Aromatic–Aliphatic acrylic monomers and polymers: Synthesis and characterization

Two new ester‐type monomers were synthesized by the condensation of acrylic acid with the products of the hydroxyethylation of 4‐nonylphenol or 4‐tert‐butylphenol. The hydroxyethylation reaction was performed with 1,3‐dioxolan‐2‐ona in the presence of alkalies. By hydroxyethylation, the phenols were changed into alcoholic derivatives able to react with acrylic acid to give acrylic esters. The insertion of the aryl–alkyl groups into the structure of the acrylic esters, and implicitly of the corresponding polymers, was carried out with the intention of increasing their thermostability and improving their behavior as pressure‐sensitive adhesives on the whole. The monomers and the polymers were characterized by elemental and thermogravimetric analyses, IR and ¹H‐NMR spectroscopy, and other special methods. The results of these investigations confirmed the formulated suppositions. The inherent viscosities of the resulting polymers were in the range of 47–64 mL/g, and their thermal stability was up to 315–320°C, far higher than that of the polyacrylates used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 802–814, 2002     

Dielectric properties of copolymers based on cyano monomers and methyl α‐acetoxyacrylate

With the aim of developing dielectric polymers containing CN groups with strong dipole moment, alternating and statistical copolymers of the cyano monomers vinylidene cyanide (VCN), acrylonitrile and methacrylonitrile with methyl α‐acetoxyacrylate (MAA) were synthesized and characterized. The copolymer's composition and microstructure were analysed by NMR spectroscopy, SEC and elemental analysis. The reactivity ratios calculated from the Q–e Alfrey–Price parameters for these copolymers indicated the alternating and statistical structures confirmed by NMR analysis. The copolymers have glass transition temperatures T_g in the range 83–146 °C and are stable up to 230 °C. The thermal stability of the copolymers depends on the nature of the cyano monomers. Their molecular dynamics were investigated by dielectric relaxation spectroscopy. We revealed a weak relaxation β at sub‐T_g temperature for poly(VCN‐co‐MAA) usually originating from molecular motions that are restricted to the scale of a few bond lengths. Strong α‐relaxation processes occurred above T_g for these copolymers. This primary relaxation was associated with cooperative movements of the polar groups (CN) at the time of mobility of the principal chains. The activation energy of the α‐relaxation process was also calculated. The values of the dielectric increment Δε for these copolymers were determined by Cole–Cole plots and indicated that the copolymers exhibit interesting dielectric properties compared with similar cyano materials. The polarity–permittivity relationship was also established. © 2012 Society of Chemical Industry     

Synthesis and properties of brominate bismaleimide monomers

Brominated bismaleimides were prepared by reacting 3(4)‐maleimidobenzoylchloride with various bisphenols, using chloroform as solvent and triethylamine as acid acceptor. These monomers were characterized by elemental analysis, infrared (IR), and proton nuclear resonance (¹H‐NMR) spectroscopy. Thermal properties of monomers were accomplished by differential scanning calorimetry (DSC) and dynamic thermogravimetric analysis (ATG). The properties of these compounds were compared with those of monomers derived from bisphenol A and bisphenol A chlorinated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3881–3885, 2006     

Effect of a chiral dopant on the electro‐optical properties of polymer‐dispersed liquid‐crystal films

Polymer‐dispersed liquid crystal (PDLC) films were prepared by the ultraviolet‐light‐induced polymerization of photopolymerizable monomers in nematic liquid crystal/monomer/chiral dopant composites, and the effect of the chiral dopant on the electro‐optical properties of the PDLC films was studied. It was demonstrated that the addition of a small amount of the chiral dopant increased the driving voltage somewhat but decreased the turn‐off time significantly. Furthermore, the transmittance of ultraviolet, visible, and near‐infrared light of the off state of PDLC films showing light scattering increased with increasing content of the chiral dopant, and the optimum electro‐optical properties of the PDLC films were obtained when the content of the chiral dopant was not more than 2 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effects of the chirality and functionality of monomers on the holographic gratings formed in photosensitive films

Photosensitive holographic polymer films were fabricated. Instead of liquid crystals, a nonreactive high‐refractive‐index diphenyl sulfide was mixed with several monomers and an initiator for the preparation of the holographic grating films. To investigate the formation of periodic arrays of the photosensitive refractive‐index modulation films and the effects of the chirality and functionality of monomers on the diffraction efficiency, chiral monomeric (?)‐bornyl acrylate, (+)‐bornyl acrylate, and the racemate (±)‐bornyl acrylate were synthesized and copolymerized with various multifunctional monomers. A reasonable schematic of the photosensitive polymerization mechanism was proposed. The effects of the multifunctional monomers, initiator concentrations, and feed monomer concentrations on the diffraction efficiencies were investigated. The morphologies of the polymer matrices were studied with scanning electron microscopy. Pictures of real light diffraction patterns with 15 grating points were obtained. In comparison with those described in the literature, the diffraction efficiency obtained in this investigation was relatively high. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2246–2254, 2003     

