Preparation and characterization of acrylic resin/titania hybrid nanocomposite coatings by photopolymerization and sol–gel process

Titania‐containing coatings were prepared through a dual‐cure process involving radical photopolymerization of a polysiloxane diacrylate and subsequent condensation of alkyltitanate groups. The kinetics of photopolymerization and condensation reaction was investigated as a function of the inorganic phase precursor (titanium tetraisopropoxide) content. AFM analysis gave evidence of a strong interaction between the organic and inorganic phase with the formation of titania domains in the nanoscale region. An increase of hydrophilicity in the coatings surface with increasing TiO₂ content was evidenced. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4659–4664, 2006     

纳米铋掺杂二氧化锡/水性聚氨酯复合材料

以自制纳米铋掺杂二氧化锡(nano-BTO)分散浆料和水性聚氨酯(PU)为原料,采用共混法制备nano-BTO/水性聚氨酯杂合材料。运用zeta电位仪、激光粒度仪和TEM等研究了nano-BTO的zeta电位分布及其分散。结果表明,nano-BTO浆料的等电点在pH=6附近;采用硅烷偶联剂KH-550和高分子分散剂DP-518对nano-BTO粉体进行分散处理可获得良好分散性的水性浆料。采用紫外-可见-近红外分光光度计和自制的隔热测试装置等研究了nano-BTO/氨酯杂合材料的力学性能、光学性能和热学性能。结果表明,当nano-BTO含量为1.0%时,涂膜的拉伸强度和断裂伸长率分别达到了9.23 MPa、223%,可见光透射率约为70%,其隔热效果同比纯PU膜可降温达8℃以上。     

Preparation of silicon dioxide/polyurethane nanocomposites by a sol–gel process

Aqueous emulsions of cationic polyurethane ionomers, based on poly(?‐caprolactone glycol) as soft segment, isophorone diisocyanate as hard segment, 3‐dimethylamino‐1,2‐propanediol as chain extender and potential ionic center, and hydrochloric acid as neutralizer, were mixed with tetraethoxysilane to prepare silicon dioxide–polyurethane (SiO₂/PU) nanocomposites by a sol–gel process during which the inorganic mineral is deposited in situ in the organic polymer matrix. The sizes and distributions of the particles were measured by dynamic light scattering, and the structure and morphology of the nanocomposites were observed by transmission electron microscope and FTIR spectrum. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2013–2016, 2004     

改性六方氮化硼/水性聚氨酯涂料的制备与性能

以聚甘油-10(PG)作为稳定剂,超声下对六方氮化硼(h-BN)进行剥离和改性制得PG功能化的少层h-BN纳米粒子(GB).利用GB与水性聚氨酯(WPU)共混得到WPU/GB.通过FTIR、TG、AFM和TEM对GB进行了表征,证实了少层GB的成功制备.动电位极化和电化学阻抗谱测试表明,WPU/GB涂层比纯WPU涂层具有更高的耐腐蚀性能.GB含量为1.0％(以WPU的质量为基准,下同)的WPU/GB1.0复合涂层的耐腐蚀性能最好,极化电阻为1.33×107?·cm2,阻抗|Z|可达到5.37×107?·cm2.此外,与纯WPU相比,WPU/GB1.0腐蚀电流密度从2.64×10–8 A/cm2减小至3.32×10–9 A/cm2,腐蚀电压从–0.309 V增大到–0.037 V,保护效率高达98.74％.     

