Evaluation of chitosaneanionic polymers based tablets for extended-release of highly watersoluble drugs

The objective of this study is to develop chitosaneanionic polymers based extendedrelease tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug loading.Here,the combination of sodium valproate(VPS)and valproic acid(VPA)were chosen as the model drugs.Anionic polymers studied include xanthan gum(XG),carrageenan(CG),sodium carboxymethyl cellulose(CMC-Na)and sodium alginate(SA).The tablets were prepared by wet granulation method.In vitro drug release was carried out under simulated gastrointestinal condition.Drug release mechanism was studied.Compared with single polymers,chitosaneanionic polymers based system caused a further slowdown of drug release rate.Among them,CS exanthan gum matrix system exhibited the best extended-release behavior and could extend drug release for up to 24 h.Differential scanning calorimetry(DSC)and Fourier transform infrared spectroscopy(FTIR)studies demonstrated that polyelectrolyte complexes(PECs)were formed on the tablet surface,which played an important role on retarding erosion and swelling of the matrix in the later stage.In conclusion,this study demonstrated that it is possible to develop highly water-soluble drugs loaded extendedrelease tablets using chitosaneanionic polymers based system.

CONTROLLED ANIONIC SYNTHESIS OF FUNCTIONALIZED AND STAR-BRANCHED POLYMERS

The use of living, alkyllithium-initiated anionic polymerization to prepare chain-end functionalized polymers and heteroarm, star-branched polymers is discussed. The scope and limitations of specific termination reactions with a variety of electrophilic species are illustrated for carbonation, hydroxyethylation, amination, and sulfonation. The methodology of using substituted 1,1-diphenylethylenes to provide a general, quantitative functionalization procedure is outlined and illustrated with examples of amine and phenol end-functionalization. A methodology is described for the synthesis of functionalized, star-branched copolymers with compositionally heterogeneous arms of controlled molecular weight and narrow molecular weight distribution using 1, 3-bis(1-pbenylethenyl) benzene.

Synthesis and Characterization of Star-branched Polyisobutylene by Combination of Anionic Polymerization and Cationic Polymerization

A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as grafting agent, a novel star-shaped branched polymer, containing several polyisobutylene, was prepared via cationic ~aolymerization. The star PS-b-PI and star-branched polyisobutylene were characterized by GPC, ＇HNMR and FT-IR, and the effects of different adding order and the amount of grafting agent were investigated.

Anionic Synthesis of Primary and Secondary Amine-Functionalized Polymers Using Imine Chemistry

A review of methods for the anionic synthesis of well-defined, amine-functionalized polymers using imines as functionalizing agents is provided. The disparate results in the literature regarding functionalizations with N -(benzylidene)trimethylsilylamine to form primary amine functionalized polymers are discussed; the efficiency of functionalization depends on the molecular weight of the polymeric organolithium(PLi). Efficient functionalizations are observed for PLi with n>10 000 g/mol. The poor functionalization yields using ketimines with enolizable hydrogens is explained. The use of N -trimethylsilyldiphenylcarbimide as a quantitative primary amine functionalizing reagent is described. Recent results on the anionic synthesis of secondary amine-functionalized polymers using N -(benzylidene)methylamine as the functionalization agent are presented.

Synthesis and Crystal Structure of a Three-dimensional Mn(Ⅱ) Coordination Polymer with 3-(Pyrazin-2-yloxy)-pyridine and Azide Anion as Mixed Bridge Ligand

A three-dimensional coordination polymer [Mn2（μ1.3-N3）4（μ-PP）2]n （PP = 3-（pyrazin-2-yloxy）-pyridine） has been synthesized with 3-（pyrazin-2-yloxy）-pyridine and azide anion as mixed bridge ligand, and its crystal structure was determined by X-ray crystallography. The crystal data： triclinic system, space group P1, with a = 6.794（4）, b = 9.885（6）, c = 9.947（6） A, α = 64.170（6）, β= 84.190（8）, γ= 85.319（8）°, V = 597.7（6）A^3, Z = 1, C18H14Mn2N18O2, Mr = 624.35, Dc = 1.735 g/cm^3, F（000） = 314 and μ = 1.117 mm^-1. In the crystal, the azide anion acts as a bridge ligand and makes adjacent Mn（Ⅱ） ions connect into a two-dimensional sheet on the ab plane, then 3-（pyrazin-2-yloxy）-pyridine serves as a bidentate bridge ligand to connect neighboring sheets along

Anion competition for Li^(+)solvated coordination environments in poly(1,3 dioxolane)electrolyte to enable high-voltage lithium metal solid-state batteries

Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.

