PAAm-LGSNa+光致变色水凝胶的合成及表征

采用接枝法将木质素磺酸钠接入聚丙烯酰胺水凝胶中,合成了聚丙烯酰胺-木质素磺酸钠水凝胶,通过浸泡工艺将钼酸铵引入水凝胶网络中实现视觉显示。UV-Vis、FT-IR和SEM分别测量了木质素磺酸钠-聚丙烯酰胺水凝胶的吸光度和透明度、结构、形貌。UV-Vis测量结果表明该水凝胶具有低成本,易于制备,5 min内快速响应的优异性能。此外,水凝胶的光致变色和褪色过程可以在紫外光照射,不同时间和温度下精确控制。FT-IR测量结果表明成功将木质素磺酸钠接入聚丙烯酰胺水凝胶中。SEM研究结果表明,水凝胶在完全干燥后表现出致密的结构,这使得水凝胶在光致变色后不易褪色。     

PEG/木薯淀粉接枝丙烯酰胺丙烯酸三元共聚物溶胀性能研究

以木薯淀粉(CSt)和丙烯酰胺(Am)、丙烯酸(AA)为主要原料,硝酸铈铵与过硫酸铵为复合引发剂(CAN--S2O28-),N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,聚乙二醇6000(PEG 6000)为成孔剂,采用水溶液聚合法制备了淀粉接枝聚丙烯酰胺丙烯酸复合PEG(PEG/CSt-g-PAAm)水凝胶材料.研究了PEG对水凝胶溶胀行为的影响,以及PEG/CSt-g-PAAm与CSt-g-PAAm两种凝胶在不同温度下的溶胀行为.实验结果表明,PEG6000的加入对凝胶材料的重复使用性能有显著改善作用,并可显著增加凝胶的溶胀速率及溶胀能力,温度可以影响PEG/CSt-g-PAAm凝胶的溶胀速率.     

无微泡抗紫外线复合防火玻璃的制备研究

传统的复合防火玻璃夹层凝胶主要以聚丙烯酰胺为基础,由于聚丙烯酰胺为有机物,并且在制备过程中容易产生气泡,因此针对复合防火玻璃易产生气泡和耐候性差等缺陷,制备了一种新型夹层凝胶用于复合防火玻璃。60℃下真空搅拌硅溶胶和KOH混合物,并在80℃下高温固化,通过加入聚二甲基硅氧烷/异丙醇复配消泡剂抑制凝胶气泡的产生,加入多元醇改善凝胶的耐温性。使用改装马弗炉进行耐火性测试,采用辐照箱做耐候性检测,以及通过其他检测方法对试样进行表征。结果表明:当SiO_2∶KOH=2∶1(摩尔比)时,防火玻璃的透光率达到达到86.6%,紫外线照射前后透光率变化了5.8%,且防火玻璃气泡较少。     

高强度/pH敏感性氧化石墨烯纳米复合双网络水凝胶的制备

通过自由基溶液聚合法,在氧化石墨烯(GO)水溶液中合成聚N,N-二甲基丙烯酰胺/氧化石墨烯(PDMA/GO)纳米复合第一网络水凝胶,之后以N,N-亚甲基双丙烯酰胺(BIS)为交联剂引入化学交联聚丙烯酸(PAA)作为第二网络制备高强度的GO纳米复合双网络水凝胶。通过热重分析、力学性能测试、pH敏感性研究了第二单体AA和GO浓度对GO纳米复合双网络水凝胶性能的影响。结果发现,热稳定性、力学性能随GO含量的增加而增加,随AA含量的增加先增加后减小。当pH4.25时,GO纳米复合双网络水凝胶具有pH敏感性。     

N-(苯并环丁烯-4-基)丙烯酰胺和丙烯酰胺的共聚物及其水凝胶的合成与性能研究

含苯并环丁烯(BCB)功能基团的单体N-(苯并环丁烯-4-基)丙烯酰胺(NBCBAA)与丙烯酰胺(AM)在溶剂中发生自由基共聚反应,固化后形成聚丙烯酰胺水凝胶,采用红外光谱对其结构进行了表征.通过系列实验对凝胶的溶胀行为进行了研究,结果表明,不同的共聚比例时凝胶的溶胀速率以及平衡溶胀比有影响,该凝胶具有良好的重复吸水性、一定的温敏性和pH敏感性.     

