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It is essential for nanoparticles to delivery drugs accurately and penetrate deeply to tumor. However, complicated tumor microenvironment such as elevated tumor interstitial fluid pressure (IFP) and solid stress reduces the transport efficiency of nanomedicines in tumor. Methods: We herein report a drug delivery system of phenylboronic acid-decorated soy protein nanoparticles with the size of 30 nm, 50 nm and 150 nm. In vitro examinations including cytotoxicity, cellular uptake and penetration in multicellular tumor spheroids and in vivo observations including IFP and tumor solid stress measurements and antitumor activity were performed. Results: It was found that phenylboronic acid moiety could endow the nanoparticles actively targeting affinity to sialic acid (SA) which overexpressed in tumor cells. Simultaneously soy protein could improve tumor microenvironment such as reduction of IFP and tumor stress. Among the soy protein nanoparticles with different sizes, 30 nm-sized nanoparticles showed the best cellular uptake and highest cytotoxicity in vitro after loading doxorubicin (DOX). In vivo, 30 nm-sized nanoparticles showed the best tumor microenvironment improvement efficiency, leading to the enhanced drug accumulation and antitumor efficiency when combination with DOX. Conclusion: Our study introduces a bioactive nanoparticulate design strategy to actively target and significantly improve tumor microenvironment for enhanced cancer therapy.

It is important for antitumor drugs to accumulate at the tumor site and penetrate deeply to play a role in treatment. However, it is difficult for the drugs to reach the destination on account of the complex tumor microenvironment such as elevated tumor interstitial fluid pressure (IFP) and solid stress. Here, we report a type of nanocarrier composed entirely of Camellia oleifera protein (COP), which could lower tumor IFP and solid stress. Its physicochemical properties, cellular uptake, in vitro cytotoxicity and tumor perfusion, biodistribution, and in vivo antitumor efficiency were evaluated. It was found that COP NPs had good cellular uptake ability and cytocompatibility. When loading doxorubicin, COP NPs showed an in vitro concentration-dependent cytotoxicity. Importantly, the tumor IFP and solid stress were greatly reduced after injecting COP NPs into tumor-bearing mice, leading to more drug accumulating in the tumor and a longer survival time for tumor-bearing mice. Therefore, our study provided a new strategy to improve the tumor microenvironment and to achieve better antitumor efficiency.

In this work, in order to investigate the reinforcement effects of organomontmorillonite (OMMT) in soybean oil-based polyurethane (PU)/epoxy (EP) interpenetrating polymer networks (IPNs), a series of OMMT-modified PU/EP IPNs were prepared. The impacts of OMMT on the structure, morphology, glass transition, damping properties, thermal stability, and mechanical properties of the PU/EP IPNs were characterized by X-ray diffraction, scanning electronic microscope, dynamic mechanical analysis, thermogravimetry analysis, and tensile test. Results reveal that the addition of OMMT increases the glass transition temperature of the PU/EP IPNs. However, the damping properties of the PU/EP IPNs are lowered with the incorporation of OMMT. The addition of OMMT heightens the thermal stability of the PU/EP IPNs. Tensile tests show that the addition of OMMT significantly increases the tensile strength and tensile modulus of the PU/EP IPNs. With 4 and 6 % loading of OMMT, the tensile strength and tensile modulus increase 64 and 391 %, respectively.

In this work, in order to investigate the reinforcement effects of organic montmorillonite (OMMT) modified epoxy mortar binders (EMBs), a series of OMMT/EMB composites with different OMMT loadings were prepared. The structure and thermal stability of OMMT were studied by X-ray diffraction (XRD), Fourier transform infrared spectrum, and thermogravimetric analysis (TGA). The effects of OMMT on the structure, glass transition, damping properties, thermal stability, mechanical properties and morphology of EMB were characterized by XRD, dynamic mechanical analysis, TGA, tensile test, and scanning electron microscopy. XRD results indicated that epoxy chains intercalated into the OMMT layers and led to the expansion of OMMT layer spacing. The presence of OMMT increased the glass transformation temperature, crosslink density of the neat EMB. Furthermore, the incorporation of OMMT improved the thermal stability of the EMB. The OMMT/EMB composites showed higher tensile strength and Young’s modulus than the neat EMB. Homogenous dispersion of OMMT in EMB matrix was observed.

A versatile composite adsorbent combination of chitosan and graphene oxide (CS–GO) has been prepared by self-assembly method. This well-obtained adsorbent has amphoteric characteristics that show pH-tunable surface charge and morphology. These vital features result in its flexible and tunable adsorption performance. CS–GO is highly efficient in removing multiple types of pollutants from water, including various dyes and metal ions with different charge properties: cationic [methylene blue (MB) and Cu(II)] and anionic species [methyl orange (MO) and Cr(VI)]. Multiple mechanisms, including electrostatic interaction, π – π stacking, and chelating effects, are involved in the adsorption of the four pollutants for their different structural characteristics and charge properties. Both pollutants can be efficiently removed at suitable pH conditions in MB/Cu(II) and MO/Cr(VI) binary systems. Moreover, CS–GO shows strongly preferential adsorption of MB over Cu(II) at lower pH levels, whereas very slight selectivity of MO over Cr(VI). According to the adsorption kinetics results, the equilibrium time of CS–GO for adsorption of each pollutant is less than 10.0 min, which is sufficiently fast and satisfactory for practical use. After saturated adsorption, CS–GO can be efficiently regenerated and reused with little uptake loss. Therefore, CS–GO is a versatile adsorbent that efficiently removes various pollutants from water.