Novel Lanthanide Cluster Polymers Based on Cubane-like [Ln4(OH)4]^8＋ Clusters and Sulfate Anions

Two lanthanide-oxo-cluster polymers were synthesized by hydrothermal reaction using Ln_2O_3 as initial lanthanide materials：[Ln_4（SO_4）_4（OH）_4（H_2O）_7]·_4H_2O（Ln = Er 1,Ho 2）,and characterized by PXRD,IR spectra,X-ray single-crystal diffraction,2D IR correlation spectra and UV-visible absorption spectra.Single-crystal X-ray analyses reveal that compounds 1 and 2 are isostructural,and they are both crystallized in the orthorhombic system Pccn space group.Compound 1 is a 3D lanthanide cluster polymer based on tetranuclear cubane-like [Er_4（μ_3-OH）_4]^8＋ cations and SO_4^2- anions.The overall structure of 1 can be assigned to 6-connected pcu-type topology with the point symbol of（4^12.6^3）.

Synthesis,Characterization and Crystal Structure of a Three-dimensional Coordination Polymer {[Cd(1,5-nds)(Him)_2(H_2O)]·2H_2O}n

A novel cadmium（Ⅱ） coordination polymer {[Cd（1,5-nds）（Him）2（H2O）]·2H2O}n （1,5-nds = naphthalene-1,5-disulfonate and Him = imidazole） was synthesized based on the reaction of cadmium oxide and 1,5-naphthalenedisulfonic acid firstly, and then mixed with imidazole in methanol medium. Its structure was characterized by elemental analysis, IR and TGA, respectively. The crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1, with a = 8.5420（10）, b = 10.2570（10）, c = 13.361（2） A, α = 100.704 （2）, β = 100.195（2）, γ = 108.873（3）°, C16H20Cd N4O9S2, Mr= 588.91, V = 1.0524（2） nm^3, Dc = 1.858 g/cm^3, Z = 2, F（000） = 592, β^ = 1.294 mm-1, R = 0.0397 and wR = 0.1007 for 3180 observed reflections （Ⅰ〉 2σ（Ⅰ））. Structural analysis shows that the cadmiun atom is coordinated with four oxygen atoms from three 1,5-nds and one water molecule together with two nitrogen atoms from two imidazoles, giving a distorted octahedral coordination geometry. The molecules are linked to form a two-dimensional coordination polymer based on bridging ligands of naphthalene- 1,5-disulfonate anions, the sheets of which are then interacted via hydrogen bonds, leading to a three-dimensional network structure.

Application of Polymers in Low Permeability Formations

For low-permeability sandstone reservoir with big channel, we researched the novel deep profile method alternative injection of anionic and cationic polymer. Evaluating various factors on adsorption capacity through lab test, the results show that with the increase of temperature, the adsorption capacity decreases and the cationic polymer is easier to be absorbed. With the increase of salinity, adsorption time or polymer concentration, the adsorption capacity increases. The adsorption equilibrium concentration of cationic polymer is 1500 mg/L;adsorption equilibrium time is 8 h. The adsorption equilibrium concentration of anionic polymer is 1000 mg/L;adsorption equilibrium time is 6 h. Physical simulation experiment shows that alternative injection of anionic and cationic polymer is better than injection of single polymer, and preferential injection of cationic polymer is better than preferential injection of anionic polymer. With the increase of injection rounds, sealing capacity gets better, but in view of cost, the rounds should not be more than 3. The profile control technique can obviously enhanced oil recovery, and water displacement recovery increases 41%. 2 wells were tested successfully in Henan Oilfield in June 2010. Approximate 154.47 tons of incremental oil was obtained with 2% water-cut decrease.

