温度及pH敏感性N-乙烯基吡咯烷酮与丙烯酸β-羟基丙酯共聚物／聚(丙烯酸)互穿网络水凝胶的合成及其性能研究

由N-乙烯基吡咯烷酮与丙烯酸β-羟基丙酯共聚物／聚(丙烯酸)所得的互穿网络水凝胶P(NVP-co-β-HPA)／PAA具有温度及pH双重敏感特性.在酸性条件下,由于P(NVP)与PAA间络合作用,随温度升高迅速退胀;在碱性条件下,凝胶的溶胀率远大于酸性条件下的溶胀率,且随温度的升高而逐渐增大.     

温度及pH敏感性N—乙烯基吡咯烷酮与丙烯酸β—羟基丙酯共聚物／聚（丙烯酸）互穿网络水凝胶的合成及其性能研究

由N－乙烯基吡咯烷酮与丙烯酸β－羟基丙酯共聚物／聚丙酸）所得的互穿网络水凝胶P（NVP－co-β－HPA）／PAA具有温度及pH双重敏感特性,在酸性条件下,由于P（NVP）与PAA间络合作用,随温度升高迅速退胀,在碱性条件下,凝胶的溶胀率远大于酸性条件下的溶胀率,且随温度的升高而逐渐增大。     

温度及pH敏感性N-乙烯基吡咯烷酮与丙烯酸β-羟基丙酯共聚物/聚(丙烯酸)互穿网络水凝胶的合成及其性能研究

由N 乙烯基吡咯烷酮与丙烯酸 β 羟基丙酯共聚物 /聚 (丙烯酸 )所得的互穿网络水凝胶P(NVP co β HPA) /PAA具有温度及pH双重敏感特性 .在酸性条件下 ,由于P(NVP)与PAA间络合作用 ,随温度升高迅速退胀 ;在碱性条件下 ,凝胶的溶胀率远大于酸性条件下的溶胀率 ,且随温度的升高而逐渐增大     

丙烯酸酯三元共聚物负载硫铂络合物的合成及催化性能

丁二醇二丙烯酸酯、丙烯酸甲酯、丙烯酸β-氯乙酯或丙烯酸ω-氯己酯进行三元共聚,合成了两类4种带ω-氯侧基的交联型聚丙烯酸酯.它们以乙硫醇硫醚化,再与氯亚铂酸钾反应,得到4种交联型聚丙烯酸酯负载的硫铂络合物.这些络合物对癸烯-1、十二烯-1、苯基烯丙醚、苯乙烯与三乙氧基硅烷的硅氢加成反应具有良好的催化活性.讨论了温度、催化剂用量对催化性能的影响及催化剂的重复使用情况.     

丙烯酸β-羟基γ-(邻乙酰氧基苯甲酰氧基)丙酯的合成及其聚合

<正> 将近来发现具有抗血小板凝聚效应的阿斯匹林进行高分子化的研究迄今尚少报告,我们曾合成了酯基上带有邻-乙酰氧苯甲酰氧基的丙烯酸酯类;甲基丙烯酸β-(乙酰水杨酰氧)乙酯;甲基丙烯酸β-(乙酰水杨酰氧)丙酯及丙烯酸β-(乙酰水杨酰氧)乙酯,本文合成了在酯基上兼有羟基和邻-乙酰氧基苯甲酰氧基的丙烯酸酯;甲基丙烯酸     

光交联法合成新型温敏性水凝胶的研究

合成了丙烯酸β－羟基丙酯（β－HPAT）－N－肉桂酰氧甲基丙烯酰胺（CMMAM）共聚物，采用光交联法制备了温敏性共聚水凝胶，实验结果表明：共聚物交联程序随光照时间延长而增大，在一定温度范围内，水凝胶的溶胀率（SR）随温度升高而减小，表现出显著的温敏行为。     

光固化氨酯改性丙烯酸系水性涂料

以丙烯酸丁酯,苯乙烯,丙烯酸及甲基丙烯酸－β－羟乙酯共聚合成了具有羟基和羧基侧基的丙烯酸共聚物,再用甲苯二异氰酸酯与甲基丙烯酸－β－羟乙酯的半加成物对上述丙烯酸树脂进行接枝改性,经胺中和后,水性化,可得较为稳定的自乳化光敏树脂水分散体系。     

