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Increasing the toughness of poly(lactic acid) (PLA), i.e., simultaneously increasing both the tensile strength and ductility, remains a major challenge. In this study, fully bio-based PLA blends with polydecalactone (PDL)-grafted cellulose copolymer (CgPD) were prepared and comprehensively analyzed to enhance the toughness of the PLA matrix. The blends were found by FT-IR and solid-state 1H NMR to be physically intact and miscible at the sub-twenty-nanometer scale. The WXRD and DSC analyses indicated that the addition of the alkyl-branched CgPD imparts a more structurally disordered PLA mesophase state to the prepared PLA_CgPD bio-blends. UTM analysis was used to characterize the macroscopic mechanical properties of the PLA_CgPD bio-blends. Both the tensile strength and elongation properties were simultaneously improved with the addition of 1 wt% CgPD loading amount to PLA (PLA_CgPD1). This study experimentally demonstrates that the enhanced mechanical properties of PLA_CgPD1 are closely related to the existence of more ordered PLA mesophases induced by the introduction of an optimal amount of CgPD into the PLA matrix.

Endovascular treatment (EVT) is less effective for intracranial atherosclerosis-induced emergent large vessel occlusion. Extracranial-intracranial (EC-IC) bypass surgery is a possible treatment option to augment cerebral blood flow in the perfusion defect area. We compared the efficacy and safety of EC-IC bypass surgery with those of EVT and maximal medical treatment for acute ischemic stroke.The data from 39 patients, for whom vessel revascularization had failed despite mechanical thrombectomy, were retrospectively analyzed. Of the 39 patients, 22 had undergone percutaneous transluminal angioplasty or intracranial stenting (PTA/S), 10 had undergone emergency EC-IC bypass surgery within 24 hours of symptom onset, and 7 had received maximal medical treatment (MMT) only. The patency, perfusion status, and postoperative infarct volume were evaluated. The clinical outcomes were assessed at 6 months postoperatively using the modified Rankin scale.The mean reperfusion time was significantly longer for the EC-IC bypass group (14.9 hours) compared with that in the PTA/S group (4.1 hours) and MMT group (7.5 hours; P0.05). The postoperative infarct volume on diffusion-weighted magnetic resonance imaging was significantly lower in the emergency EC-IC bypass group (11.3 cmEmergency EC-IC bypass surgery is an effective and safe treatment option for intracranial atherosclerosis-induced acute ischemic stroke for which EVT is inadequate.

The self-healing polyurethane films have received significant attention due to their unique shape memory behaviors and the hydrogen bonding arising from the urethane linkages. However, it is still a challenge to develop self-healing polyurethane with transparent, high impact resistance, and excellent shape recovery and mechanical properties. In particular, polycarbonate-based polyurethane shows transparency, weatherability and excellent mechanical properties. In this work, transparent self-healing polyurethane film with robust mechanical properties (breaking stress of 26 MPa and elongation at break of 630%) was synthesized by controlling the different molecular weight of the polycarbonate diol and incorporating dynamic disulfide bonds for reversibility. As a result, the self-healing polyurethane film showed an excellent self-healing ability with 98% healing efficiency and excellent shape memory ability with a recovery efficiency of ˃92%. In addition, we have identified a potential application for the self-healing flexible substrate in flexible electronics because of their stable electrical resistance even upon mechanical deformation.

To optimize a dynamic network structure is a key feature for a supramolecular self-healing material capable of perfectly and repeatedly restoring its morphology and performance following a mechanically damaging event. Despite significant progress in self-healing supramolecular networks over the past few decades, many questions surrounding the dynamic responses of these networks during healing still remain. Herein, we present the self-healing behavior of a dual dynamic supramolecular network (DDN) consisting of a weak clustery supramolecular network and a strong dendritic supramolecular network simultaneously. The DDN is easily prepared by the complexation of linear and non-linear poly(e-caprolactone)s end functionalized with 2-ureido-4[1H]-pyrimidinone, which exhibits 100%-optical and 95%-mechanical healing efficiencies within 2 and 5 min, respectively, at 90 °C. In addition, the DDN film is shown to repeatedly self-heal ten times, even when damaged at the same position. DDN healing depends significantly on the density of the supramolecular network, and is specifically accomplished by the reassociation of hydrogen bonds between UPy moieties at the thermally swollen status of the dendritic network following the thermal disassembly of the clustery network. The DDN-coated nylon fabric exhibits excellent self-healing characteristics, which opens opportunities for creating scratch-protective materials.

