温敏性聚(N-异丙基丙烯酰胺)/聚丙烯酰胺互穿网络水凝胶

采用紫外引发法制备了物理交联的聚(N-异丙基丙烯酰胺)和化学交联聚丙烯酰胺为组分的互穿网络水凝胶。利用FFIR对所得的凝胶进行了结构分析;测定了该水凝胶在20℃时的溶胀率和50℃时的水保持率;利用DMA和DSC分别研究了水凝胶的储能模量随温度的变化及相转变行为。结果表明:与聚(N-异丙基丙烯酰胺)水凝胶相比,该水凝胶有较好的溶胀率;且具有超快的响应速率,如10 min内失去90%的水;其储能模量增加;虽然其相转变行为变弱,但临界溶解温度(LCST)有所提高。     

含PEG组分的聚(N-异丙基丙烯酰胺)水凝胶的制备研究

首先合成了二丙烯酰基封端的聚乙二醇(PEG)大分子交联剂,然后使其与N,N-亚甲基双丙烯酰胺(BIS)和(N-异丙基丙烯酰胺)(NIPAM)单体进行交联反应,制备了PNIPAM-co-PEG-co-BIS水凝胶。与通常的PNIPAM-co-BIS凝胶比较,PNIPAM-co-PEG-co-BIS凝胶显示了明显加速的去溶胀动力学。这种加速的去溶胀性能归因于凝胶中的PEG组分为凝胶提供了亲水通道,在缩水过程中有利于凝胶的脱水。     

N-异丙基丙烯酰胺的合成研究

目的,研究N-异丙基丙烯酰胺的合成路线。方法,以异丙醇、丙烯腈、浓硫酸、氯化铜为原料合成了N-异丙基丙烯酰胺。结果:合成了目标化合物,收率63.5%,并通过红外光谱、核磁共振对产品进行了表征。结论,降低了成本,提高了N-异丙基丙烯酰胺的收率。     

分散聚合法合成聚(N-异丙基丙烯酰胺)温敏性微凝胶

以PVP为稳定剂,在水或醇/水介质中通过分散聚合法合成出聚（N-异丙基丙烯酰胺）（PNIPAM）温敏性微凝胶。研究结果表明,可通过改变稳定剂用量和分散介质极性来控制PNIPAM微凝胶的大小,这两种因素对PNIPAM微凝胶的溶胀比有明显的影响,而对其相转变行为影响不大;交联剂用量对PNIPAM微凝胶的粒径、溶胀比和相转变行为都有比较明显的影响。PNIPAM微凝胶可能主要通过接枝共聚物聚结机理成核,通过初级粒子之间的聚并完成粒子增长过程。     

N-异丙基丙烯酰胺共聚物的温度敏感性研究

通过自由基聚合合成了 N-异丙基丙烯酰胺和甲基丙烯酸甲酯及甲基丙烯酸的共聚物。研究了甲基丙烯酸甲酯和甲基丙烯酸的加入对聚 N-异丙烯酰胺温度敏感性的影响 ,并考察了溶液中盐浓度和 p H对共聚物温度敏感性的影响     

聚N-异丙基丙烯酰胺水凝胶研究进展

简要阐述了聚N-异丙基丙烯酰胺(简称PNIPAM)水凝胶的制备方法、性能特点、应用等方面的研究进展。利用PNIPAM特有的温敏性特点,可以将PNIPAM与其他有机物复合,改善了其机械强度和温度敏感性,大大提高了PNIPAM的响应速度和溶胀率。制备的高分子材料在生物医学、免疫分析、分离提纯、蓄热等领域都有广泛的应用。     

聚(N-异丙基丙烯酰胺)温敏性水凝胶研究进展

具有温度敏感性的PNIPAAm水凝胶是目前凝胶研究的热点之一。文章介绍了PNIPAAm温敏性水凝胶的合成方法和提高性能的方法,总结了此类凝胶的应用,最后对PNIPAAm温敏性水凝胶的发展做了展望。     