A magnetic reduced graphene oxide composite (MRGO) was successfully prepared by a simple and green method. MRGO was then used as an adsorbent and found to exhibit enhanced removal efficiency for various chlorophenols (CPs) from water compared with its precursors, graphene oxide (GO) and reduced graphene oxide. The CPs were o-chlorophenol, p-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Among them, 2,4,6-trichlorophenol, which exhibited the lowest water solubility and highest molecular weight, most easily bound to MRGO. The preferential interactions between MRGO and CPs were hydrophobic interactions (π-π stacking and hydrophobic effect). This result was confirmed by the equilibrium adsorption behavior in which isotherms were all well described by Freudlich model, indicating heterogeneous and multilayer adsorption. Therefore, CP adsorption was more favored under neutral and acidic conditions, and the decreased removal efficiency of MRGO at higher pH levels was due to the improved hydrophilicity of CPs for deprotonation effect. Moreover, MRGO showed fast removal of each CP, achieving adsorption equilibrium within 10.0 min, presented efficient separation from water under an external magnetic field, and was easily regenerated using dilute NaOH aqueous solution after reaching saturated adsorption. Adsorption capacity of the regenerated MRGO had almost no loss until after five cycles. In summary, MRGO was an efficient adsorbent for the removal of various CPs and had considerable application potential in water treatment.

Polymer mortar with excellent mechanical strength and durability has been widely used in road pavement and other construction industry. In this study, two kinds of brucites, synthetic and natural brucites were incorporated in the epoxy mortar binders as flame retardants. The components and morphology of the two kinds of brucites were investigated. The flame retardancy of brucite-modified epoxy mortar binders was evaluated by the horizontal burning and limiting oxygen index tests. The influence of flame retardants on the rotational viscosity, the thermal and mechanical properties of epoxy mortar binders was determined by differential scanning calorimetry, thermogravimetric analysis, and universal test machine. Furthermore, the morphology of flame retarded-epoxy mortar binders was characterized by scanning electron microscopy. The addition of brucites significantly improved the flame retardancy, thermal stability and tensile strength of epoxy mortar binders. Especially in the case of the addition of 20 wt% synthetic brucites in epoxy mortar binders, from FH-3 to FH-1 reduction in the horizontal burning classification, 5.5% improvement in limiting oxygen index, 15% increment in tensile strength were obtained.

In this study, the reinforcement effects of graphene on the properties of bio-based polyurethane (PU) were studied with the use of 1 wt% three functionalized graphene (dispersible graphene, reduced graphene oxide-NH2, and reduced graphene oxide-tetraethylene pentamine). Scanning electron microscope (SEM) revealed the relatively homogeneous dispersion of graphene nanoplatelets in the PU matrix. It was found that the addition of 1 wt% of the different graphenes could lead to a significant reinforcement effect on the bio-based PU. Especially, PU nanocomposite with 1 wt% dispersible graphene exhibited 6°C improvement in the Tg, 75% increment in storage modulus at 25°C, 34% increase in tensile strength, and 30% increase in Young's modulus. Practical applications: Different graphene were used to reinforce the bio-based PU. A significant reinforcement effect of graphene on bio-based PU was found. This strategy has the potential for the fabrication of advanced bio-based materials. A significant graphene reinforcement effect on bio-based PU was found. This strategy has the potential for the fabrication of advanced bio-based materials.

In this work, graphene oxide (GO) has been employed as an efficient adsorbent for the removal of three aromatic organic compounds (AOCs), namely, aniline, nitrobenzene, and chlorobenzene, from water under various initial AOC concentrations and pH levels. Based on the characteristics of surface structures of GO, a simple semiquantitative model has been provided to describe the intrinsic adsorption behavior of GO to AOCs. Accordingly, the adsorption mechanism has been discussed in detail at molecular levels. The contribution coefficients derived from the proposed model indicate that the most preferential interactions between GO and AOCs are hydrophobic interactions (π-π stacking and hydrophobic effect) that occur on graphitic zones of GO (unoxidized region). In the oxidized region, there also exist the hydrophobic interactions on sp(2) clusters, although they may be hindered by surrounding sp(3) zones which are the most unfavorable and are only accessible to AOCs through hydrogen bonding or electrostatic effects. More interestingly, aniline exhibits the highest contribution coefficients in both hydrophobic and hydrophilic zones of GO among the three measured AOCs due to its good water solubility and facile formation of hydrogen bonds. Furthermore, the analytical results of the adsorption isotherms are also fully consistent with those from the proposed model.

In this current work, a series of cellulose-based flocculants, carboxymethyl cellulose-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] (CMC-g-PDMC) with different grafting ratios were successfully synthesized. CMC-g-PDMC bears high flocculation performance in removal of an anionic dye, Acid Green 25 (AG25), at various pH conditions, which is due to improvement of both positive charge and molecular weight after modification. Moreover, the dye removal efficiency is mostly improved with the increase of grafting ratio. Among the four tested salt additives, CMC-g-PDMC exhibits good salt resistance except for sodium chloride in the measured salt concentration range. Furthermore, the image analysis in combination with fractal theory has been employed to investigate the flocs properties including floc size and fractal structure for studying the flocculation mechanism in detail. It is confirmed that charge neutralization and bridging flocculation effects both play important roles in removal of AG25 from water.