In this study, we developed a highly stretchable internally- and externally-plasticized (i.e., dually-plasticized) cellulose, which is composed of a polydecalactone (PDL)-grafted cellulose copolymer (CgPD) and a hyperbranched polycaprolactone (PCL) external plasticizer (HPC). To investigate the effect of molecular structure of PCL external plasticizers on the plasticization behavior of dually-plasticized celluloses, a linear PCL (LPC) and a star-shaped PCL (SPC) were prepared as control groups. It is observed that specific molecular interactions existed between CgPD and external plasticizers in the dually-plasticized celluloses (i.e., CgPD_LPC, CgPD_SPC, and CgPD_HPC, respectively). Especially, CgPD_HPC exhibited the lowest apparent activation energy (Ea= ∼128.8 kJ mol−1) required to achieve the plasticizing behavior, which resulted in an enhanced ductility (e = ∼136%) compared to those of the CgPD (e= ∼75%), whereas CgPD_LPC and CgPD_SPC displayed severely deteriorated values (e = ∼25 and ∼59%, respectively). In addition, the dually-plasticized cellulose bearing bulkier HPC exhibited further improved stretchability. These results comprehensively indicate that the highly-branched flexible segments of external plasticizer and structural uniformity induced by effective specific interactions between the plasticizing components play crucial roles in improving plasticization abilities of the dually-plasticized cellulose.

We used a nanofiltration (NF) membrane process to produce purified aqueous sulfuric acid from copper-refining sulfuric acid wastewater. Wastewater generated from a copper-refining process was used to explore the membrane performances and acid stabilities of six commercial NF membranes. A combination of permeate flux, sulfate permeation, and metal ion rejection clearly showed that two polyamide membranes and a polyacrylonitrile-based membrane achieved recovery of a purified sulfuric acid solution. Acid-stability and long-term performance tests showed that the polyamide membranes were unsuitable for copper-refining wastewater treatment because of their low acid stabilities. In contrast, the polyacrylonitrile-based composite membrane showed excellent acid stability, and gave greater than 90% metal ion rejection, with the exception of calcium ions, for 430 d. We also evaluated the recovery performance in 1 ton/d pilot-scale process using wastewater from copper-refining process; 90% metal ion rejection was achieved, with the exception of calcium ions, even at 95% recovery rate.

Glass transition dynamics are one of the most important characteristics with regards to governing the properties of polymers. Herein, we prepare pyrene-labeled and pyrene-doped flexible poly(vinyl chloride)s plasticized by ultra-small branched star poly(e-caprolactone) (L-PVC/USB-SPCL and D-PVC/USB-SPCL, respectively), and observe the changes in their fluorescence intensities with temperature to ascertain the actual glass transition behaviors of the polymer chains. Fluorescence spectroscopy measurements show that the D-PVC/USB-SPCLs have a single Tg, which is comparable to the Tg measured by differential scanning calorimetry (DSC). However, the L-PVC/USB-SPCLs exhibit a broad glass transition from the onset of Tg for the L-PVC/USB-SPCLs to the endset of Tg for the PVC chain itself (i.e., in the absence of USB-SPCL). In addition, the L-PVC/USB-SPCLs show a relatively low nonradiative decay degree compared to the D-PVC/USB-SPCLs. These results indicate that the labeled pyrene moieties along the PVC chains exhibited limited movement due to the cooperative reptation motion of the chains, even when the space for the polymer chain to move sufficiently is created by an increase in the free volume. As the USB-SPCL content increase in the flexible PVC, the fluorescence intensity reduction degrees of the various D- and L-PVC/USB-SPCLs decrease due to the polarity effect of USB-SPCL. However, in the case of the L-PVC/USB-SPCLs, when the USB-SPCL loading reach 40 phr, the fluorescence intensity reduction degree increases once again due to the dominance of the decrease in caging effect, which reveals that the labeled system, in which a fluorescent substance is directly attached to a polymer chain, allows identification of the motion of the polymer chain in a direct and sensitive manner.

