Waterborne polyurethane-silica nanocomposite adhesives based on castor oil-recycled polyols: Effects of (3-aminopropyl)triethoxysilane (APTES) content on properties

Waterborne castor oil-recycled polyol based polyurethane-silica nanocomposite adhesives (WPU) with polymer matrix and silica nanoparticles chemically bonded have been successfully prepared through a sol-gel process. A series of waterborne polyurethane adhesives with hard segment contents from 71.3 to 74.5 wt%, were synthesized using an isophorone diisocyanate, 2-bis(hydroxymethyl) propionic acid, recycled castor oil-based as soft segments and (3-aminopropyl)triethoxysilane (APTES) as chain extender. The depolymerized oligoester obtained from glycolysis of poly(ethylene terephthalate) (PET) waste using triethylene glycol (TEG), was transesterified with castor oil (CO) which resulted in the formation of hydroxyl-functional polyester polyol, with hydroxyl value of 414 mgKOH g⁻¹. The molecular structures and mass of glycolyzed PET oligoesters, castor oil-based polyol and castor oil-based polyurethane-silica nanocomposite adhesives were estimated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The structure and properties of the resulting films were investigated by FTIR, wide angle X-ray diffraction measurement (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis indicated that APTES can improve the thermal stability of WPU. XRD showed that the crystallinity of WPU decreased with the increase alkoxysilane content. The extent of crosslinking was investigated to show a dependence on silica concentration, which increased the glass transition temperature and particle size of polyurethane nanocomposites with increasing alkoxysilane content due to the condensation of the alkoxysilane groups. The hardness, adhesion and gloss quality of the polyurethane films were also determined considering the effect of APTES content, so this paper confirmed the suitability of using these castor oil-based waterborne polyurethane-silica nanocomposites as new adhesive materials with high performance coatings materials. The experimental results reveal that the APTES and the hard segment content play a key role in controlling the structure and properties of the PU cast films based on castor oil-recycled polyols.     

Synthesis and characterization of novel renewable castor oil-based UV-curable polyfunctional polyurethane acrylate

In recent years, a lot of interest has been given to renewable resources for their environmental friendliness and potential biodegradability in the synthesis of urethane-derived polymers. In this work, UV-curable castor oil-based polyfunctional polyurethane acrylate (COPUA) was prepared by the reaction of isophorone diisocyanate (IPDI) with castor oil and pentaerythritol triacrylate (PETA). The structures and molecular weights of the targeted IPDI–PETA and COPUA were characterized by FTIR, ¹H NMR, and GPC, respectively. In addition, the effect of reactive diluent content on damping properties, thermal stabilities, and mechanical properties of COPUA was characterized by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal test machine. DMA revealed the copolymers had a glass transition temperature (T _g) from 31.81 to 48.09°C. TGA showed that thermal initial decomposition temperatures were above 344.5°C, indicating the copolymers had certain thermal stability. Finally, some physical properties of curing films were studied by the contact angle and water absorption, and the results showed that the coatings exhibited good hydrophobicity. The COPUA obtained from castor oil can be used as eco-friendly materials and other applications alternative to the use of other petrochemicals in coatings.     

Thermomechanical and electrical characterization of epoxy‐organoclay nanocomposites

The effect of amount of clay content on the thermomechanical and electrical properties of epoxy/organoclay nanocomposites is investigated in the present research. An organoclay, cloisite 30B (C30B), was dispersed in the epoxy resin and was cured with an amine curing agent. The morphology of the nanocomposite examined by X‐ray diffraction shows exfoliation for nanocomposites with lesser clay content and intercalation for nanocomposites with higher clay content. The storage modulus (E′) of the nanocomposites increases monotonously with the increase in the amount of clay. The short time alternating current breakdown strength of the nanocomposites increases by the addition of C30B up to a certain clay content and then show a decrease. The space charge measured by pulsed electroacoustic method shows that the nanocomposite accumulate a very less amount of space charge and the charge decay in the nanocomposites are quicker than in the pure polymer. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Layered silicate-polymer nanocomposite coatings via radiation curing process for flame retardant applications

Polymer-clay nanocomposite (PCN) films were fabricated by uniformly dispersing organically modified montmorillonite clay (Cloisite 20A and 30B) in varying concentrations of 2%, 5%, 10% and 15% (w/w) in an optimized composition of aliphatic urethane acrylate (AUA)–Trimethylolpropane triacrylate (TMPTA) mixture by ultra-sonication followed by ⁶⁰Co-gamma radiation induced curing. Radiation doses were optimized to obtain non-tacky, homogeneous thin films, which were subsequently characterized by UV–vis spectrophotometry, X-ray diffraction (XRD), small angle X-ray scattering (SAXS), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Gloss of the PCN films decreased, and fracture toughness and hardness of PCN films improved with the incorporation of the clay in the PCN coatings. Limiting Oxygen Indices (LOIs) of the samples were calculated from the thermogravimetric analyses data to ascertain the efficacy of the PCN films as potential flame retardant materials.     

