A temperature-responsive polyurethane film with reversible visible light transmittance change and constant low UV light transmittance

We prepared a temperature-responsive polyurethane (PU) film with reversible visible light transmittance change, which was opaque at room temperature and became transparent when the temperature rised. The PU film has very low visible light transmittance of 1.4% at room temperature. At 45 °C, the PU film has relatively high transmittance of 66.7% looking translucent. When the temperature goes to 50 °C or above, the transmittance is more than 80% and the PU film is transparent. The reason for this interesting phenomenon about visible light transmittance change was illustrated by polarizing optical microscope and differential scanning calorimetry. While ultraviolet light transmittance of the PU film is very low at all time. Moreover, this PU film has excellent mechanical performance in a wide temperature range. We suppose this PU film has potential applications in many fields such as tunable optical devices or coating materials with smart temperature responsivity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47140.     

Improved dispersion of the graphene and corrosion resistance of waterborne epoxy–graphene composites by minor cellulose nanowhiskers

The uniform dispersion of graphene (GN) in a polymer matrix is still challenging at high loadings. In this study, we introduced a tiny number of cellulose nanowhiskers (CNWs; CNWs/GN = 1:20 w/w) to improve the dispersion of GN nanoplatelets in a waterborne epoxy (WEP) matrix at a GN loading of 1.0 wt %. Compared with that of 1.0% GN–WEP, the Young's modulus of the 1.0% GN–WEP–CNWs was enhanced by about 20.5%. The glass-transition temperature increased from 70.4°C for 1.0% GN–WEP to 72.8°C for 1.0% GN–WEP–CNWs. The water contact angle of composite film increased by 17°, from about 79° for the film without CNWs to about 96° for the film with CNWs. The anticorrosion efficiency of the coatings was also evaluated with the potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The results reveal the CNW-containing coating showed better corrosion resistance for mild steel and could be applied as a green dispersant for GN in WEP coatings. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47631.     

Color change of an iodinated poly(vinyl alcohol) film by physical deformation

The color change of an iodinated poly(vinyl alcohol) (PVA) film caused by physical deformation was investigated in this study. The color of a PVA film soaked in an aqueous potassium iodide (KI)/I₂ solution was light yellow, but it turned light blue when the film was physically deformed. The ultraviolet–visible absorption spectrum of the iodinated PVA film extended uniaxially in air was measured at various extension levels. Without deformation, the film showed UV absorption bands at 210, 290, and 360 nm. However, under deformation, the film showed new visible light absorption bands at 440 and 620 nm. From the UV–vis absorption spectra of several iodinated solutions, we found that the absorption wavelength of iodine was affected by the cohesive energy of the solvents. The KI/I₂ diethyl ether solution showed an absorption band at 460 nm, and this provided a clue to understanding the color change of the PVA–iodine complexes caused by physical deformation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43036.     

Factors influencing thermal,mechanical, optical,and adhesive properties of segmented poly(imide siloxane) copolymers films

Poly(imide siloxane), block and blend copolymer, were synthesized using different methods to explore the influence of siloxane chains. The flexible siloxane chains enrichment on surface of copolymer, enhance hydrophobic and adhesive with copper foil. It also improves light transmittance of polyimide film in the visible light region. The effect of different preparation methods on the aggregation in polymers and on polymer properties, especially adhesion and water absorptivity, are also discussed. The imidization temperature and synthesis method (blend and block) during the reaction has a significant effect on the properties of the product, especially thermal properties (T _g values are 207 °C for block and 180 °C for blend) and mechanical properties (elongation of 130% for block and 50% for blend). The bonding strength of polymer films used as hot melt adhesive was also tested. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48148.     