A series of meta-substituted fatty acid octaester derivatives and their transition-metal complexes of meso- tetraphenyl porphyrins (TPP-8OOCR, with R = C(n-1)H(2n-1), n = 8, 12, or 16) have been prepared through very simple synthesis protocols. The thermotropic phase behavior and the liquid crystalline (LC) organization structures of the synthesized porphyrin derivatives were systematically investigated by a combination of differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable-temperature small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS) techniques. The shorter octanoic acid ester substituted porphyrin (C8-TPP) did not show liquid crystallinity and its metal porphyrins exhibited an uncommon columnar mesophase. The lauric acid octaester (C12-TPP) and the palmitic acid octaester (C16-TPP) series porphyrins generated hexagonal columnar mesophase Colh. Moreover, the metal porphyrins C12-TPPM and C16-TPPM with M = Zn, Cu, or Ni, exhibited well-organized Colh mesophases of broad LC temperature ranges increasing in the order of TPPNiTPPCu≤TPPZn with their increased effective ionic radii in the square-planar coordination. The simplicity in synthesis, the well intercolumnar organization of Colh mesophase, the broadness of the discotic LC range, and the specific UV/Vis absorption and fluorescence emission behaviors make the symmetrically substituted fatty acid octaester porphyrins and their metal complexes very attractive for variant applications.

Soy polyol-based polyurethane (PU) nanocomposites were synthesized with 3-glycidoxypropyltrimethoxysilane modified palygorskite (GPTMSPal). The GPTMSPal PU nanocomposites were characterized using XRD, DMA, TGA, SEM, and universal test machine. GPTMSPal increased the glass transition temperature as well as significantly improved tensile strength and Young's modulus of the GPTMSPal PU nanocomposites. Compared to neat PU, GPTMSPal PU nanocomposite with 12 mass% GPTMSPal exhibited a 13.1 °C increase in the glass transition temperature, a 303% improvement in tensile strength, and a 518% increment in Young's modulus, respectively. TGA results showed that the thermal stability of GPTMSPal PU nanocomposites improved with increased GPTMSPal loading. Furthermore, SEM revealed a uniform dispersion of GPTMSPal in the PU matrix.

Hot mix epoxy asphalt (HMEA) binders have been widely used on the pavement of orthotropic steel bridge decks. In present paper, rotational viscosity, glass transition temperature, damping properties, mechanical properties, and morphology of HMEA were investigated using Brookfield rotational viscometer, differential scanning calorimetry, dynamic mechanical analysis (DMA), universal material tester, laser scanning confocal microscopy. Furthermore, the high temperature deformation resistance, rutting resistance, and fatigue cracking resistance of HMEA concretes (HMEACs) were evaluated using Marshall, wheel tracking, and three-point bending tests. Results show that the addition of asphalts postpones the cure reaction of epoxy resin. The rotational viscosity of HMEA binder keeps low enough to meet the demands of asphalt mixture mixing and paving at 160 °C. DMA results show that HMEA exhibits excellent damping properties. The addition of asphalts lowers the tensile strength and modulus of epoxy resin. However, the elongation at break of HMEA increases with the increase of asphalt contents. HMEACs exhibit good resistance to high temperature deformation, rutting, and fatigue cracking performances. All these results show that HMEA binder exhibits excellent performance in the steel bridge pavement.

The epoxy asphalt (EA) binder has been widely used for the pavement on the steel plate deck and in tunnels. In this study, horizontal burning and limiting oxygen index (LOI) were conducted to evaluate the effects of mixed decabrombromodiphenyl ethane (DBDPE) and antimony trioxide (Sb2O3) on flame retardancy for epoxy asphalt binder. The influence of DBDPE/Sb2O3 on the rotational viscosity, the thermal and mechanical properties of epoxy asphalt binder was evaluated by thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), and tensile test. The addition of DBDPE/Sb2O3 reduces the horizontal burning classification of epoxy asphalt binder from FH-2 to FH-1, and the LOI values of EAs is also significantly increased. The addition of flame retardants has no significant effect on the rotational viscosity of EA in the initial stage of cure reaction. TG results show that the presence of DBDPE/Sb2O3 improves the thermal stability of the epoxy asphalt binder. The addition of DBDPE/Sb2O3 has little effect on the tensile strength of the epoxy asphalt binder. However, the elongation at break of flame-retarded EAs is lower than that of the neat EA.

Flocculation is one of the most widely applied techniques in water treatment. Polysaccharide-based flocculants have been paid much attention for their eco-friendliness recently. However, precise molecular structure control is greatly important in improving their flocculation performance. In this work, a series of amphoteric starch-based flocculants with different substitution degrees of functional groups (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified carboxymethyl starch, denoted as CMS-CTA) was synthesized. The flocculation experiments confirmed that the well-designed CMS-CTA flocculants exhibited improved performance in both optimal dosage and pH sensitivity, for not only kaolin, but also hematite suspensions, which have opposite surface charges. Further quantitative mathematical correlations among the preparation recipe, structural features, and flocculation properties were built, providing operational feasibility in the precise molecular control of the flocculants to achieve their desired flocculation performance. Additional experimental results demonstrated that a suitable flocculant could be designed successfully according to the characteristics of the targeted contaminants and structure–activity relationship, proving the effectiveness of molecular structure control for optimization of the flocculation process.

In this study, we investigated the structure and loading effects of raw and silylated palygorskite (R-PA and S-PA) on the properties of soy polyol-derived polyurethane (PU) nanocomposites. Scanning electron microscope demonstrated that relatively homogeneous dispersion of both the R-PA and S-PA in the PU matrix. Dynamic mechanical analysis confirmed that both the PA could significantly improve the storage modulus and the glass transition temperature of PU nanocomposites, along with an intensified effect with the increase of PA loading. Tensile tests showed that both the PA has a prominent reinforcement effect on PU. Besides, we found that S-PA could slightly improve the thermal stability of PU nanocomposites, different from the case of the R-PA.