Preparation of waterborne hyperbranched polyurethane acrylate/LDH nanocomposite

A series of novel waterborne hyperbranched polyurethane acrylate (WHPUA)/layered double hydroxide (LDH) nanocomposites based on hyperbranched aliphatic polyester Boltorn H20 (H20) and MgAl-LDH were successfully synthesized by in situ polymerization approach. The MgAl-LDH was firstly modified by sodium dodecyl sulfate (SDS) through the coprecipitation method, and then grafted by isophorone diisocyanate (IPDI), forming a complex with NCO groups at the surface and interlayer of LDH (LDH-DS-NCO). The residual hydroxyl groups after modification with succinic anhydride were crosslinked by the semi-adduct of IPDI reacted with HEA, and LDH-DS-NCO, followed by a neutralization reaction with triethylamine. The resulting water dispersible hyperbranched polyurethane acrylate WHPUA/LDH hybrid oligomer was then exposed to a medium pressure mercury lamp, forming a partially exfoliated WHPUA/LDH nanocomposite in the presence of a fragmental photoinitiator. The chemical structure, crystal configuration, morphology of WHPUA/LDH nanocomposite were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and high resolution transmission electron microscopy. The experimental results indicated that both the intercalated and exfoliated structures were formed in the UV cured polymer/LDH nanocomposite. The TGA results showed that the thermal stability was improved. Moreover, the pencil hardness was greatly increased, and the flexibility remained at an acceptable level for the UV cured polymer/LDH nanocomposites.     

Polyethersulfone–[silicon oxide] hybrid materials via in situ sol–gel reactions for tetra-alkoxysilanes

Polyethersulfone (PES)–[silicon oxide] hybrids were derived via sol–gel reactions for tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) in dimethylacetamide solutions of the polymer. In one scheme, water was initially present, and condensation reactions between SiOR groups competed with their reactions with —OH groups at PES chain ends. In a second scheme, water addition was delayed; TMOS molecules reacted with chain ends before competing TMOS–TMOS reactions occurred. A third study involved parallel experiments, as follows: 1) introduction of EtOH to PES–TEOS solutions for a time before water addition; and 2) reactions occurring for a time in non-EtOH-containing PES–TEOS solutions before water addition. Infrared (IR) spectroscopy uncovered signatures of Si–O–Si bridges in silicon oxide phases and PES endgroup modifications (Si–O–Ph). Composites prepared according to the latter two schemes contain more Si–O–Ph linkages than those generated via the first. Differential scanning calorimetry showed that T_g can be raised, and thermogravimetric analysis revealed how the PES thermal degradation profile can be modified via these inorganic incorporations. The schemes for late water addition produced composites having increased elongation-to-break and lowered strength relative to unfilled PES. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1799–1810, 1998     

Synthesis and characterization of nanosilica/waterborne polyurethane end‐capped by alkoxysilane via a sol‐gel process

A novel method was used to synthesis nanosilica/waterborne polyurethane (WPU) hybrids by in situ hydrolysis and condensation of tetraethyl orthosilicate (TEOS) and/or 3‐aminopropyltriethoxylsilane bonding at the end of the WPU molecular chain. The hybrid was characterized by scanning electron microscopy, energy dispersive spectroscopy (EDS), transmission electron microscopy, Fourier transform infrared spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS). The results showed that the nanosilica/WPU hybrids with well‐dispersed nanosilica particles were synthesized, in which the particles had typical diameters of about 50 nm. In addition, XPS and FTIR analyses demonstrated that chemical interaction occurred between WPU and silica. The effects of TEOS on surface wettability, water resistance, mechanical strength, and thermal properties of the hybrid were also evaluated by contact angle measurements, water absorption tests, mechanical tests, and differential scanning calorimetry, respectively. An increase in advancing contact angles, water resistance, and tensile strength, as well as decrease in elongation at break and glass transition temperature, were obtained with the addition of TEOS. Water absorption decreased from 17.3 to 5.5%. The tensile strength increased to a maximum of 29.7 MPa, an increase of about 34%. Elongations at break of the hybrids decreased 191%. These results were attributed to the effects of the nanosilica and the chemical interaction between WPU and silica. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

水性纳米掺锑二氧化锡(ATO)浆料的研制

采用硅烷偶联剂对纳米掺锑二氧化锡(ATO)粒子表面进行化学改性,以分散剂对其进行物理包覆,调节分散工艺、体系黏度和pH,获得了稳定性可达到两个月以上的水性纳米ATO浆料.傅立叶红外光谱分析表明,硅烷偶联剂可以有效地包裹在纳米粒子表面.当采用硅烷偶联剂KH570,其用量为纳米ATO粒子质量的1.5%时,包覆效果最好;选用嵌段型分散剂3275,其用量为体系质量的0.2%时,分散效果最好;当体系黏度大于88 mPa·s和pH=10时,浆料稳定性最好.透射电子显微镜观测表明,纳米ATO粒子获得了良好分散.     

