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A series of sulfonated hydroxypropyl guar gum (SHG) samples with different degrees of substitution (DSs) were prepared, and the SHG solution and SHG fracturing fluid were prepared and analyzed. The SHG aqueous solutions with different DSs all exhibit shear thinning behavior, which is well correlated with the Ostwald-deWaele model. Owing to the electrostatic repulsion of SHG molecular chains, SHG solutions with a higher DS will exhibit weaker thixotropic performance and strong anti-salinity ability. In addition, the SHG fracturing fluids, which were formed by interactions between SHG and organic zirconium, exhibit good temperature- and shear-resistant properties, proppant suspension properties, and salt tolerance. Furthermore, SHG gel-breaking fluids show low interfacial and surface tensions, with low residue content and small core permeability damage. These results provide useful indicators for the applications of SHG in the oil field industry. [ABSTRACT FROM AUTHOR]

The rheology of carboxymethyl fenugreek gum (CFG) is characterized and applied it as a binder for the silicon anode of lithium-ion batteries (LIBs). First, a series of carboxymethyl fenugreek gum (namely CFG-1, CFG-2 and CFG-3) was prepared and characterized by Fourier transform infrared spectrophotometer and hydrogen nuclear magnetic resonance spectrometry studies. In rheological measurements, the CFG solutions show higher flowability, weaker viscoelastic behavior and better thixotropy than that of fenugreek gum (FG) solution. Furthermore, the higher degrees of substitution (DS) of CFG solutions lead to lower apparent viscosity and higher flow index, weaker elastic effect and smaller relaxation time, and higher viscosity recoverability than those obtained for lower DS of CFG solutions. In electrochemical measurements, the polar hydroxyl and carboxyl groups in the CFG skeleton chain provide bonding points between the CFG binders and the silicon electrode to produce binder-silicon bonds, which cause strong hydrogen bonding, and resulted in excellent electrochemical stability and specific capacity. The electrochemical performances were measured via the silicon electrodes with FG and CFG at 5 wt% content. As the DS is increased, the initial Coulombic efficiency can increase from 88.74% to 91.3%. When the electrode undergoes a volume change, the CFG binder with silicon electrodes can hold high capacity of above 1500 mAh/g after 200 charge-discharge cycles. Therefore, the carboxymethyl fenugreek gum as a binder may also be a novel extended binder-design, with applications for silicon anodes of LIBs. [ABSTRACT FROM AUTHOR]

To better understand the guar gum (GG) working process, we divided it into three steps: dissolution, gelation, and gel breaking. Freeze-drying and scanning electron microscopy were used to examine the microstructures of GG in different states. The dissolution step could be divided into two processes: swelling and dissolving. The microstructures during these two processes were lined structures and random ribbon-like structures, respectively. Further, during the gelation step, the random ribbon-like structures transformed to crosslinked ordered structures. Finally, the ribbon-like structures were broken in the gel breaking step, but the orderliness was not broken. These findings are beneficial to the potential modification or design of GG and the improvement of its hydrogel performance. [ABSTRACT FROM AUTHOR]

To explore the application of pH-responsive surfactant, a pH-responsive N , N -dimethyl-erucamide-propylamine (DEAPA) self-assembly system was prepared and characterized. The rheological property and structural transformation of DEAPA molecular aggregations were comprehensively discussed with decreasing pH or increasing of Cl − concentration using rheology, dynamic light scattering (DLS), ultraviolet-visible (UV) spectrophotometry, and cryo-transmission electron microscopy (cryo-TEM). The properties of the DEAPA-KCl viscoelastic fluid used as the fracturing fluid were discussed in terms of the viscoelasticity, temperature-tolerance, and shear-tolerance, proppant suspension, and core permeability damage at pH 1.5. Results revealed that the microstructure of the DEAPA micelle first transformed from vesicles to spherical micelles, and finally changed to worm-like micelles when HCl solution was added. In addition, on increasing the KCl concentration, the system transforms from spherical micelles to worm-like micelles. When the Cl − concentration was increased to 0.50 mol/L (pH = 1.5), the storage modulus ( G ′) of the DEAPA-KCl fluid became over 15 Pa and loss modulus ( G ″) was over 5 Pa, which suggests that elasticity is the predominant property of these worm-like micelles. Also, the viscosity of the DEAPA-KCl fracturing fluid was constant at about 110 mPa s at 80 °C and shear rate of 170 s −1 . The settling velocity of the DEAPA-KCl fluid was lower than 0.004 mm/s at 60 °C, and the core permeability damage was 6.75%. Therefore, the DEAPA-KCl system is suitable for use as an acidic viscoelastic fracturing fluid. [ABSTRACT FROM AUTHOR]