The global slaughterhouse waste (SHW) generation is rapidly soaring due to expanding population and shifts in eating pattern. Anaerobic digestion (AD) enables a sustainable and cost-efficient treatment of SHW through biological conversion of the organics into biogas. To assess the feasibility and provide basics for planning, this study investigated the characteristics of the SHW in a year basis for a thorough set of parameters including the organic compositions and the CH4 production potential. The organic wastes could be categorized as the red (heart, lung and liver) and the white (large intestine) SHWs. The white SHW had a higher lipid content (average 22.4%, wet basis) as well as the solids, resulting in the CH4 potential of 684.8 mL/g VS which was approximately 1.4-fold that of the red SHW (483.6 mL/g VS). The low C/N ratio (7.1) of the red SHW due to the high protein content (14.5%, wet basis) could lead to ammonia inhibition if this waste is solely treated. Next-generation sequencing was analyzed to depict the microbial community and the importance of initial inoculum selection could be highlighted. The community structure greatly affected the lag phase of the biological process ranging 0.26–1.28 d for the red SHW and 0.35–3.08 d for the white SHW. The energy potential of SHW AD in Korea was estimated to be 10920 TOE/yr, which is as high as 14.5% of the domestic biogas energy production in 2019. Overall, the SHW can be considered as energy-intensive feedstock for AD, and co-digestion with other wastes such as food waste or waste sludge could be recommended.

In this study, we designed novel methods to prepare a cellulose graft copolymer series (Cell-g-PDLs) with varied graft chain lengths, via direct ring-opening polymerization (ROP) of unmodified cellulose with alkyl-branched lactones. With increasing alkyl-branched graft chain length of the Cell-g-PDLs, the crystalline phase of cellulose became increasingly weakened, while the glass transition temperature significantly decreased. The latter was attributed to the extended free volume derived from the increased chain end-group concentrations of the branched graft chains. These results suggested that the incorporation of a highly alkyl-branched graft chain into unmodified cellulose is an effective way to improve its thermo-plasticity. Notably, the Cell-g-PDL with the longest graft chain (Cell-g-PDL9) was demonstrative of highly sufficient thermo-plasticity, owing to the enhanced molecular mobility resulting from the reduced frictional forces between the cellulose molecules.

Temperature is a very important parameter affecting the performance of microbial electrolysis cell (MEC). Generally, the activity of methanogens can be improved by operating at higher temperature, while electrochemically active bacteria (EAB) have the highest activity at around 30 °C. In this study, batch tests were performed to investigate the effect of temperature on the methane production and organic matter removal of MEC treating sewage sludge. As the temperature increased, the pH and alkalinity of digestate at the end of each cycle increased from 7.72 and 2055.5 mg CaCO3/L (at 30 °C) to 8.62 and 2804.9 mg CaCO3/L (at 40 °C) possibly due to the improved activity of methanogens. The VSS removal increased linearly from 35.1% to 45.8% by increasing the temperature from 30 °C to 40 °C, while COD removal was not significantly affected (

Electrospun meta-aramid nanofibers are typically extremely vulnerable to dipolar aprotic solvents, such as DMAc, DMSO, and DMF. This low chemical stability has made practical application of such nanofibers difficult. In this work, meta-aramid nanofiber mats with a directional nature were electrospun and sequentially post-treated by salt removal and heat treatment to enhance chemical stability. The salt added to dissolve the meta-aramid in the solvent was completely removed from the meta-aramid nanofibers via repetitive washing. The salt-removed meta-aramid nanofiber mat displayed a glass transition behavior not observed in the pristine nanofiber mat. The crystalline structure of the salt-removed nanofiber mats was regenerated by heat treatment above its glass transition temperature, whereas heat-treated nanofiber mats with salt remained amorphous. The salt between the meta-aramid chains interrupted their rearrangement, indicating that, in the absence of salt, the chains could be arranged during heat treatment. Additionally, the sequential post-treatment induced the reforming of intermolecular hydrogen bonds between the chains; thus, the post-treated nanofiber mat exhibited enhanced mechanical and chemical stabilities, which was confirmed by survival of the meta-aramid nanofiber in DMAc. Furthermore, a surface-modified meta-aramid nanofiber mat showing hydrophobicity and superoleophobicity was fabricated by silanization with trichloro (1H,1H,2H,2H-perfluorooctyl) silane.