原子转移自由基聚合法合成含羟基星状共聚物

以２－溴异丁酸季戊四醇四酯为引发剂在ＣｕＢｒ／ｂｐｙ催化下实施苯乙烯和丙烯酸β－羟丙酯原子转移自由基共聚合,结果表明聚合物的分子量与理论分子量接近,聚合反应具有活性聚合的特征。进一步对聚合产物进行ＧＰＣ,Ｈ－ＮＭＲ,ＩＲ和羟值滴定分析,表明合成的星状共聚合物中同时具有苯乙烯和丙烯酸β－羟丙酯结构单元,而且羟基在聚合物中近似均匀分布。     

芳香PET树脂母粒的研制

通过丙烯酸和丙烯酸正丁酯溶液共聚合，得到丙烯酸－丙烯酸正丁酯共聚物，该树脂与环氧氯丙烷反应后再与PET树脂切片继续反应，可使PET树脂切片表面形成聚丙烯酸酯自膨润型吸油网络结构，将表面具有聚丙烯酸酯自身膨润型吸油网络结构的PET树脂切片（简称为留香剂）在油溶性香精中浸泡，香精就被吸附在留香剂表面，即得到芳香PET树脂母粒。用SEM观察了母粒的表面结构形态。     

新型杯[4]冠醚衍生物聚合单体的合成

从对叔丁基杯[4]芳烃出发,对其下沿的酚羟基进行修饰,先后在1,3-和2-酚羟基位点引入冠醚环和乙基;最后在NaH/THF中与3-溴丙烯酸丙酯反应制得聚合单体——新型杯[4]冠醚衍生物,其结构经1H NMR和MS表征。     

温度及pH敏感聚(丙烯酸)/聚(N-异丙基丙烯酰胺)互穿聚合物网络水凝胶的合成及性能研究

合成聚（丙烯酸）／聚（Ｎ 异丙基丙烯酰胺）互穿聚合物网络（ＰＡＡｃ／ＰＮＩＰＡＩＰＮ）水凝胶，具有温度及ｐＨ双重敏感特性．这种水凝胶在弱碱性条件下的溶胀率远大于酸性条件下的溶胀率．在酸性条件下，随着温度上升，凝胶的溶胀率也随之逐渐上升；而在弱碱性条件下，温度低于聚（Ｎ 异丙基丙烯酰胺）（ＰＮＩＰＡ）的较低临界溶解温度（ＬＣＳＴ）时，溶胀率也随着温度的上升而上升，当温度达到ＬＣＳＴ时，凝胶的溶胀率突然急剧下降，并随着温度的逐渐上升而下降．     

Radiation preparation and thermo-response swelling of interpenetrating polymer network hydrogel composed of PNIPAAm and PMMA

Interpenetrating polymer network (IPN) hydrogel composed of hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) and hydrophobic poly(methyl methacrylate) (PMMA) were synthesized by sequential IPN method using γ-rays from ⁶⁰Co source. Compared with pure PNIPAAm hydrogel, PNIPAAm/ PMMA IPN hydrogel not only behaved with obvious temperature sensitivity, but also had higher mechanical strength. The shrinking rate of the prepared IPN hydogel was slower than that of PNIPAAm hydrogel and the relative shrinkage was higher than that of PNIPAAm hydrogel. The IPN hydrogel with less PMMA was not stable while with more PMMA it was quite stable. In addition, the release of Methylene Blue (MB) from the IPN hydrogel was slower than that from PNIPAAm hydrogel as well.     

Synthesis and characterization of κ‐carrageenan/poly(N,N‐diethylacrylamide) semi‐interpenetrating polymer network hydrogels with rapid response to temperature

In this study, a novel classical thermo‐ and salt‐sensitive semi‐interpenetrating polymer network (semi‐IPN) hydrogel composed of poly(N,N‐diethylacrylamide) (PDEAm) and κ‐carrageenan (KC) was synthesized by free radical polymerization. The structure of the hydrogels was studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR and SEM revealed that the semi‐IPN hydrogels possessed the structure of H‐bonds and larger number of pores in the network. Compared to the PDEAm hydrogel, the prepared semi‐IPN hydrogels exhibited a much faster response rate to temperature changes and had larger equilibrium swelling ratios at temperatures below the lower critical solution temperature (LCST). The salt‐sensitive behavior of the semi‐IPN hydrogels was dependent on the content of KC. In addition, during the reswelling process, semi‐IPN hydrogels showed a non‐sigmoidal swelling pattern. Copyright © 2008 John Wiley & Sons, Ltd.     

