Synthesis and characterization of paraffin/TiO2‐P(MMA‐co‐BA) phase change material microcapsules for thermal energy storage

Microcapsules based on a phase changing paraffin core and modified titanium dioxide–poly(methyl methacrylate‐co‐butyl acrylate) [P(MMA‐co‐BA)] hybrid shell were prepared via a Pickering emulsion method in this study. The microcapsules exhibit an irregularly spherical morphology with the size range of 3–24 µm. The addition of BA can enhance the toughness of the brittle polymer poly(methyl methacrylate) and improve the thermal reliability of the phase change microcapsules. The ratio of BA/MMA is in the range of 0.09–0.14, and the ratio of the monomer/paraffin is varied from 0.45 to 0.60. These microcapsules exhibit a well‐defined morphology and good thermal stability. The actual core content of the microcapsules reaches 36.09%, with an encapsulation efficiency of 73.07%. Furthermore, the prepared microcapsules present the high thermal reliability for latent‐heat storage and release after 2000 thermal cycles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46447.     

Thermochromic microgels and core‐shell microgels based on fluorescence resonance energy transfer

Microgels exhibiting thermochromic behavior based on fluorescence resonance energy transfer (FRET) are prepared. The FRET microgels consist of poly(N‐isopropylacrylamide) (PNiPAm) networks with fixed fluorescein and rhodamine moieties and exhibits volume phase transition (VPT) at 34–35°C. A critical decrease in their sizes during the VPT enhances the efficiency of FRET between fluorescein as a donor and rhodamine as an acceptor. Therefore, emission from fluorescein (523 nm) and that of rhodamine (579 nm) is dominant at temperatures below and above the VPT temperature, respectively, when fluorescein is excited. We also prepare thermochromic core‐shell FRET microgel exhibiting two‐step color change. The microgels consist of a PNiPAm core and a poly(N‐isopropylacrylamide‐co‐N,N‐diethylacrylamide) shell and exhibit dual temperate‐responsiveness at 19 and 33°C. The fluorescence spectrum of the microgels also changes in two steps at these temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Nanocapsules containing binary phase change material obtained via miniemulsion polymerization with reactive emulsifier: Synthesis,characterization, and application in fabric finishing

The nanocapsules containing n‐butyl stearate (BS) and n‐octadecane (C18) as binary phase change material and polyacrylate as shell were synthesized via miniemulsion polymerization using reactive emulsifier. The phase transition (change) temperatures and phase change enthalpies of the phase change material can be adjusted by regulating the composition of BS and C18. Moreover, the influences of emulsification method and reactive emulsifier dosage were studied. SEM and TEM analysis showed the nanocapsules were a spherical shape with core‐shell structure and the average size was about 170 nm. DSC and FT‐IR analysis indicated the binary phase change material was encapsulated with polyacrylate shell, and the fusing and crystallizing temperatures and latent heats of nanocapsules were determined as 26.07 °C and 24.85 °C, 56.89 J g^?1 and 54.02 J g^?1 respectively, and the encapsulation efficiency was above 55.09%. In addition, the results of thermoregulating and durability property revealed that the finished cotton fabric had temperature‐regulated and durability properties. POLYM. ENG. SCI., 59:E42–E51, 2019. © 2018 Society of Plastics Engineers     

Fragrance‐Containing Microcapsules Based on Interfacial Thiol‐Ene Polymerization

In this study, microcapsules containing fragrance oils as active agent were synthesized by interfacial thiol‐ene polymerization in oil‐in‐water emulsion. One water‐soluble dithiol and four oil‐soluble acrylates were used as “click”able monomers. The polymerization kinetics was studied by HPLC and ¹H‐NMR. The size and morphology of the microcapsules were characterized by means of light scattering, optical microscope, and scanning electron microscope, and their thermal property was examined by TGA. The encapsulation efficiency and stability of the microcapsules were monitored at room temperature and 45 °C for 1 month. In general, this interfacial thiol‐ene polymerization was demonstrated to be a facile and efficient approach for fragrance microencapsulation with new and stable shell materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43905.     

