Preparation and Swelling Behaviors of Rapid Responsive Semi-IPN NaCMC/PNIPAm Hydrogels

Semi-interpenetrating network（semi-IPN） hydrogels composed of sodium carboxylmethylcellulose（NaCMC） and poly N-isopropylacrylamide（PNIPAm） were prepared by free radical polymerization of N-isopropyl acrylamide（NIPAm） in dimethylsulfoxide（DMSO） in the presence of NaCMC. The structures of hydrogels were characterized by Fourier transform infrared spectroscopy（FTIR）, scanning electron microscopy（SEM） and differential scanning calorimetry（DSC）. SEM images show that the hydrogels present porous network structures. Most water in the hydrogels were free water and freezing water. The equilibrium swelling ratio（ESR） and swelling rate（SR） were quite different at various swelling temperature. ESR of the hydrogels ranged abruptly from 15.2 g/g to 1.56 g/g and the hydrogels changed from transparent into opaque with swelling temperature changing from 33 ℃ to 34 ℃, that is to say, the hydrogels exhibited the good temperature sensitivity at about 33 ℃ similar to low critical solution temperature（LCST） of pure PNIPAm, swelling rate were very different at below and above LCST due to hydrogel swelling with different swelling mechanism. Moreover, the semi-IPN hydrogels swelled much rapidly than pure PNIPAm hydrogels did at room temperature, the equillibrium swelling ratio（ESR） and swelling rate of the hydrogels increased with increasing of NaCMC content, i e. It is suggested that NaCMC could be potential for preparation of porous and rapid swelling hydrogels

响应面法优化Semi-IPN结构硅酸盐胶黏剂的制备工艺

采用响应面分析法优化了Semi-IPN结构硅酸盐胶黏剂的制备工艺。在单因素试验的基础上,应用PlackettBurman实验设计筛选影响胶黏剂胶合强度的重要参数,采用Box-Behnken设计确定重要参数的最佳水平。结果表明,影响胶合强度的重要参数为PVA/水玻璃的质量比、OP-10用量、柠檬酸用量和熟化时间。制备Semi-IPN结构硅酸盐胶黏剂的最佳工艺条件为:PVA/水玻璃的质量比为1.4,OP-10用量为0.3%,柠檬酸用量为1%,熟化时间为24h。此时胶合强度为1.1764MPa,与实际值1.14MPa接近,说明优化结果可信。

改进高效液相色谱法测定抗结核凝胶中异烟肼和左氧氟沙星的含量

目的采用改进HPLC法同时测定抗结核凝胶中异烟肼和左氧氟沙星的含量。方法色谱柱为Spursil C18-EP（250 mm×4.6 mm,5μm）,流动相为甲醇-0.05 mol·L^-1磷酸二氢钠（用磷酸调p H至3.9）,梯度洗脱,流速：0.8 mL·min-1,检测波长：262 nm,柱温：25℃,进样量：10μL。结果异烟肼和左氧氟沙星均在10-200μg·mL^-1与峰面积线性关系良好,异烟肼和左氧氟沙星低、中、高3个剂量的平均回收率分别为98.9%、99.3%、99.9%与100.4%、100.0%、100.5%;改进的方法与原方法测定3批抗结核凝胶中异烟肼和左氧氟沙星的含量无明显差异。结论本法简便、结果准确,可用于控制抗结核凝胶的质量。

A hybrid genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier ocular drug delivery platform

The objective of this study was to develop a novel hybrid genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier(NLC) drug delivery platform. An ophthalmic antiinflammatory drug, baicalin(BN) was chosen as the model drug. BN –NLC was prepared using melt-emulsification combined with ultra-sonication technique. Additionally, a dual pH-and thermo-sensitive hydrogel composed of carboxymethyl chitosan(CMCS) and poloxamer 407(F127) was fabricated by a cross-linking reaction with a nontoxic crosslinker genipin(GP). GP-CMCS/F127 hydrogel was characterized by FTIR, NMR, XRD and SEM. The swelling studies showed GP-CMCS/F127 hydrogel was both pH-and thermo-sensitive. The results of in vitro release suggested BN –NLC gel can prolong the release of baicalin comparing with BN eye drops and BN –NLC. Ex vivo cornea permeation study was evaluated using Franz diffusion cells. The apparent permeability coefficient(Papp) of BN –NLC gel was much higher(4.46-fold) than that of BN eye drops. Through the determination of corneal hydration levels, BN –NLC gel was confirmed that had no significant irritation to cornea. Ex vivo precorneal retention experiments were carried out by a flow-through approach. The results indicated that the NLC-based hydrogel can prolong precorneal residence time. In conclusion, the hybrid NLCbased hydrogel has a promising potential for application in ocular drug delivery.