Modified cellulose nanocrystals enhancement to mechanical properties and water resistance of vegetable oil-based waterborne polyurethane

Environmentally friendly and lightweight silylated cellulose nanocrystal (SCNCs)/waterborne polyurethane (WPU) composite films that exhibit excellent mechanical properties and water resistance were prepared. The cellulose nanocrystals (CNCs) of the filamentous structure were surface-modified by γ-aminopropyltriethoxysilane (APTES) and then introduced into a castor oil-based aqueous polyurethane (WPU) matrix by in situ polymerization. The morphology and silylation degree of CNCs were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier infrared transform spectroscopy at different APTES concentrations. The results showed that the surface of the nanocellulose crystal has the best silylation morphology and thermal stability with incorporation of 6 wt % APTES. The thermal stability, mechanical properties, surface morphology, and water resistance of the nanocomposites were investigated by TGA, tensile test, SEM and optical contact angle, water absorption test, and mechanical property test after immersed in water. It was found that the effective introduction of modified CNCs resulted in a significant increase in tensile strength at high levels, and the thermal stability and hydrophobicity of the material were improved simultaneously, reaching the percolation threshold at a 0.50 wt % SCNCs as determined theoretically. This study provided an approach to the design and development of surface-modified CNCs/vegetable oil-based polymer composites by using an appropriate concentration of silane coupling agent to modify CNCs and improve the compatibility between nanocellulose and vegetable oil-based polymer matrices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48228.     

羧甲基壳聚糖-蓖麻油基聚氨酯农药缓释微球的制备及性能

以羧甲基壳聚糖（CMCS）、蓖麻油（CO）和异佛尔酮二异氰酸酯（IPDI）为原料,自乳化法制备了羧甲基壳聚糖-蓖麻油基聚氨酯微球（CO-CMCS-PU）,通过分子自组装法负载阿维菌素（AVM）得到载药微球（CO-CMCS-PU@AVM）。采用FTIR、1HNMR、SEM、TGA等对产品结构及形貌进行表征,并探究了不同药量载药微球的包封率、缓释性能、抗紫外性能、叶面接触角和黏附性能。结果表明,相比AVM分散液,紫外照射后载药微球中AVM的保留率提高到43%,说明CO-CMCS-PU载体的抗紫外性能良好;载药微球比AVM分散液在黄瓜叶面上的接触角降低了20%以上,滞留量提高了40%以上,说明其在叶面上有较好的黏附性和润湿性;载药微球包封率可达80%以上,具有良好的缓释和pH响应释放性能,释药行为符合First-order动力学模型,药物释放受Fickian扩散控制。     

Characterization of corrosion resistant clay/epoxy ester composite coatings and thin films

The processibility and corrosion resistance of epoxy ester coatings was improved by the addition of cloisite 15A clay. The weight percent of clay was increased from 1% to 10% of clay. The presence of clay in the coatings was confirmed by using the Fourier transformed infrared spectroscopy, FTIR. The effect of clay on the contact angle of the coatings was determined by using the video contact angle analyzer. The surface contact angle of the coatings decreased with increasing weight percent of clay. The surface roughness as measured by atomic force microscope, AFM decreased with the addition of clay up to 1 wt.% loading. The dynamic mechanical property of the coatings was determined by using the Seiko Dynamic Mechanical Spectrometer, DMS. The reinforcement of epoxy ester with organoclay resulted in a significant increase in the glass transition temperature, Tg. However, there was no significant change in the height of the tangent of the loss angle, tan δ with variation in the clay concentration, indicating that there was no significant change in the damping behavior of the epoxy ester coatings as a result of reinforcement by organoclay.     

