Phase‐separation prevention and performance improvement of poly(vinyl acetate)/TEOS hybrid using modified sol‐gel process

The formation of covalent bonds between silanols in copolymer and those in silica prevents organic–inorganic phase separation. Two series of hybrid composite materials, poly(vinyl acetate‐co‐vinyl trimethoxysilane)/TEOS and poly[vinyl acetate‐co‐3‐(trimethoxysilyl)propyl methacrylate]/TEOS, were fabricated using a modified sol‐gel process. The hybrids were transparent. Two kinds of silane coupling agents, vinyl trimethoxysilane (VTS) and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS), were used to prevent macrophase separation through formation of covalent bonds. Thermal analysis showed that γ‐MPS was more effective than VTS for the formation of covalent bonds. Enhancement of thermal stability of the hybrids was investigated by thermogravimetric analysis. Photomicrographs of scanning electron microscopy and images of atomic force microscopy indicated that inorganic silica particles were homogeneously dispersed in less than 50 nm in organic matrix. The morphological properties of hybrids were strongly dependent on the organic–inorganic composition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2310–2318, 2001     

Synthesis and properties of cross-linkable block copolymer end-capped with 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate

A series of novel cross-linkable copolymers 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate-poly (isobutyl methacrylate)-b-poly[3-(trimethoxysilyl)propyl methacrylate] (HFMA-PIBMA-b-PTMSPMA) were synthesized via atom transfer radical polymerization (ATRP). The synthesis and structure of the polymers were characterized by gel permeation chromatography (GPC), Fourier transform infrartd (FTIR) and ¹H nuclear magnetic resonance (NMR). The properties of HFMA-PIBMA-b-PTMSPMA and the corresponding copolymers end-capped with nonfluorinated acrylate were comparatively studied by contact angle, transmission electron micrograph (TEM), and dynamic light scattering (DLS) measurement. The results indicated that the surface properties and self-assembly behaviors of HFMA-PIBMA-b-PTMSPMA were changed greatly by the introducing of only one fluorinated acrylate. Finally, the transparent solid materials with a slightly blue color were obtained based on the cross-linked behaviors of HFMA-PIBMA-b-PTMSPMA and fracture surfaces of the materials were exhibited by scanning electron microscopy (SEM).     

Colloidal properties of copolymer‐encapsulated and surface‐modified pigment dispersion and its application in inkjet printing inks

A styrene–maleic acid copolymer (PSMA)‐encapsulated 2‐[(2‐methoxy‐4‐nitrophenyl) azo]‐N‐(2‐methoxyphenyl)‐3‐oxobutyramide (PY74) dispersion was prepared by the phase‐separation technique. A surface‐modified PY74 dispersion was prepared with PSMA sodium as a dispersant by the milling method. Furthermore, the two dispersions were applied to formulate pigment inks. The colloidal properties of these two dispersions were compared. The printing and color performance of the prepared inks were also investigated. The results show that the PSMA‐encapsulated PY74 dispersion with a small particle size had higher stabilities of NaCl concentration, pH value, and temperature than the surface‐modified PY74 dispersion. The apparent viscosity of the PSMA‐encapsulated PY74 dispersion changed little, while it changed greatly in the surface‐modified PY74 dispersion with an increase of the shear rate from 10 to 100 s⁻¹. The ink printing and color performance of printed Fabrics indicated that the PSMA‐encapsulated PY74 dispersion was more suitable for the preparation of inkjet printing ink than the surface‐modified PY74 dispersion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Ultrasound assisted sol-gel TiO2 powders and thin films for photocatalytic removal of toxic pollutants

The paper presents a study on the structural, surface and photocatalytic properties of the ultrasound assisted sol-gel titanium dioxide particles, as part of stable photocatalytic ink formulations deposited on fabrics. The photocatalytic activity was validated using methylene blue as reference pollutant, under UV, VIS and combined UV+VIS radiation and allowed selecting the optimum TiO₂ samples for inks preparation. To minimize the particles agglomeration stabilizing agents were added and the stability was quantitatively evaluated considering the relative increase in the VIS transmittance for a pre-set period of 30 min. Further on, the ink(s) were deposited by cold spraying on cotton woven fabrics and a removal efficiency higher than 95% was observed in the degradation of the highly toxic mustard gas, after 30 min of UV irradiation.     

