Sorption of aromatic compounds in water using insoluble cyclodextrin polymers

Insoluble β-cyclodextrin (β-CD) polymers have been used for the recovery of various organic pollutants from aqueous solutions. These resins have been prepared by polymerization using epichlorohydrin (Epi) as a crosslinking agent. Several crosslinked polymers with various degrees of β-CD were used. Several studies (time, concentration, kinetics, and pH) are presented here. The results show that these sorbents exhibit high sorption capacities toward substituted benzene derivatives. The mechanism of sorption is both physical adsorption in the polymer network and/or the formation of an inclusion complex and/or the formation of hydrophobic guest–guest interactions. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 68: 1973–1978, 1998     

Preparation and sorption studies of microsphere copolymers containing β-cyclodextrin and poly(acrylic acid)

Microsphere polymeric materials containing β-cyclodextrin (β-CD) and poly(acrylic acid) (PAA) with tunable morphologies were prepared in order to improve their sorption characteristics in aqueous solution. The microsphere polymeric materials were prepared using a (water/oil) micro-emulsion-evaporation technique to condense β-cyclodextrin (β-CD) with PAA at various comonomer ratios and mixing speeds. The β-CD microsphere copolymers were characterized using FTIR, TGA, DSC, SEM, elemental (C and H) microanalyses, and solid state ¹³C-NMR spectroscopy. The sorption properties of the polymeric materials at 295 K in aqueous solution containing p-nitrophenol (PNP) were studied using a dye-based method with UV–Vis spectrophotometry at pH 4.6 and 10.3. The sorption isotherms of copolymer/PNP systems were evaluated with various isotherm models (e.g., Langmuir, BET, Freundlich, and Sips). The Sips isotherm showed the best overall agreement with the experimental results and the sorption parameters provided estimates of the sorbent surface area (12.0–331 m²/g) and the sorption capacity (Q_m = 0.359–2.20 mmol/g at pH = 4.6; Q_m = 0.070–0.191 mmol/g at pH = 10.3) for the microsphere copolymer/PNP systems in aqueous solution. The nitrogen adsorption properties of the microporous copolymers in the solid state were obtained at 77K with BET surface areas ranging from 0.275 to 4.47 m²/g. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Sorption properties toward substituted phenolic derivatives in water using macroporous polyamines containing β-cyclodextrin

Macroporous polyamines containing β-cyclodextrin (β-CD) are used for the recovery of various organic pollutants from aqueous solutions. Several insoluble polyamines with various degrees of β-CD were prepared. Studies concerning the sorption kinetics, the effect of pollutant concentration, pH of the solutions, and β-CD content are presented here. The results of sorption experiments show that these sorbents exhibit high sorption capacities toward substituted phenolic derivatives. The mechanism of sorption is both physical adsorption in the resin polymer network through acid–base interactions, ion exchange, and hydrogen bonding due to the amino groups and the formation of an inclusion complex due to the β-CD molecules through host–guest interactions, and hydrophobic interactions such as guest–guest interactions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2903–2910, 1999     

Synthesis and Self-Assembly of β-Cyclodextrin Terminated DMA/NIPAM Diblock Copolymers

A series of β-cyclodextrin (β-CD) terminated diblock copolymers has been prepared via click reaction. The Huisgen cycloaddition between alkyne decorated copolymer and azide functionalized β-CD was performed in organic solvent in the presence of a Cu(I) catalyst, resulting in the formation of β-CD terminated diblock copolymers, which contain thermally responsive poly(N-isopropylacrylamide) (PNIPAM) block and hydrophilic poly(N,N-dimethylacrylamide) (PDMA) block. Using dynamic light scattering and fluorescence spectroscopy measurements, it is demonstrated that these β-CD functionalized block copolymers are capable of reversibly forming micelles in response to changes in solution temperature and that the critical micelle concentration, micellar size, and transition temperature are dependent on both the NIPAM block length and the polymer functionalization.     

羟丙基-β-环糊精及β-环糊精与十六烷基三甲基溴化铵混合体系的电导研究

用电导法研究了十六烷基三甲基溴化铵 (CTMAB)与羟丙基 β 环糊精 (HP β CD)及 β 环糊精 (β CD)混合体系的电导行为。结果表明 ,由于CTMAB与HP β CD或 β CD间形成了包合物 ,使体系电导率增加的幅度减缓。当体系中HP β CD或 β CD的浓度增加时 ,CTMAB的临界胶束浓度 (CMC)增加 ,即转折点后移 ,且HP β CD对CTMAB的CMC转折点后移的影响较 β CD明显     

FLAVOR ENCAPSULATION AND RELEASE CHARACTERISTICS OF SPRAY-DRIED POWDER BY THE BLENDED ENCAPSULANT OF CYCLODEXTRIN AND GUM ARABIC

