Preparation and properties of PEG hydrogel from PEG macromonomer with sulfonate end group

A novel PEG macromonomer with methacryloyl and sulfonate group at each chain end was prepared, and new PEG‐based hydrogels were prepared by crosslinking polymerization of this PEG macromonomer in the presence of PEG dimethacrylate. Their swelling properties are measured and compared with those of reference hydrogel from methoxy PEG methacrylate to elucidate the effect of the sulfonate end group. The prepared sulfonated PEG hydrogels exhibited water absorbency in the range of 19 ～ 42 g water/g dry‐gel depending on the composition. These hydrogels with anionic sulfonate group showed swelling behavior varying with salt type, concentration, and also with pH of aqueous solution. The morphology of the sulfonated PEG gels by SEM showed irregular porous network structure varying with the composition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 56–61, 2005     

PAA/PEG复合水凝胶膜的制备及其性能

以丙烯酸(AA)为单体、聚乙二醇(PEG)为大分子模板、N,N-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,通过自由基溶液聚合法原位聚合制备了聚丙烯酸(PAA)/PEG复合水凝胶膜,研究了PEG用量对复合水凝胶成膜性、热稳定性、溶胀性能和力学性能的影响。结果表明:成功制备了PAA/PEG复合水凝胶膜;适量PEG的引入有利于复合水凝胶成膜;PAA/PEG复合水凝胶膜的热稳定性良好;PEG的引入对水凝胶膜的吸水溶胀性能不利;适量PEG有利于提高凝胶的力学性能,复合水凝胶膜软而韧;PEG与AA质量比为0.4的PAA/PEG复合水凝胶的拉伸强度和断裂标称应变最大,分别为1.58 MPa,414%。     

Poly(2-hydroxyethyl methacrylate) (PHEMA)/poly(styrene-co-acrylamide) (PSAm) blends: miscibility and hydrogel properties

The blend miscibility of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(styrene-co-acrylamide) (PSAm) was studied by DSC. A ‘miscible window’ was found in the range 47–57 mol% of acrylamide in blending PSAm with PHEMA (1:1 w/w) and was analysed by the mean-field theory. The water content and permeability coefficients of proteins were measured. The results show that the water content of the blends depends on the composition of PSAm and the blends, and the behaviour of blends swollen in water in Fickian type. However, the permeability of the solutes not only related to water content, but was also affected by phase behaviour. Controlled release of somatotropin from a cylindrical device coated with PHEMA/PSAm was achieved.     

聚丙烯酸水凝胶的制备研究

以丙烯酸为单体,N,N＇-亚甲基双丙烯酰胺为交联剂,过硫酸铵为引发剂,通过自由基聚合制备了聚丙烯酸水凝胶.考察了交联剂、引发剂、单体中和度、聚合温度以及盐溶液对水凝胶溶胀性能的影响.结果表明,引发剂为单体质量的0.6％,交联剂为0.8％,单体的中和度为70％时,凝胶的溶胀性能最佳,吸水率达到了3 000％以上,聚丙烯酸水凝胶的溶胀性能随着盐溶液浓度的增大而降低.     

L-胱氨酸交联球形壳聚糖凝胶的制备与Cu2+吸附性能

以L-胱氨酸(L-CYS)作为交联剂,利用滴液成球法制备交联球形壳聚糖凝胶,用傅里叶红外光谱、¹³C NMR、扫描电镜对产物进行了表征,结果表明L-CYS与壳聚糖发生了酰胺化及酯化反应,并且制得的凝胶内部存在着疏松的网络状大孔。交联剂L-CYS中的二硫键有助于二价铜离子的吸附。以L-CYS交联得到的球形壳聚糖凝胶对Cu²⁺的吸附量达到了72.96 mg·g^-1,接近于未交联的球形壳聚糖凝胶的吸附量,而耐溶胀性优于未交联的壳聚糖凝胶。     

聚氨酯-羧甲基壳聚糖席夫碱水凝胶的制备与性能

将2,4-二羟基苯甲醛（DDBA）作为扩链剂，丙烯酸羟乙酯(HEA)作为封端剂制备了含有醛基的水性聚氨酯（DPU），在温和的条件下引入羧甲基化壳聚糖（CMCh）合成了聚氨酯-CMCh席夫碱，再由自由基聚合法引入聚丙酰胺合成了聚氨酯-羧甲基壳聚糖席夫碱水凝胶（DPU-Ch）。通过FTIR、SEM、力学性能、溶胀保水试验、抗菌试验和血液相容性测试等对水凝胶结构和性能进行表征。结果表明，水凝胶的机械性能随着CMCh质量分数的增加而提升，同时水凝胶也显示出良好的溶胀能力和保水能力；当CMCh添加量为2%时，水凝胶对革兰氏阳性和阴性细菌菌株均显示出良好的抗菌性能；水凝胶溶血率均低于5%表明其具有良好的细胞相容性，NIH3T3细胞存活率在90%以上证明其没有细胞毒性，因此在生物医疗领域中具有潜在的应用前景。     