Electrosynthesis and characterization of an electrochromic material from poly(1,4-bis(2-thienyl)-benzene) and its application in electrochromic devices

1,4-Bis(2-thienyl)-benzene monomer is successfully synthesized via coupling reaction. Poly(1,4-bis(2-thienyl)-benzene) (PBTB) is electrochemically synthesized and characterized. Resulting polymer film has distinct electrochromic properties. Its application in electrochromic devices (ECDs) is discussed. PBTB is switched between yellow in the neutral state and green in the oxidized state. Electrochromic switching of PBTB film is performed and the polymer film shows a maximum optical contrast (ΔT %) of 44.8% at 610 nm in visible region with a response time of 1.6 s. The coloration efficiency (CE) of PBTB is calculated to be 162 cm² C⁻¹. Electrochromic device (ECD) based on PBTB and poly(3,4-ethylenedioxythiophene) (PEDOT) is also constructed and characterized. Maximum contrast (ΔT %) and switching time of the device are measured as 29.5% and 0.43 s at 628 nm. The CE of the device is calculated to be 408.9 cm² C⁻¹. Clear change from green (at neutral state) to blue color (at full oxidized state) of this ECD is demonstrated with reasonable cycle life.     

Initiator‐fragment incorporation radical polymerization of diallyl phthalate: Kinetics,formation of hyperbranched polymer,and iridescent porous film thereof

Diallyl phthalate (DAP) was polymerized in toluene using dimethyl 2,2′‐azobisisobutyrate (MAIB) of high concentrations (0.1–0.9 mol/L) as initiator. The polymerization of DAP of 1.50 mol/L with MAIB of 0.50 mol/L proceeded homogeneously at 80°C without gelation to give soluble polymers in a high yield of 93%. Kinetic results of the homogeneous polymerization at 80°C suggest significant contributions of the degradative chain transfer and the primary radical termination as shown by the rate equation, R_p = k [MAIB]^0.8[DAP]^1.0 (R_p = polymerization rate). The polymer formed in the polymerization of DAP (1.30 mol/L) with MAIB (0.50 mol/L) at 80°C for 8 h consisted of the DAP units with (17 mol %) and without (47 mol %) double bond and the methoxycarbonylpropyl group (36 mol %) as MAIB‐fragment. The large fraction of the incorporated initiator‐fragment as terminal group indicates that the polymer has a hyperbranched structure. The film cast from a solution of the hyperbranched poly(DAP) in tetrahydrofuran showed an iridescent color. The confocal scanning laser microscope image of the film revealed that the iridescent film contained the pores of about 1 μm arranged in an ordered array. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 408–415, 2006     

A compatible and crosslinked poly(2-allyl-6-methylphenol-co-2,6-dimethylphenol)/polystyrene blend for insulating adhesive film at high frequency

A polymer blend consisting of poly(2-allyl-6-methylphenol-co-2,6-dimethylphenol) (APPE) and polystyrene (PS) with additives such as 1,2-bis(4-vinylphenyl)ethane, cyanate ester, and nitrile butadiene rubber was formulated as an insulating high-frequency adhesive film. The polymer blend of APPE and PS showed very high compatibility to these additives, and the resulting thermally cured polymer blend exhibited an excellent mechanical strength, as shown by an ultimate tensile strength of 51 MPa and Young's modulus of 1.4 GPa. Moreover, the blend exhibited very good dielectric properties, with a dielectric constant of 2.3 and a dissipation factor of 0.0030 at 10 GHz. The glass-transition temperature of the cured polymer blend was 141 °C, as determined by differential scanning calorimetry, and the 5% weight loss temperature was 372 °C, indicating relatively high thermal resistance characteristics. Furthermore, its peel strength to a copper foil reached 0.80 N/mm. The present study suggested that the thermally cured APPE/PS polymer blend with additives will have potential applications for the next-generation high-frequency adhesives in microelectronic circuits. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47828.     

Color combination of polysiloxane polymer by introducing two different triphenylamine based pendent groups for electrochromism

A novel triphenylamine (TPA)‐containing polysiloxane (PTPASi) named P(PT‐TB‐TPA)Si has been synthesized through hydrosilylation method by the reaction of poly(methylhydrosiloxane) (PMHS) with two different TPA‐based alkenes (TPAA) simultaneously for electrochromic application. The thermal stability and cycling stability of the P(PT‐TB‐TPA)Si were enhanced by grafting TPA onto polysiloxane since the force of adhesion between the P(PT‐TB‐TPA)Si film and the ITO substrate can be improved. The morphology of the polymer after electro‐oxidation was investigated and no significant change was observed revealing good stability. Otherwise, the effect of two different TPA‐based alkenes which were introduced into one polymer through covalent bond on cyclic voltammetry and electrochromic spectra was studied. The color of the polymer changed from colorless to red then to deep purple which obeys the color mixing theory and reveals multielectrochromic property. In addition, the potential switching property of the P(PT‐TB‐TPA)Si at the temperature of 150 °C has been investigated. The high thermal stability makes the polymer potential for relatively high temperature and/or long‐term cycling application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46522.     