We have developed magnetic core-hydrophilic shell nanospheres as a draw solute with enhanced stability for use in forward osmosis (FO) processes, which were prepared via a ligand exchange reaction. The combined results of TEM, DLS, FT-IR, and TGA analysis indicated that spherical magnetic nanospheres with 10 nm in diameter were successfully prepared via a thermal decomposition method. Hydrophilic shell layers were prepared using a ligand exchange reaction, and the hydrophilic siloxane agents were robustly bound to the surfaces of the magnetic nanosphere without inducing morphological changes. The number of hydrophilic agents presented in the magnetic nanospheres increased dramatically as a result of the covalently attached hydrophilic siloxane agents. The magnetic core-hydrophilic shell nanosphere draw solutes generated reasonable osmotic pressures due to their hydrophilic shell layer, rendering them useful for purifying mildly brackish water. As we intended, the osmotic pressure of the magnetic core-hydrophilic shell nanosphere was well maintained during repetitive magnetic recovery processes because the robustly bound the hydrophilic shell layer prevented particle aggregation.

The dynamic effects of unentangled star-shaped polymers with extremely small branches on the plasticization of miscible polymer blends are investigated using ultra-small branched star poly(e-caprolactone)s (USB-SPCLs), poly(vinyl chloride) (PVC), and their blends. Photon correlation dynamics of USB-SPCLs supports our previous suggestion that a whole USB-SPCL molecule acts as a single coarse-grain unit with dynamically-equivalent branches because of the extremely small branches, resulting in the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs, regardless of the molecular architectures. The dynamic light scattering intensity autocorrelation curves of miscible PVC/USB-SPCL blends reveal that strong intermolecular interactions between PVC and USB-SPCL molecules determine the dynamic homogeneous behaviors of the blends despite their significantly different mobilities. The molecular motions of the blends depend on the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs. These dynamic results clearly show the plasticization of the entangled neat linear PVC matrix by distinctive and rapid molecular mobility of USB-SPCLs.

We synthesize the anatase TiO 2 /zinc phthalocyanine (ZnPc) hybrids in various sizes (245–1188 nm) and examine the visible light photocatalytic activity of TiO 2 /ZnPc hybrids, in conjunction with their Mie light scattering ability. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy show that ZnPc molecules are well-incorporated and dispersed on the surface of the TiO 2 , instead of being aggregates. From the field-emission scanning electron microscopy, dynamic light scattering, and nitrogen adsorption–desorption analysis, we confirm the formation of spherical TiO 2 /ZnPc hybrids in various sizes (245, 548, 798, 1188 nm in diameter), the large specific surface areas (up to 223.76 m 2 /g), and the mesoporous structures. The mesoporous TiO 2 /ZnPc hybrids show excellent photocatalytic efficiency (up to 89.93% after 90 min) toward the degradation of methylene blue under visible light irradiation, which is about 2 times of that of simple nanoparticular P25/ZnPc. Among the mesoporous TiO 2 /ZnPc hybrids, the hybrid with a size of 548 nm (P123–TiO 2 /ZnPc) exhibits the highest photocatalytic activity. The highest activity observed on P123–TiO 2 /ZnPc may be attributed to its efficient cascade Mie scattering effect under visible light irradiation.

The extremely small branched effects on molecular dynamics are investigated using well-defined star poly( e -caprolactone)s containing ultra-small branches (USB-SPCLs) as a model system. USB-SPCLs interestingly show total-molecular-weight-dependent glass transitions regardless of the molecular architecture parameters, such as the number and length of branches, whereas typical star polymers with polymeric large branches show the end-group-concentration-dependent glass transitions. The viscoelasticity of USB-SPCLs does not depend exponentially on the individual branched molecular weight, as observed in typical star polymers, and instead follows the modified Mark–Houwink power law and the Bueche-modified Rouse model for unentangled linear polymers. The flow activation energy and the longest Rouse relaxation time of USB-SPCLs show that the individual branches of USB-SPCL are dynamically equivalent and that a whole USB-SPCL molecule moves with a simple uni-motion. These results suggest that a whole USB-SPCL molecule presumably acts as a dynamically-equivalent single coarse-grain unit because of the extremely small branches on the scale of 20–40 atoms.

