Preparation and properties of high viscosity and elasticity asphalt by styrene–butadiene–styrene/polyurethane prepolymer composite modification

The porous asphalt pavements is often used in important occasion for its special properties and performance which can be to a great extent attributed to the binder—high viscosity and elasticity asphalt (HVEA). To prepare high demanding binder for porous asphalt pavements, the polyurethane prepolymer (PUP) and styrene–butadiene–styrene (SBS) were used to modify the matrix asphalt compositely. First, based on a series of physical tests, the effects of binder composition on performance of SBS/PUP HVEA binder (SBS/PUP-HVEA) were investigated. Then the Fourier transform infrared (FTIR) test was conducted to investigate the reaction mechanism of SBS/PUP-HVEA binder. Last, the fluorescence microscopy, stability tests, multiple stress creep recovery test, and differential scanning calorimetry test were carried out to evaluate and compare the phase structure, storage, high-temperature performance, thermostability characteristics of several HVEA binders. It is found that the composite modification of SBS and PUP can produce high quality binder which possesses high viscosity and high elasticity. And the composition of SBS/PUP-HVEA were recommended as follows: Shell-70# can be chosen as matrix asphalt, the contents of SBS modifier (SBS1301:SBS4303 = 1:2), H2122A PUP, chain extender M-OEA, and crosslinker sulfur were suggested 4%, 5%, 0.5%, and 1‰, respectively. The new functional groups observed in FTIR confirmed the existence of physical and chemical reactions in the modification process, which were beneficial to improve the high temperature performance and storage stability of the binder. SBS/PUP-HVEA had good phase structure, storage stability, high temperature performance, and thermostability compared to other HVEA binders. This study demonstrated that the SBS/PUP compositely modified asphalt possessed high viscosity and high elasticity, which can be used in the porous asphalt mixture and other highly demanding working environment as well.     

Preparation of conducting composite particles of styrene–methyl acrylate copolymer as the core and graphite-incorporated polypyrrole as the shell by surfactant-free mini emulsion polymerization

A series of nearly monodispersed poly(styrene–methyl acrylate) (SMA) copolymer latex particles were coated with polypyrrole having different graphite contents. The composite particles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The d.c. conductivity and the electrochemical behaviour of the particles were studied by using a standard four-probe method and a cyclic voltameter respectively. The dependence of electrical conductivity of the composites on the concentration of graphite in the polypyrrole shell, the methyl acrylate content in SMA copolymer and the temperature was also investigated. The electrical conductivity of the samples can be tuned by varying the graphite content in the polypyrrole shell phase. The d.c. conductivity decreases with increasing methyl acrylate content in the core particles. Electrochemical study (at a scan rate of 50 mV s⁻¹) reveals that the particles are sufficiently stable under redox potential and should find potential applications in various optoelectronic devices.     

Preparation and sorption studies of microsphere copolymers containing β-cyclodextrin and poly(acrylic acid)

Microsphere polymeric materials containing β-cyclodextrin (β-CD) and poly(acrylic acid) (PAA) with tunable morphologies were prepared in order to improve their sorption characteristics in aqueous solution. The microsphere polymeric materials were prepared using a (water/oil) micro-emulsion-evaporation technique to condense β-cyclodextrin (β-CD) with PAA at various comonomer ratios and mixing speeds. The β-CD microsphere copolymers were characterized using FTIR, TGA, DSC, SEM, elemental (C and H) microanalyses, and solid state ¹³C-NMR spectroscopy. The sorption properties of the polymeric materials at 295 K in aqueous solution containing p-nitrophenol (PNP) were studied using a dye-based method with UV–Vis spectrophotometry at pH 4.6 and 10.3. The sorption isotherms of copolymer/PNP systems were evaluated with various isotherm models (e.g., Langmuir, BET, Freundlich, and Sips). The Sips isotherm showed the best overall agreement with the experimental results and the sorption parameters provided estimates of the sorbent surface area (12.0–331 m²/g) and the sorption capacity (Q_m = 0.359–2.20 mmol/g at pH = 4.6; Q_m = 0.070–0.191 mmol/g at pH = 10.3) for the microsphere copolymer/PNP systems in aqueous solution. The nitrogen adsorption properties of the microporous copolymers in the solid state were obtained at 77K with BET surface areas ranging from 0.275 to 4.47 m²/g. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