UV–Vis irradiation fatigue resistance improvement of azo photochromic compound using polyurethane‐chitosan double shell encapsulation

Double shell photochromic microcapsules were prepared by in situ polymerization with polyurethane and chitosan as inner and outer shell respectively. FT‐IR indicated that chitosan‐glutaraldehyde copolymer formed by imine and combined with polyurethane photochromic nanocapsules. The polyurethane‐chitosan microcapsules exhibited a near‐spherical shape, and the average particle size of nanocapsules was around 1.2 μm. The half‐life of azo compound increased from 135 to 340 min after encapsulated in polyurethane‐chitosan microcapsules. The polyurethane‐chitosan shell delayed the coloration process for 14 s compared with azo compound in ethanol, however, the absorbance of azo compound increased by 17.15% in polyurethane‐chitosan microcapsules. It decreased from 0.3486 to 0.1738 in ethanol during 20 s, however, it decreased from 0.4084 to 0.2625 in polyurethane‐chitosan microcapsules in 55 s when it reached steady state during decoloration process. Polyurethane‐chitosan double shell encapsulation is an effective route for improving the fatigue resistance, increasing the absorbance of azo compound. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40895.     

Effect of water‐soluble monomers on emulsifier‐minor emulsion polymerization of butylacrylate–methacrylic acid–styrene and properties of the latices

The stability of emulsifier‐minor emulsion polymerization and the final latices depends on whether water‐soluble monomers can be bound to the particle after polymerization, which relies on the hydrophilicity of the water‐soluble monomers. Less hydrophilic monomers are apt to be buried in the latex particle, but extremely hydrophilic monomers tend to homopolymerize in the water phase. The suitable hydrophilic index I/O of water‐soluble monomers is preferably 3–5. The adhesion power and water resistance of emulsifier‐minor latex films are better than that of conventional latex film, but the impact resistance and gloss of the former are poorer. The gloss and water resistance of the emulsifier‐minor latex films are relevant to the type of water‐soluble monomers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 796–801, 2006     

Polymerization of cyclic monomers. VII. Synthesis and radical polymerization of 1,3‐bis[(1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzenes

1,3‐Bis[(1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzenes 1 [RO: CH₃O (a), C₂H₅O (b)] were synthesized by the esterification of the corresponding 1‐alkoxycarbonyl‐2‐vinylcyclopropane‐1‐carboxylic acids with resorcinol. The structure of the new vinylcyclopropanes was confirmed by elemental analysis and infrared (IR), ¹H nuclear magnetic resonance (¹H‐NMR), and ¹³C nuclear magnetic resonance (¹³C‐NMR) spectroscopy. The radical polymerization of difunctional 2‐vinyl‐cyclopropanes in bulk with 2,2′‐azoisobutyronitrile (AIBN) results in hard, transparent, crosslinked polymers. During the bulk polymerization of the crystalline bis[(1‐methoxycarbonyl‐2‐vinylcyclopropane‐1‐yl)carboxy]benzene 1a, an expansion in volume of about 1% took place. The radical solution polymerization of 1a resulted in a soluble polymer with pendant 2‐vinylcyclopropane groups. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1775–1782, 1999     

Influence of an oligomer polyol and monomers on the structure and properties of core–shell polyurethane–poly(n‐butyl acrylate‐co‐styrene) hybrid emulsions

The free‐radical polymerization of alkenyl‐terminated polyurethane dispersions with styrene and n‐butyl acrylate was performed to obtain a series of stable polyurethane–poly(n‐butyl acrylate‐co‐styrene) (PUA) hybrid emulsions. The core–shell structure of the emulsions was observed by transmission electron microscopy, and the microstructure was studied by ¹H‐NMR and Fourier transform infrared spectroscopy. The effects of the poly(propylene glycol)s (number‐average molecular weights = 1000, 1500, and 2000 Da) and the mass ratios of polyurethane to poly(n‐butyl acrylate‐co‐styrene) (PBS; 50/50, 40/60, 30/70, 20/80, and 10/90) on the structure, morphology, and properties of the PUAs were investigated. The average particle size and water absorption values of the PUAs increased with increasing of PBS content. However, the surface tension decreased from 34.61 to 30.29 mN/m. PUA‐2, with a bimodal distribution, showed Newtonian liquid behaviors, and PUA‐3 showed a great thermal stability, fast drying characteristics, and excellent adhesion to packaging films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43763.     

