Polyol Groups Research Articles

Screening of Natural Deep Eutectic Solvents for the Recovery of Valuable Phenolics From Waste of Shalgam Juice Process

Shalgam juice is one of the most popular non-alcoholic beverages in Türkiye and also in many countries. The high amount of production, regarding the high amount of consumption leads to an inevitable amount of solid waste. This amount reaches to almost 12 million kg of fermented black carrot annually. The accumulation of this waste causes fatal environmental pollution. The waste of shalgam juice process, fermented black carrot, retains significant amount of valuable components, such as phenolics, flavonoids, and anthocyanins. In this study new generation green solvents, Natural Deep Eutectic Solvents (NADESs) were screened for the extraction of valuable phenolics from fermented black carrot using ultrasound assisted extraction. The NADESs used were selected from four different groups such as acidic, sugar-based, choline chloride-sugar based and polyol-based. According to the results, the members of polyol and choline chloride sugar NADESs showed up. Choline chloride-glycerol (polyol group), extracted the highest total phenol amount (16.04 mg/g) and also provided the highest antioxidant activity (81.77%). On the other hand, NADESs belonging to choline chloride-sugar group were effective for the extraction of flavonoids and monomeric anthocyanins. Namely, choline chloride-fructose-water extract contained 21.45 mg/g of total flavonoids, while choline chloride-sucrose-water extract contained 1680.51 mg/kg of total monomeric anthocyanins. The performances of NADESs tested were found to be higher than that of water and ethanol showing the high yield recovery of valuable phenolics with NADESs. The results exhibited the significance of the components inside the waste. The remaining valuable content could be easily and efficiently extracted using NADESs and these extracts –as a mixture or after purification- can furtherly be used for different purposes in different fields, such as cosmetics, antioxidant preparations, etc, using a zero-cost waste as the input of the processes.

Investigation of the mechanism of establishing a solid–water–oil system by metastable droplets and their application in the fabrication of polyol nanosheets for rapid boron removal

The emulsion method is a typical way for the preparation of nanomaterials, however, it usually requires a lot of energy and surfactants to form and stabilize of emulsions. A critical factor limiting its application is to control the morphology of the material by modulating the size of the emulsion droplets. In this work, a novel solid-water–oil (S-W-O) system based on the integration of metastable emulsion and salt template method was proposed, and the functionalized silica nanosheets were prepared by the one-pot method. The size of the prepared nanosheets is relatively uniform, with a length of 800 to 1200 nm and a width of about 200 nm. Subsequently, a large number of epoxy group sites were introduced into the nanosheets relying on distillation precipitation polymerization, and the polyol groups were successfully loaded. Finally, the polyol-functionalized nanosheet adsorbent (NS@GMA-NMDG) was obtained and applied for the rapid removal of boron. NS@GMA-NMDG shows favorable adsorption performance for boric acid in solution, with a maximum adsorption capacity of about 35.49 mg g−1 based on the Langmuir model fitting and a fast adsorption rate of about 30 min to reach 96.3% of the adsorption equilibrium concentration. Remarkably, the investigation of the formation mechanism of nanosheets reveals that salt plays an important role in the S-W-O system. This study not only puts forward a novel method of designing and synthesizing nanosheet adsorbents, but also the application of surfactant-free and low-energy emulsification reflects the concepts of energy saving and clean production, which provides fresh inspirations for the development of new environmentally friendly adsorbents.