Surface modification on nanoscale titanium dioxide by radiation: Preparation and characterization

Electron beam mutual radiation to induce graft polymerization has been carried out respectively, between nanoscale anatase‐ or rutile‐titanium dioxide particles surface and methyl methacrylate (MMA). The composition and properties of surface modified titanium dioxide were investigated by a number of surface sensitive techniques: X‐ray photoelectron spectrum (XPS), FTIR, X‐ray diffraction (XRD), and NMR. Results of the technological measurements show how surface chemistry is affected throughout the surface modification process, finally leading to a complete and homogeneous vinyl compound overlayer on top of the titanium dioxide samples. In comparison with stereochemical structures of the graft molecular chains and the PMMA induced by radiation polymerization, the surfaces of the oxides are considered to provide a template for the graft polymerization. The grafted titanium dioxide is found to produce a stable colloidal dispersion, in good solvents for the grafted polymer, and the dispersibility of grafted dioxides is influenced by temperature. In addition, the wettability of the surface of titanium dioxide to water is readily controlled by grafting of hydrophilic or hydrophobic polymers. Based on the above results, it is concluded that MMA is covalently linked to the surface of titanium dioxide by a surface modification process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 100: 3510–3518, 2006     

Preparation of zirconia loaded poly(acrylate) antistatic hard coatings on PMMA substrates

Zirconia (ZrO₂) nanoparticles were synthesized by hydrolysis and condensation of zirconium‐n‐propoxide (ZNP) in 1‐propanol at the presence of methacrylic acid (MA), serving as a chelating agent for ZNP. The formed nanoparticles were chemically modified by the UV‐curable coupling agent, 3‐(trimethoxysilyl)propyl methacrylate (MSMA). The modified particles were then crosslinked with the hexa‐functional monomer, dipentaerythritol hexaacrylate (DPHA), to produce transparent antistatic hard coatings on poly(methyl methacrylate) (PMMA) substrates. Sizes of the modified particles, as determined by the dynamic light scattering technique, fell over a small range of 2–20 nm. Chemical analyses of the particles and the coatings were performed using FTIR and/or solid ²⁹SiNMR spectroscopy. Surface resistivities of the coatings were measured, and the results indicated that with inclusion of 10 wt % modified zirconia, surface resistivity of ～10⁹ Ω/sq could be achieved, which amounted to ～6 order magnitude lower than that of the particle‐free polymeric binder. Furthermore, this antistatic coating was very hard with pencil hardness of 8–9H, and attached perfectly to the PMMA substrate according to the peel test. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42411.     

Behavior of UV‐cured print inks on LDPE and PBAT/TPS blend substrates during curing,postcuring, and accelerated degradation

During radiation curing, a reactive formulation is converted into a highly crosslinked coating film by means of polymerization reactions. This three‐dimensional (3D) network is resistant to external degrading factors as it cannot be undone by any physical–chemical means. In this study, various ultraviolet (UV)‐curable ink formulations with different pigments were developed. The behavior of the UV‐curable inks was evaluated during UV curing in a photocalorimeter or in a UV tunnel. Inks were exposed to accelerated aging in an accelerated weathering chamber and their physical–chemical properties were investigated. The presence of residual fractions of unreacted species trapped in the 3D network formed during UV curing interferes with the degradation of the main structure during exposure in the weathering chamber. The ink formulations that did not easily absorb UV light increased in gloss and hardness, indicating that residual crosslinking is taking place at the same time that degradation is occurring. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41116.     

Syntheses of polymeric dispersants for pigmented ink‐jet inks

Drop‐on‐demand ink‐jet inks made from dyes usually show poor light fastness and poor water fastness. Therefore, many researchers have introduced pigments into ink‐jet inks to overcome the defects of dye‐based ink. Pigmented ink needs sophisticated technology which disperses the pigments stably in low viscosity. Thus, adequate dispersants are essential to achieve stable dispersions of pigments for ink‐jet inks. This study describes syntheses of dispersants, properties of formulations and comparisons of performance with an existing ink to assess their suitability for commercial application.     

