甲基丙烯酸-2-羟基乙酯-co-N-乙烯-2-吡咯烷酮水凝胶结构及溶胀行为研究

为探讨甲基丙烯酸-2-羟基乙酯（HEMA）-co-N-乙烯-2-吡咯烷酮（NVP）共聚物水凝胶薄膜的溶胀性能,以2-羟基-甲基苯基丙烷-1-酮（1173）为光引发剂,二乙二醇甲基丙烯酸酯（DEGDMA）为交联剂,用紫外灯在室温下合成不同配比的HEMA-co-NVP共聚物薄膜。FTIR证实了共聚反应,热重（TG）测试显示薄膜结构中易分解的组分含量随着单体NVP含量的增加而增加。共聚物溶胀实验结果表明：随着交联剂含量的增加,水凝胶平衡溶胀率（EWC）下降;随着单体NVP含量的增加,材料的EWC上升,共聚水凝胶的溶胀过程趋于Case-Ⅲ型;随着温度的升高,材料的EWC降低,溶胀过程趋向Fick溶胀。     

Modification of PA6,6 by Atmospheric Plasma and Grafting 2-hydroxy ethyl methacrylate (HEMA) to Improve Fabric Properties

Oxidative atmospheric pressure plasma was used to modify PA6,6 fabrics followed by graft copolymerization of 2-hydroxy ethyl methacrylate (HEMA) in 20% aqueous solution at 60°C for 1 h, with the aim to increase hydrophilicity, antistatic, and dyeing properties of the fabrics. Grafted PA6,6 fabrics were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The modified PA6,6 fabrics improved the moisture regain and the antistatic properties. Dyeing property of grafted fabrics was also studied.     

Biodegradable synthetic polymers: Preparation, functionalization and biomedical application

Biodegradable polymers have been widely used and have greatly promoted the development of biomedical fields because of their biocompatibility and biodegradability. The development of biotechnology and medical technology has set higher requirements for biomedical materials. Novel biodegradable polymers with specific properties are in great demand. Biodegradable polymers can be classified as natural or synthetic polymers according to the source. Synthetic biodegradable polymers have found more versatile and diverse biomedical applications owing to their tailorable designs or modifications. This review presents a comprehensive introduction to various types of synthetic biodegradable polymers with reactive groups and bioactive groups, and further describes their structure, preparation procedures and properties. The focus is on advances in the past decade in functionalization and responsive strategies of biodegradable polymers and their biomedical applications. The possible future developments of the materials are also discussed.     

甲基丙烯酸羟乙酯改性水性聚氨酯的合成与应用

以甲苯二异氰酸酯(TDI)和聚乙二醇(PEG)为原料,选用2,2-二羟甲基丁酸(DMBA)为扩链剂合成水性聚氨酯(WPU),通过甲基丙烯酸羟乙酯(HEMA)对水性聚氨酯进行封端,采用自乳化法,制备了HEMA改性水性聚氨酯乳液(HEMA-WPU)。通过红外、核磁和热重法(TG)分别表征了WPU和HEMA-WPU的分子结构及其热分解行为。结果表明,与WPU相比,HEMA-WPU的耐热性能明显提高,用该乳液上胶处理后的碳纤维/环氧树脂复合材料的层间剪切强度(ILSS)与未上胶的样品相比提高了7.5%,达到64.5 MPa。     

Synthesis of well‐defined responsive membranes with fixable solvent responsiveness

A versatile method is described to synthesize a new family of solvent‐responsive membranes whose response states can be not only tunable but also fixable via ultraviolet (UV) irradiation induced crosslinking. The atom transfer radical polymerization (ATRP) initiator 2‐bromoisobutyryl bromide was first immobilized on the poly(ethylene terephthalate) (PET) track‐etched membrane followed by room‐temperature ATRP grafting of poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(2‐hydroxyethyl methacrylate‐co‐2‐(dimethylamino)ethyl methacrylate) (P(HEMA‐co‐DMAEMA)) respectively. The hydroxyl groups of PHEMA were further reacted with cinnamoyl chloride (a photosensitive monomer) to obtain photo‐crosslinkable PET‐g‐PHEMA/CA membrane and PET‐g‐P(HEMA/CA‐co‐DMAEMA) membrane. The length of grafted polymer chains was controllable by varying the polymerization time. X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy in attenuated total reflection and thermogravimetric analysis were employed to characterize the resulting membranes. The various membrane surface morphologies resulting from different states of the grafted chains in water and dimethylformamide were characterized by scanning electron microscopy. It was demonstrated that the grafted P(HEMA/CA‐co‐DMAEMA) chains had more pronounced solvent responsivity than the grafted PHEMA/CA chains. The surface morphologies of the grafted membranes could be adjusted using different solvents and fixed by UV irradiation crosslinking. © 2014 Society of Chemical Industry     

Water sorption and desorption in 2-hydroxyethylmethacrylate/methylmethacrylate copolymers

Cross-linked copolymers of 2-hydroxyethylmethacrylate/methylmethacrylate HEMA/MMA) with different HEMA contents have been prepared. Water sorption and desorption kinetics have been studied at a temperature of 37°C. The results indicate that the rate controlling step of sorption and desorption is the Fickian diffusion in the swollen polymer. The diffusion coefficient is a function of the water concentration and decreases to zero below a critical value of water content, which depends on the HEMA content.     

