改性纳米SiO2/聚氨酯-含氟丙烯酸酯无皂乳液合成及其胶膜性能表征

引言水性聚氨酯相对溶剂型聚氨酯具有不燃、气味小、不污染环境等优点[1-2],从而广泛用于涂料[3]、胶黏剂[4]、油墨[5]等领域。目前,常用于软包装领域的薄膜主要是表面能很低的非极性膜,而水性聚氨酯胶黏剂具有较高的表面自由能,对非极性膜的润湿性差,因此需要降低水性聚氨酯的表面张力,达到润湿非极性膜的目的。     

Propylene-ethylene Copolymer Filled Nanocomposites: Influence of Zn-ion Coating upon Nano-SiO2 on Structural,Thermal, and Dynamic Mechanical Properties

Propylene-ethylene copolymer (EP) nanocomposites based on nano-SiO₂ with and without Zn-ion coating were developed by conventional melt blending technique in a sigma internal mixer. Two composites each with 2.5 wt% filler were developed. The first composite was made by melt blending EP with nano-SiO₂ in a co-rotating sigma internal mixer. The second one was obtained by melt blending the same EP, but with Zn-ion coated nano-SiO₂. In case of Zn-ion coated nano-SiO₂ filled EP, wide-angle X-ray diffraction study (WAXD) showed a decrease in interplanar distance and lamellar polymer crystal size when compared to nano-SiO₂ filled EP. Differential scanning calorimetric (DSC) results showed Zn-ion coated nano-SiO₂ acting more as an effective nucleating agent than that of the nano-SiO₂. Thermogravimetric analysis (TGA) results showed improved thermal stability for EP in the presence of both the nanofillers. However, the thermal stability of Zn-ion coated nano-SiO₂ filled EP is higher than that of the nano-SiO₂ filled EP. Scanning electron microscope (SEM) study reveals that the Zn-ion coated nano-SiO₂ homogeneously distributed in the matrix, whereas nano-SiO₂ forms chainlike aggregates in the matrix phase. Dynamic mechanical analysis (DMA) study indicates that both the fillers increase storage modulus, E′; this increment is more prominent in nano-SiO₂ filled EP due to the formation of chain-type aggregates of nano-SiO₂.     

Inhibited transesterification and enhanced fibrillation of TLCP by nano-SiO2 in polycarbonate matrix

Hybrid composites composed of a thermotropic liquid crystalline polymer (TLCP), nano-SiO₂ and polycarbonate (PC) were prepared by melt blending in a twin-screw extruder. Infrared spectroscopy analysis indicated that the transesterification between PC and TLCP molecules during melt blending was significantly reduced in TLCP/PC blends filled with nano-SiO₂, compared to the unfilled TLCP/PC one. Scanning electron microscopy (SEM) observation showed that better compatibility and finer TLCP dispersion were reached in the unfilled blend, which made the fibrillation of TLCP difficult in capillary flow even at high shear rate. In contrast to this, well-developed TLCP fibrils were formed by capillary flow in nano-SiO₂ filled TLCP/PC blends. By increasing the nano-SiO₂ concentration and shear rate, the fibrillation of TLCP was significantly enhanced. Thermodynamically the interfacial tension between these components and dynamically the viscosity ratio of TLCP to PC were used to investigate the mechanism of nano-SiO₂ in inhibiting the transesterification and enhancing the fibrillation of TLCP droplets in these hybrid composites.     

Fibrillation of liquid crystalline polymer in polysulfone promoted by increased system elasticity via adding nano-silica

Ternary blends composed of a liquid crystalline polymer (LCP), nano-SiO₂ and polysulfone (PSF) were prepared by melt blending. Very long and perfectly oriented LCP fibrils were in situ formed in capillary flows by adding 5 vol% of nano-SiO₂ to binary PSF/LCP blend. Dynamic rheology analysis indicated that the sharp increase of elasticity was caused by higher content of nano-SiO₂. Then the entrance angle was decreased and elongational stress increased when the polymer melt flowed through the abrupt contraction, which resulted in the fibrillation of LCP in PSF/LCP/nano-SiO₂ system.     