A series of interpenetrating polymer networks (IPNs) based on epoxy (EP) resin and polyurethane (PU) prepolymer derived from soybean oil-based polyols with different mass ratios were synthesized. The structure, thermal properties, damping properties, tensile properties, and morphology of soybean oil-based PU/EP IPNs were characterized by Fourier-transform infrared spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), universal test machine, and scanning electron microscopy (SEM). DSC and DMA results show that the glass transition temperature of the soybean oil-based PU/EP IPN decreases with the increase of PU prepolymer contents. Soybean oil-based PU/EP IPNs have better damping properties than that of the pure epoxy resin. The tensile strength and modulus of PU/EP IPNs decrease, while elongation at break increases with the increase of PU prepolymer contents. SEM observations reveal that phase separation appears in PU/EP IPNs with higher PU prepolymer contents.

Contaminants in real water are normally complicated. Surface charges of suspended colloidal particles can be either negative or positive. In this work, a series of amphoteric starch-based grafting flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified starch-graft-poly(acrylamide-co-acrylic acid)) denoted as SCPAMPAA were successfully synthesized with different grafting ratios and used for the removal of different charged contaminants from water. Various SCPAMPAA flocculants exhibited remarkably different flocculation performance and obeyed diverse flocculation mechanisms due to the differences in their structural characteristics. Therefore, precise control of the molecular structure of flocculants is of great significance to obtain the desired flocculation performance. To provide practically operational feasibility for the preparation of a predicted flocculant, a quantitative mathematical correlation between the preparation recipe and the structural features of SCPAMPAA were derived. The final well-designed flocculant demonstrated a high flocculation performance in aspects of optimal dosage, flocculation window and pH sensitivity for the removal of both negatively and positively charged colloidal contaminants from targeted wastewater.

In this current work, a series of graphene oxides (GO) with different oxidation degrees (OD) was prepared using Hummer method. Fundamental adsorption behavior of the GO series for removal of methylene blue (MB) from aqueous solutions has been studied. The GO series shows an overall fast and pH-independent MB adsorption, which is even capable of removing trace levels of dye completely from very dilute solutions. Furthermore, the effects of the oxidation degree (OD) on MB adsorption behavior have been investigated systematically, indicating that the dye uptakes of GO exponentially increase with the increase of OD. Further study on the adsorption mechanism shows that adsorption behavior of GO would change from a Freundlich-type to a Langmuir-type adsorption as the OD increases. It may be due to both the enhanced exfoliation degree of the carbon planes in graphite caused by oxidation and the production of more active adsorption sites. The binding features of the MB loaded GO gradually change from MB molecule parallel stacking on graphite plane through hydrophobic π-π interaction to vertical standing via electrostatic interaction with increasing OD, resulting in a significant improvement of MB uptakes. In addition, the adsorption capacity of the regenerated GO has little loss until four cycles.

Epoxy-modified asphalts (epoxy asphalts) have been widely used in the pavements of orthotropic steel bridge deck. In this paper, several effects on the properties of epoxy asphalts have been investigated in detail. First, the addition of asphalts showed no significant effects on the curing reaction and the glass transition temperature of epoxy resin. Second, the damping properties of epoxy asphalts were increased with the addition of asphalt contents. Furthermore, mechanical results showed that the stress at yield, stress at break, and tensile modulus of epoxy asphalts decreased with the increase of asphalt contents, whereas the strain at break increased with the increasing asphalt contents. The morphology of phase separation for epoxy asphalts was also observed.

In this present study, strongly cationic coagulants were prepared by modifying chitosan with 3-chloro-2-hydroxypropyl trimethyl ammonium (CTA). The coagulation properties of this cationic chitosan (chitosan-CTA) were systematically examined in laboratory and pilot scale studies. At the laboratory scale, the effects of coagulant dosage, temperature, initial turbidity of untreated water, pH, and salinity were investigated by a jar test using kaolin suspension as synthetic water. Compared with several conventional coagulants, chitosan-CTA showed a lower dosage requirement of approximately 0.05 mg/L, but higher turbidity removal efficiency of approximately 93.3%. Moreover, raw water from the Zhenjiang part of the Yangtze River in China was used as test water for further investigation on a pilot scale. The influences of dosage, sedimentation time, and mechanical mixing rate on the coagulation properties were studied by an orthogonal test and the optimal experimental conditions were obtained. The dosag...

In this present work, a series of hydrolyzed polyacrylamide grafted carboxymethyl cellulose (CMC-g-HPAM) was prepared. The structure and solution properties of CMC-g-HPAM were characterized by FTIR, 1H-NMR, elemental analysis and zeta potential measurements. The graft copolymers were applied as flocculants to remove methylene blue (MB), a cationic dye, from aqueous solutions. In comparison with its precursors, carboxymethyl cellulose (CMC) and polyacrylamide CMC-g-PAM, CMC-g-HPAM exhibited higher removal efficiencies. Furthermore, the flocculation performance of the copolymers was significantly improved with the increase of the hydrolysis degree, and the MB removal efficiency was more than 90 % when the hydrolysis degree of CMC-g-HPAM was higher than 80 %. More importantly, image analysis in combination with fractal theory demonstrated that the graft copolymers could produce notably denser and larger flocs, which was of great significance in practical water treatment. The improved flocculation performance was ascribed to both charge neutralization and bridging effects.