Boron Adsorption Kinetics of Microcrystalline Cellulose and Polymer Resin

Tailoring boron-polysaccharide interactions is an important strategy for developing functional soft materials such as hydrogels, fire retardants, and sorbents for environmental remediation, for example, using lignocellulosic biomass. For such applications to be realized, it is paramount to understand the adsorption kinetics of borate anions on cellulose and their local structures. Here, the kinetic aspects of boron adsorption by microcrystalline cellulose, lignin, and polymeric resin are investigated and compared. Borate anions interact with the vicinal diols in the glucopyranoside moieties of cellulose to yield chemisorbed boron chelate complexes. In contrast to cellulose, technical lignin contains fewer cis-vicinal diols, and it does not have a tendency to form such chelate complexes upon treatment with the aqueous boric acid solution. The formation kinetics and stability of these chelate complexes strongly depend on nanoscale structures, as well as reaction conditions such as pH and concentration of the sorbate and sorbent. Specifically, insights into the distinct boron adsorption sites were obtained by solid-state one-dimensional (1D) 11B magic-angle spinning NMR and the local structures and intermolecular interactions in the vicinities of boron chelate complexes are elucidated by analyzing two-dimensional (2D) 1H-13C and 11B-1H heteronuclear correlation NMR spectra. The total boron adsorption capacity of cellulose is estimated to be in the 1.3-3.0 mg range per gram of sorbent, which is lower than the boron adsorption capacity of a polystyrene-based resin, ∼17.2 mg of boron per gram of Amberlite IRA 743. Our study demonstrates that the local backbone and side chain flexibility as well as the structures of polyol groups play a significant role in determining the kinetic and thermodynamic stability of chelate complexes, yielding to different boron adsorption capabilities of lignocellulosic polymers.

Rapid High-Contrast Photoreversible Coloration of Surface-Functionalized N-Doped TiO2 Nanocrystals for Rewritable Light-Printing.

Pristine titanium dioxide (TiO2 ) changes color from white to black when it is reduced from TiIV to TiIII by photoexcited electrons. However, the black coloration requires substantial light energy to create, and it vanishes instantaneously upon exposure to air. This work reports the synthesis of surface-functionalized N-doped TiO2 nanocrystals that rapidly change color (i.e., within seconds) from whitish to black under low-power irradiation with excellent color stability in atmospheric conditions. The N-doping plays a critical role in promoting the surface-adsorption of polyol groups to stabilize the TiIII species and accelerate the coloration process. A rewritable paper fabricated using these nanocrystals exhibits excellent writing and erasing reversibility in response to UV irradiation and oxygen exposure. The low-cost, rapid response, excellent reversibility, and good color stability are vital advantages of N-doped TiO2 nanocrystals for color-switching applications.

Rapid High‐Contrast Photoreversible Coloration of Surface‐Functionalized N‐Doped TiO2Nanocrystals for Rewritable Light‐Printing

AbstractPristine titanium dioxide (TiO2) changes color from white to black when it is reduced from TiIVto TiIIIby photoexcited electrons. However, the black coloration requires substantial light energy to create, and it vanishes instantaneously upon exposure to air. This work reports the synthesis of surface‐functionalized N‐doped TiO2nanocrystals that rapidly change color (i.e., within seconds) from whitish to black under low‐power irradiation with excellent color stability in atmospheric conditions. The N‐doping plays a critical role in promoting the surface‐adsorption of polyol groups to stabilize the TiIIIspecies and accelerate the coloration process. A rewritable paper fabricated using these nanocrystals exhibits excellent writing and erasing reversibility in response to UV irradiation and oxygen exposure. The low‐cost, rapid response, excellent reversibility, and good color stability are vital advantages of N‐doped TiO2nanocrystals for color‐switching applications.

