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The low percentage of pores at which droplets are formed results in lower production efficiency, which is one of the main issues hampering the application of microporous membrane emulsification on a large scale. The effect of microporous membrane pore activation on the droplet's formation and emulsion performance was systemically investigated by changing both transmembrane pressures and membrane wettability during membrane emulsification. It indicated that the high transmembrane pressure increased the pore activation ratio (the percentage of pores at which droplets are formed) by the growing flux. These induced the enhancements of emulsification efficiency and the degradation of emulsion performance. Different wettability of membrane inflow and outflow influenced the pore activation speed (the speed which droplets are formed at pores). It indicated that the wettability of membrane outflow had a key effect on droplet formation and the high pore activation speed avoided splashing for high emulsion performance. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride)/montmorillonite (PVC/MMT) nanocomposites were synthesized via in situ intercalative polymerization and their microstructure, particle characteristics and mechanical properties were investigated. The montmorillonite layers were almost exfoliated into nanoscale layers and an exfoliated nanostructure was obtained. The mean particle size of the nanocomposites decreased and the degree of porosity of the particles increased with increasing organic modified montmorillonite (OMMT) content. The nanocomposites exhibited higher cold plasticizer absorption (CPA) and slightly greater fluid plasticity in comparison with pure PVC. The addition of OMMT into PVC matrix improved the production process and the mechanical properties of the composite resin. [Copyright &y& Elsevier]

Poly(vinyl chloride)/montmorillonite (PVC/MMT) nanocomposites were synthesized via in situ intercalative polymerization and their thermal properties were examined by means of thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). The nanocomposites exhibited a little higher glass transition temperature in comparison with pure PVC. The presence of organophilic montmorillonite enhanced the rapidest decomposition temperature and reduced the maximum decomposition rate and the onset decomposition temperature. At high temperature, a compact char formed in the surface of the nanocomposites, obstructing the thermal degradation of the polymer matrix. The compact char surface was characterized by Fourier-transformed infrared spectrophotometer (FT-IR). [Copyright &y& Elsevier]

Abstract: Polyethylene/clay composites were prepared by melt compounding polyethylene and montmorillonite clay organically modified with different intercalating agents. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) revealed that PE/clay nanocomposites formed when using a reactive intercalating agent, while only conventional microcomposites were obtained from the common alkylammonium intercalated clay. Mechanical testing indicated that the reinforcement in the nanocomposites was more effective than that in their conventional counterparts. The thermal stability and flammability of the PE/clay nanocomposites were measured by thermogravimetric analysis (TGA) and cone calorimetry. By adding only 2phr organoclay, the peak heat release rate of the nanocomposite was reduced by 54%. Further studies indicated that the improvement of flammability is due to the formation of a clay-enriched protective char during combustion. [Copyright &y& Elsevier]

At present, AIDS drugs are typical inhibitors that cannot achieve permanent effects. Therefore, the research of blocking HIV infection is essential. Especially for people in the high‐risk environment, long‐term prevention is important, because HIV can easily infect cells once the drug is interrupted. However, there is still no long‐acting AIDS prevention drug approved. Hence, the purpose of this study is to prepare a fusion inhibitor loaded poly(d, l‐lactic‐co‐glycolic acid) (PLGA) microspheres as a sustained‐release system for long‐term AIDS prevention. As the HIV membrane fusion inhibitor (LP‐98) used in this research is amphiphilic lipopeptide, W1/O/W2 double‐emulsion method was chosen, and premix membrane emulsification technique was used for controlling the uniformity of particle size. Several process parameters that can impact drug loading efficiency were summarized: the concentration of LP‐98 and PLGA, and the preparation condition of primary emulsion. Finally, the microspheres with high loading efficiency (>8%) and encapsulation efficiency (>90%) were successfully prepared under optimum conditions. Pharmacokinetic studies showed that LP‐98‐loaded microspheres were capable to continuously release for 24 days in rats. This research can promote the application of sustained‐release microspheres in AIDS prevention, and the embedding technique used in this study can also provide references for the loading of other amphipathic drugs. [ABSTRACT FROM AUTHOR]