A new guar gum derivative was synthesized though the nucleophilic substitution of sodium hydroxide-activated guar gum with n -butyl glycidyl (BGE) ether. The physicochemical properties of 2-alkenyl-3-butoxypropyl guar gum (ABPG) were characterized by attenuated total reflection Fourier transform infrared spectrometry (ATR-FTIR), X-ray diffraction (XRD) and thermal gravimetric analyses (TGA). The results showed that sodium hydroxide can be effectively substituted with BGE to form the ABPG. The steady and dynamic rheological properties of the aqueous solution and ABPG gel were determined using an RS6000 rheometer. Compared with the guar gum, ABPG enhanced the thickening property and improved the solution stability. The ABPG gel exhibited good temperature resistance and shear stability properties. [ABSTRACT FROM AUTHOR]

Titanium (Ti) oral implants, as foreign bodies, can easily trigger an inflammatory response, and the metal ions/nanoparticles released by friction/corrosion in the body can also damage soft and hard tissues, leading to implant failure. To make up for deficiencies, a multifunctional composite coating composed of silica (SiO 2) particles and zirconium hydrogen phosphate (ZrP) on the surface of Ti was prepared by combining micro-arc oxidation (MAO) and sol-gel technology. The characterization results of the surface physicochemical properties confirmed that a series of SiO 2 /ZrP-modified MAO coatings were successfully constructed. Compared with the control group, the doping of SiO 2 particles effectively improved the friction resistance of the surface MAO coating, but worsened its corrosion resistance. After the surface was further covered with ZrP coating, the corrosion resistance defect caused by SiO 2 particles was eliminated. With the increase of the ZrP thickness, the friction resistance of the target sample increased gradually. In addition, the specimens coated by ZrP coatings also presented better anti-inflammatory and osteogenic capabilities than the samples subjected to pure/SiO 2 -doped MAO treatment. Based on these advantageous properties, this novel composite coating may project good application prospects in promoting early osseointegration. • Combined application of SiO 2 particle and ZrP coating to modify Ti for the first time. • ZrP coating further enhanced the friction resistance of the SiO 2 -doped MAO coating. • The corrosion defect caused by SiO 2 particles can be eliminate by ZrP coating. • SiO 2 and ZrP synergistically improve the osteoinductive ability of MAO coating. • ZrP coatings significantly reduce the early immune rejection of MAO-treated titanium. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel multiple cross-linked PVA nanocomposite (MPAU) was constructed. • Incorporation of SiO 2 provides physical cross-linking domains. • PVA, TBPU and BGT generate chemical-coordination domains. • MPAU show excellent mechanical strength (58.9 MPa) and toughness (79.5 MJ/m3). Materials based on fiber-reinforced coating have gained increasing attention due to their environmental and industrial application tracks. Polyvinyl alcohol (PVA) composites with interpenetrating cross-linked structures and abundant functional groups exhibit obvious advantages for high-performance coating. In this work, PVA multiple cross-linked network nanocomposites (MPAUs) were established using silica nanoparticles as reinforcing fillers, ingeniously synthesized boronic esters (BGTs) and blocked-diisocyanate polyurethanes (TBPUs) as cross-linkers. Briefly, SiO 2 nanoparticles were evenly dispersed into PVA matrix to fabricate primary physical cross-linked network, which could promote subsequent cross-linking and esterification effects. After deblocking, TBPU molecules were grafted onto PVA chains via radical polymerization. Meanwhile, the borate ions B(OH) 4 − generated by the multi-stage ionization of BGT were re-coordinated with the hydroxyl groups of PVA matrix. These two effects further afforded secondary chemical cross-linking networks and coordination cross-linked domains. The mechanical and microstructural properties of MPAUs were assessed with respect to their cross-link density and multiple cross-linked network structure. Of note, the formation of