The dispersion, aggregate morphology, and interfacial strength of fillers in polymer nanocomposites are crucial in determining their physical properties. Here, we utilize the quadruple hydrogen bonding group ureidopyrimidinone (UPy) to investigate enthalpic effects on the dispersion of silica nanoparticles in a poly(butyl acrylate) copolymer matrix and to correlate dispersion with mechanical properties. Butyl acrylate was copolymerized with an UPy side chain functional methacrylate monomer and blended with silica nanoparticles containing various degrees of UPy, hexyl, or silanol surface functionality. The tensile and dynamic mechanical responses of these nanocomposites were measured, and the effects of varying surface functionality on mechanical properties are discussed and correlated to dispersion by TEM. The competing effects of filler–filler, matrix–filler, and matrix–matrix hydrogen bonding lead to a system where both the type and amount of filler surface functionality are of critical importance to the material's final strength.

We develop a regenerable anti-fouling membrane via the formation of a dynamic peel-and-stick of hydrophilic poly(ethylene glycol) (PEG) layer onto the surface of a poly(tetrafluoroethylene) (PTFE) membrane, using thermo-responsive reversible covalent bonding. In order to attach a peelable-and-stickable hydrophlilic layer onto a membrane surface, a maleimide end-modified PEG layer is coupled with a furan-modified PTFE membrane by reversible Diels–Alder (DA) cycloaddition reaction. The combined results of attenuated total reflection Fourier-transform infrared (ATR FT-IR), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FE-SEM) measurements clearly reveal that the maleimide end-modified PEG is successfully coupled with the furan-modified PTFE membrane surface by DA reaction. In addition, the hydrophilic PEG layer is readily and repeatedly reformed on the membrane surface by a thermally driven dynamic peel-and-stick process. The PEG-coupled PTFE membrane shows effective anti-fouling performance against a highly concentrated silica colloidal aqueous solution. In particular, the anti-fouling property is remarkably recovered after regeneration of the hydrophilic layer through the peel-and-stick process.

In this work, Ag–TiO2-embedded nanofiber composite (AT-in-NF) and Ag–TiO2-decorated nanofiber composite (AT-sur-NF) were comparatively studied to investigate the effect of the position of the silver-loaded titanium dioxide (Ag–TiO2) on the performance of nanofiber composites under visible light irradiation. AT-in-NF and AT-sur-NF were prepared by electrospinning and simultaneous electrospinning/electrospray process, respectively, and the compositions of the nanofiber composites were deliberately controlled to be the same with the exception of the Ag–TiO2 position. AT-sur-NF, in which the Ag–TiO2 was exposed on the nanofiber surface, showed better photo-induced self-cleaning behavior for methylene blue staining under visible light irradiation than AT-in-NF. AT-sur-NF also exhibited excellent bacterial growth inhibition for both Staphylococcus aureus (Gram-positive bacteria) and Klebsiella pneumoniae (Gram-negative bacteria) while AT-in-NF exhibited the bacterial growth inhibition for just K. pneumoniae. These results show that the presence of highly dispersed Ag–TiO2 on the nanofiber surface endows the nanofiber composite with superior photocatalytic and antimicrobial activities, and is useful for designing and optimizing the high performance nanofiber composites.

Colistimethate sodium (CMS) is increasingly used to treat multidrug-resistant Gram-negative bacilli infections. However, the incidence of CMS-associated nephrotoxicity has not been evaluated in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) pneumonia. This retrospective study included 120 patients with CRAB pneumonia treated with intravenous CMS for ≥72 h. The objective of the study was to determine risk factors for CMS-induced nephrotoxicity and 30-day mortality in patients with CRAB pneumonia. Of the 120 patients with CRAB pneumonia, 61 (51%) developed nephrotoxicity. Multivariate analysis showed that dose per ideal body weight (IBW) [odds ratio (OR)=1.28, 95% confidence interval (CI) 1.01-1.62; P=0.04], Charlson co-morbidity index (OR=1.31, 95% CI 1.06-1.60; P=0.01) and septic shock (OR=3.16, 95% CI 1.32-7.60; P=0.01) were associated with CMS-associated nephrotoxicity. Thirty-day mortality was 33% (39/120). Multivariate analysis showed that higher daily doses of CMS per IBW [hazard ratio (HR)=0.81, 95% CI 0.67-0.98; P=0.03] and longer duration of CMS therapy (HR=0.86, 95% CI 0.79-0.95; P=0.002) were associated with increased survival. Septic shock (HR=3.91, 95% CI 1.95-7.83; P