Synthesis,characterization, and enzymatic degradation of chitosan/PEG hydrogel films

Poly(ethyleneglycol) (PEG)/tartaric acid (TA)‐crosslinked chitosan hydrogel (CPT) films were prepared, and the formation of the PEG/TA‐crosslinked structure was confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) measurements. The thermal properties of the crosslinked films were also determined with thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis. The swelling properties of the films were investigated at different temperature and pH values. It was found that the swelling ratio increased with the decrease of pH value of the surrounding buffer solutions, amount of PEG, and with the increase of temperature. Swelling behavior of the PEG/TA‐crosslinked chitosan hydrogel films depended on pH and reversible with the temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

DMAEMA/NVP/HEMA共聚物水凝胶的合成与性能研究

以甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)、N-乙烯基吡咯烷酮(NVP)和甲基丙烯酸β-羟乙酯(HEMA)为共聚单体,采用自由基水溶液聚合法制备了化学交联的三元共聚水凝胶,并对水凝胶在不同温度和不同离子强度及不同pH介质中的溶胀性能进行了测定。结果表明,在不同离子强度(I)的水溶液中,随着I的增大,水凝胶的平衡溶胀比ESR不断降低;但当I>0.2后,对凝胶ESR的影响不显著;当外界环境酸度较大(pH<2)时,凝胶ESR较大,但pH值稍有增大,凝胶ESR迅速下降;温度升高,凝胶ESR减少。     

果胶-g-聚(丙烯酸-co-丙烯酰胺)水凝胶溶胀性能研究

在水溶液中通过接枝共聚法制备出果胶-g-聚(丙烯酸-co-丙烯酰胺)水凝胶(PECAA),研究了PECAA在蒸馏水中的溶胀动力学,考察了其在不同溶剂中的溶胀行为。结果表明,PECAA在蒸馏水中的溶胀动力学过程可分为3个阶段;以PECAA在蒸馏水中的饱和溶胀度为参照值,其在自来水中的饱和溶胀度比值最高,其次为NaCl溶液,在CuSO4溶液中的饱和溶胀度比值最低。     

Synthesis and characterization of pH‐and salt‐sensitive hydrogel based on chemically modified poultry feather protein isolate

Hydrogels were synthesized from poultry feather protein by crosslinking ethylene diamine tetraacetic dianhydride (EDTAD)‐modified feather protein isolate (FPI) with glutaraldehyde (Glu). Different molar ratios of EDTAD/FPI were used to obtain FPI of different degrees of acylate modification. Differential scanning calorimeter measurements of glass transition temperature suggested that hydrogel formation was based on the hydrogen bond between EDTAD‐modified FPI segments. The swelling properties of modified FPI hydrogel were investigated in deionized water and in solutions of different salt contents (i.e., ionic strengths) and pH. An optimal swelling ratio (SR) of 63 g/g was obtained when molar ratios of EDTAD/FPI and Glu/FPI were 0.12 and 0.008, respectively. SR decreased substantially with increase in ionic strength, and at a given ionic strength, SR increased with solution pH in 4.0 to 10.0 range. The water transport mechanism of the hydrogel was also pH dependent and was controlled by Fickian diffusion and polymer relaxation. At higher pH value, the water transport profile became more dependent on polymer relaxation than at lower pH. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Metal-chelating properties and biodegradability of an ethylenediaminetetraacetic acid dianhydride modified soy protein hydrogel

The heavy-metal chelating properties of a soy protein based hydrogel, prepared by crosslinking an ethylenediaminetetraacetic acid dianhydride (EDTAD) modified soy protein isolate (SPI), have been studied. The equilibrium binding capacities of the divalent calcium, zinc, mercury, and lead ions by the gel were 0.70, 0.65, 0.95, and 0.70 mmol per gram of dry gel, respectively. The distribution ratio of metal ions between the gel and the solution was in the range of 370 to 15,000 mL/g, depending on the initial metal concentration. A positive relationship between the carboxyl group content of EDTAD-modified SPI and the metal-binding ability of the gel was observed; the optimum metal binding occurred at 25°C. The metal-binding ability increased with increasing pH, in the range where the solubility of the metal ions was not affected by the pH. In binary metal ion solutions, the metal ions adsorbed to the gel in a competitive fashion, influenced by the initial ion concentration. The EDTAD-modified protein hydrogel was readily degraded by proteolytic enzymes and was biodegraded in a fungal overgrowth test. The EDTAD-SPI hydrogel was completely degraded after a 28-day incubation with fungal spores. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 891–901, 1997     