Biodegradable polymeric particles have been widely used in the biomedical fields such as drug carriers, tissue engineering, and medical imaging. It has been recognized that the physical properties of particles, such as size and shape, have a profound influence on their functions. However, it is not easy to prepare non-spherical particles by the conventional emulsion-based method because the minimization of interfacial energy leads to the spontaneous formation of spherical emulsions and it is difficult to control the uniformity and size. In order to solve this problem, we developed a direct method to fabricate non-spherical polylactic- co -glycolic acid (PLGA) particles with uniform size. This method employed a common agent, phosphate buffer saline (PBS), as the deformation initiator and combined the premix membrane emulsification technique with the solvent evaporation method to prepare uniform non-spherical particles of various shapes with aspect ratios from 2 to 40 and various sizes ranging from 800 nm to 60 μm (long axis). We found that the external driving force of stirring and the interfacial tension of the droplet dictated by the constitution of PBS and polyvinyl alcohol (PVA) have synergistic effects on the deformation. Through confocal laser microscopy (CLSM), the deforming process was observed visually in the solvent and gel state during the solidification. Moreover, octreotide acetate as a model peptide was successfully encapsulated into the non-spherical particles. The results indicated that the deformation process did not influence the encapsulation efficiency and bioactivity of the peptide, proving the feasibility of using non-spherical particles as potential drug delivery systems. [ABSTRACT FROM AUTHOR]

A high cross-linking polystyrene(PSt)-based anion-exchange material with uniformly size, high ion exchange capacity, and high hydrophilicity was synthesized by a novel surface functionalization approach in this study. Uniformly sized PSt microspheres were prepared by the membrane emulsion polymerization strategy, and then modified by (1) conversing resid ual surface vinyl groups to epoxy groups followed by quaternization, and (2) decorating aromatic ring matrix including nitration, reduction and attachment of glycidyltrimethylammonium chloride. The 3-D morphology and porous features of microspheres were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface of the modified PSt became roughness but the particle size remained same. Meanwhile, FT-IR spectra and laser scanning confocal microscope (LCSM) indicated that the modification groups had been successfully covalently coated onto the PSt microspheres. Modified PSt microspheres showed greatly improved hydrophilicity and biocompatibility with 0.387 mmol/mL ion exchange capacity (IEC). In the application evaluation procedure, exenatide can be purified from 42.9% (peptide crudes) to 88.6% by modified PSt column with 97.1% recovery yield. This modified PSt microspheres had a large potential in application for efficient separation of peptides. [ABSTRACT FROM AUTHOR]

A high cross-linking polystyrene(PSt)-based anion-exchange material with uniformly size, high ion exchange capacity, and high hydrophilicity was synthesized by a novel surface functionalization approach in this study. Uniformly sized PSt microspheres were prepared by the membrane emulsion polymerization strategy, and then modified by (1) conversing resid ual surface vinyl groups to epoxy groups followed by quaternization, and (2) decorating aromatic ring matrix including nitration, reduction and attachment of glycidyltrimethylammonium chloride. The 3-D morphology and porous features of microspheres were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface of the modified PSt became roughness but the particle size remained same. Meanwhile, FT-IR spectra and laser scanning confocal microscope (LCSM) indicated that the modification groups had been successfully covalently coated onto the PSt microspheres. Modified PSt microspheres showed greatly improved hydrophilicity and biocompatibility with 0.387 mmol/mL ion exchange capacity (IEC). In the application evaluation procedure, exenatide can be purified from 42.9% (peptide crudes) to 88.6% by modified PSt column with 97.1% recovery yield. This modified PSt microspheres had a large potential in application for efficient separation of peptides. [ABSTRACT FROM AUTHOR]

