsules. Furthermore, the image density decrease at longer irradiation time had also verified the optical responding function of the synthesized microcapsules in macroscopic viewpoint.

Postelectrospinning “Click” Modification of Degradable Amino Acid-Based Poly(ester urea) Nanofibers

Amino acid-based poly(ester urea)s (PEU) are emerging as a new class of degradable polymers that have shown promise in regenerative medicine applications. Herein, we report the synthesis of PEUs carrying pendent “clickable” groups on modified tyrosine amino acids. The pendent species include alkyne, azide, alkene, tyrosine–phenol, and ketone groups. PEUs with Mw exceeding to 100K Da were obtained via interfacial polycondensation methods, and the concentration of pendent groups was varied using a copolymerization strategy. The incorporation of derivatizable functionalities is demonstrated using 1H NMR and UV–vis spectroscopy methods. Electrospinning was used to fabricate PEU nanofibers with a diameters ranging from 350 to 500 nm. The nanofiber matricies possess mechanical strengths suitable for tissue engineering (Young’s modulus: 300 ± 45 MPa; tensile stress: 8.5 ± 1.2 MPa). A series of bioactive peptides and fluorescent molecules were conjugated to the surface of the nanofibers following electrospinning using bio-orthogonal reactions in aqueous media. The ability to derivatize PEUs with biological molecules using translationally relevant chemical methods will significantly expand their use in vitro and in vivo.

Effects of Thioether Content on the Solubility and Thermal Properties of Aromatic Polyesters

Two kinds of aromatic polyesters containing thioether units had been prepared through the reaction of 4,4′-thiodibenzoyl chloride (T-DC) (or 4,4′-bis(4-chloroformylphenylthio)benzene (BPBDC)) and 1,1-bis(4-hydroxyphenyl)-1-phenylethane (BHPPE) by the method of interfacial polycondensation. These polyesters showed good solubility, and could afford tough films with tensile strengths of 103.6–108.3 MPa. The glass transition temperature (Tg) of these polyesters ranged from 189.8 to 235.6 °C and initial degradation temperatures (Td) were 450–454 °C. The activation energies of degradation were in range of 156.6–160.3 KJ/mol. The limiting oxygen indexes (LOIs) of these polyesters ranged from 37 to 39, and UL-94 V-0 rating could achieve via this approach. The thermal degradation kinetics and thermal pyrolysis mechanism of these polyesters was studied by thermogravimetric analysis and Py-GC/MS analysis, respectively.

Scale-up of polyamide and polyester Parsol® MCX nanocapsules by interfacial polycondensation and solvent diffusion method

The scale-up of oil-containing polyamide nanocapsules produced by simultaneous interfacial polycondensation and solvent diffusion was successfully achieved. Up to 1,500 mL were produced by using a Y-shaped mixer device. The sizes of nanocapsules containing olive oil were modulated from 646 to 211 nm by changing process parameters without modification of the formulation composition. All the results of nanocapsule diameters (dsc) expressed as a function of the Reynolds number (Re) showed the existence of a typical power-law relationship. It was demonstrated that the high turbulences created upon nanocapsule formation are the most important parameter allowing to nanocapsule size to be controlled without modifying the formulation composition. Finally, the power-law relationship was used to predict the size of nanocapsules composed of polyamide or polyester and loaded with Parsol(®) MCX. The physico-chemical properties of both polyamide and polyester nanocapsules at the laboratory scale were compared to the ones obtained at the pilot scale. The encapsulation efficiency was higher than 98% in both types of nanocapsules at the laboratory and the pilot scales. The in vitro releases of Parsol(®) MCX from polyester nanocapsules were reproducible at both scales. This is the first time such a power-law was described for the preparation of nanocapsules by interfacial polycondensation and solvent diffusion.

Polyamide derived from 4,4′-thiobis(methylene)dibenzoyl chloride and aliphatic diamine: interfacial synthesis and characterization

A series of processable semi-aromatic polyamides containing thioether and methylene units were synthesized through the reaction of 4,4′-thiobis(methylene)dibenzoyl chloride and aliphatic diamine by the method of interfacial polycondensation. These polyamides had excellent thermal properties with glass transition temperatures (T g) of 104.3–130.6 °C, melting temperatures (T m) of 300.3–303.8 °C, and initial degradation temperatures (T d) of 405.2–410.3 °C. They had wider processing windows than traditional semi-aromatic polyamides (such as PA6T can not be processed by melting) and can be processed by melting method. They had better tensile strengths of 57.6–64.1 MPa, low-temperature mechanical properties, low water absorption of 0.19–0.27 %, low dielectric constants of 3.11–3.95 at 100 kHz, and better melt flowability properties of 232–60.7, 301.9–78.8, and 423.1–83.6 Pa s under a shear rate ranging from 20 to 1,170 s−1, respectively. In addition, these polyamides showed good corrosion resistance, they did not dissolve in solvents such as NMP, DMSO, hydrochloric acid (6 mol/l), and solution of NaOH (1 mol/l) and so on.