A hybrid polyacrylate/OMMT nanocomposite latex: Synthesis,characterization and its application as a coating binder

Hybrid latex particles have an increasing importance in industrial applications especially for high performance waterborne coatings. They provide combined properties of different phase compositions for the final polymer which can also be enhanced by additives such as nanoclays. The present study describes the preparation of a hybrid polyacrylate/OMMT nanocomposite latex via two stage in situ emulsion polymerization with a low emulsifier content (1 wt%) which is usually a challenge for the preparation of stable polymer/OMMT nanocomposite latexes. The obtained nanocomposite latex was stable and had a fine average size diameter of 151 nm with a very narrow size distribution. The copolymer films exhibited a well exfoliated structure observed by WAXD and TEM. Other polymer properties were investigated by FTIR, DSC, TGA, DMTA and rheological measurements. The results indicated that the addition of clay even in low amount (2 wt%) yielded significantly improved mechanical and thermal properties of the final polymer. In addition, the nanocomposite latex was also applied on leathers as coating binder in a finishing formulation and the results of the performance tests revealed substantially increased rubbing and heat resistance whereas a slight decrease was observed at water vapor permeability of the coated leathers.     

新型蓖麻油基季铵盐的合成及其抑菌性能研究

以蓖麻油酸甲酯为起始原料,与N,N-二甲基-1,3-丙二胺和溴化苄、溴乙烷通过酰胺化反应和季铵化反应生成了新型蓖麻油基季铵盐,其结构经FTIR、1HNMR、13CNMR及ESI-MS进行了确证。采用抑菌圈直径法对目标产物的抑菌性能进行了测试,结果表明,两种季铵盐均有一定的抑菌活性,N,N-二甲基-N-乙基-蓖麻油酸酰胺丙基溴化铵的抑菌活性略强于N,N-二甲基-N-苄基-蓖麻油酸酰胺丙基溴化铵。     

Preparation of polybenzimidazole/functionalized carbon nanotube nanocomposite films for use as protective coatings

Functionalized multi‐walled carbon nanotubes (MWCNTs) via microwave‐induced polymerization modification route, and polybenzimidazole (PBI) nanocomposite films containing 0.1‐5 wt% functionalized MWCNTs were successfully synthesized. The functionalized MWCNTs were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X‐ray photoelectron spectroscopy (XPS). The results verify that the polymer was successfully grafted to the MWCNTs with a polymer layer that was several nanometers thick. The TGA results showed that the quantity of the attached polymer reached approximately 9.4 wt%. The mechanical properties of the nanocomposite films were measured by tensile test and dynamic mechanical analysis (DMA). The tensile test results indicated that the Young's modulus increased by about 43.9% at 2 wt% CNT loading, and further modulus growth was observed at higher filler loading. The DMA studies indicated that the nanocomposite films had a higher storage modulus than pure PBI film in the temperature range of 30‐300°C, and the storage modulus was maintained above 0.82 GPa. Simulation results confirmed that the PBI nanocomposite films had desirable mechanical properties for use as a protective coating. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.     

Composite latex production with high solid content

Poly(methyl methacrylate-co-butyl acrylate) (PMMA-co-PBA) and poly(sytrene-co-butyl acrylate) (PSt-co-PBA) latexes in which solid content (SC) varied from 20% up to 40 wt % armored with laponite clay have been successfully synthesized using a simple method, which does not require modification of the clay particles prior to polymerization. Incorporation of quite high amounts of laponite nanoparticles into PMMA-co-PBA and PSt-co-PBA latexes with a certain amount of solids content was achieved. The nanocomposite latexes and polymer samples were characterized using Fourier transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode, dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), contact angle, zeta potential, viscosimetry and analytical ultracentrifuge (AUC). Zeta potential values showed that stable latex was obtained and precipitation problem of the nanoparticles in the latex was not seen during the storage. Obtained nanocomposite latex showed fine particle size between 88 and 160 nm. TEM images and XRD results pointed out that the exfoliated nanocomposite structure for latexes was obtained. DSC analyzes showed that the glass-transition temperature (T _g) values of nanocomposite films decreased slightly compared with those of pure (PMMA-co-PBA) films. Mechanical properties of laponite clay armored PMMA-co-PBA were tested and compared with those of pure PMMA-co-PBA, indicating that incorporated the Young's modulus and tensile strength are also improved to a noticeable extent after the incorporation of laponite. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47423.     