multiple-cross-linking network enabled MPAU films with substantial enhancements in mechanical strength and toughness, reaching to 58.9 MPa and 79.5 MJ/m3, respectively. The results of application studies indicated that the obtained MPAUs could integrate with cellulose paper to accomplish excellent physical strength and surface properties. In conclusion, this work paves the way to fabricate multifunctional nanocomposites, which enriches the commercial value of versatile paper-based materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel multiple cross-linked PVA nanocomposite (MPAU) was constructed. • Incorporation of SiO 2 provides physical cross-linking domains. • PVA, TBPU and BGT generate chemical-coordination domains. • MPAU show excellent mechanical strength (58.9 MPa) and toughness (79.5 MJ/m3). Materials based on fiber-reinforced coating have gained increasing attention due to their environmental and industrial application tracks. Polyvinyl alcohol (PVA) composites with interpenetrating cross-linked structures and abundant functional groups exhibit obvious advantages for high-performance coating. In this work, PVA multiple cross-linked network nanocomposites (MPAUs) were established using silica nanoparticles as reinforcing fillers, ingeniously synthesized boronic esters (BGTs) and blocked-diisocyanate polyurethanes (TBPUs) as cross-linkers. Briefly, SiO 2 nanoparticles were evenly dispersed into PVA matrix to fabricate primary physical cross-linked network, which could promote subsequent cross-linking and esterification effects. After deblocking, TBPU molecules were grafted onto PVA chains via radical polymerization. Meanwhile, the borate ions B(OH) 4 − generated by the multi-stage ionization of BGT were re-coordinated with the hydroxyl groups of PVA matrix. These two effects further afforded secondary chemical cross-linking networks and coordination cross-linked domains. The mechanical and microstructural properties of MPAUs were assessed with respect to their cross-link density and multiple cross-linked network structure. Of note, the formation of multiple-cross-linking network enabled MPAU films with substantial enhancements in mechanical strength and toughness, reaching to 58.9 MPa and 79.5 MJ/m3, respectively. The results of application studies indicated that the obtained MPAUs could integrate with cellulose paper to accomplish excellent physical strength and surface properties. In conclusion, this work paves the way to fabricate multifunctional nanocomposites, which enriches the commercial value of versatile paper-based materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple process was employed for synthesizing stable lipid-polymer hybrid nanoparticles. • Bone-targeting oligopeptides modified nanoparticles showed bone affinity in vitro and in vivo. • The nanoparticles show a potential in the treatment of osteoporosis. The lack of safety, efficacy, and specificity has made the delivery of anti-osteoporotic drugs at a proper dose a challenge. In our study, cathepsin K inhibitor loaded poly (D, L-lactide-co-glycolide) derived lipid hybrid nanoparticles (DNPs) were modified with bone-specific polyaspartic acid [(Asp) 8 -DNPs] to treat osteoporosis. (Asp) 8 -DNPs showed its hydroxyapatite binding affinity and achieved a sustained release of cathepsin K inhibitor for up to 5 days. Cathepsin K inhibitor loaded (Asp) 8 -DNPs significantly decreased the tartrate-resistant acid phosphatase (TRAP) activity and resorption-related genes in osteoclasts. Animal studies also exhibited high accumulation of (Asp) 8 -DNPs in the tibia and femur and a greater bone mass in trabecular bone and better organized three-dimensional architecture in osteoporotic rat models. Herein, the bone targeting drug delivery system show its potential in treatment of osteoporosis. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new epoxide modified polyurethane/polyacrylate emulsion was synthesized. [•] Surface tension analysis assured the surface activity of the polyurethane emulsion. [•] The ring-opening mechanism between epoxide and carboxylic acid groups was discussed. [•] The fitting peak results confirm the formation of polyurethane/polyacrylate. [Copyright &y& Elsevier]