聚(异丙基丙烯酰胺-羟甲基丙烯酰胺)/壳聚糖水凝胶的制备及其释药性能

以异丙基丙烯酰胺(NIPAAm)和羟甲基丙烯酰胺(NHMAm)为共聚单体与壳聚糖(CS)制备形成了温度敏感和pH敏感的互穿网络(IPN)水凝胶Poly(NIPAAm-co-NHMAm)/CS;用红外光谱表征了其结构特征,研究了不同条件下水凝胶的溶胀性能,并初步研究了水凝胶对药物双氯芬酸钠(DS)的缓释效果。结果表明,该水凝胶具有明显的温度和pH敏感性,温度越高,溶胀度越小,释药越慢;pH越小,溶胀度越大;CS含量为0.6%时溶胀度最大。在NHMAm单体质量配比为8.7%时,水凝胶的低临界溶液温度(LCST)达到38℃,且此时对DS持续释药时间可达到24 h。水凝胶的释药动力学曲线符合修正的一级动力学模型。该水凝胶体系可通过改变NHMAm单体配比来调节温敏特性,是一种潜在的温度和pH双重敏感的药物缓释载体。     

聚(N-异丙基丙烯酰胺)均聚凝胶的合成及其性能研究

采用自由基聚合反应,在20℃调节单体的浓度及交联剂的用量合成了聚N-异丙基丙烯酰胺均聚凝胶,对材料的结构进行了表征和分析,同时研究了单体浓度及交联剂用量对材料的温敏性、光学性能以及溶胀性能等的影响。实验结果表明:凝胶的温敏性及透射比随单体浓度及交联剂用量的增加而降低,其初始溶胀度随单体浓度及交联剂用量的增加而增加,体积相转变温度保持为34℃,不随单体浓度及交联剂用量而改变。     

N-异丙基丙烯酰胺的合成与表征

介绍了一种N-异丙基丙烯酰胺(NIPAM)的改进合成方法,即以丙烯腈(0.15 mol)、异丙醇(0.15 mol)、对羟基苯甲醚(3×10-4 mol)、浓硫酸(0.45 mol)为原料合成NIPAM,收率为54.2%,并结合NIPAM的分子结构,用红外光谱、核磁共振氢谱、碳谱对其结构进行了表征,结果表明,所得的产物为NIPAM。     

Interpolymer complexes of poly(acrylamide) and poly(N-isopropylacrylamide) with poly(acrylic acid): a comparative study

The interpolymer complexation, through successive hydrogen bonding, between poly(acrylamide) (PAAm) and poly(N-isopropylacrylamide) (PNiPAAm) with poly(acrylic acid) (PAA) in aqueous solution has been viscometrically and potentiometrically investigated. The stoichiometry of the complexes formed was determined. By comparing the strength of the two complexes the very important contribution of the hydrophobic interaction in their formation has been indicated.     

Photopolymerization synthesis of poly(N-isopropylacrylamide) hydrogels

Poly(N-isopropylacrylamide) (NIPAAm) gels were formed by photopolymerization of NIPAAm in the absence of a crosslinker using a water solvent at 25°C. Factors affecting formation were the wavelength region of irradiated light, the type of photoinitiators, and the concentrations of the photoinitiator and monomer. A high-pressure mercury lamp (400 W) was used as a light source. An NIPAAm concentration of 10 wt % and irradiation time of 15 h was used for the photopolymerization. The gel (68% yield) was formed when the quartz glass system was used, but no gelation was observed for the Pyrex glass system that transmits light with π > 290 nm. The gel (100% yield) was easily formed, even in the latter system, when 30 mmol/L of hydrogen peroxide and potassium persulfate were used as the photoinitiator. Water soluble photoinitiators such as ferric chloride and sodium anthraquinone-2,7-disulfonate were not effective for the gel formation. Yield of the gel increased with increasing the potassium persulfate concentration (1–30 mmol/L), but it decreased when a high concentration of hydrogen peroxide (60 mmol/L) was used. The gel yield increased with the NIPAAm concentration (5–20 wt %). The degree of swelling of the resultant poly(NIPAAm) gels, which was measured by immersing the gels in water at various temperatures (0–50°C) for 24 h, steeply decreased at about 30°C with increasing temperature, exhibiting a temperature-responsive character. The gels swelled and shrank in water below and above the temperature, respectively. The extent of the character depended on the concentrations of hydrogen peroxide and monomer. The formation mechanism of the gel in the photopolymerization of NIPAAm using hydrogen peroxide photoinitiator was discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1313–1318, 1997     

Temperature and glucose dual-responsive carriers bearing poly(N-isopropylacrylamide) and phenylboronic acid for insulin-controlled release: A review

Insulin injection is a definitive therapy for diabetic patients, but mismatched dosage and untimely intervention lead to wide fluctuations in blood sugar levels. Therefore it is essential to combine exogenous insulin and intelligent carriers, which is promising to normalize glucose concentrations. The temperature and glucose dual-responsive materials bearing poly(N-isopropylacrylamide) (PNIPAAm) and phenylboronic acid (PBA) have been confirmed for insulin-controlled release in experimental stages. The recent progress on different types of smart PNIPAAm and PBA-containing carriers is summarized in this review. The new challenges and future direction regarding the studies on elaborate insulin-controlled-release systems are also proposed.     