高介电HfO_xN_y薄膜的制备及其光学性能研究

采用直流反应磁控溅射方法,在硅衬底制备了高介电HfOxNy薄膜。用椭偏仪研究了后期退火处理对薄膜光学性质的影响,结果表明,薄膜的折射率随退火温度的升高而增加,这主要是由于高温退火导致薄膜内部缺陷减少,使得薄膜松散的内部结构变得更加致密;薄膜的消光系数随退火温度的升高而降低,这是由于因为退火后薄膜内的缺陷减少。光学禁带宽度随退火温度的升高而增加,这是由于退火过程中薄膜中N含量的减少而导致。     

Light scattering materials with tunable optical properties by controlling refractive index of the dispersed phase

Traditionally, the morphologies of the dispersed phase in Polycarbonate (PC)/poly(styrene‐co‐acrylonitrile) (SAN) blends were strongly influenced if AN content in SAN changed significantly even under constant processing conditions. This would hinder the pure research intended to study the effect of the refractive index difference between the polymer host and the polymeric dispersed particles on the optical properties tough. Therefore, we respectively prepared different PC/SAN light diffusion sheets with four types of SAN containing different AN content ranging just from 20 to 25 wt %, a narrow range that sufficiently ensures the relatively stable morphology of different SAN in PC matrix. The results suggest that the refractive index of SAN increases with an decreasing AN content, thus narrowing the refractive index difference between PC and SAN and producing PC/SAN(70/30) light diffusion sheets with an increasing transmittance and decreasing haze. The interesting phenomenon is further analyzed using Mie scattering theory. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44156.     

Synthesis and properties of PMMA‐ZrO2 organic–inorganic hybrid films

In this work we report the synthesis process and properties of PMMA‐ZrO₂ organic–inorganic hybrid films. The hybrid films were deposited by a modified sol‐gel process using zirconium propoxide (ZP) as the inorganic (zirconia) source, methyl methacrylate (MMA) as the organic source, and 3‐trimetoxy‐silyl‐propyl‐methacrylate (TMSPM) as the coupling agent between organic and inorganic phases. The films were deposited by dip coating on glass slide substrates from a hybrid precursor solution containing the three precursors with molar ratio 1 : 0.25 : 0.25 for ZP, TMSPM, and MMA, respectively. After deposition, the hybrid thin films were heat‐treated at 100°C for 24 h. The macroscopic characteristics of the hybrid films such as high homogeneity and high optical transparence evidenced the formation of a cross‐linked, interpenetrated organic–inorganic network. The deposited PMMA‐ZrO₂ hybrid films were homogeneous, highly transparent and very well adhered to substrates. Fourier Transform Infra‐Red measurements of the hybrid films display absorption bands of chemical groups associated with both PMMA and ZrO₂ phases. The amounts of organic and inorganic phases in the hybrid films were determined from thermogravimetric measurements. The surface morphology and homogeneity of the hybrid films at microscopic level were analyzed by scanning electron microscopy and atomic force microscopy images. From the analysis of optical transmission and reflection spectra, the optical constants (refraction index and extinction coefficient) of the hybrid films were determined, employing a physical model to simulate the hybrid optical layers. The refraction index of the hybrid films at 532 nm was 1.56. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42738.     

Effect of EDTA concentration on the physical and optical properties of Cds thin films

Application of ethylenediamine tetraacetic acid (EDTA) in the chemical bath solution to enhance the physical and optical properties of chemical bath deposited CdS film was realised. The observed beneficial effect on the crystallisation of CdS crystallites in the bath solution followed by deposition on glass substrates reduces the amorphousity and enhances the crystallinity of the film. The optical transparency of the film attains a maximum of 80% over the wavelength range of 650–1100 nm for the film deposited from EDTA‐added solution having the concentration of 0.006 mol/L. Also, the observed intensity of the characteristic photoluminescence emission was found to be dependent on the concentration of EDTA in the bath solution. © 2011 Canadian Society for Chemical Engineering     

Preparation and characterization of green reflective films of polyaniline analogs containing azobenzene units

Pd‐catalyzed polycondensation of aniline derivatives and 4,4′‐dibromoazobenzene affords polyaniline analogs containing azobenzene units. The polymers are red in solution and in thin films state, whereas they have a green luster in thick films. Substitution of 4,4′‐dibromoazobenzene for 4,4′‐dibromostilbene changes the reflection color from green to blue, whereas the introduction of a non‐conjugated unit slightly affects the reflection color. The glossiness of the film is dependent on the smoothness of the film surface. The reflectance measurements using polarized light reveal that reflection spectra correlate well with the complex refractive index (ñ = n + ik) of the film. These results confirm that the green luster can be attributed to the uniform surface reflection of the object, which has a large refractive index and absorption coefficient at around 500 nm. The polymer films exhibit good transmission of radio frequency signals owing to the lack of free electron carriers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41275.     