The flavor inclusion powder was prepared by spray drying, using the combined encapsulation method of inclusion by β-cyclodextrin (β-CD) and emulsified by gum arabic (GA). d-Limonene and ethyl n-hexanoate were used as model flavors. The application of high pressure by Microfluidizer to the mixture of flavors and β-CD slurry was an effective means of forming inclusion complex. Flavor retention during spray drying under various compositions of the encapsulants was investigated. The flavor retention using the blended encapsulant was increased by adding GA in the encapsulant. The characteristics of release of encapsulated flavor during storage were evaluated at 50°C and 75% of relative humidity. The release rate of flavor in spray-dried powder depended on kinds of the flavors and composition of the encapsulant. The blending MD and β-CD in the feed liquid decreased the release rate of flavors. The rate of release of flavor was analyzed by Avrami's Equation.     

Core-shell structured nanoassemblies based on β-cyclodextrin containing block copolymer and poly(β-benzyl L-aspartate) via host-guest complexation

Double hydrophilic copolymers (PEG-b-PCDs) with one PEG block and another block containing β-cyclodextrin (β-CD) units were synthesized by macromolecular substitution reaction. Via a dialysis procedure, complex assemblies with a core-shell structure were prepared using PEG-b-PCDs in the presence of a hydrophobic homopolymer poly(β-benzyl l-aspartate) (PBLA). The hydrophobic PBLA resided preferably in the cores of assemblies, while the extending PEG chains acted as the outer shell. Host-guest interaction between β-CD and hydrophobic benzyl group was found to mediate the formation of the assemblies, where PEG-b-PCD and PBLA served as the host and guest macromolecules, respectively. The particle size of the assemblies could be modulated by the composition of the host PEG-b-PCD copolymer. The molecular weight of the guest polymer also had a significant effect on the size of the assemblies. The assemblies prepared from the host and guest polymer pair were stable during a long-term storage. These assemblies could also be successfully reconstituted after freeze-drying. The assemblies may therefore be used as novel nanocarriers for the delivery of hydrophobic drugs.     

ARGET-ATRP using β-CD as reducing agent for the synthesis of PMMA-b-PS-b-PMMA triblock copolymers

We studied the role of β-cyclodextrin (CD), a polyhydroxy cyclic sugar as reducing agent (RA) for the copper mediated activators regenerated by electron transfer atom transfer radical polymerization (ATRP) with the successful chain extension of methyl methacrylate blocks on the bifunctional polystyrene macroinitiator (PS-MI) using nonaqueous solvent system for the first time. The PS-MI was prepared by ATRP, had a polydispersity of 1.05 and gave triblock copolymers in the presence of β-CD. We found that alcoholic groups of β-CD show provisional reducing character and in situ convert Cu(II) to Cu(I) during polymerization. A well-defined triblock copolymer with narrow molecular weight distribution (polydispersity index < 1.5) was obtained at 100 °C. The molecular weight of the block copolymers increased linearly with monomer conversion and the reaction showed good control over the molecular weights when compared to the theoretical values. We show that the mild reducing power of β-CD is retained in a nonaqueous solvent also and is efficient with catalyst/RA ratio of 1:0.5. The effect of temperature on the reducing competency of β-CD was evaluated and found to be active at around 80 °C even though its melting temperature is 290 °C. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47117.     

带β-环糊精侧基水凝胶的制备与性能研究

用顺丁烯二酸酐（MAH）对β-环糊精（β-CD）进行化学改性制备丁烯二酸单酯化β-环糊精单体（MAH-β-CD）。用氧化还原自由基引发单体MAH-β-CD、丙烯酰胺（AM）以及丙烯磺酸钠（SAS）共聚,合成水凝胶,用红外光谱对产物结构表征。溶胀研究结果表明该水凝胶具有良好的温度、pH敏感性。     

温度及pH敏感水凝胶的制备与溶胀性能研究

用顺丁烯二酸酐(MAH)对β-环糊精(β-CD)进行化学改性,合成出了一种新型功能性单体MAH-β-CD。以N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,过硫酸铵(APS)为引发剂,通过氧化还原自由基引发单体MAH-β-CD、N-异丙基丙烯酰胺(NIPA)及阴离子单体丙烯酸钠(SA)共聚,合成出一种新型水凝胶。用核磁共振、红外光谱对水凝胶进行了表征。溶胀研究结果表明,该水凝胶具有较好的pH及温度敏感性。     

Effect of hydrophilic and hydrophobic cyclodextrins on the release of encapsulated allyl isothiocyanate (AITC) and their potential application for plastic film extrusion