TiCl4 immobilized on a composite support SiO2/MgCl2·x(1,4-butanediol)/poly[styrene-co-(acrylic acid)] for ethylene polymerization: The barrier effect of poly[styrene-co-(acrylic acid)]

By immobilizing titanium-based Ziegler–Natta catalyst on composite support, SiO₂/MgCl₂·x(1,4-butanediol)/poly[styrene-co-(acrylic acid)] (SiO₂/MgCl₂·xBD/PSA) and SiO₂/MgCl₂·xBD/PSA/TiCl₄ (SMPT) were synthesized for ethylene polymerization. SiO₂/MgCl₂·xBD/TiCl₄ without PSA was also prepared for comparison. The results of energy-dispersive X-ray analysis, SEM, and thermogravimetric analysis demonstrated that SMPT had a unique core-mantle-shell structure. The PSA layer can be considered as a barrier for the mass-transfer of reactants based on the results of self-diffusion measurement by pulsed field gradient NMR and ethylene polymerization. The polyethylene produced by SMPT showed high molecular weight (MW) and broad molecular weight distribution (MWD). The influences of PSA content, hydrogen, and comonomer on the ethylene polymerization behavior were also investigated. The results further demonstrated that the PSA layer in the composite support had different diffusion capabilities to the reactants. The physical properties of the produced polyethylene implied the possibility to control the MW and MWD of polyethylene by the manipulation of PSA layer. The catalyst fragmentation during ethylene polymerization was also affected by the PSA shell due to its barrier effect. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synergistic effect of organically modified layered double hydroxide on thermal and flame-retardant properties of poly(butyl acrylate–vinyl acetate)

Organically modified layered double hydroxide (O-LDH) was successfully synthesized by coprecipitation and characterized through Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). O-LDH/poly(butyl acrylate–vinyl acetate) (P(BA-VAc) emulsion was prepared via in situ polymerization, then ammonium polyphosphate (APP) was introduced to obtain the O-LDH/APP/P(BA-VAc) flame-retardant latex. The flame retardancy and thermal behavior of the latexes after evaporation of water were investigated by the limiting oxygen index (LOI) test, vertical burning test (UL-94), and thermal gravimetric analysis (TGA). Compared with the APP/P(BA-VAc) composite, the LOI value of O-LDH/APP/P(BA-VAc) containing 0.5 wt.% O-LDH at the same total additive loading increased to over 30.0%, and its UL-94 increased from no rating to V-0. TG data show that the amount of residues increases obviously when O-LDH is added. The LOI values increased with increasing amounts of char residues. The morphology and microstructure of residues generated during the LOI test were investigated by scanning electron microscopy (SEM). FTIR and X-ray photoelectron spectroscopy (XPS) were used to determine the composition of the residues formed after combustion at 450 °C for 5 min to support a fundamental analysis of the mechanism of char formation.     

Study of the styrene–acrylic emulsion modified by hydroxyl-phosphate ester and its stoving varnish

A styrene–acrylic copolymer emulsion containing hydroxyl-phosphate as flash-rust functional monomer and hydroxypropyl acrylate as cross-linking monomer was synthesized. The effects of the hydroxyl phosphate dosage, the hydroxypropyl acrylate dosage as well as the ratio of soft to hard monomer on the emulsion and coating film were investigated. The results showed that the emulsion of 4% hydroxyl phosphate function monomer and 3% hydroxypropyl acrylate with soft and hard monomer ratio of 1:1.6 and modified emulsion and amino resin ratio of 6:1 resulted in a coating film with the best performance.     