核壳型纳米SiO2/含氟聚丙烯酸酯复合乳液的合成与表征

采用原位乳液聚合法,在可聚合阴离子乳化剂/非离子乳化剂复配体系下,以γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)改性的纳米SiO2、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸(AA)等为核相组成,以MMA、BA及甲基丙烯酸十二氟庚酯(DFMA)为壳相单体,合成纳米SiO2/含氟聚丙烯酸酯复合乳液.考察了纳...     

Effect of acrylic acid and hydroxyethyl methacrylate modified nano-SiO2 particles on poly(methyl methacrylate-hydroxyethyl methacrylate) soap-free emulsion polymerization

Nano-SiO₂ powder was modified with acrylic acid (AA) and hydroxyethyl methacrylate (HEMA), respectively. The kinetics of the soap-free emulsion polymerization of methyl methacrylate (MMA) and HEMA in the presence of unmodified or modified nano-SiO₂ particles was investigated. The structure of the nano-SiO₂ particles and the Poly(MMA-HEMA) composite emulsion was characterized by Fourier transform infrared spectroscope (FT-IR). The particle size and size distribution of the emulsion, the morphology of emulsion particle, the surface tension, and ionic conductivity of these systems before and after polymerization were determined. The IR spectra showed that the organic modifiers were incorporated onto the surface of the nano-particles. In addition, the solid content and monomer conversion of the Poly(MMA-HEMA) composite emulsion with modified nano-SiO₂ are higher than that with original inorganic particles. The particle size became smaller and the particle distribution narrowed after applying the modified nano-SiO₂ particles. The SEM observation demonstrated that the shapes of these emulsion particles were uniform sphere. The surface tension and ionic conductivity increased significantly after polymerization.     

Surface and mechanical properties of an organic-inorganic super- hydrophobic coating using modified nano-SiO2 and mixing polyurethane emulsion as raw materials

A series of organic-inorganic super-hydrophobic coatings were prepared using nano-SiO₂ particles modified by fluorine and silicone coupling agents, and a mixing polyurethane emulsion as main raw materials. The mixing polyurethane emulsion was consisted of the polyurethane emulsion end-terminated by double bond (WPUD) and polyurethane emulsion modified by silicone (WPUS). The influence of content of modified nano-SiO₂ particles and the weight ratio of WPUS to WPUD on microstructure and hydrophobicity of the coating surface were studied. The morphologies of coating surface were examined using SEM and AFM, hydrophobicity of the coating was researched by examining static water contact angle and so on. It was found that modified nano-SiO₂ particle was an indispensable factor during the preparation of super-hydrophobic coating. The roughness and hydrophobicity of the coating surface were enhanced obviously with an increase of the content of the modified nano-SiO₂ particles. When the content of the modified nano-SiO₂ particles increased up to 1.5%, the surface of coating possessed good super-hydrophobicity, and static water contact angle reached 169.1°. It was also noticed that the weight ratio of WPUS to WPUD in the base layer has also an important influence on the hydrophobicity and mechanical property of coating surface. With an increase of the ratio of WPUS to WPUD the hydrophobicity of the coating was enhanced, the tensile strength and peel strength reduced, but the elongation at break increased. When the weight ratio of WPUS to WPUD reaches up to 9/100, the static water contact angle reaches the maximum value of 169.1°.     

Preparation of novel hydrophobic magnetic Fe3O4/waterborne polyurethane nanocomposites

Magnetic Fe₃O₄/waterborne polyurethane nanocomposites were synthesized based on waterborne polyurethane (WPU) and amino-functionalized Fe₃O₄ by in situ polymerization. The Fe₃O₄ nanoparticle was found to be uniformly distributed in Fe₃O₄/WPU nanocomposites with linear or crosslinked structure. In addition, the formation mechanism and magnetic conduction mechanism of stable inorganic–organic nanocomposites were discussed. The experimental results showed that the thermal stability, magnetic, and mechanical properties of magnetic Fe₃O₄/waterborne polyurethane nanocomposites were improved by amino functionalized Fe₃O₄. Furthermore, the defoaming property of the emulsion and the hydrophobic property of magnetic Fe₃O₄/waterborne polyurethane nanocomposites were improved by the 1-hexadecanol-terminated prepolymer. What more, polycaprolactone (PCL)-based Fe₃O₄/WPU nanocomposites have excellent mechanical properties (The tensile strength is over 30 MPa, the elongation rate is above 300%.) and magnetic properties. Magnetic Fe₃O₄/waterborne polyurethane nanocomposites will be used in the field of hydrophobic and microwave absorbent materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48546.     