Comparison of Nanocomposite Film and Electrospun Nanocomposite Fibers Based on Poly (2-Hydroxy Ethyl Methacrylate) and Microcrystalline Cellulose as Anticancer Implants

In the present study nanocomposite fibers and film scaffolds based on poly (2-hydroxy ethyl methacrylate) and microcrystalline cellulose were prepared by electrospinning method and solvent casting method, respectively. Paclitaxel (20 ppm) was incorporated during the preparation of fibers and film to result in paclitaxel-incorporated nanocomposite film and fibers with an encapsulation efficiency of 63% and 72%, respectively. These prepared nanocomposite films and fibers were characterized and confirmed by FTIR, XRD and SEM analysis. The biocompatibility of the nanocomposite scaffolds were assessed using VERO cell lines. The in vitro release of paclitaxel from the nanocomposite fibers, and film was found to be 74 ± 1.2% and 64 ± 1.2%, respectively.     

Thermosensitive nanospheres of low-density core - An approach to hollow nanoparticles

A novel strategy for the preparation of hollow core-shell nano- and microparticle is reported. Nanoparticle cores were created from poly(N-isopropylacrylamide) (PNIPAM) by controlled heating above the LCST of this polymer in the presence of a small amount of sodium dodecyl sulfate. Shells were formed by radical copolymerization of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (PEG-DMA) as cross-linking agent. The PNIPAM particles were acting as nucleating agents so that core-shell colloidal particles of PNIPAM covered with cross-linked PHEMA resulted. Subsequent release of a part of the PNIPAM chains from the interior of the particles was obtained by dialysis. The sizes and the temperature behavior of obtained particles were measured by DLS, TEM and SEM. The semi-hollow particles showed reversible volume response to cyclic temperature changes.     

Preparation and Use of Poly(hydroxyethyl methacrylate) Cryogels Containing L‐Histidine for β‐Casein Adsorption

The objective of this study was to determine β‐casein adsorption by using supermacroporous poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐(l) ‐histidine methyl ester) [p(HEMA‐MAH)] cryogel. β‐Casein adsorption properties of p(HEMA‐MAH) cryogel were studied for the application of β‐casein purification. The cryogel was produced by free radical polymerization initiated by N,N,N’,N’‐tetramethylene diamine and ammonium persulfate pairs in an ice bath. P(HEMA‐MAH) cryogel was characterized by swelling tests, Fourier transform infrared spectroscopy, and scanning electron microscopy. The effects of the flow rate, pH, temperature, initial β‐casein concentration, and ionic strength on the adsorption efficiency of cryogel were studied. The equilibrium swelling degree of the p(HEMA‐MAH) cryogel was 6.73 g H₂O/g cryogel. β‐Casein adsorption capacity of p(HEMA‐MAH) cryogel from aqueous solution was estimated as 31.17 mg/g cryogel. It was also observed that β‐casein could be repeatedly adsorbed and desorbed with p(HEMA‐MAH) cryogel without significant loss in the adsorption capacity.     

Synthesis and characterization of amphiphilic graft copolymers with poly(ethylene glycol) and cholesterol side chains

Amphiphilic graft copolymers comprising monomeric units of methoxy poly(ethylene glycol) (mPEG)-acrylate, 2-hydroxyethyl methacrylate (HEMA)–cholesterol conjugates and HEMA were synthesized and their properties characterized. The value of the critical micelle concentration (CMC) for these copolymers is linearly proportional to the ratio of the number of mPEG–acrylates to that of the HEMA–cholesterol conjugates per macromolecule (N_PEG/N_c), which is the most important parameter which influences the formation of polymeric micelles. The latter show excellent colloidal stability and their sizes decrease with increasing CMC. Based on the quenching of pyrene fluorescence, the relatively high levels of the loading capacity of pyrene are attributed to the elevated hydrophobicity of the micelle core. The loading capacity of pyrene decreases with increasing CMC. The weight-average partition coefficient for pyrene in polymeric micelles increases with increasing polymer concentration because more micelles are available for accommodating pyrene. Copyright © 2004 Society of Chemical Industry