Preparation of proton exchange membranes by radiation-induced grafting of alpha methyl styrene–butyl acrylate mixture onto polyetheretherketone (PEEK) films

Radiation-induced graft copolymerization of alpha methyl styrene (AMS)–butyl acrylate (BA) mixture onto poly(etheretherketone) (PEEK) was carried out to produce copolymer films which were subsequently sulfonated to develop proton exchange membranes. The characterization of membranes was carried out with infrared spectroscopy (FTIR), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis (XRD), contact angle and electron probe microanalysis (EPMA). The presence of sulfonic acid groups within the polymer matrix was confirmed by FTIR. The crystallinity of membranes decreased significantly upon sulfonation process. The melting temperature of the membranes also decreased as compared to the virgin and the grafted films. At the same time, glass transition temperature (T _g) of membranes increased as the grafting increased. Virgin film showed stable thermogram up to ~500 °C while the grafted film had two-step degradation pattern. Sulfonation introduced one additional decomposition range in the membrane. Contact angle images showed the hydrophilic nature of the membrane surface. The EPMA showed the presence of the sulphur across the membrane matrix in a homogenous manner. The membranes showed low resistivity of 62 Ω cm for the graft level of 27 %.     

Synthesis and characteristics of poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles

In this work, the poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles was synthesized by three processes. The first process was to synthesize the poly(methyl methacrylate-co- methacrylic acid) (poly(MMA–MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second process was to polymerize MAA, N-isopropylacrylamide (NIPAAm) and N,N′-Methylenebisacrylamide (MBA) in the presence of poly(MMA–MAA) latex particles to form the linear poly(MMA–MAA)/crosslinking poly(MAA-NIPAAm) core–shell latex particles, and then the core–shell latex particles were heated in the presence of ammonia solution to form the poly(MAA-NIPAAm) thermosensitive hollow latex particles. In the third process, the poly(MAA-NIPAAm) hollow latex particles reacted with ZnO nanoparticles to form the poly(MAA-NIPAAm)/ZnO thermosensitive composite hollow latex particles on which the ZnO nanoparticles were adsorbed. Besides, a novel process was used to synthesize the poly(MAA-NIPAAm)/ZnO composite latex particles in which the ZnO nanoparticles were encapsulated. The effects of various variables on the morphology of poly(MAA-NIPAAm)/ZnO composite hollow latex particle were studied.     

Preparation and characterization of water-based polyurethane–acrylic hybrid nanocomposite emulsion based on a new silane-containing acrylic macromonomer

A new silane-containing acrylic macromonomer, maleimidedoethoxybutoxydimethylsiloxy butyl acrylate (MEBDMSBA), based on maleic anhydride (MA), ethanolamine (EA), 1,4-butanediol (BDO), dichlorodimethylsilane (DCDMS), and acrylic acid (AA) has been synthesized for formulation of waterborne polyurethane (WPU). Also a series of new silane-containing WPU, methyl methacrylate (MMA), MEBDMSBA, and montmorillonite (MMT) with organically modified montmorillonite (OMMT) content (1.25 wt%) hybrid nanocomposites have been successfully prepared by the emulsion polymerization in the presence of a WPU dispersion, using ammonium peroxodisulfate (APS) as an initiator. The WPU dispersion has been synthesized by a polyaddition reaction of isophorone diisocyanate (IPDI) on polypropylene glycol (PPG-1000) and dimethylol propionic acid (DMPA) as chain extender. The monomer was characterized by Fourier transformer infrared spectroscopy (FTIR), elemental analysis, proton (¹H NMR), and carbon (¹³C NMR) nuclear magnetic resonance spectroscopes, respectively. The nanocomposite emulsions were also characterized using Fourier transform infrared spectroscopy (FTIR) and laser light scattering. Thermal properties of the copolymers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The OMMT was characterized by FTIR and X-ray diffraction (XRD). The morphology of copolymers was investigated by scanning electron microscopy (SEM) and transition electron microscopy (TEM), and then the effects of silane concentrations on the water absorption ratio were examined. Results showed that OMMT could improve the properties of emulsion; in other words, the properties of nanocomposite emulsion were better when compared with those of the silane–acrylate emulsion.     