Fabrication of a high-strength hydrogel with an interpenetrating network structure

Hydrogels have potential applications in many fields, but the poor mechanical strength has limited their further development. In this article, we designed a high-strength hydrogel with an interpenetrating network (IPN) structure from polyacrylamide (PAM) and poly(vinyl alcohol) (PVA). Synthesis parameters, such as PVA/AM mass ratio, crosslinker dosage and elongation time were carried out for high tensile strength and elongation. The results showed that chemical crosslinking, physical entanglement and PVA precipitates were the dominant parameters for the improvement of mechanical properties. The PVA structure transferred from crystal to amorphous due to intermolecular and intramolecular interactions (such as hydrogen bond and self-crosslinking). PVA precipitates scatterred in the brittle PAM matrix homogeneously which dispersed the applied stress and improved the hydrogel toughness. The tensile strength and elongation were extremely high, they were 2.4 MPa and 3100%, respectively. The simple method is versatile in synthesizing high-strength IPN hydrogels using many kinds of polymer species.     

The Research on Intelligent Controlled DDS of Polymer Carrier

The intelligent controlled drug delivery systems (DDS) are a series of the preparations including microcapsules or nanocapsules composed of intelligent polymers and medication. The properties of preparations can change with the external stimuli, such as pH value, temperature,chemical substance, light, electricity and magnetism etc. According to this properties, the DDS can be intelligently controlled. This paper has reviemed research on syntheses and applications of intelligent controlled DDS of polymer carriers.Drug delivery system with pH stimuliThe volume of polymer hydrogel can change with the pH value of external environment. The sensitive polymer hydrogels to pH are often as carriers. The polymer hydrogel carrying medicine is especially suitable for taking orally. In order to protect medicine from losing activation, we enwrapped medicine into polymer hydrogel with acidic group. In the acidic environment of stomach,the volume of polymer hydrogel contracts because of the hydrogen bond. The medicine in the polymer hydrogel cannot disperse out. When it goes to the intestine of basic environment, the hydrogen bond will be broken, and the medicine can release.Drug delivery system with temperatureTemperature sensitive polymer hydrogel can change its volume with changing of environmental temperature. This kind of polymer hydrogel can be also used as a carrier of medicine. At a low temperature, the polymer chains form hydrogen bond with water to swell to let medicine disperse out from the hydrogel. On the other hand, the hydrogen bond will be broken and polymer chain will lose water to contract with temperature's increasing. And the medicine will not disperse out. For example,the poly(N-isopropylacrylamide)(PNIPAAm) is the hydrogel that is swelled at lower temperature and contracted at higher temperature. PNIPAAm has the lower critical solution temperature(LCST).We can adjust its LCST to control PNIPAAm hydrogel's swelling or contraction to let medicine release or not.Drug delivery system with other stimuliThe polymer carrier drug delivery system can be intelligently controlled with the stimuli of pH value and temperature. In addition, there are still some other stimuli for DDS. For example, DDS with light; DDS with electricity(or electric field); DDS with magnetism(magnetic field); DDS with chemical substance; etc. The characteristic of intelligent polymer carrier is based on P.J.Flory's gel-swelling theory. Intelligent polymer carrier DDS will be widely used in biological and medical fields.     