We develop an anti-scaling ultrafiltration/microfiltration (UF/MF) membrane by introducing a high-density positive charge to a poly(vinylidene fluoride) (PVDF) membrane to suppress membrane scaling in Ca2+/silica-rich wastewater. Positively charged modifiers are synthesized by conjugating an amphiphilic polymer (Brij S10) and branched poly(ethylene imine) (b-PEI) at various molar ratios, and these are then implanted to PVDF membranes during the phase-inversion process. Attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectra reveal that the positive modifiers successfully anchors onto the surface of the membrane by hydrophilic-hydrophobic phase recognition. As introducing the positive charge on the membrane surface, the membranes show positive surface charge and their pure water permeability (PWP) increases due to the protonation of b-PEI. Anti-scaling properties are also confirmed to be improved by filtration tests using a metal ions/silica-rich feed solution, which results from the repulsion of metal ion by the positively charged branch on the membrane. In addition, the water flux recovery by simple membrane backwashing of the modified membrane is double that of the neat PVDF membrane.

Mn3O4-coated activated carbon (Mn3O4/AC) was prepared by supercritical technique and applied for the removal of Pb and Cu ions from aqueous solution. Kinetic and isotherm data of the adsorption by Mn3O4/AC were compared with those of activated carbon (AC) and pure Mn3O4. Adsorption of metals was adequately described by pseudo-second-order kinetics and Langmuir isotherm models. Maximum adsorption capacities of Pb and Cu ions determined by Langmuir model were enhanced 2.2 and 6.1 times for Pb and Cu ions by Mn3O4 coating onto AC, which might be attributed to reduced resistance of intraparticle diffusion and enhanced surface electrostatic interaction and complexation by Mn3O4.

We demonstrate here the fabrication of a novel morphology of bowl-shaped TiO2 aggregates via a facile electrospray technique using TiO2 nanowires. These have been prepared by using lauric acid via solvothermal synthetic route. The modulation of surface energies of the different crystallographic faces through the use of lauric acid is the key parameter for the anisotropic growth. These aggregates have high specific surface area of up to 93.10 m2/g, and relatively large pores with a mean size of 4.68 nm. These porous structures can provide a high number of active adsorption sites and act as photo-related reaction centers. The prepared bowl-shaped TiO2 are in micrometer size and have good morphology and high specific surface area. A possible mechanism for the formation of bowl-shaped TiO2 aggregates is also proposed, based on the results. The light scattering properties of bowl-shaped architectures are characterized by the UV–Vis spectrometry. The superior light scattering abilities of bowl-shape makes them promising architectures for applications in the photovoltaic devices.

Phthalocyanine (Pc) derivatives and hyperbranched poly(amidoamine) (HPAMAM) were synthesized and then modified with maleimide groups. They were then coupled to a poly(tetrafluoroethylene) (PTFE) membrane modified with furan groups through a Diels-Alder (DA) reaction. In this multi-functional PTFE membrane, Pc fluorescence was quenched by heavy-metal-ions, while HPAMAM adsorbed them to prevent leakage. In addition, HPAMAM hydrophilicity improved water permeability through the membrane. Thermally reversible DA bonding between furan and maleimide groups also allows selective regeneration and replacement of the functional materials on the membrane. Modification and functionality of the membrane were characterized with Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, fluorescence spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The analyses revealed a renewable, multi-functional membrane that detected and eliminated heavy metal ions.

For the removal of endocrine disrupting chemicals (EDCs), such as di-(2-ethylhexyl) phthalate (DEHP), from drinking water, we prepared β -cyclodextrin included polysulfone (PSf/CD) hollow fiber membranes. β -Cyclodextrin ( β -CD) was modified with fatty acid chlorides to produce amphiphilic β -CDs. PSf/CD hollow fiber membrane was prepared from polysulfone (PSf) dope solution with those amphiphilic β -CDs by phase inversion process. In the membrane formation process, the amphiphilic β -CDs migrated to the membrane surfaces via hydrophilic- and hydrophobic-mediated self-assembly. The performances of PSf/CD hollow fiber membranes were measured and the results showed that PSf/CD hollow fiber membranes can effectively remove DEHP from aqueous solutions and provided good water permeability.