Design, assembly and application of boronate ester polymer

In the last hundred years, polymer science has been flourishing. Industrial products of polymers have been used in many aspects of our life. Each new polymer and its assembly driving force indicates the blooming of the “new branch” of the towering tree of polymer. Researchers are always looking for new polymer and new self-assembly driving force to imbue the towering tree of polymer with magic. The traditional self-assembly driving forces are limited to noncovalent interactions, such as electrostatic interaction, hydrogen bond, π-effects or Van der Waals interaction. The bonding energy of noncovalent interaction is weak and directionless. Therefore, the as-formed assemblies have the problems of poor stability and low structural order. Compared with the good designability of the assembly building blocks, the driving forces of self-assembly is monotonous and limited. In recent years, interactions like coordination, dynamic covalent bond and host-guest recognition have been introduced into the self-assembly system, which leads to new methods of self-assembly. The structure of self-assembly which depends on strong bond is inert, so it is difficult to realize the intelligent characteristics including irritating response, self-regulation and self-evolution. The driving force of ideal self-assembly should simultaneously have the characteristics of weak bonding strength, directionality and tunable chemical bonds. Boronate ester polymers, which are formed by incorporating dynamic boronate ester bonds into the main chain, side chain or cross-linking point of polymers, can be described as a new polymer material with high synergy of “stability” and “dynamic”. Stability refers to the high-efficiency condensation ability of phenylboronic acid group with 1,2-diol or 1,3-diol structures and polymers, as well as the protection of polyhydroxy groups, especially phenolic hydroxyl groups. The dynamic feature of boronate ester polymer is due to their reversible cleavage and reformation under the stimulation of temperature, pH and guest molecules. Catechol group is one of the polyhydroxy functional groups used to construct boronate ester polymers. It can form coordination, hydrogen-bonding, electrostatic interaction, with metal ions, inorganic nonmetallic oxides, etc. The introduction of catechol as a building block into boronate ester polymer system could make surface engineering more intelligent. When nitrogen-containing functional groups are present in molecular chains, B-N coordination can also be formed between boronate ester polymer chains. These supramolecular driving forces can induce the self-assembly of boronate ester polymers in solution and interfacial. Boronate ester polymers not only have flexible designability of molecular structure, but also give full play to the intrinsic characteristics of boric acid groups, phenylboronic acid groups and polyol groups. From the molecular structure level, boronate ester polymer is a kind of multifunctional polymer. From the supramolecular point of view, the B-N coordination of boronate ester polymer and the strong interface binding force of catechol has a unique advantage in driving the ordering of polymer chains. Boronate ester polymers have been widely used in surface engineering, intelligent materials, biomedicine, energy storage and other fields, due to its wide range of molecular structure designability and unique B-N coordination between chain segments. In this review, starting from molecular block and self-assembly mechanism, the synthesis strategy, properties, supramolecular behavior and application fields of boronate ester polymers were summarized; the development direction of boronate ester polymer functional materials was prospected.

MRNA loading into ATP-responsive polyplex micelles with optimal density of phenylboronate ester crosslinking to balance robustness in the biological milieu and intracellular translational efficiency

Carriers for messenger RNA (mRNA) delivery require propensities to protect the mRNA from enzymatic degradation and to selectively release mRNA in the cytosol for smooth mRNA translation. To meet these requirements, we designed mRNA-loaded polyplex micelles (PMs) with ATP-responsive crosslinking in the inner core by complexing mRNA with poly(ethylene glycol)-polycation block copolymers derivatized with phenylboronic acid and polyol groups, which form crosslinking structures via spontaneous phenylboronate ester formation. PMs thus prepared are tolerable against enzymatic attack and, in turn, disintegrate in the cytosol to release mRNA when triggered by the cleavage of phenylboronate ester linkages in response to elevated ATP concentration. Two structural factors of the PM, including (i) the introduction ratios of phenylboronate ester crosslinkers and (ii) the structure and protonation degree of amino groups in the polycation segment, are critical for maximizing protein expression in cultured cells due to the optimized balance between the robustness in the biological milieu and the ATP-responsive mRNA release in the cytosol. The optimal PM formulation was further stabilized by installing cholesterol moieties into both the mRNA and ω-end of the block copolymer to elicit longevity in blood circulation after intravenous injection.