Polystyrene-grafted-graphene oxide hybrid was prepared via γ-ray irradiation-induced graft polymerization and then reduced to polystyrene-grafted-graphene hybrid by the solvothermal reduction method. The structure, thermal stability and morphology of polystyrene-grafted-graphene hybrid were investigated by Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analysis and scanning electron microscopy. It reveals that γ-ray irradiation is expected to be an effective and facile technique for scale-up preparation of polymer functionalized graphene. The hybrid modified glassy carbon electrodes were applied to the electrochemical sensor of dopamine and a good linearity with the concentration in the range of 5–100 μM was obtained. The excellent behavior as electrochemical sensor of the polymer functionalized hybrid may lead to new applications in electrochemical analysis.

In the current work, a series of amphoteric grafting chitosan-based flocculants (carboxymethyl chitosan-graft-polyacrylamide, denoted as CMC-g-PAM) was designed and prepared successfully. The flocculants were applied to eliminate various dyes from aqueous solutions. Among different graft copolymers, CMC-g-PAM11 with a PAM grafting ratio of 74% demonstrated the most efficient performance for removal of both the anionic dye (Methyl Orange, MO) and the cationic dye (Basic Bright Yellow, 7GL) under the corresponding favored conditions (80 mg/L of the flocculant at pH 4.0, and 160 mg/L at pH 11.0). In comparison with its precursors, chitosan and carboxymethyl chitosan, CMC-g-PAM11 showed higher removal efficiencies and wider flocculation windows. More importantly, the graft copolymer produced notably more compacted flocs based on image analysis in combination with fractal theory, which was of great significance in practical water treatment. Furthermore, the flocculation mechanism was discussed in detail. The grafted polyacrylamide chains were found to contribute much to the improved bridging and sweeping flocculation effects, but reduced charge neutralization flocculation for the effect of charge screening.

In this work, a kind of novel full biodegradable magnetic adsorbent based on glutamic acid modified chitosan and silica coated Fe 3 O 4 nanoparticles was prepared successfully by a one-step method. The structure of the glutamic acid modified chitosan magnetic composite microspheres (CS-Glu-MCMs) was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), vibrating-sample magnetometer (VSM), scanning electron microscope (SEM), and equilibrium swelling experiment. Then, CS-Glu-MCM was employed as adsorbent for removal of three different kinds of cationic dyes, methylene blue (MB), crystal violet (CV) and cationic light yellow 7GL (7GL), from aqueous solutions. Compared with chitosan magnetic composite microspheres (CS-MCMs) without modification, CS-Glu-MCM shows much higher dye uptakes. The fundamental adsorption experiments reveal that CS-Glu-MCM is more efficient in dye removal at pH higher than 5.0. Adsorption isotherms and adsorption kinetics of CS-Glu-MCM are all well described by Langmuir model and the pseudo-second order model, respectively, which indicates that the dyes adsorption behavior of CS-Glu-MCM is a homogeneous monolayer chemisorption process. Furthermore, the magnetic adsorbents could be easily regenerated at lower pH and reused with almost no loss of adsorption capacity.

Triphenylene (TP) derivatives are typical and probably the most widely studied discotic liquid crystalline (DLC) materials. Through polymer analogous reactions to attach TP mesogens to the well-synthesized poly(ethylene glycol)-b-poly(2-hydroxyethyl acrylate) (PEG–PHEA) by ATRP, a series of well-defined side chain DLC diblock copolymers PEG–poly(TPm) (m = 6 or 10) with DLC block weight fraction (fw,DLC) ranging from 37% to 90% have been successfully prepared with narrow molecular weight distribution (PDI ≤ 1.11). An intriguing microphase-separated superstructure evolution and the correlation between overall morphologies and discotic mesogenic orders as a function of fw,DLC and temperature have been demonstrated by combination of DSC, POM, and variable temperature SAXS/WAXS. Those copolymers with lower DLC contents (fw,DLC = 37% and 43%) and at lower temperatures formed lamellar structures of variant periods and underwent order–order transitions upon PEG region crystallization at 45 °C and different discot...

In this study, the widely applied modified Smoluchowski model of flocculation kinetics based on the existence of two simultaneous processes, namely aggregation and breakup, is further developed by combining it with the fractal theory. The floc properties including the floc size and fractal dimension are extracted using online data acquisition through light scattering technique and combined into the model. The new method has been carefully examined by three flocculation systems using kaolin suspension as synthetic water and different typical flocculants. The theoretic flocculation kinetic curves are in good agreement with the experimental data with the determination coefficients larger than 0.9 by nonlinear regression. Moreover, the flocculation kinetic characteristics of different flocculation systems under various conditions are discussed based on the kinetic rates calculated from the modified model in detail. In summary, the new method for calculation of flocculation kinetics is more universal and simpler to operate, and is expected to be a useful tool in real water treatment operations.

In the current paper, a novel amphoteric straw-based adsorbent was prepared and applied to adsorb various dyes from aqueous solutions. The amphoteric adsorbent was proven effective in eliminating both cationic and anionic dyes (methylene blue and acid green 25), especially at corresponding favored pH conditions. The fundamental adsorption behavior of the adsorbent on removing various dyes was also investigated at different temperatures. The adsorption isotherms were all best-fitted by the Langmuir equation, whereas the adsorption kinetics was well-described by both the pseudo-second order model and the Elovich model. The experimental result revealed that the adsorption mechanism followed the monolayer chemical adsorption with an ion-exchange process.