[Display omitted] • Introduce the end-blocked structure into the water-based functional polyurethane segments applied as a "latent cross-linker" for surface sizing, • A novel compound sizing system containing water-based blocked polyurethane and polyvinyl alcohol, • Chemical bonding and hydrogen bonding between highly active isocyanate groups and paper fiber after unblocking, • Application of water-based blocked polyurethane in surface sizing of special paper. Efficient improvement of paper strength while optimized sizing technique remains challenging and fascinating since specialty paper are required to low-cost, high printing quality and environmental sustainability. Herein, a novel controlled reactivity polyester glycol-based cross-linker (TBPU) applied in paper surface sizing was exploited by simple two-steps polymerization and blending process. An end-blocked structure design strategy of containing densely distributed multiple soft segments and active hydrogen nucleophilic segments (Butanone oxime, MEKO as end closure units) in isocyanate dispersion was achieved to address the scarcity of mechanical properties and the inconvenient in surface-sizing progress. TBPU can block the NCO groups in IPDI segments at 60 °C, and NCO groups can be deblocked at the temperature higher than 110 °C, which endow TBPU with latent cross-linking property. Afterward, we took advantage of the structural feature of polyhydroxy compounds and the adhesion to cellulose via using polyvinyl alcohol (PVA) as a blending component to form TBPU/PVA emulsion. The organization of NCO groups react with hydroxyl groups, carbamate groups cross-linked with hydrogen bonds, and crystallized PCL segments generates phase-separated hierarchical domains. Serving as high-reactivity paper-sizing fillers capable of cross-linking and disintegration under an external change of temperature, the hierarchical domains can strengthen the specialty papers and enhance their water resistance and ink adhesion. The influences of TBPU content, PVA content and NCO/ OH molar ratio on the physicochemical properties of the resultant emulsions and sized paper have been investigated. As a result, the paper sized with TBPU-1.6/PVA emulsion exhibit a tensile index of ≈107.19 Nm/g, a tearing index of ≈11.79 m N • m2/g, a folding resistance of ≈4511 s, an optimum blending temperature of 70 °C and exceptional cooperation ratio with PVA and TBPU (4.0 wt%, 3.0 wt%), which are 1.649 times, 1.966 times, and 2.652 times than those of untreated papers (65 Nm/g, 6 m N • m2/g, 1701 s). Furthermore, sizing liquid can be conveniently applied and recycled due to their excellent environmental friendliness and Biodegradability, this work provides a promising solution for optimizing surface sizing technology. [ABSTRACT FROM AUTHOR]

Abstract: The cationic polyurethane-fluorinated acrylic (PUFA) hybrid latexes were obtained from double bond-end capped polyurethane macromonomer having quaternary ammonium groups with perfluoroalkyl acrylate (FA) by radical copolymerization. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed that the FA monomer had been introduced into the chain of the PUFA hybrid polymer. Particle size distribution (PSD) analysis showed that the particle size of PUFA increased with the increase of the FA content. TEM indicated that the PUFA hybrid possessed core–shell structure. The analysis of the contact angles (CAs), XPS and atomic force microscopy (AFM) had shown that there was a remarkable enrichment of fluorine on the film–air interface, which was more evident when the PUFA hybrid film annealed at higher temperature. At the same time, the influences of the soft segment molecular weight, the N-methyldiethanolamine (MDEA) content and the FA content on other properties such as the surface tension of the PUFA latexes, the surface free energy of the PUFA films and the thermal properties were studied. The results showed that the MDEA content had contrary influence on latex''s and film''s surface properties. Thermal stabilization usually brought by fluorine was not observed in our investigated systems. [Copyright &y& Elsevier]

• β-estradiol (E2) condensed with Ca2+ precursors to form bioresponsive nanocores. • MC3T3-E1 cell membranes expressing azide groups are used for nanocore coating. • The cell membrane coating is functionalized by alendronate for bone targeting. • The nanoparticles restore bone homeostasis for osteoporosis treatment. Osteoporosis is a common bone disease characterized by the systemic disruption of hone homeostasis, where the imbalance between bone resorption and formation causes deterioration of bone structure and bone mass loss. Targeted restoration of bone hemostasis has thus become a promising strategy for osteoporosis treatment. For this purpose, we report a bone-targeted nanoformulation based on CaCO 3 nanomaterials, which could be activated in the acidic osteoporotic microenvironment and cooperatively regulate the activity of osteoclasts and osteoblasts to reverse bone deterioration. Herein, a clinical antiosteoporosis drug β-estradiol (E2) is first biomineralized using CaCO 3 to form physiologically stable nanocores. Meanwhile, azido groups are introduced onto MC3T3-E1 cells through incubation with AC 4 ManNAz. The azido-tagged MC3T3-E1 cell membranes are extracted for the camouflaging of the CaCO 3 @E2 nanocores to enhance their in vivo stability and availability, while also enabling the surface modification of bone-targeting dibenzocyclooctyne-tagged alendronate moieties via copper-free click reaction. After the selective deposition into acidic osteoporotic bone tissues, the CaCO 3 @E2 cores would be spontaneously degraded to release E2 and Ca2+ ions, which would systematically inhibit the activity of osteoclasts while promoting osteoblast-mediated new bone formation, eventually ameliorating the osteoporosis symptoms. This study offers an effective approach for osteoporosis treatment in the clinics. [ABSTRACT FROM AUTHOR]