A new conducting polymer bearing 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) subunit: Synthesis and characterization

A new monomer system based on thiophene, pyrrole and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dye (SNS-BODIPY) was synthesized and its corresponding polymer (PSNS-BODIPY) was obtained via repetitive cycling or constant potential electrolysis in 0.1 M tetrabutylammonium hexafluorophosphate dissolved in dichloromethane. The PSNS-BODIPY film has very stable and well-defined reversible redox couples during p-doping process. Multi-electrochromic polymer film has a band gap of 2.9 eV with two absorption bands in its neutral state at 351 and 525 nm, attributed to the polymer backbone and BODIPY subunits, respectively. The percentage transmittance changes between both states (neutral and oxidized) were found as 12.1% for 351 nm and 17.7% for 525 nm in the visible region as well as 46.2% for 1050 nm in the near-infrared region. Beyond the robustness, the PSNS-BODIPY film has high redox stability (retaining 53.3% of its electroactivity at 351 nm after 2000 switching) with a low response time of 1.0 s.     

Fullerene polymer film as a highly efficient photocatalyst for selective solar fuel production from CO2

C₆₀-based polymeric systems have been constantly anticipated for sustainable solar energy conversion. Reported, herein is a C₆₀ polymer film as visible light active photocatalyst for efficient and selective reduction of CO₂ for the first time. The C₆₀ polymer photocatalyst is synthesized via covalent coupling of C₆₀ monomer units consisting of tetra substituted C₆₀-pyrene conjugates through spacer groups. The synthesized C₆₀ polymer photocatalyst possesses an extended network of well-defined repeating monomer units with good stability and visible light-induced photocatalytic activity. The enhanced visible light harvesting ability of C₆₀ polymer photocatalyst reasonably yields it with higher catalytic ability than its monomer unit. The C₆₀ polymer film photocatalyst upon coupling with the biocatalyst carries out highly selective visible light driven reduction of CO₂ to HCOOH (239.46 μmol). The tandem way of incorporating C₆₀ into visible light active polymeric films for continuous use may be highly rewarding for their extended photocatalytic activity for solar fuel production from CO₂. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48536.     

Human-lymphocyte cell friendly starch–hydroxyapatite biodegradable composites: Hydrophilic mechanism,mechanical, and structural impact

Biodegradable starch (Str) polymer was derived from potato, a plant-based natural carbohydrate polymers source, by one-pot synthesis. Hydroxyapatite (HA) was produced from goat bone by step sintering. The inexpensive starch/HA thin film composites were fabricated by customized spin coating. This study revealed that the hydrogen bond energy and distance have significant effect on glass transition temperature of the polymer. The 40 wt % HA contained starch (StrHA40) composite thin film showed excellent tensile strength (3.03 + −0.03 MPa), elongation (21.5 + −5.5%) and modulus (15.5 + −0.2 MPa) closed to human skin. The in vitro swelling and biodegradation kinetics of pristine starch and pure HA has been controlled and improved by using suitable composition. This study postulated the probable water molecule-adsorption mechanisms of pristine starch and starch/HA composite films. The StrHA40 composite showed excellent biocompatibility to the human-blood derived lymphocyte cells. Therefore, the starch/HA thin film composite-based biodegradable scaffolds developed in the present study can be an excellent potential candidate for soft tissue regeneration and/or replacement applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48913.     

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.     