Octreotide, a disulfide-cyclized eight amino acids long analogue of somatostatin, has been used to treat the symptoms associated with metastatic carcinoid tumors (flushing and diarrhea), and vasoactive intestinal peptide secreting adenomas (watery diarrhea). As composed by D-amino acids, C-terminal alcohol, and disulfide bond, octreotide can be only prepared using chemistry synthesis method, which increases difficulty of the traditional reversed-phase separation. In this paper, we report a very fast separation of octreotide from synthetic peptide crude mixtures on a poly(styrene–co-divinylbenzene) (PSt)-based reversed phases prepared by a quick membrane emulsification process. In general, fourier-transformed infrared resonance (FT-IR) spectroscopy, reversed-phase high performance liquid chromatography (HPLC) combined with electrospray ionisation mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR) spectroscopy are routinely used for analyses of resultant peptides. Under the optimized conditions, the octreotide is purified from 42.89% to 99.99%. Consequently, the poly(styrene–co-divinylbenzene)-based phase can provide more flexibility to improve separation efficiency for the octreotide from the synthetic peptide crude mixtures. [ABSTRACT FROM AUTHOR]

Epoxy-based polymer (EP) membrane with 3D bicontinuous skeleton structure was firstly processed into tubular membrane and used in membrane emulsification for water-in-oil (W/O) microspheres. Since uniform W/O microspheres have not been obtained using shirasu porous glass (SPG) membrane unless SPG membrane was rendered hydrophobic by treatment with silanes, it is desired to find a hydrophobic polymer membrane which is capable of providing uniform W/O microspheres. To testify the feasibility of EP membrane in membrane emulsification, uniform agarose (coefficient variation (CV)=11.8%) and Ca-alginate (CV=11.4%) microspheres were achieved with EP membrane by direct and premix membrane emulsification, respectively. In comparison with SPG membrane, EP membrane showed good performance in whether direct or premix membrane emulsification in terms of the droplets size distribution and stability of membranes due to its narrow pore size distribution and uniform hydrophobic surface. SPG membrane is chemically unstable and dissolves under basic aqueous condition. However, it was found that EP membrane could tolerate 1 M NaOH aqueous solution for at least one week and keep its stable hydrophobic surface. Hence, EP membrane could be used in alkali condition, which enables to extend the range of applications in membrane emulsification. So EP membrane had huge potential in further preparation of W/O emulsions. [ABSTRACT FROM AUTHOR]

Abstract: Bio-waste cotton (Gossypium hirsutum L.) stalks were converted into succinic acid by simultaneous saccharification and fermentation (SSF) using Actinobacillus succinogenes 130Z. After 54h SSF at 40°C and pH 7.0, the production of succinic acid was 63g/L, with 1.17g/L/h productivity and 64% conversion yield. After SSF, a simple method for the decolorization and deproteinization of crude SSF broth was developed through adsorption tests of polystyrene (PSt) microspheres. Under optimized conditions (5% PSt loading (w/v), pH 4.0, 60°C and adsorption time of 40min), the ratios of decolorization, deproteinization and succinic acid loss ratios were 96.6, 84.5 and 4.1%, respectively. The method developed will provide a potential approach for large-scale production of succinic acid from the biomass waste. [Copyright &y& Elsevier]

Abstract: Friedel–Crafts (FC) acylation is regarded as one of the key routes for graft substitution reaction. In this study, by-product HCl formed in the FC reaction has a major drawback inhibitory effect on the Lewis acid catalysts’ activity, and therefore reduces the FC reaction yield. With the need for more environmentally and economically benign processes, in situ inhibitor removal approach can be applied as a new strategy on one pot heterogeneous FC acylation. The inhibitor can be taken away from the vicinity of the catalysts as soon as it is formed. The chlorine weight percentage after FC acylation on polystyrene (PSt) microspheres under mild reaction conditions can be enhanced from 3.2% to 4.0% in acetone, from 2.9% to 3.6% in methanol, and from 4.4% to 5.3% in chloroform, respectively. It is important to note that the key feature of this reaction is operational simplicity and high yield. [Copyright &y& Elsevier]