Synthesis, Crystal Structure and Thermal Behavior of a 3-D Barium(II)/Iron(III)-Oxalate Polymer

Reaction of Ba(NO3)2 with Fe(NO3)3·9H2O and H2C2O4·2H2O in aqueous medium readily affords, in high yield, the bimetallic complex polymer of chemical composition {Ba6(H2O)17[Fe(C2O4)3]4}·7H2O (1), consistent with the expected ratio of 3BaII vs. 2FeIII. Compound 1 was fully characterized by elemental and thermal analyses, vibrational FTIR spectroscopy, and by single crystal X-ray structure determination. The bulk structure of 1 is a 3-D metal-organic framework held together by intermetallic linkages across oxalate and aqua oxygen bridgings. Thermal analyses of 1 show significant weight losses corresponding to water molecules (lattice and coordinated), followed by the decomposition of the network.

A Chiral Three Dimensional Potassium(I)/Strontium(II)/Chromium(III) Oxalato-Bridged Coordination Polymer: Synthesis, Characterization and Thermal Analysis

A new compound of general formula {[(H2O)2K(μ-H2O)Sr]@[Cr(C2O4)3]}n (1) has been synthesized in water and characterized by elemental and thermal analyses, EDX, IR and UV-Vis spectroscopies and by single crystal X-ray structure determination. Compound 1 crystallizes in the chiral space group Fdd2 of orthorhombic system with a = 14.110 (4) ?, b = 36.074 (11)?, c =11.034 (3)? and Z = 16. Compound 1 is a coordination polymer in which the three-dimensional lattice framework is realized by the interconnectivity between K+ cations, Sr2+ cations, aqua ligands and [Cr(C2O4)3]3– complex anions. The asymmetric unit of 1 consists of one cationic motif formally written [(H2O)2K(μ-H2O)Sr]3+ and one anionic entity, [Cr(C2O4)3]3–. The K+ and Sr2+ ions in the cationic motif are both eight-coordinate while the Cr3+ ions in the anionic complex are six-coordinate in a distorted octahedral geometry. Coulombic interactions between the ionic motifs and the three-dimensional H-bonding involving aqua ligands help to consolidate the bulk structure. Thermogra-vimetric analysis (TGA) shows that compound 1 is stable to heat up to ca. 80℃.

接枝多胺聚合物制备大孔阴离子交换色谱介质及其蛋白吸附行为评价

以环氧活化聚甲基丙烯酸酯大孔微球(FastSep-epoxy)为基质,通过接枝聚(烯丙基胺)(PAA)制备了大孔阴离子交换色谱介质(FastSep-PAA)。考察了介质的合成条件对离子交换容量(IC)及蛋白结合容量的影响,发现IC随PAA浓度、反应时间和溶液pH的增加均表现为增长趋势;同时结合蛋白吸附容量的变化选择了最优合成条件。通过扫描电子显微镜观察介质的表面形貌,发现其孔隙连通性较好,且接枝前后介质孔道结构无明显变化,PAA配基密度对介质结构无明显影响。此外,通过压汞法和氮气吸附法测定接枝前后不同介质的孔径尺寸和孔径分布情况,并考察该类介质的孔径与蛋白吸附行为的关系,发现其蛋白结合容量未出现随介质孔径尺寸增加而显著下降的现象,且孔径尺寸增加更有利于蛋白在介质内部传质。在126 cm/h的流速下FastSep-PAA介质的原始孔径(即FastSep-epoxy的孔径)为400 nm时的蛋白动态结合容量(DBC)最高(70.3 g/L),该孔径下介质比表面积大,蛋白可吸附位点较多;原始孔径为700 nm及以下的介质蛋白DBC均随流速增加而均有一定下降;原始孔径为1000 nm的介质蛋白DBC几乎不受流速影响,流速由126 cm/h增加至628 cm/h时蛋白DBC仅下降3.5%,且在628 cm/h的流速下能保持57.7 g/L,蛋白分子在该孔径下的扩散速率受限较小,传质性能优异,这一特性表明该类大孔聚合物阴离子交换色谱介质在蛋白高通量分离中具有较大的优势。

