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Chronic iron overload is a serious condition that develops as a consequence of long-term accumulation of iron, eventually overwhelming iron storage systems and causing oxidative stress and subsequent organ damage. Current pharmaceuticals used to treat iron overload typically suffer from toxicities leading to relatively high rates of adverse events. To address this need, we designed a new class of nonabsorbable iron binding polymers (IBPs) that bind and sequester iron within the gastrointestinal (GI) tract. IBPs were synthesized by cross-linking polyallylamine containing various amounts of conjugated 2,3-dihydroxybenzoic acid (DHBA). In vitro studies indicated that IBPs possessed high affinity, substantial binding capacity, and excellent selectivity toward iron. Moreover, in vivo studies demonstrated that IBPs showed no signs of side effects in mice and increased fecal iron excretion when compared to a similar dose of cross-linked polyallylamine. IBPs are a novel, nonabsorbed oral therapeutic agent that may ultimately prevent iron absorption as a safe alternative to iron chelation therapies for patients with hemochromatosis or other iron overload diseases.

Current antiobesity therapeutics are associated with side effects and/or poor long-term patient compliance, necessitating development of more efficacious and safer alternatives. Herein, we designed and engineered a new class of orally acting pharmaceutical agents, or micelle sequestrant polymers (MSPs), that could respond to the pH change in the gastrointestinal (GI) tract and potentially sequester lipid micelles; inhibiting lipid absorption through a pH-triggered flocculation process. These MSPs, derived from poly(2-(diisopropylamino)ethyl methacrylate) and poly(2-(dibutylamino)ethyl methacrylate), were soluble in acidic media, but they transitioned to become insoluble around pH 7.2 and 6.1, respectively. MSPs showed substantial bile acid and triglyceride sequestration capacity with fast pH response tested in vitro. In vivo study showed that orally dosed MSPs significantly enhanced fecal elimination of triglycerides and bile acids. Several MSPs increased fecal elimination of triglycerides by 9-10 times compared with that of the control. In contrast, fecal concentration of bile acids, but not triglycerides, was increased by cholestyramine or Welchol. Importantly, fecal elimination of bile acids and triglycerides was unaltered by addition of control dietary fibers. MSPs may serve as a novel approach to weight loss that inhibits excess caloric intake by preventing absorption of excess dietary triglycerides.

Increasing antibiotic resistance has compelled the development of novel antibiotics and adjuvant therapies that enhance the efficacy of existing antibiotics. Iron plays a critical role in bacterial infections, yet the use of iron chelators as adjuvant therapy with antibiotics has yielded highly variable outcomes. Multivalent polymeric materials offer an alternative approach to bind and sequester iron via high avidity interactions. Here, a biomimetic iron-sequestering polymer (PAI-DHBA) was synthesized by modifying side chains of cross-linked polyallylamine (cPAI) with 2,3-dihydroxybenzoic acid (DHBA). PAI-DHBA polymer gels with various DHBA contents showed high iron affinity indices and high selectivity for iron. The polymers showed mild antibiotic properties when used to treat established bacterial cultures. Pretreating culture media with PAI-DHBA polymer, however, removed all detectable iron from media and effectively inhibited the growth of Pseudomonas aeruginosa. In addition, bacterial growth was more susceptible to antibiotics combined with PAI-DHBA. Multivalent polymers that bind and sequester iron, such as PAI-DHBA, offer a promising early intervention or adjuvant to antibiotics.

Biocomposite of wood flour (WF)/polypropylene (PP) composite (WPC) is not easily flame-retarded because of the different flame retardant mechanisms of PP and WF. In order to improve the flame retardancy of WPC, a single flame retardant of ammonium polyphosphate (APP) modified via ion exchange reaction with ethanolamine, which is named as ETA-APP, was used to prepare flame-retardant WPC. The flammability was investigated by limiting oxygen index (LOI), UL-94 vertical burning test, and cone calorimeter. The results show the flame retardant properties of the flame-retardant WPC are improved greatly. The limiting oxygen index is 43.0%, which is increased by 71.6% compared with that of WPC with the same content of APP. And the vertical burning test can pass UL-94 V-0 rating. The results of cone calorimeter test show that the heat release rate (HRR) and total heat release (THR) of the WPC with ETA-APP are decreased in comparison with WPC/APP. The flame-retardant mechanism of WPC/ETA-APP system was investigated ...