Allyl isothiocyanate (AITC), a natural pungent flavor from wasabi and horseradish, is well-known antimicrobial agents against foodborne pathogens. However, its highly volatile nature and low thermal stability restrict its application in the food packaging industry. Also, its strong organoleptic characteristics hinder its application at a higher dosage. We encapsulated AITC in β-cyclodextrin (β-CD) and triacetyl-β-CD (TA-β-CD) and evaluated the performance as slow releasing active compounds through low-density polyethylene (LDPE)–cyclodextrins (CDs) matrix. Also, the thermal, optical, mechanical, and barrier properties of two ternary blends, LDPE/β-CD/AITC(L-CDs) and LDPE/TA-β-CD/AITC(L-TACDs), were investigated to compare their compatibility under the plastic extrusion process. During the 15 days of the storage period, L-TACDs maintained more consistent AITC release and a higher concentration than L-CDs. Also, the blending of LDPE and TA-β-CD was more compatible with that of LDPE and β-CD. No significant optical, mechanical, and barrier property changes were observed in LDPE with less than 3% of TA-β-CD while L-CDs showed substantial agglomeration on the ternary blend films and the lower mechanical and barrier properties than pure LDPE. The results indicate that the LDPE films containing TA-β-CD/AITC can be applied as an effective antimicrobial packaging material for food and nonfood applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48137.     

Sorption equilibria and diffusion coefficients of ethanol and water in the PVA membranes containing cyclodextrin

Effects of cyclodextrin (CD) on the pervaporation characteristics for water/ethanol through the PVA/CD membranes (PVA membranes containing β-CD oligomer) have been investigated in terms of sorption equilibria and diffusion coefficients based on the sorption–diffusion theory. The increase in water selectivity through the pervaporation by CD was due mainly to the changes in the diffusion coefficients by CD, which depended on the feed composition and the cross-linking time. The water selectivity through the sorption equilibria was not increased by the addition of CD, and the ethanol-sorption amount was increased by CD. These effects of CD were interpreted by the inclusion strength in the CD cavity and the cross-linking density of the PVA phase. © 1994 John Wiley & Sons, Inc.     

β-环糊精-Cu(Ⅱ)配合物催化氧化邻苯二酚及其反应动力学

以β-环糊精(β-CD)作为骨架,经磺酰化反应、卤代反应和与L-组氨酸的亲核取代反应,得到了两种β-环糊精-组氨酸衍生物配体,再将配体与Cu(Ⅱ)配位,合成了具有多酚氧化酶催化活性的β-环糊精-Cu(Ⅱ)配合物。采用元素分析、傅里叶变换红外光谱、核磁共振波谱和原子吸收光谱等方法对配体和配合物的结构进行了表征。以O₂为氧化剂,用分光光度法测定了它们催化邻苯二酚氧化反应的性能,并考察了反应温度、pH值等因素对催化反应速率的影响。结果表明：β-环糊精-Cu(Ⅱ)配合物具有良好的催化性能;C-2位修饰得到的环糊精类金属衍生物因为活性基团与反应中心之间相对位置适宜,表现出较大的加速效果;反应动力学表明组胺基配位Cu(Ⅱ) 、β- CD疏水空腔和碱催化作用是反应加速的3个因素。     

Adsorption Behavior of Azo Dye Eriochrome Black T from Aqueous Solution by β-Cyclodextrins/Polyurethane Foam Material

β-cyclodextrin/polyurethane (β-CD/PU) materials were prepared by foaming technique. The adsorption behavior of EBT on β-CD/PU material and the influences on the adsorption efficiency were investigated. Under the optimal experimental conditions, the maximum adsorption efficiency of EBT was 93.14%. The kinetics characteristic and thermodynamic parameters were analyzed. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations and the results indicated that the Langmuir isotherm showed a better fit for EBT adsorption. The experimental results suggest that the β-CD/PU foam materials have potential application for the wastewater treatment containing EBT dye.     

β-环糊精琥珀酸钠/壳聚糖离子复合膜的制备及其药物控释研究

采用酯化反应,以琥珀酸酐(SUC)为酰化剂,合成了琥珀酰β 环糊精酯(β CD SUC),进一步与NaOH反应生成β 环糊精琥珀酸钠(β CD SUS),并以此为离子交联剂与阳离子聚合物壳聚糖(CTS)复合,制备了含β 环糊精结构单元的壳聚糖复合膜(β CD SUS/CTS)。滴定实验表明了离子间存在着静电相互作用,并决定了膜在水溶液中具有pH敏感性。选用喜树碱(CPT)为模型药物,通过研究环糊精与CPT以及环糊精与CTS间的相互作用,探讨了其药物控制释放机理。     

Synthesis of supramolecular biodendrimeric β-CD-(spacer-β-CD)21 via click reaction and evaluation of its application as anticancer drug delivery agent

The per-β-CD dendrimer (10), having 21 β-CD residues connected to the core β-CD in the primary and secondary sides with encapsulation efficacy and β-CDs moiety to preserve the biocompatibility properties was synthesized using click reaction. The dendritic network and β-CD cavity of the obtained dendrimer were utilized to form a supramolecular compound via the formation of a host-guest inclusion complex with methotrexate (MTX) drug molecule. The MTT assay of compound 10 showed very low toxicity on T47D cancer cells. In vitro drug release investigation at pHs 7.4, 5, and 3 indicated that the release manner was remarkably pH dependent.     