Ultrasound-Assisted Osmotic Dehydration of Apples in Polyols and Dihydroxyacetone (DHA) Solutions

The aim of this work was to analyse the effect of ultrasound-assisted osmotic dehydration of apples v. Elise on mass transfer parameters, water activity, and colour changes. Ultrasound treatment was performed at a frequency of 21 kHz with a temperature of 40 °C for 30–180 min using four osmotic solutions: 30% concentrated syrups of erythritol, xylitol, maltitol, and dihydroxyacetone (DHA). The efficiency of the used solutes from the polyol groups was compared to reference dehydration in 50% concentrated sucrose solution. Peleg’s model was used to fit experimental data. Erythritol, xylitol, and DHA solutions showed similar efficiency to sucrose and good water removal properties in compared values of true water loss. The application of ultrasound by two methods was in most cases unnoticeable and weaker than was expected. On the other hand, sonication by the continuous method allowed for a significant reduction in water activity in apple tissue in all tested solutions.

Polyurethane/clay nanocomposites from palm oil for surface-coating applications

Synthesis of palm oil-based polyurethane (PU) and the formation of nanocomposite from a mixture of PU with clay filler has been performed. Polyol which is the basic material of PU is formed by epoxidation and hydroxylation process and then mixed with isocyanate. Clay used as filler in this study was obtained from the local area of North Aceh, which is a type of swelling of clay that has been modified with cetyltrimethyl ammonium bromide surfactant. Nanocomposites are formed from PU with clay fill variations of 3%, 5%, and 8% by weight of the total mixture of 40 g. The resulting material is tested in character by some type of characterization. Based on the test results with Fourier transform infrared spectroscopy, the hydroxyl polyol group was obtained in groups of 3390.870 (O–H) and –NH as the PU microdomain structure was obtained at a wavelength of 2987 cm−1. Morphological test results using scanning electron microscopy revealed that the addition of modified clay increases the adhesion in the paint and PU coatings and also increases the gloss from the surface and homogeneous material. The thermal endurance test with thermogravimetric analysis reported that the addition of clay fillers in PU showed enhanced effects for better thermal stability in nanocomposite materials when compared with neat polymers. Samples of PU/clay nanocomposites with the addition of 8 wt% clay filler were the most optimum composites among other variations with the thermal degradation temperature value of 296°C. This research generates prospects for applying various industrial surface coatings that are resistant to corrosion and heat, have good mechanical properties, and are more environmentally friendly.

Effect of xylitol and sugar-free chewing gums on salivary bacterial count of streptococcus mutans and lactobacilli in a group of Egyptian school children of different ages: A randomized clinical trial

AimThe purpose of this randomized clinical trial was to compare the effect of xylitol containing and sugar free brands of chewing gum on the salivary Colony Forming Unit (CFU) count of streptococcus mutans (SM) and lactobacilli (LB) cariogenic organisms in a group of Egyptian school children of different ages. Study designThis pragmatic randomized controlled trial (parallel group design) was approved by the Research Ethics Committee of the Faculty of Dentistry, Ain Shams University. Materials and methods42 high caries risk children (DMFT/dmft/deft of 3 or more) were randomly allocated to either the xylitol or polyol group. Each main group was divided into three equal subgroups. Each subgroup comprised a block of seven children of the same age group as follows: Nursery group aging 3–6 years, junior primary school group aging 6–9 years and senior primary school group aging 9–12 years. Salivary analysis was carried out at baseline and after three weeks of daily gum chewing to all participating children by recording his/her stimulated salivary flow and salivary CFU counts of SM and LB bacteria. ResultsCompared to polyol gum, xylitol gum showed lower SM CFU counts. LB CFU counts were not affected by either gum types. However, there was no statistically significant difference between the two chewing gum groups in the different ages and regardless of age. ConclusionXylitol gum is more effective in decreasing SM count in saliva compared to polyol gum wheras both sugarless chewing gums show similar effect on LB species.