All-solid-state electrochromic device of electrodeposited WO3 and prussian blue film with PVC gel electrolyte

An all-solid-state electrochromic device (SED) employing electrodeposited WO₃ and prussian blue film with poly(vinyl chloride) (PVC) gel electrolyte that has high conductivity (10⁻³ S/cm) at room temperature has been fabricated. The SED has been found to have excellent electrochromism and memory characteristics. A reversible color change between blue and colorless was observed when an appropriate potential was applied repeatedly to the electrochromic display device. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1955–1958, 1998     

Study of effect of two sulfonating agents on electrochemical properties of surface-modified polyethersulfone membrane

The work deals with the selection of sulfonating agent and preparation of polymeric coating on membrane step by step. The surface modification of a commercial ultrafiltration polyethersulfone (PES) membrane was covalently attached to the poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride). The whole process was tracked step by step using analytical methods. Chlorosulfonic acid and trimethylsilyl chlorosulfonate were tested as sulfonating agents. Ion-exchange capacity (IEC), water content, specific resistance, and permselectivity were measured and scanning electron microscope analyzed the surface of the cation exchange membrane. The best results were achieved using 5 wt % chlorosulfonic acid as sulfonating agent. IEC reached values of up to 2.44 meq g⁻¹ of dry matter, permselectivity of 93.6%, area resistances of 10.1 Ω cm², and specific resistance around 299 Ω cm. The prepared cation exchange PES membrane with chlorosulfonic acid can be used in electrochemical processes, for example, in electrodialysis. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48826.     

Preparation and properties of microcapsule with EVA core‐PU shell structure

Microcapsule with poly(ethylene‐co‐vinylacetate) (EVA) core‐polyurethane (PU) shell structure was synthesized by interfacial polymerization in aqueous polyol dispersion with ethylene diamine as the chain extender of toluene diisocyanate in poly(vinyl alcohol) aqueous solution as the stabilizing agent. The effects of polyol constituent on the average particle size and distributions, morphologies, color strength, and friction fastness of core‐shell particles were investigated to design microcapsule. The friction fastness of printed fabrics with EVA core‐PU shell microcapsules became the increase to 4–5 grades. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 893–902, 2007     

Polyaniline nanofibers and porous Ni[OH]2 sheets coated carbon fabric for high performance super capacitor

In this work, we used combination of two materials as a hybrid electrode material for supercapacitor. Ni(OH)₂ was coated on carbon fabric via electrochemical synthesis, and polyaniline salt was coated on Ni(OH)₂-coated carbon fabric via in situ chemical oxidative polymerization of aniline in aqueous acidic medium (PNCF). For comparison, polyaniline salt was coated on bare carbon fabric (PCF) by same procedure. These fabrics were characterized by Raman, FE-SEM, and EDAX and also were used as electrodes in symmetric supercapacitor cell. These cells were evaluated using cyclic voltammetry, charge–discharge and impedance spectral measurements. PNCF showed high energy density of 100 W h kg⁻¹ at a power density of 175 W kg⁻¹ and even at a high power density (875 W kg⁻¹), it showed high energy density (74 W h kg⁻¹). PNCF also showed 71% retention capacitance after 25 000 cycles at 1 A g⁻¹. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48042.     

Photochromic performance optimization of polyurethane microcapsules by interfacial polymerization method

Spiropyran photochromic materials have been widely studied in military camouflage, optical data storage, information encryption, and fashion ornaments. The non-photochromism and low endurance of solid spiropyran make the challenges of their application. Photochromic microcapsules with a butyl acetate solution of spiropyran as core and polyurethane as shell are synthesized via interfacial polymerization. The optimized polyurethane photochromic microcapsules are prepared with a Tween 20 concentration of 4 wt%, core–shell ratio of 16:5, and spiropyran concentration of 0.40 wt%. Polyurethane photochromic microcapsules with a mean particle diameter of 0.33 μm are obtained. The morphology shows smooth spheres, and the core–shell structure is observed. Butyl acetate in the microcapsule core does not evaporate at a temperature lower than 218.01°C as the microcapsule shell insulates heat. The polyurethane photochromic microcapsules are mixed with adhesive, thickener, and water into a paste and screen-printed on cotton fabric. The printed fabric shows the ΔE of 17.56, 11.93, and 6.96 after 80s irradiation with the xenon lamp intensity of 102, 68, and 34 mW cm⁻². The light stability of the photochromic fabric is excellent as ΔE decreases about 8.28% after 20 cycles of UV-Vis irradiation.     