There have been increasing interests in the conversion of organic residues into biochars in order to reduce the rate of decomposition, thereby enhancing carbon (C) sequestration in soils. However energy is required to initiate the pyrolysis process during biochar production which can also lead to the release of greenhouse gasses. Alternative methods can be used to stabilize C in composts and other organic residues without impacting their quality. The objectives of this study include: (i) to compare the rate of decomposition among various organic amendments and (ii) to examine the effect of clay materials on the stabilization of C in organic amendments. The decomposition of a number of organic amendments (composts and biochars) was examined by monitoring the release of carbon-dioxide using respiration experiments. The results indicated that the rate of decomposition as measured by half life (t1/2) varied between the organic amendments and was higher in sandy soil than in clay soil. The half life value ranged from 139 days in the sandy soil and 187 days in the clay soil for poultry manure compost to 9989 days for green waste biochar. Addition of clay materials to compost decreased the rate of decomposition, thereby increasing the stabilization of C. The half life value for poultry manure compost increased from 139 days to 620, 806 and 474 days with the addition of goethite, gibbsite and allophane, respectively. The increase in the stabilization of C with the addition of clay materials may be attributed to the immobilization of C, thereby preventing it from microbial decomposition. Stabilization of C in compost using clay materials did not impact negatively the value of composts in improving soil quality as measured by potentially mineralizable nitrogen and microbial biomass carbon in soil. Refereed/Peer-reviewed

We performed the encapsulation of β-cyclodextrin (β-CD) in PVC by in situ polymerization with vinyl chloride monomer (VCM), and investigated the effect of CD encapsulation on the suppression of dioctyl phthalate (DOP) migration suspected as endocrine disruptor. β-CD was partially modified with 3-(methacryloxy)propyl trimethoxysilane and modified β-CD (MCD) was then encapsulated in PVC through suspension polymerization via radical reaction between double bonds MCD and VCM. Resulting MCD-encapsulated PVC (MCD x –PVC) exhibited the similar morphology and characteristics to commercial PVC. For MCD x –PVCs plasticized with DOP, they showed the considerably suppressed DOP migration as well as the similar optical and mechanical properties to conventionally plasticized PVC. In particular, the plasticized MCD x –PVCs exhibited the superior suppression of DOP migration compared to the plasticized PVC where MCD and DOP were introduced by conventional melt mixing. Therefore, the encapsulation of MCD in PVC is thought to be an effective approach to producing the ecological PVC material.

Acrylonitrile–butadiene copolymer (NBR) nanocomposites were prepared with varied silicate loadings by the melt mixing between NBR and organoclays (OCs) containing intercalants with different polarity and chain length. WXRD exhibited that the NBR nanocomposites had an intercalated structure with distinct differences in gallery height depending on the intercalant characteristics. However, WXRD failed to show a structural change with increasing silicate contents. Hence, tensile strain–stress measurements were carried out at various strain rates (0.162, 0.0975, and 0.0187 s−1), and then the results of tensile measurement applied to the strain–time correspondence (STC) principle, resulting in the tensile modulus master curves of the NBR nanocomposites as a function of time. For pure NBR, a master curve was constructed using only the horizontal shift factor, indicating that the material was structurally homogeneous. However, the NBR nanocomposites required both vertical shift (modulus shift, Γ(α)) and horizontal shift to form the master curves, indicating structural heterogeneity ascribed to the domain structure such as silicate tactoid. From master curves, we found that NBR nanocomposite with OC having polar organic intercalant, NBROC30B, had the lowest n value in the nanocomposites. This indicates that NBROC30B had the most dispersive silicate structure in the nanocomposites due to the polar interaction, being in good agreement with WXRD results. In particular, STC was not applicable at all nanocomposites with silicate loadings over 8 wt%, regardless type of organoclay, and tensile strength and toughness of the nanocomposites with silicate loading of 8 wt% were better than expected. These could be explained as the network-like percolation of the silicate tactoids in all nanocomposites with silicate loadings over 8 wt%, which were consistent with the results observed from HR-TEM.