Preparation and optical properties of polymer films having lamellar structure and cylindrical air bubbles

Polymer films displaying lustrous, iridescent colors were obtained by irradiation of poly(methyl methacrylate) films containing 1,4-benzoquinone with a medium pressure mercury lamp followed by solvent treatment. The colors were not produced by visible light-absorbing species in the polymer films because the color seen in reflection was complementary to that seen in transmission. It was found from optical and scanning electron microscopic studies of the polymer films that they have two characteristic optical structures; a great number of microcylindrical air bubbles oriented perpendicularly to the film surface and periodic lamellas with planes parallel to the film surface. The colors of the polymer films were thought to be produced by this periodic lamellar structure which would act as a three dimensional optical reflection grating. Continuous color change on tilting the sample could also be explained by the Bragg equation.     

Self-doped N-propansulfonic acid polyaniline-polyethylene terephthalate film used as active sensor element for humidity or gas detection

In this work, we report the fabrication of sensors’ element for humidity or gases, prepared by in situ polymerization of aniline N-propansulfonic acid using ammonium persulfate in acidic medium. The polymer is being used in the form of powder or deposited in multiple layers onto the PET film. Various techniques including Fourier Transform infrared (FTIR), ultraviolet-–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the as-prepared sensing materials. The film has been tested for humidity influence, where the significant variations in electrical characteristics were observed, suggesting its usefulness for humidity sensors. Also, for different organic and inorganic gases, a relatively low operating temperature and important sensitivity were observed that indicate its applicability as an active element for general gases sensors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47743.     

Effect of nano silicon dioxide on the structure and properties of FeCl3-doped polyvinyl alcohol photopolymer film

The polyvinyl alcohol (PVA) photopolymer films (PFs) were prepared based on iron(III) trichloride as the photosensitizer and PVA as the polymer matrix (Fe(III)-PVA). The nano silicon dioxide (nano-SiO₂) was mixed with the resin in proportions of 0.5, 1.0, 2.0, and 5.0 wt %, respectively. The iodine gallium lamp (350–450 nm) was used as a UV curing light source. The effects of nano-SiO₂ on the structures and properties of Fe(III)-PVA PFs were studied by scanning electron microscopy(SEM) analysis, ultraviolet–visible absorption spectroscopy(UV/Vis), X-ray diffraction (XRD), dynamic thermomechanical analysis(DMA), gel content test, tensile strength test, and Shore hardness test. The Fe(III)-PVA PFs with the content of 1.0 wt %-nano-SiO₂ exhibits the highest gel content and tensile strength. The Fe(III)-PVA PFs with the content of 2.0 wt % nano-SiO₂ exhibits the highest Shore hardness. Photolithographic patterning of the Fe(III)-PVA PFs using a UV source has been carried out, which leads to a good contrast behavior after development in an aqueous media when the content of nano-SiO₂ was lower than 2.0 wt %. After evaluating the structure, performance, and development results, the Fe(III)-PVA PFs with the content of 1.0 wt % nano-SiO₂ exhibits the best overall properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47702.     

Influence of processing on the mechanical properties and morphology of starch-based blends for film applications

This article describes the effect of processing on the properties and morphology of thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT) blends and films with high starch content. Different process parameters were modified during compounding of blends and extrusion of blown films. Morphology was examined through scanning electron microscopy. Mechanical and optical characterization of films was carried out as well. Decreasing specific throughput during compounding led to an increase in strain at break of the blends from 66 to 497%. The tensile strength increased from 6 to 22 MPa as well. The highest elastic modulus and tear resistance were achieved at intermediate specific throughputs, whereas the maximum TPS particle size and the lowest color difference were obtained at high specific throughputs. A decrease of color difference from 6.4 to 2.2 was observed by reducing the temperature profile in 5 °C. In the case of blown film extrusion, increasing the temperature profile resulted in a reduction of color difference of the films from 7.9 to 4.2. In addition, tensile strength and strain at break slightly increased. Color difference decreased with decreasing screw speed as well. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47990.     