聚丙烯酰胺水溶液的分子动力学模拟研究

为模拟实际选煤过程中产生的含聚污水,采用分子动力学的方法,选择COMPASS II力场,分别对含非离子型聚丙烯酰胺(NPAM)的水溶液体系和含阴离子型聚丙烯酰胺(HPAM)的水溶液体系进行模拟。通过分析聚合物的平衡构象、均方位移曲线、径向分布函数、扩散轨迹及均方回转半径等,进一步探究聚丙酰胺(PAM)水溶液的微观结构与高分子溶液性质的关系。研究结果表明:NPAM在溶液中形成疏水内核球体而悬浮,而HPAM在溶液底部聚集;含HPAM的水溶液中水分子比含NPAM的水溶液中水分子扩散系数较大;HPAM表面与附近水分子作用数较多,形成强氢键;HPAM在溶液中水分子位移和活动范围都比NPAM中水分子大;在水溶液中NPAM比HPAM更好地舒展。

Charting the course to solid-state dual-ion batteries

An electrolyte destined for use in a dual-ion battery(DIB)must be stable at the inherently high potential required for anion intercalation in the graphite electrode,while also protecting the Al current collector from anodic dissolution.A higher salt concentration is needed in the electrolyte,in comparison to typical battery electrolytes,to maximize energy density,while ensuring acceptable ionic conductivity and operational safety.In recent years,studies have demonstrated that highly concentrated organic electrolytes,ionic liquids,gel polymer electrolytes(GPEs),ionogels,and water-in-salt electrolytes can potentially be used in DIBs.GPEs can help reduce the use of solvents and thus lead to a substantial change in the Coulombic efficiency,energy density,and long-term cycle life of DIBs.Furthermore,GPEs are suited to manufacture compact DIB designs without separators by virtue of their mechanical strength and electrical performance.In this review,we highlight the latest advances in the application of different electrolytes in DIBs,with particular emphasis on GPEs.

Enhanced Li+migration in solid polymer electrolyte driven by anion-containing polymer-chains

Li-ion batteries with solid polymer electrolytes(SPEs)are safer than conventional liquid electrolytes due to the absence of highly flammable liquid electrolytes.However,their performance is limited by the poor Li+transport in SPEs at room temperature.Anion-containing polymer-chains incorporated SPEs(ASPEs)are therefore developed to enhance Li^(+) diffusion kinetics.Herein,we propose a novel and feasible strategy to incorporate the anion-containing polymer-chains,such as lithiated perfluorinated sulfonic acid(PFSA),into polyvinylidene fluoride(PVDF)polymer-based SPEs.The immobile anion groups from the PFSA-chains impede the migration of mobile anion groups dissociated from the Li salt.The transference number is thus raised from∼0.3 to 0.52 with the introduction of anion-containing polymer-chains into SPEs.The electrostatic repulsion among anion-containing chains also reduces the close chain stacking and brings 159%increase in the ionic conductivity to 0.83×10^(−3) S/cm at 30℃ in contrast with the pure PVDF-based SPE.In addition,LiFeO_(4)/Li batteries with ASPEs exhibit 55%capacity boost at 0.5 C in contrast to the capacity of batteries with pure-PVDF SPEs,and also offer more than 1000 charge/discharge cycles.Our research findings potentially offer a facile strategy to design thermal stable SPEs with superior Li^(+) transport behaviors towards developing high-performance SPEs-based batteries.