Melting and crystallization behaviors of compatibilized poly(trimethylene terephthalate)/acrylonitrile–butadiene–styrene blends

The melting and crystallization behaviors of poly(trimethylene terephthalate) (PTT)/acrylonitrile–butadiene–styrene (ABS) blends were investigated with and without epoxy or styrene–butadiene–maleic anhydride copolymer (SBM) as a reactive compatibilizer. The existence of two separate composition-dependent glass-transition temperatures (T_g's) indicated that PTT was partially miscible with ABS over the entire composition range. The melting temperature of the PTT phase in the blends was also composition dependent and shifted to lower temperatures with increasing ABS content. Both the cold crystallization temperature and T_g of the PTT phase moved to higher temperatures in the presence of compatibilizers, which indicated their compatibilization effects on the blends. A crystallization exotherm of the PTT phase was noticed for all of the PTT/ABS blends. The crystallization behaviors were completely different at low and high ABS contents. When ABS was 0–50 wt %, the crystallization process of PTT shifted slightly to higher temperatures as the ABS content was increased. When ABS was 60 wt % or greater, PTT showed fractionated crystallization. The effects of both the epoxy and SBM compatibilizers on the crystallization of PTT were content dependent. At a lower contents of 1–3 wt % epoxy or 1 wt % SBM, the crystallization was retarded, whereas at a higher content of 5 wt %, the crystallization was accelerated. The crystallization kinetics were analyzed with a modified Avrami equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of styrene–acrylic emulsion on bond performance and interface microstructure of repair mortar of ternary cementitious system

This study investigates the effects of styrene–acrylic emulsion (SAE) as a modifier and interfacial agent on the interfacial bond performance of ordinary Portland cement–aluminate cement–gypsum (PAG) repair mortar. The hydration products and interfacial microstructure are analyzed via x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The results demonstrate that the addition of SAE can effectively enhance the tensile bond strength and flexural bond strength of the PAG repair mortar, and the optimal addition amount of SAE is 10 wt%. The tensile and flexural bond strengths of the PAG repair mortar with SAE interfacial agent at 40% concentration are 1.38 and 1.34 times than those of the mortar without the interfacial agent, respectively. XPS and FTIR analyses reveal that the carboxyl groups in SAE and Ca²⁺ generated from cement hydration form Ca²⁺–carboxyl complexes. The SEM and XRD analyses indicate that SAE can alter the distribution and size of crystals at the bond interface and considerably reduce the thickness of the bond interface; however, SAE cannot change the type of hydration products at the bond interface.     

Preparation of tetrafluoro-λ6-sulfanyl bridged-bonding perfluoroalkyl styrene and its emulsion copolymerization with acrylate monomers for cotton fabrics finishing

4-(Perfluorobutyl)styrene, 4-(Perfluorohexyl)styrene, 4-[Perfluorobutyl(tetrafluoro-λ⁶-sulfanyl)]styrene (C₄F₉ SF₄ styrene), and 4-[Perfluorohexyl(tetrafluoro-λ⁶-sulfanyl)]styrene (C₆F₁₃ SF₄ styrene) were prepared in two or three steps. The short-chain perfluoroalkyl groups are modified through the insertion of tetrafluoro-λ⁶-sulfanyl linked groups ( SF₄ ). The prepared perfluoroalkyl styrene acts as functional monomers to react with butyl acrylate, methyl methacrylate, and hydroxyethyl methacrylate for emulsion copolymerization to obtain side-chain fluoropolymers. The long-chain fluoropolymer formed in contrast to the tetrafluorosulfanyl ( SF₄ ) modified ones. The emulsions were applied on cotton fabrics to give hydrophobicity. The result showed that the fabrics treated with tetrafluorosulfanyl-modified fluoropolymers were more hydrophobic, indicating that the introduction of  SF₄ was beneficial to provide lower surface energy and obtain better water repellent performance. The water contact angles record the varying degrees of variation in polymer degradation under UV exposure. The result showed that, as the perfluoroalkyl is bonded by  SF₄ , when comparing with the carbon-chain perfluoroalkyl polymer, the tetrafluorosulfanyl-modified fluoropolymer is more degradable during UV irradiation.     