乙醇浓度及温度响应型智能高分子的制备及其性能

采用自由基聚合法将亲水单体N,N-二甲基丙烯酰胺(DMAA)和疏水单体甲基丙烯酸丁酯(BMA)分别与N-异丙基丙烯酰胺共聚,从而制备聚(N-异丙基丙烯酰胺-co-N,N-二甲基丙烯酰胺)高分子(PND)和聚(N-异丙基丙烯酰胺-co-甲基丙烯酸丁酯)高分子(PNB)。考察了共聚高分子在水溶液中的相转变温度以及在相转变温度以下对乙醇溶液浓度的响应特性。实验证明亲水单体DMAA和疏水单体BMA能够很好地调节PN共聚高分子的相转变温度和乙醇响应浓度。     

Poly(N-isopropylacrylamide)/mesoporous silica thermosensitive composite hydrogels for drug loading and release

Temperature-sensitive hydrogels are attracting increasing attention for controlled drug delivery. However, achieving high drug loadings and sustained drug release remains challenging. Herein, we describe the successful synthesis of a series of novel temperature-sensitive poly(N-isopropylacrylamide) (PNIPA)/mesoporous silica nanoparticles (MSN) hydrogels by physical crosslinking of NIPA with MSN. The external and internal structures, temperature sensitivity, drug-loading capacity, and blood compatibility of the PNIPA/MSN composite hydrogels are studied. Results show that MSN addition improved the network structure and adjusted the size of the hole, MSN could also act as drug carrier, thereby enhancing the drug loading capacity. The composite hydrogels underwent a phase transition at 33.7 °C (at the lower critical solution temperature). The hemolysis rate of the composite hydrogels was less than 1%, thus they can be classified as a nonhemolytic materials with good biocompatibility. The composite hydrogels reported here thus have great potential in drug transport and temperature-activated drug release. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48391.     

侧链含芘基的聚N-异丙基丙烯酰胺的合成及性能

将N-异丙基丙烯酰胺（NIPAM）和甲基丙烯酸-β-(1-芘丁酰氧基)乙酯（PyBEMA）通过自由基溶液共聚合成了侧链含芘基的聚N-异丙基丙烯酰胺共聚物，并采用红外光谱、紫外光谱、核磁共振氢谱对共聚物进行了结构表征。研究了不同投料比对共聚物收率、组成和相对分子质量及其分布的影响。共聚物水溶液温敏性研究表明，共聚物是一类具有低临界溶解温度（LCST）温敏性聚合物，随着共聚物中的芘基含量的升高，其LCST下降；加入α-环糊精（α-CD）会引起共聚物LCST略微升高，而加入β-CD和γ-CD，会导致LCST降低，而且γ-CD引起LCST的降低更显著。共聚物水溶液荧光性能研究表明，共聚物在水中有轻微的疏水聚集，出现侧链芘基激基缔合物荧光。室温下，加入β-CD能够降低共聚物侧链芘基之间的疏水聚集。随着温度的升高，芘基的荧光强度（IM）先下降，后突然升高，然后达到稳定并略微下降；而芘激基缔合物的荧光强度（IE）先出现略微升高，然后基本保持不变，接着缓慢下降。I1/I3荧光强度比值随着温度的升高呈现下降趋势，在聚合物发生相转变时的温度区间内迅速降低。     

Drug release from poly(ortho esters)–poly(ethylene glycol) polyblend

A polyblend of poly(ortho esters)–poly(ethylene glycol) (POE–PEG) was prepared. The release behavior of the acetanilide‐loaded film of the POE–PEG polyblend was studied. Blending POE with water‐soluble PEG can promote the release of drug in pH 7.4 PBS buffer at 37°C, while POE has plasticizing effect on PEG. Infrared and X‐ray diffraction studies reveal that there is some interaction between POE and acetanilide. The SEM micrographs disclose that the porosity of the drug‐loaded film enhances with an increase immersing time. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 303–309, 1999