Preparation of phase change materials microcapsules by using PMMA network‐silica hybrid shell via sol‐gel process

Encapsulation of phase change materials (PCM) using a poly(methyl methacrylate) network‐silica hybrid as the shell material has been developed. n‐Octadecane melted at 28°C was used as PCM. Based on the suspension polymerization process, the microcapsules were prepared successfully by mixing and by the reaction of ethylene glycol dimethacrylate with precopolymer solution with tetraethoxysilane (TEOS), whose resultant microcapsules had higher latent heat (ΔH = 151 J/g) than those without TEOS (ΔH = 88.3 J/g). The average size of the PCM microcapsules was about 10 μm. The silica content, n‐octadecane content, and latent heat of microcapsules were changed with varying ageing conditions, ageing time, and temperature. The highest amount of latent heat (ΔH = 178.9 J/g) and n‐octadecane content (73.3%) of the microcapsule were obtained when the inorganic/organic ratio of the microcapsule was 5%. It was difficult to increase n‐octadecane content (74% to 55.7–67.9%) and latent heat (180.5 J/g to 135.9–165.7 J/g) of the microcapsules by introducing different functional groups of coupling agents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A waterproof and breathable nanofibrous membrane with thermal-regulated property for multifunctional textile application

In this work, a waterproof and breathable nanofibrous membrane with thermal-regulated performance and exhibits excellent mechanical property is fabricated by coaxial electrospinning. The fiber shell is consisted of polyvinylidene fluoride (PVDF) and polyvinyl butyral (PVB), and the core is octadecane. First, well-performed waterproof and breathable membranes are obtained by optimizing its morphology and pore structure. Then octadecane is loaded into the fibers in the form of core by coaxial electrospinning, though it gives the membranes a thermal regulating function, but the drawback is the sacrifice of overall properties. Thus, carbon nanotubes are loaded into the shell and studied, finally, the best membrane has a comprehensive performance with hydrostatic pressure of 59.2 kPa, water vapor transmission rate (WVTR) of 7.846 kg m⁻² d⁻¹, latent heat of 50.1 J g⁻¹, as well as excellent tensile strength of 20.2 MPa, which shows its certain reference significance to the synthesis of multifunctional membrane.     

Preparation and characterization of paraffin microcapsules for energy-saving applications

A series of microencapsulated phase-change materials (PCMs) with styrene–divinyl benzene shells composed of an n-octadecane (OD or C₁₈)–n-hexadecane (HD or C₁₆) mixture as the core were synthesized by an emulsion polymerization method. The effects of the core/shell ratio (C/S) and surfactant concentration (C_surf) on the thermal properties and encapsulation ratios of the PCMs were investigated. The chemical structures and morphological properties of the microcapsules were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy analysis, respectively. The characteristic peaks of the paraffin mixtures and shell material located in the FTIR spectrum of the microencapsulated PCMs proved that the encapsulation of the PCM mixture was performed successfully. The thermal properties of the paraffin microcapsules were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis. DSC analysis demonstrated that the microcapsules containing the maximum amount of paraffin mixture (C/S = 2:1) and the minimum C_surf (45 mmol/L) had the highest latent heat value of 88 kJ/kg and a latent heat of temperature of 21.06°C. Moreover, the maximum encapsulation ratio of the paraffin mixture was found to be 56.77%. With respect to the analysis results, the encapsulated binary mixture, which consisted of OD–HD with a poly(styrene-co-divinyl benzene) shell, is a promising material for thermal energy storage applications operating at low temperatures, such as in the thermal control of indoor temperatures and air-conditioning applications in buildings for desirable thermal comfort and energy conservation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47874.     

Synthesis and characterization of triarylamine-based polyimides for electrochromic and optoelectronic conversion behaviors

In this study, four novel triarylamine-based polyimides with different substituted groups (tert-butyl and -H) containing pyrrole moieties were successfully prepared by polycondensation reaction. The electrochemical and electrochromic properties of the polyimides were measured by cyclic voltammetry and spectro-electrochemistry. The polyimides exhibited obvious electrochromic behavior with good thermal stability (the 10% weight-loss temperatures were recorded in the range of 345-386°C), film-forming ability and reversible stability after 1000 s. The color of the polyimide films changed from colorless to light blue or yellow to blue on increasing the applied potential. The highest coloration efficiency reached up to 190 cm²C⁻¹. The polyimide films exhibited a stable response to the light (on or off) after 200 s. Especially, PyHBTPI displayed effective solubility, superior optical contrast (~30%) in the visible region, faster response time (1.19 s for coloring process), and obvious color change from yellow to blue with good stability, thus, confirming the potential use for high contrast displays. Overall, the study demonstrates the successful development of high-performance polyimides for electrochromic and optoelectronic behaviors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48808.     

Carbonized thiourea formaldehyde resin blending polypyrrole hollow spheres composites with improved supercapacitor performances as electrodes

Thiourea formaldehyde resin has been condensation-polymerized in the polypyrrole hollow spheres suspension to obtain TF/PPy. Then, TF/PPy has been carbonized at 750 °C to acquire CTF/PPy composites. Scanning electron microscope and transmission electron microscope images were used to observe the morphology of the samples, TGA, XRD, Raman, XPS, and BET were used to analyze the structure of the materials. The results show PPy was blended with the TF resin, and the obtained CTF/PPy exhibited improved supercapacitive performances compared with CTF. The specific capacitance of CTF/PPy is 226.8 F g⁻¹ at the current density of 1 A g⁻¹ according to GCD curves, much higher than that of CTF. More interestingly, the cycling retention of CTF/PPy electrode at the current density of 10 A g⁻¹ is up to 120.2% after 10 000 cycles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47816.     