Synthesis, characterization, and sorption properties of water-insoluble poly(2-acrylamido-2-methyl-1-propane sulfonic acid)–montmorillonite composite

The sorption properties of composites based on 2-acrylamido-2-methyl-1-propane sulfonic acid and montmorillonite are presented. Gel-type composites were obtained via in situ polymerization. Resin particles presented exfoliated morphologies, as suggested by X-ray diffraction. The addition of montmorillonite resulted in enhanced mechanical properties, as evaluated by Vickers microhardness tests. The swelling performances of the resins exhibited a fast initial water uptake, reaching the maximum absorption capacity after less of 1 h of contact. A batch procedure was used to evaluate the sorption characteristics of the composites, and the effects of pH, montmorillonite content, and time were studied. The composites showed high adsorption capacities at pH values of 3.0 and 5.0, and the addition of montmorillonite did not result in a significant enhancement of their adsorption capacity. The equilibrium adsorption performance can be described by the Langmuir isotherm, while kinetic experiments revealed an excellent agreement with the pseudo-second-order model.     

Mechanical properties and microstructure of porous BN–SiO2–Si3N4 composite ceramics

Porous silicon nitride (Si₃N₄) ceramics incorporated with hexagonal boron nitride (h-BN) and silica (SiO₂) nanoparticles were fabricated by pressureless-sintering at relatively low temperature, in which stearic acid was used as pore-making agent. Bending strength at room and high temperatures, thermal shock resistance, fracture toughness, elastic modulus, porosity and microstructure were investigated in detail. The mechanical properties and thermal shock resistance behavior of porous Si₃N₄ ceramics were greatly influenced by incorporation of BN and SiO₂ nanoparticles. Porous BN–SiO₂–Si₃N₄ composites were successfully obtained with good critical thermal shock temperature of 800 °C, high bending strength (130 MPa at room temperature and 60 MPa at 1000 °C) and high porosity.     

Preparation and properties of chromium‐containing hydrotreating catalysts (Ni–Mo)/ZrO2–Cr2O3

The properties of hydrotreating catalysts (Ni–Mo)/ZrO₂–Cr₂O₃ containing either 10 or 90 mol% of Cr₂O₃ have been studied in the model reactions of thiophene hydrodesulfurisation (HDS) and tetralin hydrogenation (HYD). Catalysts were characterized by X‐ray diffraction, UV‐visible spectroscopy and measurements of textural properties. It has been shown that the presence of chromium in the NiMo/ZrO₂ systems makes them more hydrogenating, because of the formation of chromium sulphide Cr₂S₃. Mixed hydrous or crystalline oxide Cr–Zr can be sulfided under mild conditions (400°C, H₂S/H₂) leading to highly dispersed Cr₂S₃ which is impossible for individual Cr₂O₃. Such systems are several times more active in HYD of tetralin than industrial NiMo/Al₂O₃ reference catalyst. At the same time in the presence of chromium, the synergy of catalytic activity between Ni and Mo in the reaction of HDS of thiophene was lowered, apparently because of hindering of formation of mixed sulfide Ni–Mo–S active sites due to the stronger interaction between Ni and Cr species than that of Ni and Mo. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis of emulsion styrene butadiene rubber by reversible addition–fragmentation chain transfer polymerization and its properties