Graphical abstract The WAR-PANI was synthesized by graft PANI onto alkyd resin and its anti-corrosion properties were studied. The results demonstrated that PANI was successfully grafted onto the alkyd resin and WAR-PANI can offer higher corrosion protection than the WAR and WAR/PANI. Highlights • Anti-corrosion coating WAR-PANI was developed by graft PANI onto alkyd resin. • Comparison study was made between WAR-PANI and physical blend. • WAR-PANI displayed higher corrosion resistance than WAR and WAR/PANI. • WAR-PANI coating also presented long-term anti-corrosion properties. Abstract Waterborne polyaniline grafted alkyd resin (WAR-PANI) anti-corrosion coatings were prepared via the chemical reaction between glycidyl methacrylate (GMA) modified WAR and polyaniline (PANI). The physical blend of PANI and WAR (WAR/PANI) were also prepared for comparison. The obtained WAR-PANI was characterized by fourier transform infrared spectroscopy and transmission electron microscopy. The results show that PANI was successfully grafted onto the chain of WAR. Polarization tests displayed that the corrosion potential of PANI grafted WAR coating became more positive compared with WAR/PANI physical blend, and the cathodic corrosion was effectively inhibited. When the dosage of GMA was 2.67%, the anticorrosion performance of WAR-PANI composite reached the optimum, the corrosion potential shifted from −690 mV to −530 mV, and the corrosion current density decreased from 6.92 × 10−5 to 9.66 × 10−11 A cm2. Electrochemical tests further proved that the impedance modulus and coating resistance of WAR-PANI increased by four orders in comparison with WAR, which were also three orders of magnitude higher than that of WAR/PANI. The surface morphology of the coatings after immersion in 3.5% NaCl solution also demonstrated that the WAR-PANI had good corrosion resistance performance, which displayed much more promising anticorrosion performance for steel substrate than WAR/PANI physical blend. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The dispersion of reduced graphene oxide (RGO) in polymer matrix was improved. • In situ incorporation of titanate functionalized RGO into polymer was used. • Isopropyl tri(diotylpyrophosphate) titanate (T3) was a good modifier for RGO. • The compatibility and interaction between T3-RGO and polymer were improved. • The one-component coating displayed excellent long-term corrosion resistance. Abstract Achieving a uniform dispersion of reduced graphene oxide (RGO) nanosheets in waterborne polymer matrix remains a challenge. Here, we significantly improved the dispersion stability of RGO in a polymer matrix through functionalizing RGO with titanate coupling agent of different dendritic structure. Titanate coupling agents of two branched dioctylpyrophosphate (T2) and three branched dioctylpyrophosphate (T3) were used. Rather than simply blending graphene with polymer matrix, functionalized graphene (T2-RGO or T3-RGO) was introduced into the reaction system with monomers to participate in the polymerization; resulting in improved compatibility and interaction between the graphene and polymer, especially for T3-RGO. One-component waterborne poly (urethane-acrylate) nanocomposite coatings (WPUA/T2G or WPUA/T3G) were then obtained. The particle size of WPUA/T3G colloidal particle size is much smaller than that of WPUA/T2G, the colloidal stability was also increased with the incorporation of T3-RGO. Compared with pure WPUA, the tensile strength of WPUA/T3G nanocomposite increased from 17.78 MPa to 40.01 MPa, and the elongation at break increased from 249% to 424%. The tensile strength and elongation at break of WPUA/T2G were 32.01 MPa and 366%, which were inferior to that of WPUA/T3G. Moreover, in comparison with pure WPUA, the impedance modulus of WPUA/T3G increased from 1.12 × 105 Ω.cm2 to 1.15 × 108 Ω.cm2, the coating resistance of WPUA/T3G increased from 8.41 × 104 Ω.cm2 to 1.39 × 108 Ω.cm2, which was also much higher than the impedance modulus (6.93 × 106 Ω.cm2) and coating resistance (7.31 × 106 Ω.cm2) of WPUA/T2G. WPUA/T3G nanocomposite coating exhibited excellent long-term corrosion resistance, being superior to the previously reported performance of solventborne polyurethane/graphene composite. [ABSTRACT FROM AUTHOR]