Structure and properties of polyurethane/nanosilica composites

Nanosilica particles were directly introduced into polyester polyol resins through in situ polymerization and blending methods, then cured by isophorone diisocyanate (IPDI) trimers to obtain nanocomposite polyurethanes. FTIR and TGA analyses indicated that more polyester segments had reacted with silica particles during in situ polymerization than during the blending method, accompanied by higher T_g and more homogeneous dispersion of nanosilica particles in the polymer matrix from in situ polymerization. Maximum values in T_g, tensile properties, macrohardness, abrasion resistance, and UV absorbance were obtained when the particle size of silica was about 28 nm. The polyurethane/nanosilica composites obtained by in situ polymerization generally had better mechanical properties than those by the blending method except for some unexpected macrohardness at relatively high silica content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1032–1039, 2005     

Effect of nano-SiO2 on the compatibility of PVA/RSF blend

A series of poly(vinyl alcohol) (PVA)/regenerated silk fibroin (RSF)/nano-silicon dioxide (nano-SiO₂) blend films were prepared by solution casting method, in which nano-SiO₂ was obtained via sol?Cgel process. The structure, properties, and morphology of the films related to the compatibility were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). XRD peaks of PVA/RSF/nano-SiO₂ (1.0?wt?%) blends decreased in intensity indicated that formation of PVA and RSF crystal lattices was hindered by nano-SiO₂ particles. FTIR spectroscopy analysis of PVA/RSF/nano-SiO₂ films confirmed that both Si?CO?CC linkage and hydrogen bonding were formed among PVA, RSF, and nano-SiO₂. SEM showed that there was no obvious phase separation in PVA/RSF/nano-SiO₂ (1.0?wt?%) film although small uniform blur particles can still be found. In addition, TEM showed nano-particles were well dispersed through the PVA/RSF polymer matrix. Besides, the observed shift in glass transition temperatures (T _g) and improvement in thermal properties of composite films suggested the enhanced compatibility due to interfacial bonding and intermolecular interactions. Therefore, these results indicated that the compatibility of PVA/RSF was improved effectively by the addition of nano-SiO₂.     

Preparation and photochromic properties of waterborne polyurethane containing spirooxazine groups

Two novel photochromic spirooxazines, SO 1 and SO 3, were successfully prepared and characterized by Fourier transform infrared spectroscopy (FTIR), ¹H-NMR, and mass spectrometry with electrospray ionization (ESI-MS). SO 1 was doped and grafted with waterborne polyurethane (WPU) to afford D₁-WPU and G₁-WPU. D₃-WPU was prepared by doping SO 3 with waterborne polyurethane. FTIR spectra indicated that SO 1 was grafted onto waterborne polyurethane successfully. Scanning electron microscopy proved that spirooxazines of D-WPU can be effectively dispersed in a waterborne polyurethane matrix, and spirooxazines of G-WPU are evenly distributed in the copolymer. The results showed that the light transmittance of modified waterborne polyurethane films decreased compared with pure waterborne polyurethane films, but the water resistance and tensile strength were better. Ultraviolet–visible spectra demonstrated that the thermal stability of spirooxazine derivatives improved significantly after being modified. The fading rate constant of the D₃-WPU film (k = 0.0079 s^-1) during the discoloration process decreased 9.77 times in contrast to SO 3 in ethanol, which showed that the thermal stability of spirooxazine in WPU film was obviously enhanced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47067.     

Effect of nano-SiO2 particle size on the formation of LLDPE/SiO2 nanocomposite synthesized via the in situ polymerization with metallocene catalyst

Here, we revealed the effect of particle size of the nanoscale SiO₂ on catalytic and characteristic properties of LLDPE/nano-SiO₂ composites synthesized via the in situ polymerization with a zirconocene/MAO catalyst. In the experiment, SiO₂ (10 and 15 nm) was first impregnated with MAO. Then, copolymerization of ethylene/1-hexene was performed in the presence of nano-SiO₂/MAO to produce LLDPE/nano-SiO₂ composites. It was found that the larger particle exhibited higher polymerization activity due to fewer interactions between SiO₂ and MAO. The larger particle also rendered higher insertion of 1-hexene leading to decreased melting temperature (T_m). There was no significant change in the LLDPE molecular structure by means of ¹³C NMR.     