Synthesis and properties of castor oil-based waterborne polyurethane cloisite 30B nanocomposite coatings

Waterborne polyurethane dispersions (WPUDs) were synthesized successfully from castor oil-based polyol, isophorone diisocyanate and dimethylol propionic acid with NCO/OH ratio of 1.5. Different weight percentages of cloisite 30B (1, 2, and 3 wt%) were loaded with WPUDs to prepare nanocomposite films. Prepared prepolymer and nanocomposite films were characterized using FTIR, XRD, SEM, TEM, DSC, and TGA techniques, and coating properties, such as pencil hardness, abrasion resistance, impact resistance, and contact angle, were evaluated. The results obtained from different amounts of clay loading were compared with the pristine castor oil-based WPUDs. The FTIR spectra deconvolution technique was used to study the hydrogen bonding effect within the polymer with an increase in clay content. TGA analysis showed that the thermal stability of WPUDs increases with cloisite 30B (C30B) content. The surface morphology and hydrophilicity/hydrophobicity nature of the nanocomposite films were characterized using scanning electron microscopy and contact angle measurement. The results obtained from tensile tests indicated that the mechanical property of the dispersion system improved with C30B content. A high-performance castor oil-based nanocomposite coating with low volatile organic component can be targeted as an outcome of this work.     

Fluorine‐containing photocurable hybrid coatings via anhydrous sol–gel method

In this study, fluorine‐doped photocurable hybrid coatings were prepared by combining UV‐curing technology with an anhydrous sol–gel method. First, methacryloxymethyl triethoxysilane (MEMO) was hydrolyzed via an anhydrous sol–gel process. Then MEMO was mixed with acrylic oligomers and predetermined amounts of fluoroacrylate resin. UV curable hybrid coatings were applied on corona‐treated plexiglass substrates. The addition of fluorine showed a significant impact on the properties of the coatings. As the fluorine content was increased in the formulations, flame retardancy and the contact angle values of the coatings increased. It was found that the optical transmittance of the coatings was higher than 95%. The surface morphology of the hybrid films was characterized by scanning electron microscopy (SEM). The chemical composition of the surface of the coatings was identified by energy dispersion spectrum (SEM–EDS) technique. SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. J. VINYL ADDIT. TECHNOL., 21:272–277, 2015. © 2014 Society of Plastics Engineers     

Stability and properties of waterborne polyurethane/clay nanocomposite dispersions

Factors that can affect the stability of waterborne polyurethane (WBPU)/clay nanocomposite dispersions are reported. It is suggested that the dispersion stability depends on the carboxyl acid salt content, clay content, sonication (mechanical forces), and clay surface structure. It was observed that the dispersion stability increased with increasing carboxyl acid salt content after applying sonication (mechanical forces) in clay with OH groups (Cloisite 30B) up to 23.58 mol% DMPA. Encapsulated (WBPU20-30B4-M and WBPU23-30B5-M) clay in PU particles was formed using the above combination. The dispersion with clay encapsulated in PU particles had the longest storage time of all of the dispersions. The zeta potential, particle size, particle size distribution, and viscosity of the dispersions also depend on carboxyl acid salt content, clay content, sonication (mechanical forces), and clay surface structure.     

水性聚氨酯涂料的功能化及性能

综述了近年水性聚氨酯涂料功能化及性能的最新研究进展,主要包括阻燃型水性聚氨酯涂料、防腐型水性聚氨酯涂料、防水型水性聚氨酯涂料、防霉型水性聚氨酯涂料以及其它功能化水性聚氨酯涂料,并对功能化水性聚氨酯涂料未来的发展趋势进行了阐述和总结。研制具有自修复功能和可生物降解的新型水性聚氨酯涂料以及开发具有较高性价比的水性聚氨酯涂料功能化的新技术和新工艺将是该领域今后的主要目标。     