SYNTHESIS OF HETEROARM STAR POLYMERS COMPRISING POLY(4-METHYLPHENYL VINYL SULFOXIDE) SEGMENT BY LIVING ANIONIC POLYMERIZATION

A series of 3-arm ABC and AA＇B and 4-arm ABCD, AA＇BC and AA＇A＂B heteroarm star polymers comprising one poly（4-methylphenyl vinyl sulfoxide） segment and other segments such as polystyrene, poly（a-methylstyrene）, poly（4-methoxystyrene） and poly（4-trimethylsilylstyrene） were synthesized by living anionic polymerization based on diphenylethylene （DPE） chemistry. The DPE-functionalized polymers were synthesized by iterative methodology, and the objective star polymers were prepared by two distinct methodologies based on anionic polymerization using DPE-functionalized polymers. The first methodology involves an addition reaction of living anionic polymer with excess DPE-functionalized polymer and a subsequent living anionic polymerization of 4-methylphenyl vinyl sulfoxide （MePVSO） initiated from the in situ formed polymer anion with two or three polymer segments. The second methodology comprises an addition reaction of DPE-functionalized polymer with excess sec-BuLi and a following anionic polymerization of MePVSO initiated from the in situ formed polymer anion and 3-methyl-1,1-diphenylpentyl anion as well. Both approaches could afford the target heteroarm star polymers with predetermined molecular weight, narrow molecular weight distribution （Mw/Mn 〈 1.03） and desired composition, evidenced by SEC, 1H-NMR and SLS analyses. These polymers can be used as model polymers to investigate structure-property relationships in heteroarm star polymers.

Anionic polymerization initiated by lithium amides for preparing high molecular weight polyacrylonitrile

Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage molecular weight ranging from 1.02 × 10~6 g/mol to 1.23 ×10~6 g/mol (M_w/M_n= 1.9-2.2) could be prepared utilizing lithium amides derived from diisopropylamine, diethylamine, hexamethyldisilazane,dicyclohexylamine, and 2,2,6,6-tetramethylpiperidine as initiators. The polymerization of acrylonitrile proceeded in a homogeneous manner in N,N-di methyl for mamide and insignificant contribution of side reactions was confirmed.

Synthesis and characterization of novel polypropylene paper releasing anion

Polypropylene synthetic paper releasing anion was prepared from polypropylene resin, anion additives, titanium dioxide, etc., by calendar forming method. The synthetic paper was tested by anion detector, SEM, AFM, etc. Tensile strength, elongation at break, fight angle tear strength of the polypropylene synthetic paper reached the GB 13022 or QB/T1130 Standard. The synthetic paper was water and oil resistance, and released anions 10,530 cm^-3. It was environment-friendly, and a kind of good material for human＇s health.

Synthesis of Well-defined Long Chain Branched Polyethylene via Anionic Polymerization Combined with Graft-onto Method

Comb-like polyethylene（PE） was prepared via anionic polymerization combined with ＂graft-onto＂ process. The polybutadiene（PB） backbone underwent hydroxylation at 1,2-vinyl groups to obtain a controlled number of hydroxyl groups along the main chain. After the translation of hydroxyl groups to tosyl groups, a nucleophilic substitution by living anionic PB chains was achieved. The comb PE was finally obtained by the hydrogenation of the obtained unsaturated comb polymer. Since the living anionic polymerization was used to prepare the backbones and the branch chains, molecular weight to molecular weight distribution（Mw/Mn〈1.5） can be well-controlled in the final comb polymer, including the average number and length of branches.

Helical Poly(α,β-unsaturated ketone)with Bulky Pendant of Binaphthyl from Anionic Polymerization of(−)-Menthyl(S)-6'-Acrylyl-2'-methyloxy-1,1'-binaphthalene-2-carboxylate

(−)-Menthyl(S)-6'-acrylyl-2'-methyloxy-1,1'-binaphthalene-2-carboxylate(3)was synthesized and anionically polymerized using n-BuLi as an initiator in toluene.The monomer 3 was levorotatory and had an[α]_(D)^(25)value of−72.4,but its corresponding polymer poly-3 was dextrorotatory and showed an[α]_(D)^(25)value of+162.0.Poly-3 was confirmed to exist in the form of one-handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as(−)-menthyl(S)-6'-propionyl-2'-methyloxy-1,1'-binaphthalene-2-carboxylate 2b and(−)-menthyl(S)-6'-heptanoyl-2'-methyloxy-1,1'-binaphthalene-2-carboxylate 2c.This conclusion was also confirmed by the fact that the g-value of poly-3 is about 11 times of that of monomer 3.