A new insight into “polyelectrolyte effect” which referred to the reduced viscosity of polyelectrolyte upon dilution resulting from the intra-molecular electrostatic repulsion was proposed, depending on the results by the authors concerning the viscosity theory of polymer solutions through theoretical and experimental methods. The results reveal that the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region are ascribed to the interface effects. The polymeric solutes are readily adsorbed on the viscometer capillary wall surface, which greatly influences the viscosity measurement of polymer solutions, and results in apparent abnormal viscosity behavior. It is suggested that the so-called “abnormal” viscosity data, difficult to deal with and ignored by previous researchers, are not actually abnormal, but contain a lot of structural information on polymer both on the capillary wall and in solutions. In the present article, recent progresses in the studies on the viscosity behaviors of various polyelectrolytes are summarized, mainly depending on the findings of the authors and their collaborators involving synthetic polyelectrolytes, natural polyelectrolytes and amphoteric proteins.

The effect of surfactant concentration on the complex structures of the thermosensitive poly(N-isopropylacrylamide) (PNIPAM) with sodium n-dodecyl sulfate (SDS) in dilute aqueous solutions and belo...

The partially sulfonated polystyrene (SPS) is a very simple and easily prepared material. In this work, SPS was used for the first time as a macromolecular compatibilizer to improve the compatibili...

In this paper, based on the synthesis of precursor linear-dendritic block copolymers (LDBCs) with a linear poly(ethylene glycol) (PEG) block of molecular weight around 2000 and dendritic polyamidoamine (PAMAM) segments of generation G0 to G3, a series of azobenzene-containing amphiphilic LDBCs mPEG-dendr[PAMAM-(AZO)n] (n = 2, 4, 8, 16) have been successfully prepared in moderate yields 45–60%, through complete Michael addition between the peripheral amine groups of dendritic segment and the reactive azobenzene acrylate mesogen units bearing octyloxy tails and flexible decylmethylene spacers. The purified copolymers have been characterized and confirmed by NMR, FT-IR, MALDI-TOF MS, and GPC showing narrow molecular weight distribution in the range 1.09–1.20. A generation-dependent polymeric micellar aggregation behavior of thus obtained amphiphilic LDBCs from nanofibers of uniform diameter around 20 nm to nanospheres/oval sheets, vesicles, and porous large compound micelles (LCMs) of micrometer size has been demonstrated in selective solvent mixture of dioxane/water. Furthermore, photoisomerization transformation of these azobenzene-containing LDBCs and their kinetics of reversible trans-cis-trans photochemical transitions in THF solution have also been investigated, the measured trans-cis photoisomerization rate constant 0.0240 s−1 for G3 copolymer is twice of the 0.0127 s−1 determined for the precursor azobenzene compound, manifesting a kind of promising photoresponsive copolymer materials.

In this paper, chitosan hydrogel beads (CS) have been modified by etherization reaction with the etherification agent of chloroacetic acid. The surface carboxymethylated chitosan beads (CMC) provide not only enhanced but also improved selective adsorption for copper(II) (Cu(II)) ions from lead (Pb(II)) and magnesium (Mg(II)) ions in aqueous solutions. The fundamental Cu(II) ions adsorption behaviors of CMC, including the effect of pH, temperature, adsorption equilibrium, and kinetics, were investigated. The adsorption isotherms of CMC closely follow Langmuir model and the adsorption kinetics are well described by the pseudo-second order equation, which indicate that the adsorption behaviors are a monolayer chemical adsorption. X-ray photoelectron spectroscopy (XPS) investigations further reveal that the carboxyl groups are facile to form bidentate carboxylates with metal ions. Furthermore, the adsorbent could be easily regenerated at lower pH and reused almost without any loss of adsorption capacity. Moreover, the Cu(II) ions loaded CMC are stable enough at higher pHs, and suitable to be applied as a new adsorbent for phosphate adsorption, of which the maximal uptakes is around 58.0 mgP g −1 achieved at pH about 5.0.

Soy polyol-based polyurethane (PU) nanocomposites (PUNCs) with 1 wt.% hydroxyl-functionalized multi-wall carbon nanotubes (CNT-OH) were prepared via in situ polymerization. CNT-OH increased the glass transition temperature as well as significantly improved the thermal stability and conductivity of the PUNCs. The PUNC Young’s modulus was much lower than that of neat PU. The tensile strength of the PUNCs with large CNT-OH diameters was slightly higher than that of neat PU. Compared with neat PU, the elongation at break of the PUNCs improved by 30%, 39%, and 45% with increased CNT-OH diameters. Scanning and transmission electron microscopic methods revealed CNT-OH relatively homogeneous dispersion in the PU matrix.

It was found that the interface effects in viscous capillary flow influenced the process of viscosity measurement greatly, and the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region were ascribed to interface effect. According to this theory, we have reviewed the previous viscosity data of derivatives of poly-2-vinylpyridine reported by Maclay and Fuoss first. Then, the abnormal viscosity behaviors of a series of sodium polystyrene sulfonate samples with various molecular weights in dilute aqueous solutions were studied further. The solute adsorption behaviors and structural information of polymers have been discussed carefully.

In this paper, carboxymethyl straw has been applied to eliminate methylene blue (MB) in a fixed-bed column. The straw based adsorbent has shown high MB uptake in column. Various models such as Thomas, Clark, Adams–Bohart, Yoon–Nelson, Wolborska, and BDST model have been employed to fit the experimental data carefully. Among them, Thomas model is found to be the most suitable one to describe the adsorption behaviors, according with the monolayer chemical adsorption mechanism. Then the effects of initial solution pH, bed height, temperature, initial MB concentration and flow rate on column adsorption have been studied in detail based on Thomas model. It has been found that initial solution pH, bed height, initial MB concentration and flow rate can affect the breakthrough curves obviously, while temperature has no evident influence on the MB adsorption of the modified straw.