Recovery and valorization of tannins from a forest waste as an adsorbent for antimony uptake

Abstract In the current context, it is imperative to seek for a sustainable management and an efficient use of natural resources. Pinus pinaster bark is a forest and industrial waste whose chemical richness is commonly ignored. In this work, tannins were extracted from P. pinaster bark and converted into adsorbents through polymerization. Aqueous (alkaline) extraction yielded more formaldehyde-condensable phenols than an organic extraction using ethanol (Soxhlet) (53 ± 8 vs. 13 ± 4 mg of gallic acid equivalents per g of bark). The polymerization reaction was optimized and higher amounts of adsorbent were produced using 6.0 mL of 0.25 mol L−1 sodium hydroxide solution and 0.40 mL of formaldehyde (36 % wt) per g of extract. The performance of the produced adsorbent was assessed on the sequestration of Sb(III) and Sb(V) species from water. The adsorbent was effective for both species, in diluted and heavily-contaminated waters, providing maximum adsorption capacities (Langmuir model) of 24 ± 3 mg g−1 (pH 6) and 27 ± 7 mg g−1 (pH 2), respectively for Sb(III) and Sb(V). No significant effect was observed due to the presence of arsenic, chloride, nitrate, sulfate or phosphate and little influence was obtained when a tailings water from a mine site was used as aqueous matrix. Electrostatic attraction and Sb(III) and Sb(V) complexation with polyol groups of tannin-adsorbents were the suggested adsorption mechanisms. Moreover, tannin-adsorbents were stable at different pH (no color leaching; total dissolved carbon ≤16 mg L−1) and their production does not require high energy or expensive chemicals.

Efficiency of Osmotic Dehydration of Apples in Polyols Solutions.

The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.

Structures of the Largest Amphidinol Homologues from the Dinoflagellate Amphidinium carterae and Structure-Activity Relationships.

Amphidinols are polyketide metabolites produced by marine dinoflagellates and are chiefly composed of a long linear chain with polyol groups and polyolefins. Two new homologues, amphidinols 20 (AM20, 1) and 21 (AM21, 2), were isolated from Amphidinium carterae collected in Korea. Their structures were elucidated by detailed NMR analyses as amphidinol 6-type compounds with remarkably long polyol chains. Amphidinol 21 (2) has the longest linear structure among the amphidinol homologues reported so far. The congeners, particularly amphidinol 21 (2), showed weaker activity in hemolysis and antifungal assays compared to known amphidinols.

The caries preventive effect of 1-year use of low-dose xylitol chewing gum. A randomized placebo-controlled clinical trial in high-caries-risk adults

ObjectivesThe caries preventive effect of long-term use (1 year) of low-dosage (2.5 g/die) of xylitol chewing gum in a high-caries-risk adult population was evaluated.Materials and methodsIn this randomized clinical trial, 179 high-caries-risk adults were assigned to two experimental groups, xylitol and polyols. Caries status, salivary mutans streptococci (MS), and plaque pH were re-evaluated after 2 years from baseline in 66 xylitol and 64 polyol subjects. Outcomes (the net caries increment for initial, moderate, and extensive caries lesions and for the caries experience) were evaluated using the nonparametric Mann–Whitney U test.ResultsThe total caries experience increment was 1.25 ± 1.26 in the xylitol group and 1.80 ± 2.33 in the polyol group (p = 0.01). Subjects treated with xylitol chewing gums had a reduction of risk rate at tooth level of 23% with respect to those treated with polyols with a number needed to treat of 55 teeth. The area under the curve at pH 5.7 was statistically significantly lower (p = 0.02) during the experimental period in the xylitol group. A decrease of the concentration of salivary MS was noted in the xylitol group (p < 0.01).ConclusionsSubjects using the low-dose xylitol chewing gum showed a significantly lower increment of initial and extensive caries lesions and overall a lower increment of caries experience.Clinical relevanceOne-year use of chewing gums provides an effective means for the prevention of caries disease.Trial registration numberNCT02310308