We reported herein the synthesis of block copolymers and their application in the in-situ emulsion polymerization of waterborne poly (urethane-acrylate) (WPUA) nanoemulsions based on phase inversion process. The polymerizable surfmers containing terminal unsaturated double bonds (MSA-r) were successfully synthesized via catalytic chain transfer polymerization (CCTP). Random copolymer (MSA-t) prepared through radical polymerization was utilized as control. The structure, surface tension and aggregation behavior of surfmers were characterized. The phase inversion, formation and stability of WPUA nanoemulsions were systematically investigated. Effects of MSA-r surfmer content and BMA/MMA ratio on the water resistance and thermal stability of the corresponding films were also discussed. It was found that the phase inversion mechanism of PUA prepolymer in the presence of MSA-r surfmers is different from conventional polyurethane prepolymer. The addition of MSA-r and MSA-t surfmers alters the rheological behaviors of PUA prepolymer via PUA-surfmer interactions, as well as the phase inversion process. Compared with WPUA/MSA-t emulsion, WPUA/MSA-r nanoemulsion displayed improved stability at higher solid content. The minimum particle size of WPUA/MSA-r nanoemulsion was 88.7 nm and kept almost constant after 12-month storage, while the particle size of WPUA/MSA-t emulsion was 131.3 nm and increased to 178.9 nm. Moreover, the WPUA/MSA-r film possessed improved water resistance and thermal stability. [ABSTRACT FROM AUTHOR]

To guarantee the stable and quantitative adding of surfactant into the pressure pipe and not be affected by the inlet and outlet pressure changing, the method utilizing jet pump cavitation characteristics to add surfactant was proposed. Keeping pressure ratio lower than the critical pressure ratio, the adding quantity could remain unchanged. In order to improve the stabilities, reduce the pressure loss and improve the critical pressure ratio of the jet cavitation adding method, a new two-stage cavitation jet adding method and device were proposed, and the performance was investigated experimentally under different working flows and outlet pressures, and compared to the cavitation jet pump in this paper. The results showed that the negative pressure remained unchanged within a certain range of outlet pressure, then decreased gradually with the increase of outlet pressure for the new device, which was similar with the traditional one. Furthermore, the critical pressure ratio of the new device was larger than the traditional one, which indicated that the pressure loss for the new device was smaller and it was more stable as the adding amount of surfactant was constant. In addition, the critical pressure ratio could increase by reducing the additive proportion of surfactant. Based on the above contributions and field investigation, it is believed that the study will play an important role for automatic quantitative control. [ABSTRACT FROM AUTHOR]

Stable alkoxysilane-functionalized poly (urethane-acrylate) (IPUASi) VOC-free hybrid microemulsion was successfully prepared through in-situ surfactant-free emulsion polymerization. Two approaches of introducing silane coupling agent (MPTS) were compared. The stability of microemulsion was determined by light scattering technique and rheology. The surface property and morphology were evaluated through X-ray photoelectron spectroscopy and atomic force microscopy. In addition, the static and dynamic mechanical properties, thermal behavior and water resistance of IPUASi films were systematically investigated. When MPTS was introduced during polyurethane prepolymer preparation, slight change took place in the particle size and distribution of IPUASi10 microemulsion even after being stored for a year. And the modulus of IPUASi10 microemulsion kept almost invariable with time at 60 °C. In contrast, when the MPTS was added in the process of water dispersion, the particle size and modulus of IPUASi10A microemulsion greatly increased due to the enhanced instability. Si and C-Si compositions on the surface of IPUASi10A film were much higher than those of IPUASi10 film, and improved phase mixing characteristic nature was detected for IPUASi10, as well as higher mechanical property and water resistance. In the presence of MPTS, the particle size decreased from 95.51 nm to 50.23 nm, the morphology of IPUASi microemulsion transformed from irregular morphology to more uniform globular structure, the interaction between colloidal particles decreased, while the viscoelasticity increased. In addition, the intermolecular interaction was enhanced with increasing MPTS content, resulting in increased mechanical property, thermal property and water resistance. However, excessive MPTS was unfavorable to the performance of IPUASi film. [ABSTRACT FROM AUTHOR]