Epoxy-terminated siloxane-contained resin (BCDS/OBBA-ETS) with high tensile strength and lap shear strength as well as good thermal stability was synthesized and characterized by 1H-NMR and Fourier transform infrared spectroscopy. Carboxy-capped disiloxane-4,4′-oxybis (benzoic acid) ester oligomer (BCDS/OBBA) was firstly prepared from the reaction between 1,3-bis(chloromethyl)-1,1,3,3-tetramethyl-disiloxane and 4,4′-oxybis(benzoic acid) (OBBA) in N,N-dimethylformamide in the presence of triethylamine. Then, the BCDS/OBBA oligomer was reacted with epichlorohydrin to obtain the title BCDS/OBBA-ETS resin. Cured with liquid polyamide L-651, or diethylenetriamine, the mechanical and thermal properties as well as the lap shear strength of the BCDS/OBBA-ETS resin were evaluated. The results indicated that the BCDS/OBBA-ETS resin exhibited good thermal stability below 200°C, and the glass transition temperature (Tg) was about 64°C after cured with L-651. The tensile strength of same cured BCDS/OBBA-ETS resin was 27.46 MPa with a stain at break of 42.11%, and the lap shear strength for bonding stainless steel was 18.59 MPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In this study, a kind of amphoteric chitosan-based flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CTA) modified carboxymethyl chitosan, denoted as CMC-CTA) have been prepared. The amphoteric flocculants showed notable improvement in solubility and salt-resistance in the whole pH range compared with its precursors, i.e., chitosan and cationic chitosan. The flocculation properties of CMC-CTA were systematically studied at both the laboratory and pilot scales. At laboratory scale, kaolin suspension was employed as synthetic water in the beaker experiment. The effects of pH, temperature, and original turbidity of untreated water on the dosage and flocculation performances were investigated, respectively. At pH below and above the isoelectric point of CMC-CTA, the optimal flocculation performances were obtained with a dosage of 0.03–0.20 mg/L and 0.8–1.0 mg/L, respectively. The flocculation mechanism was discussed in detail from the morphologies of polymeric flocculants and flocculation kinetics: The shape and charge of polymer chains in the solution greatly influenced the final flocculation performances; The flocculation kinetics agreed well with the particle collision model. Moreover, raw water from the Zhenjiang part of the Yangtze River in China was used for the further investigation of the flocculation properties at the pilot scale. The influences of dosage, sedimentation time, and mechanical mixing rate to the flocculation properties were studied by orthogonal testing. The optimal experimental condition was then obtained. Compared with the currently used flocculants in the Zhenjiang Water Factory, i.e., polyferric sulfate, which has an optimal dosage around 40 mg/L, the value of CMC-CTA (1.1 mg/L) decreased greatly. Above all, the flocculation experiments at the laboratory and pilot scales both indicate that the amphoteric chitosan-based flocculants have good flocculation performances in a wide pH range.

Novel polyurethane acrylates (PUAs) were prepared by the reaction of soy polyols with isophorone diisocyanate and hydroxyethylacrylate. FTIR results con- firmed the formation of PUAs from different kinds of soy polyols. The glass transition, damping properties, thermal stabilities, and mechanical properties of PUAs were char- acterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal test machine. The morphol- ogy of PUAs was investigated by scanning electron micro- scope (SEM). The results of the swelling experiments showed that the crosslinking density of polyurethanes and PUAs directly correlated with the hydroxyl (OH) number of polyols. The DSC and DMA results displayed that the glass transition temperature of PUAs was higher than that of polyurethanes and increased with OH number. Further- more, the formation of PUA networks improved the damping properties of polyurethanes. TGA results demon- strated the acrylation of polyurethanes improved its ther- mal stability. The initial decomposition temperature of polyurethanes and PUAs also increased with OH number. When compared with polyurethanes, the tensile strengths of PUAs were improved by 118%, 39%, and 9%, respec- tively, with the increase of OH number of three soy poly- ols. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2449- 2455, 2011

Poly(N-alkylacrylamide) is a group of thermo-sensitive polymers that include poly (N-isopropylacrylamide), poly(N-n-propylacrylamide), poly(N-isopropylmethacryl-amide), and so on. The polymers exhibit different levels of lower critical solution temperatures (LCST) in aqueous solutions. In this article, their monomers and oligomers with 10 repeating units are selected, respectively, to demonstrate the cause of different LCST levels of the polymers in aqueous solutions using molecular dynamics simulations and quantum mechanics calculations. The monomers have functional groups of different steric volume that greatly affect the conformational transition of chains and LCST levels of the polymers. A branched chain of N-propyl group in N-isopropylacrylamide and an additional methyl group at α-carbon in N-isopropylmethacrylamide both increase the steric effect, making it more difficult for monomers to draw closer and resulting in higher LCST levels of the polymers. In addition, the simulated results from their corresponding oligomers exhibit the similar trend to those from the monomers.

Recently, more attentions have been paid to natural polymer-based flocculants in water treatment, since they are believed to be low-cost, nontoxic, and environmentally friendly materials. In this work, strong cationic chitosan-based graft copolymer flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CTA) modified chitosan-graft-polyacrylamide, denoted as chitosan-CTA-g-PAM) have been prepared, and their flocculating properties were studied systematically, both at the laboratory scale and at the pilot scale. In laboratory scale, a kaolin suspension was employed as synthetic wastewater. The effects of dosage, temperature, and original turbidity of untreated wastewater were investigated, respectively. Moreover, in pilot scale, the raw water from the Zhenjiang part of the Yangtse River in China was used as wastewater. The influences of three external factors—dosage, sedimentation time, and mechanical mixing rate—on the flocculating performances have been studied by orthogonal testing, respectiv...