In situ synthesis and properties of PMR PI/SiO2 nanocomposites

Phenylethynyl-terminated polymerization of monomer reactant thermosetting polyimide (PI) was synthesized, and the PI/SiO₂ nanocomposite films were prepared via in situ polymerization of monomer with the nano-SiO₂ particles. Analysis indicated that the surfaces of the nano-SiO₂ slightly react to the PI, and nano-SiO₂ was homogeneously dispersed in the PI at low filling content while agglomerate was a presence of high filling content. Thermogravimetric analysis showed that the decomposition temperatures of the PI/SiO₂ nanocomposites were increasing as the increasing of filler contents when the nano-SiO₂ content was below 9 wt %, but it showed a decreased tendency when it was above 9 wt %. Tribological studies showed that the nano-SiO₂ contributed to the significant decreasing of the friction coefficient and wear rates of the PI at dry sliding condition of low filler content, and the PI/SiO₂ nanocomposites could be promising material used as tribomaterial in dry sliding condition against GCr15 steel. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of block and graft waterborne polyurethane modified with α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane and α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane

In this study, α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane and α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane were used to prepare block and graft waterborne polyureathane–polysiloxane copolymer dispersions. α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane was synthesized by hydrosilylation, methoxylation and equilibrium reactions; α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane was synthesized via hydroxyl protection, alkylation, anionic ring‐opening polymerization, hydrosilylation, and deprotection. Block and graft waterborne polyurethane–polysiloxane copolymer dispersions were prepared by the reaction of poly(propylene glycol) (PPG), toluene diisocyanate (TDI), 2,2‐dimethylol propionic acid (DMPA), 1,4‐butanediol (BDO), α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane, and α‐N,N‐dihydroxy‐ethylaminopropyl‐ω‐butylpolydimethylsiloxane. The water absorption of block and graft waterborne polyurethane–polysiloxane copolymer films decreased from 163.9 to 40.2% and 17.3%, respectively, when percent of polysiloxane (w/w) increased from 0 to 5%, and the tensile strength of the block waterborne polyurethane–polysiloxane copolymer films decreased while the tensile strength of graft waterborne polyurethane–polysiloxane copolymer films increased with increase of percent of polysiloxane. For graft waterborne polyurethane–polysiloxane films, the tensile strength would decrease when percent of polysiloxane was more than 3%. POLYM. ENG. SCI., 54:805–811, 2014. © 2013 Society of Plastics Engineers     

Effect of Long-Chain Acrylate on the Properties of Polyacrylate/Nano-SiO2 Composite Leather Finishing Agent

Polyacrylate/nano-SiO₂ composite leather finishing agent was prepared via emulsion polymerization with butyl acrylate, methyl methacrylate, lauryl methacrylate as the main raw materials. The effects of different polymerization processes, lauryl methacrylate on the properties of composite were studied. The results show pre-emulsified emulsion polymerizations obtain a lower gel rate and higher conversion rate. Adding lauryl methacrylate can improve the water resistance, physical and mechanical properties of the composite film. Leather finished with P(Butyl acrylate/Methyl methacrylate/Lauryl methacrylate)/nano-SiO₂ composite latex show lower water-vapor permeability, lower water uptake and better resistence to the external force than that of the leather finished with P(Butyl acrylate/Methyl methacrylate)/nano-SiO₂ composite latex.     

纳米二氧化硅复合涂料的制备及其性能

通过表面改性技术制备了疏水性的纳米二氧化硅粒子,粒径约50 nm.在机械搅拌和超声场共同作用下,将纳米二氧化硅均匀分散到聚氨酯清漆中,制得纳米二氧化硅复合涂料,考察了纳米二氧化硅复合量对复合涂料性能的影响.直接腐蚀实验、阳极极化和交流阻抗测试结果表明,加入偶联剂改性的纳米二氧化硅后,复合聚氨酯清漆在氯化钠溶液中的抗腐蚀能力明显提高,浸泡腐蚀失重量减小约20％～70％,阳极腐蚀电流降低1个数量级以上,低频区涂层阻抗值增大2个数量级以上.油漆剪切强度和剥离强度实验显示,纳米复合漆膜的附着力增加.     