Styrene/phosphonic acid copolymers: Synthesis and thermal,mechanical, and electrochemical characterization

In this study, a series of poly(styrene‐co‐vinyl phosphonic acid) [P(S‐co‐VPA)] copolymers were synthesized by the free‐radical copolymerization of styrene and vinyl dimethyl phosphonate followed by alkaline hydrolysis. The P(S‐co‐VPA) copolymers were characterized by size exclusion chromatography (gel permeation chromatography), Fourier transform infrared vibrational spectroscopy, proton nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and electrochemical impedance spectroscopy. Despite the difference between the copolymerization ratios of styrene and vinyl dimethyl phosphonate, the resulting copolymers presented single glass transitions at temperatures that depended on the acidic group amount. The glass transition shifted to a higher temperature and became broader as the amount of phosphonic acid increased. The storage modulus at temperatures higher than the glass transition also increased with increasing acidic groups because of intramolecular and intermolecular interactions. All of the acid copolymers were thermally stable to at least 300°C. A high oxidative stability was found for 3 : 1 P(S‐co‐VPA), which also presented conductivity values on the order of 10⁻⁶ Ω⁻¹ cm⁻¹ at room temperature. The 1 : 1 P(S‐co‐VPA) membrane presented Arrhenius‐type behavior at temperatures from 30 to 80°C and conductivity on the order of 10⁻⁵ Ω⁻¹ cm⁻¹. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Copolyesters developed from bio-based 2,5-furandicarboxylic acid: Synthesis,sequence distribution,mechanical, and barrier properties of poly(propylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s

A series of poly(propylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s (PPCFs) with different compositions were synthesized from bio-based aromatic monomer 2,5-furandicarboxylic acid and 1,3-propanediol (PDO), along with 1,4-cyclohexanedimethylene (CHDM). The chemical structure, composition, and sequence distribution of PPCFs were determined by nuclear magnetic resonance (¹H NMR and ¹³C NMR). Results showed that the compositions of copolyesters depended on the feed molar ratio of PDO and CHDM, and all the obtained PPCFs copolyesters had triad component in a random sequential structure. With the addition of CHDM, the gas barrier properties of poly(propylene 2,5-furandicarboxylate) (PPF) deteriorated. However, when the content of CHDM reached 79%, PPCF79 still showed the CO₂ and O₂ barrier improvement factor of 4.5 and 3.25, respectively, which were better than those of poly(ethylene naphthalate), a well-known polymer with barrier property. Besides, PPCF79 showed good performance on tensile modulus, tensile strength, elongation at break, and the crystallization enthalpy was improved from 3.2 J g⁻¹ for PPF to 30.7 J g⁻¹ for PPCF79. It has the potential to serve as a promising bio-based polymer with excellent comprehensive performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47291.     

Syntheses,characterization, and antibacterial activity of chitosan grafted hydrogels and associated mica‐containing nanocomposite hydrogels

Chitosan (CS) grafted poly[(acrylic acid)‐co‐(2‐hydroxyethyl methacrylate)] (CS‐g‐poly(AA‐co‐HEMA)) at different molar ratios of AA and HEMA, and the associated nanocomposite hydrogels of CS‐g‐poly(AA‐co‐HEMA)/mica were synthesized by radical copolymerization. The grafting positions at the amino or hydroxyl groups in the CS were identified by Fourier transform infrared spectroscopy. CS‐g‐poly(AA‐co‐HEMA) hydrogels were intercalated in the mica and the amount of hydrogel insertion did not affect the spacing of the silicate layers in mica. The higher mica loadings produced a rougher surface of the nanocomposite hydrogel. The water absorbency of the CS‐g‐poly(AA‐co‐HEMA)/mica nanocomposite hydrogels decreased with increasing levels of mica loading to a lower level than those of the CS‐g‐poly(AA‐co‐HEMA) hydrogels. Both CS‐g‐poly(AA) and CS‐g‐poly(AA‐co‐HEMA)/mica nanocomposite hydrogels exhibited a higher antiproliferative activity against Staphylococcus aureus than did the neat CS hydrogel with CS‐g‐poly(AA) revealing a very pronounced minimum inhibition concentration (MIC) of 1.56 mg mL^?1. The extent of mica loading in the CS‐g‐poly(AA‐co‐HEMA) nanocomposite hydrogels did not affect the MIC (12.5 mg mL^?1). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Cationic fluorinated polyacrylate core‐shell latex with pendant long chain alkyl: Synthesis,film morphology,and its performance on cotton substrates