细乳液聚合制备改性硅溶胶／聚丙烯酸酯复合乳液

常温下一步法制备改性硅溶胶,并通过细乳液聚合制备改性硅溶胶／聚丙烯酸酯复合乳液。考查了温度对聚合速率和单体转化率的影响以及不同乳化剂含量下聚合过程中乳胶粒粒径的变化情况;测试了乳胶膜的吸水率,并用接触角法表征了乳胶膜的表面自由能。     

Preparation and characterization of a novel calcium-conducting polymer inclusion membrane: Part I

The preparation and characterization of a novel type of castor oil-based polymer inclusion membrane (PIM) was investigated, focusing on its flux and selective recovery of Ca²⁺ over competitive ions such as K⁺, Na⁺, and Mg²⁺. The PIM contains a cross-linked high-molecular-weight green polyol (GPO) as a polymer base, benzene-18-crown-6 as a carrier, and an ionic liquid called 1-Butyl-3-methylimidazolium chloride as a plasticizer. GPO was first synthesized by a reaction between an epoxidized castor oil and a cellulose acetate, thereafter, cross-linked by isophorene isocyanate. The base polymer and the prepared PIM were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The FTIR results indicate that oxirane groups in the epoxidized castor oil molecules reacted with the primary hydroxyl groups of cellulose acetate chains. The contact angle measurement hints at the hydrophobic characteristics of the prepared membrane. Compared to the PVC-, CA-, and PVDF-based polymer inclusion membrane, the cured GPO-based PIM, showed higher selectivity and flux of calcium ions with the same composition. The greater stability and significantly higher surface roughness are further favorable features of the novel PIM.     

Preparation and characterization of silica sol/fluoroacrylate core–shell nanocomposite emulsion

The silica sol/fluoroacrylate core?Cshell nanocomposite emulsion was successfully synthesized via traditional emulsion polymerization through grafting of KH-570 onto silica particles. Comparing the performance of the polyacrylate copolymer, the fluorinated polyacrylate copolymer and the silica sol/fluoroacrylate core?Cshell nanocomposite emulsion, we can come to a conclusion that the silica sol/fluoroacrylate core?Cshell nanocomposite emulsion presents significantly excellent performance in all aspects. The products were characterized by Fourier transform infrared (FTIR), photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), thermogravimetry (TGA), Contact angle and UV?Cvis analyses techniques. The chemical structure of polyacrylate copolymer, fluorinated polyacrylate copolymer and silica sol/fluoroacrylate nanocomposite were detected by FTIR. The size and stability of emulsion latex particles were determined by PCS technique. TEM analysis confirmed that the resultant latex particle has the core?Cshell structure, obviously. The water absorption and contact angle data also showed that the silica sol/fluoroacrylate nanocomposite film has good hydrophobic performance. TGA analysis indicated the weight loss of the silica sol/fluoroacrylate nanocomposite film begins at around 350?°C which testifies its good thermal stability. The UV?Cvis spectroscopy analysis showed that the silica sol/fluoroacrylate nanocomposite film possess UV?Cvis shielding effect when the added volume amount of KH570 modified silica sol is up to 5?mL. Therefore, the excellent properties of hydrophobicity, thermodynamics and resistance to ultraviolet provide the silica sol/fluoroacrylate nanocomposite film with potential applications in variety fields. In addition, the formation mechanism of core?Cshell structure silica sol/fluoroacrylate nanocomposite latex particles was speculated.     

Investigation on the Mechanical and Thermal Properties of Intercalated Epoxy/Layered Silicate Nanocomposites

Epoxy resin/layered silicate nanocomposites with various clay contents were prepared. The structural studies showed the intercalation of epoxy polymer chains into the clay galleries. The adhesion analysis of nanocomposite coating films on metallic substrates showed the excellent adhesion of epoxy-based nanocomposite coatings on iron plates, especially in lower clay loadings. According to the hardness test results, the organoclay minerals caused the increasing of the hardness of epoxy nanocomposites. The thermal properties of nanocomposites were evaluated by means of DSC and TGA analysis. The tensile and compression strengths of cured epoxy/clay systems were also investigated.     