Preparation and characterization of polystyrene/titanium dioxide composite particles containing organic ultraviolet‐stabilizer groups

Polystyrene/titanium dioxide (TiO₂) composite particles containing organic ultraviolet (UV)‐stabilizer groups were prepared by the emulsion copolymerization of styrene and 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy)benzophenone with sodium sulfopropyl lauryl maleate as a surfactant in the presence of rutile TiO₂ modified with 3‐(trimethoxysilyl) propyl methacrylate, and the product was poly[styrene‐co‐sodium sulfopropyl lauryl maleate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy) benzophenone] [poly(St‐co‐M12‐co‐BPMA)]/TiO₂ composite particles. The structures of the composite particles were characterized with Fourier transform infrared spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The Fourier transform infrared and UV–vis measurements showed that poly(St‐co‐M12‐co‐BPMA) was grafted from the surface of TiO₂, and this copolymer possessed a high absorbance capacity for UV light, which is very important for improving the UV resistance of polystyrene. The thermogravimetric analysis measurements indicated that the percentage of grafting and the grafting efficiency could reach 513.9 and 59.9%, respectively. The differential scanning calorimetry measurement indicated that the glass‐transition temperature of the poly(St‐co‐M12‐co‐BPMA)/TiO₂ composite particles was higher than that of poly (St‐co‐M12‐co‐BPMA).These research results are very important for preparing polystyrene with high UV resistance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation of acrylate polymer/silica nanocomposite particles with high silica encapsulation efficiency via miniemulsion polymerization

Acrylate polymer/silica nanocomposite particles were prepared through miniemulsion polymerization by using methyl methacrylate/butyl acrylate mixture containing the well-dispersed nano-sized silica particles coupling treated with 3-(trimethoxysilyl)propyl methacrylate (MPS). The encapsulation efficiency of silica particles was determined through the elution and hydrofluoride acid etching experiments, and the size distribution and the morphology of the composite latex particles were characterized by dynamic light scattering and transmission electron microscopy. The coupling treatment of silica with MPS can improve the encapsulation efficiency of silica and the degree of grafting of polymer onto silica. When 0.10 g MPS/g silica was used to modify silica, the encapsulation efficiency of silica was greater than 95%, and the degree of grafting of acrylate polymer onto silica was about 60%. Although the average size and the size distribution index of the composite latex particles increased as the weight fraction of silica increased, the stable latex containing the ‘guava-like’ composite particles was obtained. The grafting of polymer onto silica particles improved the dispersion of silica particles in the solvents for acrylate polymer and in the polymer matrix.     

Preparation of pigmented ink‐jet ink by a combination of surface treatments and synthetic dispersant

Drop‐on‐demand ink‐jet inks prepared from dyes usually show inadequate light and water fastness. Thus, in our previous paper, we studied black pigmented ink‐jet inks with the aim of overcoming the drawbacks of dye‐based ink by employing a variety of synthetic dispersants with gas black. In this study, pigmented ink‐jet inks were prepared by a combination of the synthetic dispersant and the surface treatments of a furnace black that is more common than gas blacks. The results of this study show that the surface treatment of the furnace black and the use of the synthetic dispersant are useful in the preparation of ink‐jet inks and endow them with properties that are comparable with those of commercial ink‐jet inks.     

Preparation and characterization of UV‐curable MPS‐modified silica nanocomposite coats

A series of UV‐curable nanocomposites were prepared with 3‐(trimethoxysilyl) propyl methacrylate (MPS) modified nanosilica under the initiation of 2,2‐dimethoxy‐1,2‐diphenylethan‐1‐one. It was found that MPS‐modified nanosilica together with free MPS could form transparent nanocomposite coats. As the particle size of nanosilica increased, the photopolymerization rate, final double bond conversion, and tack‐free time of nanocomposites increased while the surface roughness, glass‐transition temperature, and UV absorbance of nanocomposites decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2274–2281, 2005     

Synthesis of low viscosity,fast UV curing solder resist based on epoxy resin for ink‐jet printing