Cross-linked polyvinyl alcohol (AZ-CIPVA) for effective paper sizing was prepared by using N-(isobutoxymethyl)acrylamide (IBMA) and aziridine cross-linker (AZ) as modifiers. The structure and the performances of the AZ-CIPVA with different dosage of AZ were characterized. The enhancing mechanism of paper sized by AZ-CIPVA was clarified. The results show that cross-linking structure is formed by the reaction between AZ and carboxyl groups in CIPVA molecules. With the increase of AZ content, the gel content, cross-linking density and thermal stability of the AZ-CIPVA film are increased. When the AZ dosage is 3.5%, both tensile strength and modulus of AZ-CIPVA film reach maximum, and the value are 68.34 MPa and 1037.02 MPa, respectively. The water absorption of the film reaches minimum and the folding endurance of the sizing paper reaches maximum when the content of AZ is 2.8%. When applied to the surface of the paper, the maximum dry and wet tensile indexes of the paper are increased by 223.77% and 432.56%, respectively. Roughness of the sizing paper increases slightly and the surface becomes uneven. The micro-structure shows that larger pores between the paper fibers are filled and cross-linked after sizing, which is beneficial to improve the mechanical strength of paper. • A series of cross-linked polyvinyl alcohol (AZ-CIPVA) modified by IBMA and AZ are successfully prepared. • The increasing of AZ can improve the degree of cross-linking and comprehensive performance of both AZ-CIPVA film and sizing paper. • The enhancing mechanism of paper by AZ-CIPVA is proposed. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) has been as an essential gasotransmitter and a potential therapeutic approach for several biomedical treatments such as cardiovascular disorders, hypertension, and other diseases. The endogenous and exogenous H 2 S also plays a crucial role in the bone anabolic process and a protective mechanism in cell signalling. In this study, we have utilized two types of polymers, polycaprolactone (PCL) and gelatin (Gel), for the fabrication of JK-2 (H 2 S donor) loaded nanofibrous scaffold via electrospinning process for bone healing and bone tissue engineering. Comparing the PCL/Gel and PCL/Gel-JK-2 scaffolds, the latter demonstrated enhanced cell adhesion and proliferation capabilities. Furthermore, both experimental scaffolds have been subjected to an in vivo experiment for 4 and 8 weeks in a bone-defect model of a rabbit to determine their biological responses under physiological conditions. There was an obvious increase in bone regeneration in the PCL/Gel-JK-2 group compared to the control and PCL/Gel groups. These results indicate the use of PCL/Gel scaffolds loaded with JK-2 should be considered for possible bone regeneration. Scheme of PCL/Gel-JK-2 fabrication and use for improving the bone formation in vitro and in vivo. [Display omitted] • JK-2, a novel donor of H 2 S, is used to prepare electrospun fibers for the first time. • PCL/Gel-JK-2 shows the best osteoinductive ability in vitro by releasing H 2 S slowly. • PCL/Gel-JK-2 nanofibers effectively enhance the regeneration of skull defect in vivo. [ABSTRACT FROM AUTHOR]