Emulsion polymerization is generally used to synthesize styrene butadiene rubber (SBR), and the molecular weight of this rubber can be easily increased. However, the broad molecular weight distribution (MWD) of SBR increases energy loss and adversely affects the dynamic viscoelastic properties. To overcome this disadvantage, reversible addition–fragmentation chain transfer (RAFT) polymerization, which is a type of living polymerization, is applied to emulsion polymerization for preparing RAFT emulsion SBR (ESBR). The molecular weight and microstructure of RAFT ESBR are compared to those of commercially available ESBR 1502 by gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. The aforementioned two polymers are used to prepare unfilled ESBR compounds, which are compared in terms of key physical properties (abrasion resistance, mechanical properties, and dynamic viscoelastic properties). It is confirmed that various physical properties of RAFT ESBR are improved due to its narrow MWD. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47069.     

Preparation,properties, and laser processing of poly(ɛ-caprolactone)/poly(lactic acid) blends with addition of natural fibers as a potential for printing plates application

In this research, biodegradable blend of poly(ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA) is proposed as a new material for the production of a printing plate for embossing process. Printing plates for embossing consist of raised printing elements and recessed nonimage elements. In production of printing plates, laser technology was used in order to form a relief printing plate. The embossing process is based on the principle of the pressure of the relief printing plate into the printing substrate, which causes the controlled deformation of the substrate and three-dimensional (3D) effect. Coir fibers (CFs) were added as a natural filler to PCL/PLA blends to improve and adjust the properties of produced blends. Scanning electron microscopy micrographs, dynamic mechanical analysis analysis, roughness, and hardness were measured on prepared materials, and 2D and 3D microscopy was conducted on laser engraved printing plates. Results have shown that the addition of CFs improved the mechanical properties of produced materials. DMA results indicate the semicrystalline structure of all prepared blends, and that the addition of CFs raises the elasticity of the composites. Laser engraving showed that it is possible to engrave the produced biodegradable materials and to use it as a material for production of printing plates.     

Preparation and study of the mechanical and optical properties of infrared transparent Y2O3–MgO composite ceramics

In this study, fine Y₂O₃–MgO composite nanopowders were synthesized via the sol–gel method. Dense Y₂O₃–MgO composite ceramics were fabricated by pre-sintering the green body in air at different temperatures for 1 h and then subjecting the sintered bodies to hot isostatic pressing at 1300°C for 1 h. The effects of pre-sintering temperature on the microstructural, mechanical, and optical properties of the resulting ceramics were studied. The average grain size of the ceramics was increased, whereas their hardness and fracture toughness were decreased with increasing pre-sintering temperature. A maximum fracture toughness of 1.42 MPa·m^1/2 and Vickers hardness of 10.4 GPa were obtained. The average flexural strength of the ceramics was 411 MPa at room temperature and reached 361 MPa at 600°C. A transmittance of 84% in the 3–5 µm region was obtained when the composite ceramics were sintered at 1400°C. Moreover, a transmittance of 76% in the 3–5 µm region was obtained at 500°C.     

Effect of functionalised core–shell microgels prepared by emulsion polymerisation on acrylic coatings properties

The influence of hydroxyl-functionalised acrylic core–shell microgels incorporated into a solvent-borne acrylic binder system on the properties of coatings is described in this paper. Our approach has been to show the usefulness of prepared functionalised microgels as coating modifiers. This subject was shown to be connected with the selection of an appropriate solvent with good affinity for microgels and the film-forming polymer. Therefore the swelling behaviour of microgels in selected solvents as a function of microgel composition is discussed as well. The structured microgels were prepared by first making an aqueous emulsion via the semi-batch emulsion copolymerisation, then dehydrating the system by air drying followed by grinding in a mill. The resulting agglomerates of spherical microgel particles were dispersed in convenient organic solvent media and after that added to the thermosetting solvent-borne acrylic binder system. It was shown that the application of core–shell microgels did not affect the surface appearance and transparency of coatings. Moreover, the presence of microgel network precursors improved corrosion resistance of coatings.