Shade darkening effect of polyorganosiloxane modified with amino and hydroxy groups on dyed polyester microfiber fabric

The novel polyorganosiloxane material S‐101 modified with amino and hydroxy groups is synthesized. Shade darkening effect of modified polyorganosiloxane on dyed polyester microfiber fabric is investigated by reflectance spectrum, color yield (K/S), and the color differences (ΔE). The colorimetric data of CIELAB is discussed. The results show that the novel material of silicone polymer modified with amino and hydroxy groups has excellent shade darkening effect on dyed polyester microfiber fabric. The rates of the color yield increase (I%) of all dyed fabric with four dyes (Disperse Yellow S‐4RL, Red GS, Blue 2BLN, and Black SF‐R) exceed 10%. The shapes of the reflectance spectra curves of the dyed fabrics before and after treated with S‐101 are not noticeable change. The dyed fabrics with the polymer have not significant effect on the wash fastness and wet rubbing fastness. The low reflectance thin film on dyed fabrics is formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Crosslinked quaternized poly(arylene ether sulfone) copolymer membrane applied in an electric double-layer capacitor for high energy density

The low energy density of supercapacitors, especially supercapacitors based on aqueous electrolytes, is the main factor limiting their application, and the energy density is closely related to the operating potential window of the supercapacitor. The polymer electrolyte is the main contributor to the safe operation and good ion conductivity of the supercapacitor. In this study, a crosslinked quaternized poly(arylene ether sulfone) (PAES) membrane was prepared via crosslinking during membrane formation with a thermal-only treatment and applied in an electric double-layer capacitor (EDLC). The pre-prepared PAES membrane formed a polymer electrolyte with 1 mol/L Li₂SO₄ and was then fabricated into an EDLC single cell. The properties of both the membrane and ELDC were investigated. The preferred cPAES-N-0.2 polymer electrolyte showed an ionic conductivity of 1.18 mS/cm. The optimized EDLC exhibited a single-electrode gravimetric capacitance of 104.92 F/g at a current density of 1.0 A/g and a high operating potential window (1.5 V); it, thereby, achieved a high energy density of 8.20 W h/kg. The EDLC also exhibited excellent cycling properties over 3000 charge–discharge cycles. The crosslinked structures promoted the tensile strength and thermal stability of the PAES membranes; this was accompanied by a slight decrease in the ionic conductivity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47759.     

Electrochromism of novel triphenylamine-containing polyamide polymers

A series of novel polymers (coded as BCT-1 to BCT-6 (BTC is block triphenylamine)) based on N¹-(4-aminophenyl)-N¹-phenyl benzene-1,4-diamine, pyridine-2,6-dicarboxylic acid, 4,4′-(phenyl azanediyl)dibenzoic acid (PDA), and different diamine compounds were synthesized successfully through a polymer condensation reaction. For comparison, model polymers, BCT–2,6-pyridine dicarboxylic acid (PA) and BCT–PDA, were synthesized as well. The electrochromic properties of the BCTs were determined via an electrochemical workstation and a UV–visible spectrophotometer. Through electrooxidation, the polymer films showed reversible redox processes and steady color changes. In a comparision of the electrochromic characteristics of the BCTs, almost all the novel polymer films showed a better electrochromism stability, a higher electrochromic coloration efficiency (CE), and a more rapid switching time than BCT–PA and BCT–PDA. Among these polymers, BCT-1 exhibited the highest CE of 266.7 cm²/C, and BCT-4 showed the most rapid switching time (color switching time = 3.08 s and bleaching time = 2.01 s). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47264.     

Understanding the oxygen barrier property of highly transparent poly(lactic acid)/benzoxazine composite film by analyzing the UV-shielding performance

This work reports a new composite film from poly(lactic acid) (PLA) and benzoxazine (BOZ). Introduction of BOZ to PLA simultaneously improves the ultraviolet (UV)-shielding and oxygen barrier properties, which show strong dependence on the content of BOZ. The PLA film demonstrates almost no UV-shielding capacity, but the PLA/BOZ composite film can reach UV-shielding capacity of 98.3% at 350 nm. The corresponding average oxygen permeability coefficient of the composite film is as low as 1.168 × 10⁻¹⁸ m³ m m⁻² s⁻¹ Pa⁻¹, which is significantly lower than that of PLA (5.540 × 10⁻¹⁷ m³ m m⁻² s⁻¹ Pa⁻¹). Meanwhile, the composite film retains visible transparency ≥90.0% at 550 nm. The relationship and its implication between the oxygen barrier performance and UV-shielding capacity are discussed, which propose new guidelines for the development of high barrier PLA film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47510.