A novel photosensitive low viscosity epoxy resin was synthesized by polyethylene glycol (PEG)‐modified bisphenol‐A epoxy resin (E51). The resin was modified by ethylene glycol, diethylene glycol, and different molecule weights (200,300,400) PEGs to optimize the minimum viscosity. FTIR was used to determine molecule structure. Cationic photoinitiator (UVI‐6976) mixed with modified resin (10 wt %), was utilized to boost the resin curing under UV light. The curing degree was beyond 90% within 40 s and the whole process was monitored by photo‐DSC. The modified resin diluted with ethylene glycol diglycidyl ether, was screen printed onto polyimide and polyethylene terephthalate substrate, and the properties of solder mask were up to China printed circuit association standard. The solder resist also meet all requirements under ink‐jet printing technology as the viscosity is under 60 mPa·s and the curing duration is <1 min. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of a nanosilica‐modified negative‐type acrylate photoresist

A new type of negative photoresist, which incorporated nanosized silica into a photosensitive acrylic resin, was developed. First, free‐radical polymerization was employed to synthesize the acrylic resin, poly[methyl methacrylate/methacrylic acid/3‐(trimethoxysilyl) propyl methacrylate], and then a silica precursor, prepared by hydrolysis and condensation of tetraethoxysilane in a sol–gel process, was introduced into the as‐formed resin solution. After the addition of photosensitive monomers and photoinitiators, a negative‐type organic–inorganic photoresist was produced. The morphology of the UV‐cured photoresist, as observed by field emission scanning electron microscopy, indicated that the size of the silica domain in the material could be reduced from 300 to about 50 nm by appropriate dosage of 3‐(trimethoxysilyl) propyl methacrylate. Thermogravimetric analysis, dynamic mechanical analysis, differential scanning calorimetry, and thermal mechanical analysis were used to evaluate the thermal and dimensional stabilities of the cured photoresists. It was found that the thermal decomposition temperature and glass‐transition temperature increased, whereas the thermal expansion coefficients before and after the glass transition decreased, with increasing silica content. The incorporation of 3‐(trimethoxysilyl) propyl methacrylate also enhanced the thermal and dimensional stabilities; however, the level of enhancement was moderate for the thermal decomposition temperature and thermal expansion coefficient and low for the glass‐transition temperature. In addition, a photoresist coated on a copper substrate demonstrated high hardness (5H) and strong adhesion (100%) with a resolution of 30 μm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Synthesising polymeric dispersants to apply to carbon black pigmented mill bases for use in ink‐jet inks

Dyes are an important component of drop‐on‐demand ink‐jet inks and are commonly used in desktop printers. While they offer bright, vivid colour, these dyes exhibit poor light and water fastness. To combat this, researchers have started using pigmented ink‐jet inks instead of dye‐based inks to improve light and water fastness, but the pigments are insoluble in ink vehicles. To use pigments, dispersants must be applied; however, this is a delicate process because the properties of the dispersant substantially affect how the pigmented mill base must be prepared. In this study, polymeric dispersants are synthesised based on the properties and ratios of monomers and the molecular weights of polymers. In total, 14 types of polymeric dispersants are synthesised and examined, with special attention paid to the dispersing properties of particle size reduction and the stability of the pigmented mill base used to prepare drop‐on‐demand ink‐jet inks. This study describes the synthesis of the dispersants in terms of their suitability for commercial application.     

高含量高透明度PS/TiO2纳米复合材料膜的紫外防护性能研究

采用溶剂热法非水合成了粒径小于20 nm的二氧化钛（TiO2）纳米粒子,并用硅烷偶联剂（KH 570）对纳米粒子进行原位修饰以提高粒子在聚苯乙烯（PS）的对二甲苯溶液中的分散性。采用旋涂法制备不同纳米TiO2粒子含量的PS复合材料膜,用紫外可见光光谱仪检测了薄膜的紫外防护性能。结果表明,纳米TiO2的最高含量达到95 %（质量分数,下同）;随着纳米TiO2粒子含量的增加,薄膜的紫外屏蔽性能逐渐增强,同时可见光区的透明度不会线性减少,而是趋于饱和,当纳米TiO2粒子含量达到95 %时,在人眼最敏感的550 nm波长处,依然可以获得82 %的透明度。     

Synthesis of silica hybrid nanoparticles modified with photofunctional polymers and construction of colloidal crystals