We synthesized a novel cationic fluorinated polyacrylate latex (FLDH) with pendant long chain alkyl by copolymerization of perfluoroalkyl ethyl acrylate, lauryl methacrylate, dimethylaminoethyl methacrylate, and 2‐hydroxypropyl acrylate. FTIR, ¹H‐NMR, TEM, DSC, and TGA were used to characterize the as‐prepared FLDH. Then fine morphology, components, and hydrophobicity of films on silicon wafer and cotton substrates were investigated by scanning electron microscope, field emission scanning electronic microscope, atomic force microscope, X‐ray photoelectron spectroscopy (XPS), contact angle meter, etc. Results showed that the FLDH particles had quasi‐spherical core‐shell structure with an average diameter of 144 nm. The core‐shell FLDH film thus had two T_g and its thermal property was improved compared to fluorine‐free acrylate latex. FLDH could form a film on both the cotton fiber and silicon wafer substrate. At an amplification of <60,000 (of the original fiber) and the observation rule (working distance) of >100 nm, FLDH showed a smooth resin film on the treated fabric/fiber surface. However, as the observation rule decreased to 2 nm‐almost a molecular lever‐the FLDH film mostly exhibited an inhomogeneous structure and uneven morphology in its atomic force microscope images. There were many low or high peaks in FLDH topography. Consequently, in 5 μm² scanning field, the root mean square roughness of FLDH film reached to 0.506 nm. XPS analysis indicated the perfluoroalkyl groups had the tendency to enrich at the surface. In addition, water contact angle of the treated fabric could attain 146.2°. FLDH do not influence whiteness of the treated fabric but will make it slightly stiff at high doses. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Preparation and characterization of flame retardant phase change materials by microencapsulated paraffin and diethyl ethylphosphonate with poly(methacrylic acid‐co‐ethyl methacrylate) shell

Microcapsules containing paraffin and diethyl ethylphosphonate (DEEP) flame retardant with uncrosslinked and crosslinked poly (methacrylic acid‐co‐ethyl methacrylate) (P(MAA‐co‐EMA)) shell were fabricated by suspension‐like polymerization. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy. The thermal properties and thermal stabilities of the microPCMs were investigated by differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The flame retarding performances of the microcapsule‐treated foams were calculated by using an oxygen index instrument. The DSC results showed that the crosslinking of the polymer shell led to an increase in the melting enthalpies of the microcapsule by more than 15%. The crosslinked P(MAA‐co‐EMA) microcapsules with DEEP and without DEEP have melting enthalpies of 67.2 and 102.9 J/g, respectively. The TGA results indicated that the thermal resistant temperature of the crosslinked microcapsules with DEEP was up to 171°C, which was higher than that of its uncrosslinked counterpart by ～20°C. The incorporation of DEEP into the microPCM increased the limiting oxygen index value of the microcapsule‐treated foams by over 5%. Thermal images showed that both microcapsule‐treated foams with and without DEEP possessed favorably temperature‐regulated properties. As a result, the microPCMs with paraffin and DEEP as core and P(MAA‐co‐EMA) as shell have good thermal energy storage and thermal regulation potentials, such as thermal‐regulated foams heat insulation materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41880.     

Poly(vinylidene-co-hexafluoropropylene) membrane modified with glass fibers and polyvinyl pyrrolidone: Mechanical and electrochemical properties

The polymer electrolytes based on poly(vinylidene-co-hexafluoropropylene) (PVDF-co-HFP) have been widely studied and applied in devices for its excellent electrochemical and mechanical properties. Here, porous PVDF-co-HFP membrane modified with glass fibers (GFs) and polyvinyl pyrrolidone (PVP) were fabricated by phase-transfer method. When the dosage of GFs exceeded 1 wt%, the composite membranes exhibited 6.11 MPa tensile strength. When the dosage of GFs and PVP reached 1% (PVP₁GF₁), respectively, the composite membranes in porous network structure possessed the highest electrolyte uptake of 251.02%, the thermal stability of 343°C and the ionic conductivity of 3.05 × 10⁻³ S cm⁻¹. Electrochromic device (ECD) was assembled with PVP₁GF₁ electrolyte, showing quick responses between the bleached and the color states within 3 s. The PVDF-co-HFP composite electrolyte was expected to be effective substitutes for liquid electrolytes used in ECDs.