The sorption behaviors of carboxymethyl cellulose (CMC) for methylene blue (MB) were investigated in this work. The experimental results indicated that the sorption capacity increased from 50 mg g −1 for unmodified cellulose (UmC) to more than 300 mg g −1 for CMC. The most favorable sorption of MB was observed at an alkaline condition. The sorption isotherms closely followed the Langmuir mode, and the sorption kinetics was in agreement with the pseudo-second order equation. The results from the batch experiments illuminated that the sorption mechanism was ion-exchange controlled process. In fixed-bed tests, CMC also exhibited high efficiency for removal for MB, in which sorption behaviors followed Thomas model. Desorption of the dye from the MB-sorbed CMC (MBsCMC) indicated that MBsCMC was stable, and MB was seldom released at neutral and alkaline conditions. Furthermore, a more efficient method for reuse of the disused sorbents was tried. MBsCMC was employed for removal of methyl orange (MO) in a secondary sorption at neutral or alkaline conditions. The maximal MO uptake of MBsCMC was over 100 mg g −1 , which was much higher than those of CMC and UmC. It was indicated that MBsCMC was efficient in sorption of MO for the electrostatic interaction between MO and MBsCMC, and secondary sorption was an appropriate way for reuse of this kind of disused sorbents.

In this paper, the wheat straw materials have been simply modified by carboxymethylation to prepare a kind of new adsorbent. The adsorption of methylene blue (MB) from aqueous solutions onto modified straw has been studied. It was found that the adsorption capability of straw increased dramatically after modification. The investigation of pH effects indicated that the adsorbents had better adsorption performances in neutral and alkaline conditions. The adsorption isotherms were best fitted by the Langmuir equation while the adsorption kinetics was well described by both pseudo-second order equation and the Elovich equation. The adsorption behavior in a fixed-bed system followed Thomas model. It indicated that the adsorption behavior was a monolayer chemical adsorption and the rate-limiting step might be ion exchange reaction. Interestingly, after adsorption of MB, the disused adsorbents were not recovered for recycle as usual, but tried to remove another dye matter of methylene orange (MO) from aqueous solutions directly. It was proved that the MB loaded adsorbents were stable enough at pH > 6.0, and effective in the secondary adsorption of MO for altered surface structures of the straw based adsorbents after adsorption of MB.

The traditional treatment for disused adsorbents is usually recovery for recycling or direct discarding. In this paper, a more efficient and economical method is introduced to treat disused adsorbents. Chitosan hydrogel beads (CS) are proven to be effective biosorbents for the removal of many heavy metal ions from aqueous solutions. The CS after the saturated adsorption of metal ions are usually recovered in dilute acidic solutions. However, in this work, the disused CS after the removal of copper(II) (Cu(II)) were not recovered but were directly applied to adsorb phosphate from the aqueous solutions. The CS after the adsorption of Cu(II) were stable and suitable for phosphate adsorption within a wide pH range. The results of pH effects on the adsorption capacities of phosphate indicated that the maximum was achieved at around pH 5.0 near 28.86 mgP/g. In the various forms of phosphates, the Cu(II)-loaded CS preferred to adsorb dihydrogen phosphate. Further adsorption equilibrium and kinetics study showed that the adsorption behaviors were mainly ascribed to chemical adsorption. The adsorption isotherm was well described by the Langmuir equation. The adsorption kinetics followed both pseudo first-order and second-order models. The effects of electrolytes on the adsorption of phosphate indicated that the additional NaCl and Na2SO4 both slightly decreased the adsorption capacities for the anions’ competition of adsorption active sites.

In this paper, poly(acrylic acid) blended chitosan (CS/PAA) hydrogel beads have been prepared by one-step method simply. It was found that glutaraldehyde (GLA) cross-linked CS/PAA beads had better stability in lower pH solutions and higher mechanical strength than CS-GLA beads without PAA. Results from removal of Copper(Cu) ions from aqueous solutions showed that the adsorption capacity of CS/PAA-GLA beads was greater than that of CS-GLA beads. Moreover, the adsorption capacity for two types of beads both showed temperature independent. Furthermore, the adsorption isotherms of various beads at different temperatures were both better fitted for Langmuir equation, while the adsorption kinetics was both better described by the pseudo-second order equation. Furthermore, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy have been employed to investigate the adsorption mechanisms from molecular levels. It indicated that the efficient effects of CS/PAA-GLA beads on removal of Cu(II) resulted from the fact that carboxyl groups were facile to form bidentate carboxylates with metal ions. In addition, Cu(II) ions could be desorbed efficiently from both aforementioned beads at pH below 4.0, and the adsorption capacity of the regenerated beads had no loss until six cycles.

The response factors of refractive index (RI) and ultraviolet (UV) detectors of size exclusion chromatography (SEC) defined as the ratio of area of output signal to the mass of injected sample are studied and analyzed by using five narrowly distributed polystyrene (PS) standard samples with known molar masses. It is found that the individual response factor for a given sample varies with the concentration of the injected solution within a limited range bounded by an upper and a lower limiting response factor values. This variation reveals the conformational change of the polymer chains with the concentration of the injected solution. The dynamic contact concentrations c s of the PS samples derived from the response factor data are in good accordance with those reported earlier by other methods. The physical meanings of the signals of the two detectors are further analyzed and theoretically formulated. The solvation of the polymer chain and the conformation changes play an important role in these detecting systems. Both of the solvation number of the structural repeating unit and the extra embedded solvent due to cluster forming in higher concentrations could be deduced from the variation of response factor with the concentration of the injected solution.