埃洛石纳米管改性复合吸水材料的耐盐性能与凝胶强度

采用硅烷偶联剂对埃洛石纳米管(HNTs)进行表面改性,通过溶液聚合法制备了聚(丙烯酸-丙烯酰胺)/埃洛石纳米管复合吸水材料,借助红外光谱分析证实了复合材料的化学结构。进一步研究了复合材料的耐盐性能与凝胶强度。结果表明:当HNTs用量为10wt%,交联剂用量为0.03wt%,丙烯酸中和度为80%,聚合温度为70℃,复合材料吸盐水率可达120.5g/g;增加HNTs用量与丙烯酸中和度导致复合材料凝胶强度先增大后减小,提高交联剂用量和反应温度则使凝胶强度逐渐增大;复合材料的保水性能明显优于聚(丙烯酸-丙烯酰胺)吸水材料。     

聚（AA-co-AM）／壳聚糖IPN超大孔水凝胶的制备及性能

以丙烯酸、丙烯酰胺为基体,壳聚糖为添加物,N,N’-亚甲基双丙烯酰胺、戊二醛为复合交联剂,利用水溶液聚合法和发泡技术制备了聚(丙烯酸-丙烯酰胺)/壳聚糖互穿网络超大孔水凝胶。采用差示扫描量热法(DSC)、红外光谱(FT-IR)和扫描电镜(SEM)等分析技术进行了表征,研究了水凝胶的溶胀行为和凝胶压缩强度。实验结果表明,该互穿网络超大孔水凝胶具有较快的溶胀速率和较好的凝胶强度。     

LaSrCoO4催化材料的制备及性能的研究

采用明胶法、聚乙二醇凝胶法和聚丙烯酰胺法制备了类钙钛矿LaSrCoO4复合氧化物，考察了它们对CO和C3H8的氧化反应活性，研究了制备方法对催化材料结构和性能的影响，并运用XRD、BET、TEM、TPR和TPD等方法对催化材料进行了表征．结果表明，该类复合氧化物具有四方K2NiF4结构，制备方法对催化材料的结构和性能有较大影响，其中以聚丙烯酰胺法最好．聚丙烯酰胺法所制LaSrCoO4的比表面较大，氧缺陷和易移动品格氧较多，催化活性较高．焙烧温度越低，比表面越大，氧缺陷及晶格氧越多，催化活性越高．     

深度调剖提高原油采收率的聚丙烯酰胺类凝胶体系综述

在石油开采过程中,聚丙烯酰胺类交联凝胶体系是由堵水和调剖发展起来的一种新型体系。它是利用聚合物的交联反应形成可动凝胶,减缓水的窜流,驱替水驱残余油。本文将评述可应用于深井开采的苛刻油藏环境下的聚丙烯酰胺类凝胶体系的机理,并着重介绍国内外的最新研究——聚丙烯酰胺纳米复合水凝胶、聚电解质配合纳米粒子聚丙烯酰胺水凝胶和低毒性有机交联两性聚丙烯酰胺水凝胶等。     

一种壳聚糖/聚丙烯酰胺水凝胶基底材料的研究

制备一种新的硬度可变的生物基底材料。通过红外光谱对比分析、吸水称重法、旋转流变仪法、MTT法等实验对壳聚糖/聚丙烯酰胺水凝胶材料的结构、溶胀性、弹性模量、细胞毒性等性能进行测定。将HepG2细胞接种到壳聚糖/聚丙烯酰胺水凝胶基底材料上,24h后对材料上生长的细胞进行形态学观察比较细胞的生长情况。结果发现不同配方制成的壳聚糖/聚丙烯酰胺水凝胶的硬度具有明显梯度差异,具有良好的生物相容性。这种新的生物基底材料可以为细胞力学基础研究提供帮助。     