改性纤维素纳米晶/水性聚氨酯防腐涂料的制备

采用γ-氨基丙基三乙氧基硅烷（APTES）对纤维素纳米晶（CNC）进行表面改性,通过原位聚合法将改性CNC与水性聚氨酯（WPU）交联复合,在交联剂三羟甲基丙烷（TMP）的协同作用下,合成高度交联的改性CNC/WPU复合材料。通过FTIR、XRD、SEM、拉伸试验、电化学极化曲线和EIS等测试来研究复合材料的结构及性能。结果表明,当TMP与质量分数为1.5 %的改性CNC共同添加时为最优化的条件,所得复合涂层表面致密,拉伸强度得到明显提高;涂层吸水率降低至6.0 %左右,耐水性能良好;腐蚀电流密度降到9.76×10-8 A/cm2,阻抗谱容抗弧半径达到3.15×107 Ω·cm2,盐水中浸泡168 h表面无明显变化,得到了综合性能优良的耐腐蚀涂料。     

Preparation and properties of organosoluble polyimide/silica hybrid materials by sol–gel process

Organosoluble polyimide/silica hybrid materials were prepared using the sol–gel process. The organosoluble polyimide was based on pyromellitic anhydride (PMDA) and 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane (MMDA). The silica particle size in the hybrid is increased from 100–200 nm for the hybrid containing 5 wt % silica to 1–2 µm for the hybrid containing 20 wt % silica. The strength and the toughness of the hybrids are improved simultaneously when the silica content is below 10 wt %. As the silica content is increased, the glass transition temperature (T_g) of the hybrids is increased slightly. The thermal stability of the hybrids is improved obviously and their coefficients of thermal expansion are reduced. The hybrids are soluble in strong polar aprotic organic solvents when the silica content is below 5 wt %. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2977–2984, 1999     

Preparation and properties of modified graphene oxide incorporated waterborne polyurethane acrylate

In this study, a new modifier (KPG) was prepared by modifying graphene oxide with γ‐glycidoxypropyl trimethoxysilane (KH560) and polydimethylsiloxane (PDMS). KPG was in turn added to aqueous urethane acrylate for the fabrication of waterborne polyurethane polyacrylate emulsion modified with KH560‐PDMS composite (KPG/WPUA). Textural characterizations of the KPG/WPUA coating were achieved via Fourier transform infrared, SEM, TGA and AFM techniques, which revealed that the KPG/WPUA film possessed a smooth surface. The synthesized KPG/WPUA films were tested for mechanical properties, hydrophobicity and acid/water corrosion performance which suggested their highly hydrophobic surface. KPG/WPUA with 0.1% KPG showed a contact angle of 118.35°, 30.35° higher than that of pristine WPUA. The KPG/WPUA film exhibited higher thermal stability, i.e. a 5% weight loss temperature of 305 °C, which was 30 °C higher than that of pristine WPUA film. The Young's modulus and elongation at break of the KPG/WPUA film were 34.1 MPa and 74.88% respectively, which were higher than that of WPUA film. Furthermore, KPG/WPUA films exhibited greater resistance (without obvious blistering and the white spotting phenomenon) to H₂O₂, HCl and water corrosion than pristine WPUA. The superior performance of KPG/WPUA films was attributed to the network chain structure formed upon the introduction of KPG into WPUA. The outstanding performance of KPG/WPUA films in terms of mechanical properties, thermal stability and high resistance to acidic and water corrosion makes them interesting alternative contenders for target applications. © 2019 Society of Chemical Industry     

Structure–properties relationship of starch/waterborne polyurethane composites

The blend materials from waterborne polyurethane (WPU)/starch (ST) with different contents (10–90 wt %) were satisfactorily prepared by using the solution casting method. Their miscibility, structure, and properties were investigated by wide‐angle X‐ray diffraction (WAXD), scanning electron microscope (SEM), different scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and the tensile tests, respectively. The results indicated that tensile strength of composite materials not only depended on the starch content, but also related to the microstructure of WPU. The sample WPU2 (1.75 of NCO/OH molar ratio) exhibited hard‐segment order, but WPU1 (1.25 of NCO/OH molar ratio) had no hard‐segment order. The appropriate starch filled into WPU not only decreased the ordered region of soft‐segment matrix, but also hindered the formation of hard‐segment ordered structure. The blend material from 80 wt % WPU1 and 20 wt % starch exhibited better tensile strength (27 MPa), elongation at break (949%), and toughness than others. With an increase of starch content, the WPU matrix with dispersed starch in the blends transited to dual‐phase continuity and then to starch matrix with dispersed WPU. The results suggested that a certain extent of miscibility existed between WPU and starch in the blend materials on the whole composition ratio. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3325–3332, 2003     