膨润土/羧甲基纤维素钠水凝胶的制备及其应用

通过化学交联技术制备了一种生态友好和成本低廉的BT-g-CMC水凝胶，并对其结构和形貌进行了表征，并将其用于废水中回收磷和缓释磷肥。吸附研究表明，当CMC/BT的质量比值为1时，在298 K下水凝胶对H2PO4-具有良好的亲和力，吸附容量为18.78 mg/g，吸附平衡时间为120 min；其次，将富含磷的BT-g-CMC1.0水凝胶用作缓释肥料（SRFs），结果表明，SRFs具有优良的保水和缓释能力。盆栽实验表明，SRFs对蔬菜生长具有促进作用。土壤修复实验表明，当SRFs用量为0.3g，浸出3次时，对土壤中Cr(Ⅲ)的固定化率为82.9%。因此，SRFs具有广泛的工业和绿色农业应用。     

Hydrolyzed collagen‐based hydrogel with salt and pH‐responsiveness properties

A novel hydrolyzed collagen‐based hydrogel has been prepared by grafting the binary mixture of acrylamide and 2‐acrylamido‐2‐methylpropanesulfonic acid onto the collagen backbone in the presence of a crosslinking agent. Its physicochemical properties in aqueous solution were studied. The effect of reaction variables on both gel content and swelling capacity was investigated to achieve a hydrogel with improved absorbency and gel content. The absorbency under load of optimized hydrogel was also investigated by using an absorbency under load tester at various applied pressures. The swelling ratio in various salt solutions was also determined and additionally, the swelling of hydrogels was measured in solutions with pH ranged 1–13. The synthesized hydrogel exhibited a pH‐responsiveness character so that a swelling‐collapsing pulsatile behavior was recorded at pH 2 and 8. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

N-异丙基丙烯酰胺pH敏感型水凝胶的制备及对甲基紫吸附性能研究

以N-异丙基丙烯酰胺和海藻酸钠(SA)为主要原料,制备了具有pH敏感型的智能水凝胶。探究了不同海藻酸钠、引发剂、交联剂等配比的凝胶在不同pH值环境下的溶胀性能,并对制备的凝胶进行甲基紫的吸附性能测试。结果表明:碱性条件下,凝胶溶胀度随SA用量的增加而增大,酸性条件下则相反;凝胶的溶胀度随交联剂用量的增加而减小;引发剂用量为3%时凝胶的溶胀度较高;凝胶在适宜条件下对甲基紫溶液有良好的吸附性能。     

聚乙二醇/丙烯酸共聚水凝胶的制备及pH敏感性研究

采用热引发反应制备了聚乙二醇(PEG)／丙烯酸(AAc)共聚物水凝胶,研究了PEG与AAc比例、交联剂、引发剂含量及反应时间等因素对反应转化率和不同pH缓冲液对水凝胶溶胀比的影响。结果发现PEG／AAc配比为(3：7)～(4：6)之间时,凝胶转化率较大;引发剂、交联剂含量分别为PEG和AAc总含量的0．5％和0．4％时,反应时间为5h,凝胶转化率较高;PEG：AAc为6：4时,水凝胶具有较明显的pH敏感性。     

Preparation of biodegradable crosslinking agents and application in PVP hydrogel

Firstly, biodegradable crosslinking agents (BCA) were synthesized by ring‐opening polymerization reaction of lactide, four kinds of which with different molecular weights were got by means of changing the ratio of DL ‐lactide(LA) and glycerol(GL). Then a series of poly(N‐vinyl pyrrolidone) (PVP) hydrogels were prepared successfully by radical polymerization of BCA and N‐vinyl pyrrolidone(NVP). Both the ratio of NVP/BCA and the molecular weight of BCA were used to control the performance of PVP hydrogels, which were measured in terms of the ratio of swelling, contact angle, mechanical properties, and biodegradability in vitro. This study showed that increasing both the ratio of NVP/BCA and the molecular weight of BCA resulted in a low crosslinking density of the hydrogels. The crosslinking density played an important role in determining the properties of biodegradable PVP hydrogels. Both the ratio of NVP/BCA and the molecular weight of BCA contributed to high ratio of swelling. A smaller amount of crosslinking agent caused a lower contact angle, while the molecular weight of BCA had little effect on it. In terms of mechanics of hydrogels on both dry and wet conditions, tensile modulus decreased along with decreasing BCA, while the extension at break increased at the beginning and decreased at the end. In the end, measured by mass loss, biodegradability in vitro of hydrogels had two stages: an initial stage with approximately constant loss of mass (stage 1) followed by a stage with rapid mass loss (stage 2). Both increased content and molecular weight of BCA improved the degradation rate of the hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1515–1521, 2006     