Characterization of structure and corrosion resistivity of polyurethane/organoclay nanocomposite coatings prepared through an ultrasonication assisted process

In this study, a series of castor oil based polyurethane/organically modified montmorillonite (OMMT) clay nanocomposite coatings have been successfully prepared by effective dispersing of OMMT nano-layers in polyurethane matrix through an ultrasonication assisted process. Effectiveness of ultrasonication process in de-agglomeration of clay stacks in castor oil dispersions was evaluated by optical microscopy and sedimentation test. Structure of nanocomposite coatings was investigated by wide angle X-ray diffraction (WAXD) and Fourier-transform infrared spectroscopy (FT-IR). The anticorrosive properties of nanocomposite coatings were characterized by electrochemical impedance spectroscopy (EIS), Tafel polarization study, water absorption and pull-off adhesion tests. The experimental results showed that PU/OMMT nanocomposite coatings were superior to the neat PU in corrosion protection effects. Also, it was observed that the corrosion protection of polyurethane organoclay nanocomposite coatings is improved as the clay loading is increased up to 3 wt.%.     

Structure and properties of poly(o‐methoxyaniline)–clay nanocomposite materials

In this study, we prepared a series of polymer–clay nanocomposite (PCN) materials that consisted of an emeraldine base of poly(o‐methoxyaniline) and layered montmorillonite. Organic o‐methoxyaniline monomers were first intercalated into the interlayer regions of organophilic clay hosts followed by a one‐step in situ oxidative polymerization. The as‐synthesized PCN materials were subsequently characterized by FTIR spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The molecular weights of PMA extracted from PCN materials and bulk PMA were determined by GPC with THF as eluant. Effects of the material composition on the thermal stability, flame resistance, electrical conductivity, and corrosion inhibition performance of PMA, along with a series of PCN materials in the form of fine powder and coating, were also studied by TGA, limiting oxygen index measurements, four‐point probe technique, and electrochemical corrosion measurements, respectively. Morphological images of as‐synthesized materials were also investigated by SEM. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1072–1080, 2003     

Morphology and mechanical properties of UV-curable castor oil-based waterborne polyurethane/organic montmorillonite nanocomposites

Water resistance is a unique advantage of castor oil-based polyurethane, permitting the application of coatings in humid environments. However, its low thermal decomposition temperature remains a limitation. Here, to demonstrate a simple method to improve the thermal stability of cured films, we prepared an organic montmorillonite dispersion utilising 3-(methacryloyloxy)propyltrimethoxysilane and protonated 3-aminopropyltriethoxysilane for modifying the clay. The method was put into practice by directly mixing the dispersion with a UV-curable castor oil-based waterborne polyurethane dispersion. The inclusion of organic molecule chains from the silane coupling agents noticeably improves the compatibility of polyurethane with organic montmorillonite, which imparts the composite latex with better thermal stability and mechanical properties when the organic montmorillonite additive is 5.0?wt-%.     

Superhydrophobic Silica Nanocomposite Coating by a Low-Temperature Process

We successfully prepared transparent and durable superhydrophobic silica-coating films on cotton substrates at low temperatures. The coatings were produced via cohydrolysis and polycondensation of a hexadecyltrimethoxysilane (HDTMS), tetraethoxyorthosilcate (TEOS), and 3-glycidyloxypropyltrimethoxysilane (GPTMS) mixture. The hydrophobic properties of the nanocomposite coatings were determined using contact-angle and water-gain measurements. The water contact angle for the coated substrates was 141°, whereas, before coating, the contact angle was 0° because of the superhydrophilic nature of cotton. The nanocomposite coating has new applications in daily used materials, especially those with low heat resistance, such as textiles and plastics, and as an environmentally friendly water-repellent substitute for fluorine compounds.     

环氧树脂蓖麻油双重改性水性聚氨酯皮革涂饰剂的合成与性能

以聚氧化丙烯二醇(PPG)和异佛尔酮二异氰酸酯(IPDI)为原料,蓖麻油(CO)和环氧树脂(E-44)为交联剂,采用预聚体分散法合成了一系列用于皮革涂饰的环氧树脂蓖麻油双重改性水性聚氨酯(ECOWPU)。采用FTIR、TEM、DSC、TGA对聚合物结构及膜的性能进行了分析。FTIR表明聚合物中引入了蓖麻油和环氧树脂,羟基和环氧基均参与反应。通过TEM可观察乳液颗粒呈球形,粒径较为均匀。DSC表明,改性后胶膜的微相分离程度增大。TGA表明,环氧树脂和蓖麻油的加入提高了聚氨酯的热稳定性。蓖麻油、E-44含量的增加,均使胶膜拉伸强度逐渐增大,断裂伸长率、吸水率降低。当蓖麻油添加量为4.9%,E-44添加量为7%时,胶膜的综合性能最佳。