Photofunctional polymer as silane coupling agent (PFD) was prepared by free radical copolymerization of 4‐vinylbenzyl N,N‐diethyldithiocarbamate (VBDC) and methyl methacrylate (MMA) in the presence of (3‐mercaptopropyl)trimethoxysilane (MPMS) as chain transfer agent. Next, silane (SiO₂; the average diameter D_n = 192 nm) nanoparticles was surface‐modified with PFD and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS) by covalent bond formed between silanol groups and silane coupling agents. The PFD and γ‐MPS functionalizations changed the silica surface into hydrophobic nature and provided grafting initiation sites and methacrylate terminal groups respectively. We performed the construction of hybrid nanocomposites by using these modified SiO₂ nanoparticles. It was found from electron microscopy observations that SiO₂ particles were packed into repeating cubic arrangements in a poly(methyl methacrylate) (PMMA) matrix such as colloidal crystals. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Photo‐curing behaviors of bio‐based isosorbide dimethacrylate by irradiation of light‐emitting diodes and the physical properties of its photo‐cured materials

Bio‐based isosorbide (1,4:3,6‐dianhydroglucitol), which was obtained from biomass‐derived carbohydrates, has recently attracted much attention as an alternative to bisphenol A (BPA) because of its rigidity and transparency. BPA is still widely used for a variety of chemical applications even though it is known to be an endocrine‐disrupting chemical. BPA is a key precursor to most photo‐curable materials ranging from encapsulants of electronic devices to dental sealants. In this study, photo‐curable isosorbide dimethacrylate (ISDM) was synthesized from bio‐based isosorbide as a substitute for BPA, and the photo‐curing behaviors of ISDM by irradiation with light‐emitting diode (LED) light were investigated. The photo‐curing conversion and rates of ISDM formation were determined based on the change in the peak corresponding to the double bond within the methacrylate groups using attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopy. The effects of initiators and the wavelength of LED light on the photo‐curing conversion and rates of ISDM formation were examined, and a comparative study was carried out with 2,2‐bis[4(2‐hydroxy‐3‐methacryloyloxy‐propyloxy)phenylpropane] (Bis‐GMA), which is a photo‐curing material bearing a BPA moiety. In addition, the mechanical properties, such as surface hardness, adhesion strength, and transparency, after photo‐curing of ISDM were evaluated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42726.     

羧酸改性钛白粉促进光固化研究

采用油酸对商用二氧化钛进行表面改性,通过 X-射线光电子能谱仪（ XPS）、红外光谱（FT-IR）和 X射线粉末衍射分析（ XRD）对改性后的 TiO₂粒子进行了结构表征,并借助热重分析测定了改性剂的含量。采用光差示扫描量热法（ photo-DSC）研究了无机膜保护型 TiO₂、去包膜型 TiO₂、油酸改性 TiO₂和三甲基苯甲酰二苯基氧化膦（ TPO）对丙烯酸酯光聚合动力学的影响。结果表明：油酸改性的 TiO₂与无机膜保护的 TiO₂和去包膜的 TiO₂相比,能在空气中引发丙烯酸酯的光聚合,并能增强以 TPO为光引发剂的丙烯酸酯的光聚合,从而在相同固化效果下,可减少小分子光引发剂的添加,降低残留。本研究为后续紫外光（UV）固化白色涂料、油墨固化不完善等问题提供了解决途径。     

Photocatalytic properties of PMMA‐TiO2 class I and class II hybrid nanofibers obtained by electrospinning

The preparation, characterization, and photocatalytic activity evaluation of three hybrid fibrous materials composed mainly by poly(methyl methacrylate) (PMMA), methyl methacrylate (MMA): 3‐(trimethoxysilyl) propyl methacrylate (TMSPM): titanium butoxide (TBT), TiO₂ nanoparticles (NPTiO₂), and TiO₂ nanowires (NWTiO₂) is studied. Two types of fibe?s structures were prepared, single and core‐shell structures. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed both structures, single and core‐shell, as well as the inorganic phase were dispersed in the hybrid fibers. Infrared spectroscopic analysis (FT‐IR) and thermal analysis showed the organic and inorganic components, as well as the weight percentage of the inorganic phase present in hybrid fibers. The photocatalytic activity of the hybrid fibers class I and II showed that the best photodegradative efficiency for methylene blue in aqueous solution (2.9 × 10^?5 M) was 95%, provided by PMMA—10 wt % NPTiO₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44334.