Synthesis and characterization of novel polyimide/SiO2 nanocomposite materials containing phenylphosphine oxide via sol‐gel technique

In this article, a series of novel polyimide/silica (PI/SiO₂) nanocomposite coating materials were prepared from tetraethoxysilane (TEOS), γ‐glycidyloxypropyltrimethoxysilane (GOTMS), and polyamic acid (PAA) via sol‐gel technique. PAA was prepared by the reaction of 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and bis (3‐aminophenyl) phenyphosphine oxide (BAPPO) in N‐methyl‐2‐ pyrrolidone (NMP). BAPPO was synthesized hydrogenation of bis (3‐nitrophenyl) phenyphosphine oxide (BNPPO) in the presence of Pd/C. The silica content in the hybrid coating materials was varied from 0 to 20 wt %. The molecular structures of the composite materials were analyzed by means of FT‐IR and ²⁹Si‐NMR spectroscopy techniques. The physical and mechanical properties of the nanocomposites were evaluated by various techniques such as, hardness, contact angle, and optical transmission and tensile tests. These measurements revealed that all the properties of the nanocomposite coatings were improved noticeable, by the addition of sol‐gel precursor into the coating formulation. Thermogravimetric analysis showed that the incorporation of sol‐gel precursor into the polyimide matrix leads to an enhancement in the thermal stability and also flame resistance properties of the coating material. The surface morphology of the hybrid coating was characterized by scanning electron microscopy (SEM). SEM studies indicated that nanometer‐scaled inorganic particles were homogenously dispersed throughout the polyimide matrix © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of microstructure compatible porous supports by sol–gel synthesis for catalyst coatings

To enhance the inner surface of microchannel reactors, porous metal oxide coatings based on alumina, silica, and titanium oxide have been developed as support for catalytically active components. The oxides were made by the sol–gel process. Thin film coating was accomplished by dip coating using an Fe-based alloy as support. The influence of the sol composition, sol viscosity, and thermal treatment procedure on the surface enhancement factor and the porosity of the coating was investigated. The resulting surface enhancement factor reached 800 m²/m².     

In situ polyurethane/silica composite formation via a sol‐gel process

Polyurethane acrylate anionomer (PUAA)/silica composite gels were prepared by the sol‐gel reaction of tetraethoxysilane (TEOS) and methacryloxypropyl trimethoxysilane (MPTS) incorporated to PUAA gels by using a swelling method. The formation and structure of composites were confirmed by FTIR, X‐ray diffraction, and SEM. As a result, we found that silica components in composites are located within the ionic domains of their gels and interacted with PUAA via hydrogen bonding. This drastically enhanced the mechanical properties of the composites. Mechanical properties are also improved by MPTS, because MPTS improves the dispersibility and adhesion of silica components in PUAA/silica composite gels. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2327–2334, 2002     

Properties and preparation of thermoplastic polyurethane/silica hybrid using sol–gel process

A thermoplastic polyurethane elastomer/silica hybrid (TPU/SiO₂) was prepared using the sol–gel process. This work was undertaken to investigate the thermal and physical properties of this type of hybrid by employing different catalyst systems during sol–gel processing. Two types of catalyst systems including acetic acid (HOAc) and hydrochloric acid (HCl) were used to prepare sol particles. The mixing of the sol solution and TPU solution was then carried out to form a TPU/silica hybrid. Fourier transform IR spectra and dynamic mechanical properties were recorded to depict the enhanced interfacial interaction. Thermogravimetric analysis was used to determine the actual silica content forming in the hybrid and to evaluate the heat resistance of the hybrid. Mechanical properties such as the tensile strength and cutting strength were investigated at various concentrations of in situ silica. The tensile strength increased at all concentrations of silica. In contrast, the cutting strength decreased, probably because of a reduction of the energy dissipation from silica as physical crosslinks. The HOAc catalyzed system showed better optical properties than the HCl catalyzed system. The fracture surface was revealed through scanning electron microscopy to observe the degree of dispersion of SiO₂, which in turn confirmed the results for the optical and mechanical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1316–1325, 2005