Grafting Polymer Based in Active Polyurethane Matrixes Via Free Radical

Polyurethanes (PUs) are novel and versatile polymers based on the reaction of diisocyanate and polyol groups; its advantage lies in its mechanical properties and the modifications that can be made of those properties through changes in synthesis conditions. On the other hand, graft polymers are produced by the insertion of polymer chains into the main chain of other polymer in order to give specific and novel properties. The main purpose on this work was developing PU cores as precursors of new graft polymers which can be easily polymerized by free radicals. In this context, a vinyl monomer (vinyl benzyl-N-methyl-D-glucamine, VbNMDG) was synthesized from N-methyl-D-glucamine and p-chloromethylstyrene. The synthesized monomer was employed for the formation of PU core using 4,4́-methylene-bis-(phenyl isocyanate) (MDI). The monomer synthesis and the double bond incorporation to the PU matrix were verified by NMR 13C and 1H. Thereafter, 0.1g of different PU cores was mixed with an equal VbNMDG amount, using a dioxane-water mixture as solvent in the presence of radical initiator (ammonium per sulfate, 2% molar of VbNMDG). The reaction was carried out at 70°C using nitrogen atmosphere for 24h. The graft polymers obtained were characterized by FT-IR and elemental analysis. The insertion of poly(VbNMDG) chains into the PU cores gives them the boron retention capacity in aqueous solutions. Our results show the possibility to obtained PU cores which can be polymerized via free radicals to the graft of functional polymer chain in a second polymerization.

Binding of mucin to water-soluble and surface-grafted boronate-containing polymers

The binding of mucin to water-soluble copolymers of N,N-dimethylacrylamide and N-acryloyl-m-aminophenylboronic acid grafted on the surface of glass is studied. Atomic force microscopy studies show that many graft copolymer islands 20-200 nm in diameter and 50 nm in height occur on the modified surface of flat glass. Owing to the presence of phenyl boronate groups, the copolymer behaves as a weak polyelectrolyte (pK(a) = 9.0) and, in the grafted state in an aqueous solution, experiences reversible transitions between states with higher and lower degrees of ionization. As evidenced by spectral correlation interferometry, this phenomenon brings about a change in the thickness of the grafted layer by approximately 0.5 nm. The ability of phenyl boronate groups to form cyclic esters with diol and polyol groups results in complexation of the soluble copolymer with mucin oligosaccharides and entails the appearance of slowly growing submicron particles formed by similarly charged polymers. The specificity of complexation is confirmed by dissolution of particles in the presence of fructose: a saccharide with a strong affinity for phenyl boronate groups. The binding of mucin to glass, which is chemically modified with the above copolymer, leads to formation of an adsorption layer with a thickness of 1.2-1.8 nm. Thus, boronate-containing copolymers are suitable for preparing carriers with controllable adsorption properties with respect to polyols, including mucinlike proteins of cellular glycocalyxes. (Less)

Identifying new lignin bioengineering targets: 1. Monolignol-substitute impacts on lignin formation and cell wall fermentability