Ammonium polyphosphates (APP) modified with piperazine (PA-APP) was used to improve the flame retardancy of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) aerogels, which were prepared via an environmentally friendly freeze-drying method. The thermal stabilities of the samples were evaluated by thermogravimetric analysis (TG); the flammability behaviors of samples were investigated by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CC) tests. TG test results showed that the 5% weight loss temperature (T5%) of PVA/MMT/PA-APP was 10 °C higher than that of PVA/MMT/APP. In combustion testing, all of PVA/MMT/PA-APP aerogels achieved V-0 ratings and have a higher LOI values than the unmodified PVA/MMT aerogel. Moreover, the aerogel with 1% PA-APP5, which means that the content of piperazine is 5% in PA-APP, decreased the cone calorimetry THR value to 5.71 MJ/m(2), and increased the char residue to 52%. The compressive modulus of PVA/MMT/PA-APP was increased by 93.4% compared with PVA/MMT/APP because of the increase in interfacial adhesion between matrix and PA-APP fillers. The densities of the PVA/MMT/PA-APP samples were slightly lower than those of the unmodified aerogels because of reduced shrinkage in the presence of PA-APP. All the tests results indicated that the incorporation of PA-APP not only improved the thermal stability and flame retardancy of aerogels but also maintained their mechanical properties.

In this work, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA, phosphorus valence +1), melamine hypophosphite (MHPA, phosphorus valence +1), melamine phosphite (MPOA, phosphorus valence +3), and melamine pyrophosphate (MPyP, phosphorus valence +5) were respectively used as flame retardants for flexible polyurethane foam (FPUF), and fire performance as well as pyrolysis behaviors of FPUF were investigated systematically. CMA and MHPA were found to have better flame retardance than MPOA and MPyP for FPUF, which mainly played a role in the gas phase due to the release of many phosphorus-containing volatiles and melamine derivatives. The types of phosphorus-containing gaseous pyrolysis products of CMA were much more than that of MHPA due to the different chemical moieties surrounding the phosphorus atom, which made it have the highest flame-retardant efficiency for FPUF. Besides this, the possible thermal degradation mechanisms of CMA and MHPA were proposed.

A halogen-free phosphorus-containing triol named phosphoryltrimethanol (PTMA) was synthesized and used as a cross-linking agent and a reactive-type flame retardant to prepare inherently flame-retardant flexible polyurethane foam (FPUF). Incorporation of a low content (7.8 wt %) of PTMA into the polyurethane chains can increase the flame retardance of FPUF because of good char formation. The residual chars and evolved gases of PTMA-cross-linked FPUFs were analyzed by SEM, FTIR spectroscopy, inductively coupled plasma-atomic emission spectrometry (ICP-AES), energy-dispersive X-ray (EDX) spectroscopy, and thermogravimetric analysis (TGA) coupled with FTIR spectroscopy. The results indicated that more than 60% of the phosphorus in PTMA-cross-linked FPUF was decomposed into polyphosphoric acid or its derivatives and retained in the char residue. This shows that PTMA mainly played a role in the condensed phase of flame-retardant FPUF. Based on the results, a possible thermal degradation mechanism of PTMA-cross-...

An effective flame retardant and smoke suppression oligomer, poly(melamine-ethoxyphosphinyl-diisocyanate) (PMPC), was successfully synthesized. The chemical structure was characterized by Fourier transform infrared (FTIR), 1H nuclear magnetic resonance (1H NMR), and 31P nuclear magnetic resonance (31P NMR) spectroscopies. PMPC was used alone as the flame retardant for epoxy resins (EP). The results showed that PMPC endowed EP with good flame retardancy. The limiting oxygen index (LOI) value of a EP/PMPC system containing 20 wt % PMPC increased to 28.0%, and can achieve a UL-94 V-0 rating. The cone calorimeter data showed that the heat release rate (HRR) and total heat release (THR) were considerably reduced with the addition of PMPC, and the smoke production rate (SPR), total smoke production (TSP), and carbon monoxide production (COP) were also reduced. Moreover, the thermal degradation behavior of PMPC and the flame-retardant mode of the EP systems were also investigated.