A flexible, robust, and high ion-conducting solid electrolyte membranes enabled by interpenetrated network structure for all-solid-state lithium metal battery

Poly(vinyl alcohol)/poly(ethylene glycol)(PVA/PEG) semi-interpenetrating networks(s-IPN) were synthesized for the application of solid electrolyte membranes of lithium metal batteries. Thermal, mechanical and dimensional stability, lithium-ion conductivity, interfacial compatibility, and cell performance were evaluated to assure their application. As this s-IPN structure suppressed the crystallinity by formation of network structure, both the lithium-ion conductivity and mechanical strength were simultaneously enhanced. The PVA/PEG-3s-IPN showed the highest lithium-ion conductivity of 3.26 × 10^(-4)S cm^(-1)in a wide electrochemical window(5.8 V vs. Li/Li^(+)), maintaining the robust solid-state with the tensile strength beyond 16.2 MPa at room temperature. The synthesized solid electrolyte membranes exhibited quite high specific capacity over 122 m Ah g^(-1)at 0.1 C from Li|PVA/PEG-3s-IPN|LiFePO_(4) cell and the long-term stable lithium stripping/plating performance for 1000 cycles from Li symmetric cell.

Sprayable nanodrug-loaded hydrogels with enzyme-catalyzed semiinter penetrating polymer network(Semi-IPN)for solar dermatitis

Solar dermatitis is an acute or chronic high incidence of skin injury caused by ultraviolet(UV)radiation based on strong sunlight,which seriously endangers people's health.In this study,we designed and demonstrated enzyme-catalyzed semi-inter penetrating polymer network(Semi-IPN)sprayable nanodrug-loaded hydrogels based on gelatin,3-(4-hydroxyphenyl)propionic acid(HPA),polyvinyl alcohol(PVA),glycerol,and dexamethasone sodium phosphate(DEXP)for solar dermatitis.The hydrogels had high water content,excellent biocompatibility,effective encapsulation and sustained release of nanodrugs,antiinflammatory,and strong anti-ultraviolet B(anti-UVB)radiation properties based on glycerol and phenol functional groups,but also controllable spray gelation mode to make them adhere well on the dynamic skin surfaces and achieve continuous transdermal drugs delivery for solar dermatitis.The sprayable nanodrug-loaded hydrogel systems could be used as a highly effective therapeutic method for solar dermatitis,and also provide a good strategy for designing novel nanodrug-loaded hydrogel delivery systems.

Preparation of porous semi-IPN temperature-sensitive hydrogel-supported nZVI and its application in the reduction of nitrophenol