Development of formulations based on acrylate monomers for optical cable applications

Methyl methacrylate and 2‐ethyl hexyl acrylate were copolymerized in the presence of different crosslinkers with free‐radical initiation. The double‐bond conversion was monitored with in situ Fourier transform near‐infrared spectroscopic techniques. Dynamic mechanical properties of the resultant polymers were measured, and the curves were interpreted on the basis of the heterogeneity and flexibility of the samples. The optical properties of the cables made out of these systems were measured with transmission spectra. The effect of the addition of additives on the optical properties was demonstrated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3001–3012, 2001     

Plasma surface modification of silica and its effect on properties of styrene–butadiene rubber compound

The effects of surface modification of silicas by plasma‐polymerization coating, together with modification using a silane coupling agent for a comparison on the dispersion and physical properties of styrene–butadiene rubber (SBR) are reported. The chemical compositions of the plasma‐polymerization coating were characterized using FTIR and Auger spectrometer and it was found that the plasma coating was composed of C?C and C? H bonds. The surface modification of silica by either plasma polymerization or silane greatly improved the dispersion of silica particles in SBR vulcanizates. The plasma‐polymerization modification of silica improved the tensile modulus of SBR vulcanizates without deterioration of important basic properties such as tensile strength and elongation at break. © 2002 Society of Chemical Industry     

The effect of octamethylcyclotetrasiloxane (D4) addition on the structure and properties of film‐forming polyacrylate/silica core–shell composite particles

The film‐forming polyacrylate/silica core–shell nanocomposite particles with octamethylcyclotetrasiloxane (D₄) were successfully synthesized via aqueous emulsion polymerization in the presence of a glycerol‐functionalized nano silica sol. The ring‐opening polymerization of D₄ and the reaction with the glycerol‐functionalized nano silica particles before emulsion polymerization was the key procedure in this process. Transmission electron microscopy results showed that more nano silica particles tended to coat on the polyacrylate particles surface after the nano silica sols were modified with D₄. The silica aggregation efficiency was increased from 90.9 to 98.6% when the amount of D₄ used in the system was varied from 0 to 8.0 wt %. The transparency of the nanocomposite films was not compromised after D₄ was incorporated into the system. The films of the nanocomposite particles with or without D₄ both exhibited superior abrasive resistance. Furthermore, the water resistance and hydrophobicity of the films of these particles with D₄ were also improved significantly. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42003.     

Synthesis of polystyrene nanocapsules by redox interface‐initiated inversed microemulsion polymerization for drug release

Polystyrene nanocapsules with a diameter of 140 nm and a water‐soluble sodium salicylate core were prepared by redox interface‐initiated emulsion polymerization (RIEP) in an inversed microemulsion with cumene hydroperoxide/iron(II) sulfate as the redox initiation couple. The morphology of the nanocapsules was characterized by transmission electron microscopy and field emission scanning electron microscopy. Dynamic light scattering was used to determine the nanocapsule size and polydispersity (0.14–0.20). The release of sodium salicylate from the nanocapsules was monitored by ultraviolet–visible spectroscopy. All of the results indicate that the fabrication of core–shell nanocapsules with the water‐soluble active chemical as the core via RIEP was successful. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and second-order nonlinear optical properties of hyperbranched polymers containing pendant azobenzene chromophores

Two hyperbranched polymers with methyl ester (P1) and epoxy (P2) terminal groups containing pendant azobenzene chromophores were prepared through an “A₂ + B₃” approach used for second-order nonlinear optical materials. Their chemical structures were characterized by NMR and GPC analyses. The polymers have good solubility in common organic solvents and film-forming ability. The pure films were fabricated successively without doping into other matrices. The poled films exhibit high second-harmonic generation coefficients (>50 pm/V) due to the three-dimensional spatial isolation effect resulting from their highly branched structures. The optical nonlinearity of the poled P2 film is thermally more stable than that of P1 due to the cross-linking of epoxy groups with carboxylic acid groups in the former during poling. The onset decay temperature of SHG intensity of P2 was determined to be at around 155 °C, which was 20 °C higher than that of P1.