Dye Sorption and Water Uptake Properties of Crosslinked Acrylamide/Sodium Methacrylate Copolymers and Semi-Interpenetrating Polymer Networks Composed of PEG

A series of novel semi-interpenetrating polymer networks hydrogels composed of poly(ethylene glycol) and random copolymer of acrylamide/sodium methacrylate were prepared by polymerization of aqueous solution of acrylamide, sodium methacrylate using ammonium persulphate/N,N,N′,N′-tetramethylethylenediamine as a redox-initiating pair in the presence of poly(ethylene glycol) and poly(ethylene glycol)diacrylate as crosslinker. Fourier Transform Infrared spectroscopy was used to identify the presence of different repeating units in the semi IPNs. Water uptake and dye-sorption properties of acrylamide/sodium methacrylate hydrogels and acrylamide/sodium methacrylate/poly(ethylene glycol) semi IPNs were investigated as a function of chemical composition of the hydrogels. Cationic dye, Janus Green B have been used in sorption studies as a model molecule. This study has given the quantitative information on the swelling and sorption characteristic of acrylamide/sodium methacrylate hydrogels and acrylamide/sodium methacrylate/poly(ethylene glycol) semi IPNs in many potential applications.     

Preparation and properties of hydrogels based on hemicellulose

Xylan with glucuronic acid functionalities, separated from birchwood, was converted into hydrogels by dissolving it together with chitosan in acidic conditions. The hydrogels were formed at certain xylan/chitosan compositions. The mechanism of the gel formation was investigated with FTIR. Complexation between glucuronic acid functionalities of xylan and amino groups of chitosan is suggested to be responsible for network formation. The swelling behavior of these hydrogels was studied at various pH levels and salt concentrations, and the hydrogels responded in a reversible manner to various stimuli. DMA of the films showed separated transitions that may correspond to different phases. Imaging with AFM in TappingMode™ of the surfaces indicated discrete xylan and chitosan phases. A sponge-like microporous structure, as shown with SEM, was formed when a hydrogel was freeze dried. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1661–1667, 1998     

磁性半纤维素接枝聚丙烯酰胺水凝胶的制备及其性能研究

以半纤维素和丙烯酰胺为原料,利用自由基聚合法制备了多孔半纤维素接枝聚丙烯酰胺水凝胶,并且通过原位共沉淀法在凝胶上负载Fe3O4粒子,从而得到了磁性水凝胶。分别用FT-IR和SEM对水凝胶的结构和表面形态进行分析;考察了多孔半纤维素接枝聚丙烯酰胺凝胶的溶胀性能并对溶胀动力学进行了数学拟合。研究表明多孔半纤维素接枝聚丙烯酰胺水凝胶的平衡溶胀率随着交联剂量的增大而减小,随着半纤维素/丙烯酰胺比例的增大而增大,随着pH的增大而增大,水凝胶在pH=5.6的溶胀符合Schott溶胀动力学模型。振动样品磁强计(VSM)磁性能测试表明,磁性半纤维素接枝聚丙烯酰胺凝胶具有超顺磁性特征,其饱和磁化强度为10 emu/g。     

Chitosan modified MMT‐poly(AMPS) nanocomposite hydrogel: Heating effect on swelling and rheological behavior

Vulnerability of hydrogels against thermal circumstances may be substantially eliminated via incorporating nanoclay to prepare nanocomposite hydrogels. In this research, chitosan‐intercalated montmorillonite (ChitoMMT) was used as a bionanoclay to yield novel nanocomposite hydrogels based on 2‐acrylamido‐2‐methylpropanesulfonic acid. The bionanoclay is suitable especially for preparing biomaterials used in biomedical, food, and pharmaceutical applications, unlike conventional commercial nanoclays (alkyl ammonium‐intercalated MMT) which are not appropriate for bio‐applications due to toxicity of the intercalant particularly where the clay content is high. Two different crosslinkers (i.e., methylene bisacrylamide, and polyethyleneglycol dimethacrylate) were employed to synthesize the nanocomposites. The variations in swelling, rheological and thermal properties of the hydrogels were essentially attributed to thermally induced crosslink cleavage/formation depending upon the crosslinker nature. The nanocomposites comprised superior thermal properties in comparison with the clay‐free hydrogel counterpart. They can preserve substantially their swelling ability for longer heating periods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010