Nanoscale zero-valent iron(n ZVI) particles supported on a porous, semi-interpenetrating(semi-IPN), temperature-sensitive composite hydrogel(PNIPAm-PHEMA). n ZVI@PNIPAmPHEMA, was successfully synthesized and characterized by FT-IR, SEM, EDS, XRD and the weighing method. The loading of nZVI was 0.1548 ± 0.0015 g/g and the particle size was30–100 nm. NZVI was uniformly dispersed on the pore walls inside the PNIPAm-PHEMA.Because of the well-dispersed n ZVI, the highly porous structure, and the synergistic effect of PNIPAm-PHEMA, nZVI@PNIPAm-PHEMA showed excellent reductive activity and wide p H applicability. 95% of 4-NP in 100 m L of 400 mg/L 4-NP solution with initial p H 3.0–9.0 could be completely reduced into 4-AP by about 0.0548 g of fresh supported n ZVI at 18–25 °C under stirring(110 r/min) within 45 min reaction time. A greater than 99% 4-NP degradation ratio was obtained when the initial p H was 5.0–9.0. The reduction of 4-NP by nZVI@PNIPAm-PHEMA was in agreement with the pseudo-first-order kinetics model with Kobsvalues of 0.0885–0.101 min-1.NZVI@PNIPAm-PHEMA was able to be recycled, and about 85% degradation ratio of 4-NP was obtained after its sixth reuse cycle. According to the temperature sensitivity of PNIPAmPHEMA, n ZVI@PNIPAm-PHEMA exhibited very good storage stability, and about 88.9%degradation ratio of 4-NP was obtained after its storage for 30 days. The hybrid reducer was highly efficient for the reduction of 2-NP, 3-NP, 2-chloro-4-nitrophenol and 2-chloro-4-nitrophenol. Our results suggest that PNIPAm-PHEMA could be a good potential carrier, with n ZVI@PNIPAm-PHEMA having potential value in the application of reductive degradation of nitrophenol pollutants.

燃料电池用Semi-IPN膜的性能测定

本文以季铵化壳聚糖和苯乙烯为原料,戊二醛为交联剂制备燃料电池用半互穿网络膜(Semi-IPN)。实验过程中对制得的Semi-IPN的化学结构进行了FT-IR表征,结果标明,季铵化壳聚糖与苯乙烯已经形成半互穿网络结构。半互穿网络膜的含水量、离子交换量也被进行了测定。离子交换量的测定结果标明,该膜的离子交换量随苯乙烯加入量的增加而降低。含水量的测定结果表明,膜的含水量在溶剂的一定浓度范围内随苯乙烯量增加而降低,随交联剂戊二醛浓度的增大而降低。本实验中引发剂—过硫酸钾的用量也进行了考察。结果标明,本实验得到的半互穿网络膜的含水量,离子交换量,机械强度等不随引发剂用量的变化而变化。

Synthesis and Characterization of Self-oscillating P(AA-co-AM)/PEG SemiIPN Hydrogels Based on a p H Oscillator in Closed System

Various semi-interpenetrating polymer network（semi-IPN） hydrogels composed of pore-forming agent polyethylene glycol（PEG）, acrylic acid（AA） and acrylamide（AM） were prepared by using free radical polymerization with a two-step method. The chemical structures of the synthesized hydrogels were characterized by FTIR spectroscopy and the morphologies were studied by scanning electron microscopy（SEM） method. The swelling properties, such as the p Hresponsive behavior, salt sensitivity, oscillatory swelling/de-swelling behaviors in different solutions with various p H values and self-oscillating behaviors in bath p H oscillator were investigated in detail. The results revealed that the prepared hydrogels exhibited high p H sensitivity and excellent salt sensitivity when the p H values of the medium changes from 3.0 and 7.0 and well reversible properties by undergoing a number of swelling/de-swelling recycles. In particular, the hydrogels exhibited self-oscillation behavior in a closed system containing Br O3？-SO32？-Fe（CN）64？-H＋. This study may create a new possibility as biomaterial for new self-walking actuators and other devices.

Transparent and semi-interpenetrating network P(vinyl alcohol)-P(Acrylic acid)hydrogels:pH responsive and electroactive application

In this paper,poly(vinyl alcohol)-poly(acrylic acid)based transparent semi-interpenetrating network(semi-IPN)hydrogels were synthesized by using a solvent mixture of dimethyl sulfoxide and deionized water via free radical polymerization and subsequent freeze-thaw technique.The formation of the semi-IPN hydrogels was conformed from FT-IR spectra.The acrylic acid concentration effect on the hydrogels was investigated in terms of transparency,crystalline structure and thermal stability by using UV-visible spectroscopy,X-ray diffraction and thermogravimetric analysis.Swelling behaviours of the semi-IPNPAP hydrogels were studied in deionized water and different pH solutions.The compression and electroactive behaviour was tested in fully hydrated stage by using compression test and by applying electrical voltage.The hydrogels showed displacements under the applying voltage and detailed experiment is illustrated.