Preparation and rheological behaviors of PA6/SiO2 nanocompiste

The polyamide 6 (PA6)/SiO₂ nanocomposites were prepared by in situ polymerization and the rheological behaviors were investigated. The morphology of resultant materials was characterized by scanning electron microscopy (SEM) and the rheological behaviors were characterized by capillary rheometer. The results showed that the SiO₂ particle size was around 50 nm and the particles dispersed evenly in PA6 matrix. The nanocomposites were pesudoplastic fluids and the apparent viscosities of nanocomposites increased initially and then decreased with the increase in nano-SiO₂ content at the same temperature. The non-Newtonian indexes of nanocomposites were smaller than those of pure PA6. With the increase in nano-SiO₂ content the apparent viscous activation energies of nanocomposites increased initially and then decreased. The rheological behaviors revealed that there were strong interactions between PA6 macromolecule chains and nano-SiO₂ particles.     

Mechanical properties of carbon fiber composites modified with nano-SiO2 in the interphase

The performance of carbon fibers-reinforced composites is dependent to a great extent on the properties of fiber–matrix interface. To improve the interfacial properties in carbon fibers/epoxy composites, nano-SiO₂ particles were introduced to the surface of carbon fibers by sizing treatment. Atomic force microscope (AFM) results showed that nano-SiO₂ particles had been introduced on the surface of carbon fibers and increase the surface roughness of carbon fibers. X-ray photoelectron spectroscopy (XPS) showed that nano-SiO₂ particles increased the content of oxygen-containing groups on carbon fibers surface. Single fiber pull-out test (IFSS) and short-beam bending test (ILSS) results showed that the IFSS and ILSS of carbon fibers/epoxy composites could obtain 30.8 and 10.6% improvement compared with the composites without nano-SiO₂, respectively, when the nano-SiO₂ content was 1 wt % in sizing agents. Impact test of carbon fibers/epoxy composites treated by nano-SiO₂ containing sizing showed higher absorption energy than that of carbon fibers/epoxy composites treated by sizing agent without nano-SiO₂. Scanning electron microscopy (SEM) of impact fracture surface showed that the interfacial adhesion between fibers and matrix was improved after nano-SiO₂-modified sizing treatment. Dynamic mechanical thermal analysis (DMTA) showed that the introduction of nano-SiO₂ to carbon fibers surface effectively improved the storage modulus of carbon fibers/epoxy.     

有机硅协同改性含氟聚氨酯

采用细乳液法结合超声分散技术制备出水性聚氨酯（WPU）、含氟水性聚氨酯（FPAPU）和KH570、羟基硅油协同改性的氟硅水性聚氨酯乳液（SiFPAPU）。通过红外光谱（FTIR）、粒度分布（PSA）、接触角（CA）、表面能分析、原子力显微镜（AFM）、扫描电镜（SEM）、热失重（TG）、拉伸试验表征了WPU、FPAPU、SiFPAPU复合乳液表面性能、热稳定性和力学性能。结果表明随着有机硅协同组分加入,SiFPAPU乳液粒径降低为44.0nm,但粒径分布变宽;成膜后,水相和油相（CH₂I₂）接触角分别达到122.6°、92.5°,表面能降低为11.82mJ/m²,乳胶膜表面平整均一,断面出现明显分层。同时SiFPAPU热稳定性增强,拉伸强度较未改性聚氨酯提高126.1%。     

TIPS behavior for IPP/nano-SiO2 blend membrane formation and its contribution to membrane morphology and performance

In the present work, the TIPS behavior of isotactic polypropylene(iP P)/di-n-butyl phthalate(DBP)/dioctyl phthalate(DOP)/nano-SiO_2 system and the competition relation between liquid–liquid phase separation and polymer crystallization are successfully adjusted by adding nano-SiO_2. The liquid–liquid phase separation temperature of the system increases with increasing nano-SiO_2 content. Besides, iP P crystallization temperature is also changed after adding nano-SiO_2. IPP/nano-SiO_2 blend hollow fiber microporous membrane is prepared via TIPS method. SEM photos show that the membrane exhibits mixed morphology combining cellular structure relating to liquid–liquid phase separation and branch structure originating from polymer crystallization. The relative weight of cellular structure first decreases and then increases with the increase of nano-SiO_2 content. Furthermore, porosity, connectivity among pores and pure water flux of the membrane first increase and then decrease with increasing nano-SiO_2 content. However, mechanical performance of the membrane is improved at all times with increasing nano-SiO_2 content.