炭纤维前驱体丙烯腈-丙烯酰胺共聚物溶液的流变性

采用锥板流变仪,研究了共聚单体丙烯酰胺(AM)含量对聚丙烯腈溶液流变性的影响,探索一种预示炭纤维前驱体聚丙烯腈溶液可纺性的方法。发现:在低剪切速率区(<200 s-1),黏度随AM引入增加;在高剪切速率区(>200 s-1),均聚物和共聚物的流动曲线几乎重合。溶液的弹性因AM的引入而变大,松弛时间延长了5~6倍,这可能会造成纺丝过程中更大的挤出胀大比,溶液可纺性下降。溶液的时间稳定性和温度敏感性随AM的引入而降低。     

聚丙烯酰胺及其多孔材料吸湿性功能研究

以丙烯酰胺(AM)为单体,N,N’-亚甲基双丙烯酰胺为交联剂,亚硫酸钠-过硫酸铵为引发剂,采用水溶液聚合法制备聚丙烯酰胺(PAM)吸湿材料。系统研究了单体浓度、交联剂用量和水解度等聚合条件对其吸湿性能的影响。吸湿实验表明,PAM的吸湿性能优于传统的无机吸湿材料硅胶和分子筛。采用聚乙二醇(PEG)、碳酸钙(CaCO3)两种致孔剂合成多孔PAM,并与PAM的吸湿性能进行对比。实验结果知PAM/PEG的吸湿速率比PAM提高50%以上,吸湿容量也显著提高;而PAM/CaCO3的吸湿效果并不理想。热失重分析TGA得出PAM/PEG比PAM的热稳定性稍稍降低,而PAM/CaCO3的热稳定性则稍稍提高。     

水性室温交联聚丙烯酸酯乳液的流变性

以两种加料方法合成了含双丙酮丙烯酰胺(DAAM)功能单体的聚丙烯酸酯乳液,添加己二酰肼,获得单组分室温可固化乳液,并对两种乳液的流变性作了研究。研究发现,乳液的表观黏度(aη)、稠度系数(K)、零剪切黏度(0η)随DAAM含量的增加而增加,而流动指数(n)则减小;两段均预乳化法的aη、K、0η均大于仅一段预乳化法。     

聚丙烯酰胺/改性纳米纤维素晶体纳米复合水凝胶的光聚合制备与表征

先用马来酸酐对纳米纤维素晶体(NCC)进行表面改性得表面含碳-碳双键的改性NCC(mNCC),然后将丙烯酰胺(AM)和mNCC一起光聚合得PAM/mNCC纳米复合水凝胶;通过红外光谱、扫描电镜、热重分析、差热分析、溶胀实验和拉伸实验研究了水凝胶的结构和性能。结果表明,PAM/mNCC纳米复合水凝胶是一种物理/化学共交联水凝胶;与用质量分数0.25%N,N-亚甲基双丙烯酰胺交联的PAM水凝胶相比,PAM/mNCC纳米复合水凝胶中的微孔尺寸分布更宽,PAM分子链的起始分解温度和玻璃化转变温度升高;当mNCC的用量占AM质量的5%~10%时,PAM/mNCC纳米复合水凝胶的饱和溶胀率、拉伸强度、断裂伸长率分别为PAM水凝胶的2.1~2.7倍、0.45~1.1倍、3.8~7.1倍。     

不同分子量丙烯腈-丙烯酰胺共聚物溶液的流变性研究

将不同分子量的丙烯腈（AN）与丙烯酰胺（AM）的共聚物溶解于二甲亚砜（DMSO）中，获得聚丙烯腈（PAN）溶液。采用旋转粘度计和锥板流变仪，从非牛顿指数n、流动活化能△Eq、结构粘度指数△ηa和弹性模量G等方面比较了不同分子量PAN溶液的流变性能。结果表明，分子量高的PAN溶液的表观粘度对应力变化敏感，分子理低的PAN溶液的表现粘度对温度的变化敏感，无论是从粘性还是从弹性角度看，低分子量PAN溶液的物理稳定性好。     