Layered silicate nanostructures of NBR nanocomposites prepared using the various organoclays (OCs) and silicate loadings were investigated by analyzing the viscoelastic behavior, activation energy ( E a ), and average relaxation times ( τ HN ) obtained from dynamic mechanical measurements. Viscoelastic behavior revealed that NBR nanocomposite with OC having polar organic modifier (NBROC30B) has the highest elasticity in NBR nanocomposites, indicating the formation of the largest gallery height. In addition, E a and τ HN showed that the mobility of NBROC30B was the closest to that of NBR, providing further evidence that NBROC30B has the largest gallery height. Interestingly, viscoelastic behavior, E a , and τ HN of the nanocomposites with silicate loadings in excess of 7 wt% were remarkably higher than those of the nanocomposites with silicate loadings below 7 wt%. These results imply the sudden change of silicate structure and suggest the formation of three-dimensional network-like percolated silicate structure at NBR nanocomposites with silicate loadings over 8 wt%, which was consistent with HR-TEM results.

Exfoliated poly(ethylene terephthalate) (PET) nanocomposite excluding organic modifier (M-P et LSN eom ) was successfully prepared by the melt processing via solution method with solvent–nonsolvent system. PET nanocomposites including organic modifier (M-P et LSN iom and D-P et LSN) as counterpart of M-P et LSN eom were prepared by using the melt processing via solution method without solvent–nonsolvent system and the only conventional direct melt mixing process, respectively. From elemental analysis (EA) and thermogravimetric analysis (TGA), organic modifier in M-P et LSN eom was confirmed to be well removed by solution method with solvent–nonsolvent system. Then, it was found that M-P et LSN eom and M-P et LSN iom had exfoliated structure by wide angle X-ray diffraction (WAXD) and high-resolution transmission electron microscopy (HR-TEM), whereas no expansion of gallery height was observed for D-P et LSN. To elucidate the effect of organic modifier on the physical properties of PET nanocomposites, the crystallization behavior, optical transparency, thermal stability, and mechanical properties of M-P et LSN eom , M-P et LSN iom , D-P et LSN, and neat PET were evaluated by differential scanning calorimetry (DSC), UV–visible (UV–vis) spectroscopy, TGA, and universal testing machine (UTM). All of the PET nanocomposites exhibited faster crystallization kinetics and better thermal and mechanical properties compared to neat PET due to the presence of silicate layer in PET. However, M-P et LSN iom and D-P et LSN including organic modifier showed lower crystallization constant rates, longer crystallization half times, and poorer optical, thermal, and mechanical properties than M-P et LSN eom . These results were ascribed to the thermal decomposition of the organic modifiers presented in M-P et LSN iom and D-P et LSN during the melt processing.

The glass transitions of acrylonitrile–butadiene rubber (NBR)/organoclay nanocomposites with various silicate contents were investigated using positron annihilation lifetime spectroscopy (PALS). The nanocomposites were prepared through melt intercalation of NBR with various concentrations of organoclay (OC30B) modified with the organic modifier, methyl tallow bis(2-hydroxyethyl) quaternary ammonium (MT2EtOH), i.e., Cloisite ® 30B. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) measurements of the NBR/OC30B nanocomposites showed that the NBR chains were intercalated between the silicate layers, thereby increasing the gallery heights of the organosilicates. The glass transition temperature of NBR was determined using differential scanning calorimetry (DSC). However, it seemed to be very difficult to clearly resolve the very small differences in T g s caused from various loading of nanosized silicate in NBR/OC30B nanocomposites. Hence, we performed positron annihilation lifetime spectroscopy (PALS) on NBR/OC30B nanocomposites containing various amounts of OC30B (1–10 wt%). Significant changes in the temperature dependencies of free volume parameters (i.e., lifetimes and intensities) were observed at the transition temperature, T g,PALS , and the T g,PALS values were found to increase with increasing organoclay content in the samples. These observations are consistent with PALS having a higher sensitivity in the detection of very small changes in free volume properties. The present findings thus highlight the usefulness of PALS for studying phase transition phenomena in polymeric materials with nanoscale structural variations.