超声协同交联β -环糊精处理苯酚废水

环糊精因其特殊的结构特点,尤其是经过交联剂改性的交联β-环糊精（MDI-β-CD）,可以处理与其空腔尺寸匹配的苯酚污染物,具有更好的处理苯酚废水的能力。为进一步提高MDI-β-CD处理苯酚废水的效果,研究其在超声协同条件下的废水处理能力和适合工况。通过对MDI-β-CD用量、废水pH值、废水浓度、超声声强和频率的研究,找到处理苯酚废水的适合工艺条件：超声频率20 kHz,超声声强0.2 W/cm2,苯酚初始浓度100 mg/L,pH值6.0,溶液体积100 mL,反应温度40 ℃,吸附时间120 min,MDI-β-CD用量40 g/L;在此条件下,MDI-β-CD与超声协同处理苯酚废水吸附效率可以达到94.1%。     

Dodecenyl succinic-β-cyclodextrin with high degree of substitution: Synthesis,characterization and evaluation

β-cyclodextrin (β-CD) has the characteristics of safety, non-toxicity, and a wide range of sources. It can be used in improving surface activity. However, due to the limitation of molecular polarity and solubility, its surface activity and emulsification ability are weak. Therefore, it is necessary to improve adsorption capacity on phase interface by hydrophobic modification. In this article, dodecenyl succinic-β-cyclodextrin (DDS-β-CD) with different substitution degree was prepared by esterification of β-CD with dodecenyl succinic anhydride (DDSA) as the esterifying agent. The product was characterized by FT-IR, ¹H NMR, SEM, and TGA, respectively. Results showed that DDS was successfully introduced into β-CD. Both the degree of substitution (DS) and productivity (P) increased with the addition of DDSA and can reach 0.283 and 85.8%, respectively, when the molar ratio of DDSA to β-CD was 3:1. The modified cyclodextrin showed lower surface tension and higher foaming ability. Compared with octenyl succinic-β-cyclodextrin (OS-β-CD), it was found that the length of hydrophobic segment had a significant effect on the surface tension. Due to its unique properties, it can be used as a good emulsifier for oil-in-water emulsions and a host material for lavender flavor.     

Preparation and characterization of poly-carboxymethyl-β-cyclodextrin superplasticizer

A new superplasticizer of poly-carboxymethyl-β-cyclodextrin (PCM-β-CD) was prepared by ring-opening polymerization of epoxy chloropropane and CM-β-CD using sodium hydroxide as initiator. The structure of PCM-β-CD was characterized by FTIR and NMR as well as GPC. The performances of the CM-β-CD were tested by measuring paste luidity, setting time, adsorption and zeta-potential. The result showed the performances of PCM-β-CD closed to the control polycarboxylate superplasticizer (PCs) used in this study, especially the fluidity loss is smaller and the setting time is longer than the PCs. The reason might be the synergism of the steric hindrance with the hollow truncated cone and the electrostatic repulsion from –COO^? groups. The mechanism of dispersion and retardation by PCM-β-CD was elucidated based on the results of adsorption properties and zeta‐potential of the cement particles. The study offers a new approach to synthesize superplasticizer based on β-CD and an alternative to concrete engineering.     

环糊精对黄酮的包合作用及其在银杏黄酮提取中的应用

对β-环糊精(-βCD)进行甲基化修饰和表征,并通过相溶解度法研究了β-CD以及甲基化β-环糊精(M-β-CD)对银杏黄酮的替代品———芦丁的包合作用。实验表明,两种环糊精都能有效增加芦丁在水中的溶解度,尤其是M--βCD可使溶解度增加30倍。以此为依据,该研究用含有β-CD和M-β-CD的水溶液来提取银杏叶中的黄酮,探讨了环糊精与黄酮的摩尔比、提取温度和提取时间对提取效果的影响,结果发现:当n(M--βCD)∶n(黄酮)=3∶1,60℃下提取3 h后,黄酮的提取率达72%,w(黄酮)=12.4%,较传统的水浸法〔提取率42%,w(黄酮)=4.5%〕和醇提法〔提取率63%,w(黄酮)=6.1%〕有明显的提高。这表明通过-βCD及M--βCD对银杏黄酮的溶解和包合作用,可有效地提高黄酮的提取率以及提取物纯度。