Schematic illustration of the PCL/Gel membrane prepared by co-electrospinning technique for bone tissue engineering. PCL was utilized to provide sufficient mechanical strength for enhancing overall integrity of the membranes. These co-electrospun membranes could slow-release hydrophobic drugs (loading in PCL nanofibers) and controlled-release hydrophilic drugs (loading in Gel nanofibers). In addition, the combination of the natural polymers could enhance the biocompatibility of these membranes and perform their respective functions in the bone healing process. [Display omitted] • PCL and Gel synergistically provide the mechanical properties and bioactivity. • Co-electrospun membrane can slowly release both hydrophilic and hydrophobic drugs. • Regulating PCL content can result in a time-tunable release of hydrophilic drugs. • PCL controls drug release by inhibiting the dissolution/diffusion of Gel fibers. The rising popularity of co-electrospinning technique in the field of biomaterial has enabled the possibility of combining various polymers, in which they provide the mechanical properties and the bioactivity for each other. Herein, a series of polycaprolactone/gelatin (PCL/Gel) composite membranes were prepared by co-electrospinning, and their biocompatibility and drug-controlled release ability were evaluated in detail for the first time. The addition of Gel significantly enhanced the adhesion and differentiation of osteoblasts, while the addition of PCL significantly improved the mechanical properties. Moreover, the in vitro degradation and drug release results showed that by adjust the PCL fibers amount and size, the degradation of Gel and the release profile of hydrophilic drugs/proteins could be effectively controlled: in the low PCL groups (PCL/Gel-1 & PCL/Gel-4), the Gel nano-fibers dissolved rapidly, resulting in an early explosive release within 1 week; however, with the increase of PCL content, the drug release rate decreased gradually, and the total release period could be extended to over 2 weeks (PCL/Gel-2, PCL/Gel-3 & PCL/Gel-5) or more (PCL/Gel-6). Therefore, the preparation of a controllable drug delivery system with good biological activity by co-electrospinning of PCL and Gel could provide an effective strategy for bone regeneration. [ABSTRACT FROM AUTHOR]

Abstract: Solid-state NMR techniques have been employed to investigate the domain structure and mobility of the bacterial biopolymeric metabolites such as poly(3-hydroxybutyrate) (PHB) and its copolymers poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 2.7mol% (PHBV2.7) and 6.5mol% (PHBV6.5) 3-hydroxyvalerate. Both single-pulse excitation with magic-angle spinning (SPEMAS) and cross-polarization magic-angle spinning (CPMAS) 13C NMR results showed that these biopolymers were composed of amorphous and crystalline regions having distinct molecular dynamics. Under magic-angle spinning, 1H T 1ρ and 13C T 1 showed two processes for each carbon. Proton relaxation-induced spectral editing (PRISE) techniques allowed the neat separation of the 13C resonances in the crystalline regions from those in the amorphous ones. The proton spin–lattice relaxation time in the tilted rotating frame, , measured using the Lee–Goldburg sequence with frequency modulation (LGFM) as the spin–locking scheme, was also double exponential and significantly longer than 1H T 1ρ . The difference between for the amorphous and crystalline domains was greater than that of 1H T 1ρ . Our results showed that the differences could be exploited in LGFM–CPMAS experiments to separate the signals from two distinct regions. 1H spin-diffusion results showed that the domain size of the mobile components in PHB, PHBV2.7 and PHBV6.5 were about 13, 24 and 36nm whereas the ordered domain sizes were smaller than 76, 65 and 55nm, respectively. The results indicated that the introduction of 3-hydroxyvalerate into PHB led to marked molecular mobility enhancement in the biopolymers. [Copyright &y& Elsevier]

In this study, an anion-cation compound foaming agent (ACFA) was proposed based on the synergistic mechanism, so as to realize efficient production of low-concentration foam for preventing coal spontaneous combustion. The foaming and coal spontaneous combustion prevention properties of ACFA and anion compound foaming agent (AFA) were investigated by using Foamscan and the coal spontaneous combustion testing system, respectively. The results show that foaming speeds of the two agents both increase with the rise of concentration. The critical micelle concentrations of ACFA and AFA are 1‰ and 4‰, respectively. Compared with AFA, ACFA can reach the required foam volume faster. Besides, the foam produced by ACFA can stabilize 115% longer and maintain its effect longer, because ACFA contains more liquid than AFA at the critical micelle concentration. Moreover, the densely and uniformly distributed foam produced by ACFA can more effectively prevent oxygen from feeding the coal. Since coal samples treated with ACFA and AFA both boast high inhibition rates, they can serve as foam fire-extinguishing agents to prevent coal spontaneous combustion in underground mines, but ACFA is more efficient and economical. [ABSTRACT FROM AUTHOR]