BackgroundRecent discoveries highlighting the metabolic malleability of plant lignification indicate that lignin can be engineered to dramatically alter its composition and properties. Current plant biotechnology efforts are primarily aimed at manipulating the biosynthesis of normal monolignols, but in the future apoplastic targeting of phenolics from other metabolic pathways may provide new approaches for designing lignins that are less inhibitory toward the enzymatic hydrolysis of structural polysaccharides, both with and without biomass pretreatment. To identify promising new avenues for lignin bioengineering, we artificially lignified cell walls from maize cell suspensions with various combinations of normal monolignols (coniferyl and sinapyl alcohols) plus a variety of phenolic monolignol substitutes. Cell walls were then incubated in vitro with anaerobic rumen microflora to assess the potential impact of lignin modifications on the enzymatic degradability of fibrous crops used for ruminant livestock or biofuel production.ResultsIn the absence of anatomical constraints to digestion, lignification with normal monolignols hindered both the rate and extent of cell wall hydrolysis by rumen microflora. Inclusion of methyl caffeate, caffeoylquinic acid, or feruloylquinic acid with monolignols considerably depressed lignin formation and strikingly improved the degradability of cell walls. In contrast, dihydroconiferyl alcohol, guaiacyl glycerol, epicatechin, epigallocatechin, and epigallocatechin gallate readily formed copolymer-lignins with normal monolignols; cell wall degradability was moderately enhanced by greater hydroxylation or 1,2,3-triol functionality. Mono- or diferuloyl esters with various aliphatic or polyol groups readily copolymerized with monolignols, but in some cases they accelerated inactivation of wall-bound peroxidase and reduced lignification; cell wall degradability was influenced by lignin content and the degree of ester group hydroxylation.ConclusionOverall, monolignol substitutes improved the inherent degradability of non-pretreated cell walls by restricting lignification or possibly by reducing lignin hydrophobicity or cross-linking to structural polysaccharides. Furthermore some monolignol substitutes, chiefly readily cleaved bi-phenolic conjugates like epigallocatechin gallate or diferuloyl polyol esters, are expected to greatly boost the enzymatic degradability of cell walls following chemical pretreatment. In ongoing work, we are characterizing the enzymatic saccharification of intact and chemically pretreated cell walls lignified by these and other monolignol substitutes to identify promising genetic engineering targets for improving plant fiber utilization.

NCO]/[OH] and acryl-polyol concentration dependence of the gelation process and the microstructure analysis of polyurethane resin by dynamic light scattering

The gelation process and the microstructure after the gelation of polyurethane resin consisting of acryl-polyol and polyisocyanate was investigated by dynamic light scattering (DLS) as a function of stoichiometric ratio, [NCO]/[OH], and the concentration of acryl-polyol, C polyol. The following conclusions were obtained. First, the sol–gel transition was explained by the so-called site–bond percolation theory. Here polyol groups act as site-occupants, and isocyanate groups act as chemical cross-linkers. Second, the scattering inhomogeneities increased rather gradually around the gelation point, which are the characteristics of the gelation process not from monomeric but from oligomer units. Third, at the gelation point, the characteristic decay time of the fast mode, τ fast, decreased, and the fraction of the collective diffusion mode, A, increased with [NCO]/[OH], which are due to introduction of cross-linking and/or increase of the rigidity of the network. Finally, the ensemble average scattering intensities, 〈 I〉 E, the static inhomogeneities, 〈 I C〉 E, the time-average dynamic fluctuating component, 〈 I F〉 T and the collective diffusion coefficient, D, showed remarkable dependence not only on C polyol but also on [NCO]/[OH]. These are due to the competition between the cross-linking and the progress of micro-phase separation.

Behavior of Chelating Fibers Having Polyol Groups in Column Mode Adsorption of Boric Acid

Behavior of Chelating Fibers Having Polyol Groups in Column Mode Adsorption of Boric Acid

Novel organic–inorganic hybrid mesoporous materials for boron adsorption

Amine groups and polyol groups were sequentially grafted on mesoporous SBA-15 and MCM-41 to synthesize novel organic–inorganic hybrid mesoporous materials as boron adsorbents by a two-step post-grafting method. By means of small-angle XRD, N 2 adsorption–desorption, solid-state NMR, Fourier transform infrared (FT-IR) and elemental analysis, the structure and physicochemical properties of the materials were characterized. The behaviors of the resulting adsorbents in adsorption of boron from solutions were investigated. The results show that the organic functional groups are successfully grafted on the SBA-15 and MCM-41, while the quantity and the distribution of the functional groups are varied due to the different pore properties of the materials. The boron adsorption isotherms of the adsorbents are in good accordance with the Langmuir equation. The polyol-functionalized SBA-15 was proved to be a promising adsorbent with the high adsorption capacity of boron up to 0.63 mmol/g as well as the high selectivity towards boron.