A comparison of the swelling behaviour of copolymer and interpenetrating network microgel particles

 A comparison of the swelling behaviour of two types of hydrogel particles, namely, random poly[(acrylic acid)-co-(acrylamide)] [P(AAc-co-AAm)] particles and PAAc/PAAm interpenetrating network (IPN) particles, has been made using temperature and pH as the triggers. Both types of particles were synthesised by inverse microemulsion polymerisation. The conversion yield of AAc was found to be around 60 wt% due to the partition of this monomer between the aqueous and organic phases. The AAc content was thus lower in the final particles than in the initial composition. Both types of hydrogel particle exhibit an upper critical solution temperature associated with the breakage of the polymer–polymer hydrogen bonds. The maximum swelling ratio occurred in both cases at approximately equimolar AAc and AAm content of the particles. A sharper swelling transition was observed for the PAAc/PAAm IPN particles. This is because of the co-operative nature of the interactions between the PAAc and PAAm chains, the so-called “zipper effect”. A very much higher swelling ratio was obtained using pH as the trigger compared to using temperature. This difference in behaviour is related to the relative strengths of the forces involved in the particle swelling. Electrostatic repulsion forces, associated with the AAc dissociation with increasing pH, are much stronger than the hydrogen bonds. Received: 18 August 1999/Accepted: 28 August 1999     

A novel pH‐ and thermo‐sensitive PVP/CMC semi‐IPN hydrogel: Swelling,phase behavior,and drug release study

Poly(N‐vinyl‐pyrrolidone) (PVP) hydrogel has been considered as a very interesting and promising thermosensitive material. The most vital shortcoming of PVP hydrogel as thermosensitive material is that it does not exhibit thermosensitivity under usual conditions. In this work, semi‐interpenetrating polymer network (semi‐IPN) hydrogels based on PVP and carboxymethylcellulose (CMC) were prepared. The volume phase transition temperature (VPTT) of the hydrogels was determined by swelling behavior and differential scanning calorimetry (DSC). The results showed that the VPTT was significantly dependent on CMC content and the pH of the swelling medium. The amount of CMC in the semi‐IPN hydrogels was 0.050, 0.075, and 0.100 g, the VPTT in buffer solution of pH 1.2 was 29.9 °C, 27.5 °C and 24.5 °C, respectively. In addition, the VPTT occurred in buffer solution of pH 1.2, but did not appear in alkaline medium. Bovine serum albumin (BSA) as a model drug was loaded and the in vitro release studies were carried out in different buffer solutions and at different temperatures. The results of this study suggest that PVP/CMC semi‐IPN hydrogels could serve as potential candidates for protein drug delivery in the intestine. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1749–1756, 2010     

Preparation and properties of poly(N‐isopropylacrylamide)/poly(N‐isopropylacrylamide) interpenetrating polymer networks for drug delivery

A novel poly(N‐isopropylacrylamide) (PNIPA)/PNIPA interpenetrating polymer network (IPN) was synthesized and characterized. In comparison with conventional PNIPA hydrogels, the shrinking rate of the IPN hydrogel increased when gels, swollen at 20 °C, were immersed in 50 °C water. The phase‐transition temperature of the IPN gel remained unchangeable because of the same chemical constituent in the PNIPA gel. The reswelling kinetics were slower than those of the PNIPA hydrogel because of the higher crosslinking density of the IPN hydrogel. The IPN hydrogel had better mechanical strength because of its higher crosslinking density and polymer volume fraction. The release behavior of 5‐fluorouracil (5‐Fu) from the IPN hydrogel showed that, at a lower temperature, the release of 5‐Fu was controlled by the diffusion of water molecules in the gel network. At a higher temperature, 5‐Fu inside the gel could not diffuse into the medium after a burst release caused by the release of the drug on the surface of the gel. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1249–1254, 2004     

A novel positively thermo-sensitive hydrogel based on ethylenediaminetetraacetic dianhydride and piperazine: Design, synthesis and characterization

A new positively thermo-sensitive hydrogel was designed and synthesized by a condensation polymerization reaction of ethylenediaminetetraacetic dianhydride（EDTAD） and piperazine（PA） to give poly（ethylenediaminetetraacetic dianhydride-copiperazine） （PEP）.The obtained polymers’ structure was characterized by FTIR and ¹³C NMR.The backbone of the polymer linked by amide bond and abundant of carboxyl groups as pendant group could form strong intermolecular and intramolecular hydrogen bond at lower temperature and dissociate at higher temperature,resulting in the polymer with thermo-sensitivity.The aqueous solution of PEP at lower temperature（<20℃） showed micro-gel formation and transformed to transparent solution at higher temperature（>40℃）.Transition temperature shifted to higher value with the increasing of concentration.The hydrogel exhibited reversible phase transition and the transmittance change was not weakened by multiple temperature changes.