The optical properties of a plasmonic surface have been engineered using the rectangular nanohole dimers. One or two transmission peak(s), associated with two symmetrical or asymmetrical transmission channels, has (have) been revealed. We found that, similar to the plasmon coupling of a nanorod dimer, a strong coupling effect is also present in a rectangular nanohole dimer. The effect is closely correlated with the surrounding currents of waveguide modes, which mediate, via the magnetic field, an attractive or repulsive interaction between the dimer holes. The resulted low-energy or high-energy mode will couple with the film surface waves, thus producing the transmission peak with a red- or blue-shift. Moreover, the dependence of coupling modes on the sizes and separation of dimer holes has been systematically investigated, and an anticrossing-like coupling behavior has been suggested. We also suggest that, using the rectangular hole dimers with the perpendicular arrangement, the polarization of light can...

Transformation of reactive isochromenylium intermediates to the corresponding storable and stable reagents has been achieved, and a number of isochromenylium tetrafluoroborates (ICTBs, 1) have been conveniently prepared and characterized. Direct metal-free treatment of isochromenylium tetrafluoroborate 1a with olefins afforded a variety of polycyclic frameworks 4 via mild cascade reactions. Starting from the prefunctionalized o-alkynylbenzaldehydes, a one-pot metal-free procedure of intramolecular cascade annulation to 2,3-dihydrophenanthren-4(1H)-one derivatives was also developed.

A feasible methodology for the preparation of vesicles through self-assembly of supramolecular graft copolymers (SGPs) was developed. Two types of polymeric vesicles were prepared through self-assembly of two SGPs. For the first SGP, hydrophobic poly(4-vinylpyridine) (PVPy) were used as main chains, and hydrophilic poly(N-vinylpyrrolidone) with carboxylic end groups (PNVP-COOH) were grafted onto the main chains through ionic interaction between the carboxylic groups and pyridine groups. For the second SGP, hydrophobic poly(4-acrylamidobenzoic acid) (PABA) were used as main chains, and poly(N-vinylpyrrolidone) with amino end groups were grafted onto the main chains through ionic interaction between the amino groups and carboxylic groups. Both SGPs could self-assemble to form vesicles in aqueous solution. The size of the vesicles prepared from the PVPy/PNVP-COOH (or PABA/PNVP-NH2) system could be controlled through modulation of the mass ratio of PVPy and PNVP-COOH (or PABA and PNVP-NH2). Both vesicles were...

Polymeric vesicles were prepared through self-assembly of amphiphilic supramolecular block copolymers (SBP). Hydrophilic poly(N-isopropylacrylamide) with amino end groups (PNIPAM-NH2) and hydrophobic polystyrene with carboxylic end groups (PSt-COOH) were prepared by free radical polymerization using cysteamine hydrochloride and thioglycolic acid as chain transfer reagents, respectively. These two polymer chains could be connected through the ionic interaction of the amino groups and carboxylic groups in dioxane to form an amphiphilic SBP. The self-assembly behavior of SBP was investigated in dioxane/H2O and dioxane/ethanol systems. In the dioxane/H2O system, these amphiphilic SBP could self-assemble to form spherical vesicles. In the dioxane/ethanol system, the morphologies of the formed aggregates were dependent on the SBP concentration. As the SBP concentration increased from 0.01 to 0.075 g mL−1, the aggregates changed from wormlike vesicles to spherical vesicles. A temperature-induced morphological tr...

Above the lower critical solution temperature (LCST), the poly(N-isopropylacrylamide) (PNIPAM) nuclei formed by the hydrophobic oligomers were used as non-cross-linked templates, then coated with cross-linked PNIPAM shells. Reducing the temperature below the LCST led to the dissolution of the non-cross-linked templates. Hollow spheres were finally obtained via a one-pot process.