Effect of Multiwalled Carbon Nanotubes on the Conductivity and Swelling Properties of Porous Polyacrylamide Hydrogels

Multiwalled carbon nanotubes (MWCNTs) were added to polyacrylamide (PAM) hydrogels in different proportions to tune their electrical and mechanical properties. The choice of MWCNTs as a reinforcement is justified by the fact that these are highly conducting, fairly stable and flexible particles. A series of MWCNT/PAM hydrogels were prepared by freezing method. The characteristic absorption peaks at 1480 and 1213 cm^?1 in the FTIR spectra reveal that MWCNTs are embedded in the PAM hydrogels. Powder x-ray diffractograms and thermogravimetric analysis (TGA) images show that the MWCNT/PAM hydrogels are crystalline, more thermally stable and have a higher electrical conductivity than a traditional PAM hydrogel. Scanning electron micrographs reveal about reduced pore size, homogeneous and denser texture. The swelling properties of all these hybrid hydrogels were found to be better than those of the parent PAM hydrogel. The Li–Tanaka equation was employed to produce the swelling parameters. The diffusion coefficients (D _c ) of PAM hydrogel is 10 times higher than the literature value. 0.8% MWCNTs reinforced PAM hydrogel has excellent τ_c and electrical conductivity (0.76 mS/cm) with improvements in all properties. Lower D _c of 0.8% MWCNTs/PAM hydrogel reveal that extent of crosslinking is much important than density of the system for a better collective diffusion of the respective solvent.     

导电水凝胶中交联剂含量对综合性能的影响

以丙烯酰胺（AM）为基体原料,N, N’-亚甲基双丙烯酰胺（MBAA）为交联剂,氯化钠（NaCl）为导电填料,采用自由基聚合的方法制备了聚丙烯酰胺（PAM）导电水凝胶,详细探究了交联剂含量对导电水凝胶力学行为和电学行为的影响。分别采用拉伸试验机和电化学工作站等手段对PAM导电水凝胶的力学性能及其导电行为进行了研究。结果表明：随着MBAA含量的增加,导致凝胶断裂伸长率及电导率下降,但回复性能提高。当将其组装成柔性传感器时,制备的导电水凝胶表现出了良好的传感性能（GF=1.76,ε=100%）,并能够有效监测人体手指和膝盖的运动,表明导电水凝胶在人体健康监测领域具有良好的应用前景。     

Thermal stability and melt rheology of poly(<Emphasis Type="Italic">p</Emphasis>-dioxanone)

Melt viscosities of poly(p-dioxanone) (PPDO) samples having different molecular weights were studied using a controlled-strain rotational rheometer under a nitrogen atmosphere. First, PPDO’s thermal stability was evaluated by recording changes in its viscosity with time. The result, that samples’ viscosities decreased with time when heated, demonstrated that PPDO is thermally unstable: its degradation activation energy, obtained by using a modified MacCallum equation, was a relatively low 71.8 kJ/mol K. Next, viscoelastic information was acquired through dynamic frequency measurements, which showed a shear thinning behavior among high molecular weight PPDOs, but a Newtonian flow behavior in a low molecular weight polymer (M _w = 18 kDa). Dynamic viscosity values were transferred to steady shear viscosities according to the Cox–Merz rule, and zero shear viscosities were derived according to the Cross model with a shear thinning index of 0.80. Then flow activation energy (48 kJ/mol K) was extrapolated for PPDO melts using an Arrhenius type equation. This activation energy is independent of polymer molecular weight. A linear relationship between zero shear viscosity and molecular weight was obtained using a double-logarithmic plot with a slope of 4.0, which is near the usually observed value of 3.4 for entangled linear polymers. Finally, the rheological behaviors of PPDO polymer blends having bimodal molecular weight distributions were investigated, with the results indicating that the relationship between zero shear viscosity and low molecular weight composition fraction can be described with a Christov model.     

Injectable solid hydrogel: mechanism of shear-thinning and immediate recovery of injectable β-hairpin peptide hydrogels

β-Hairpin peptide-based hydrogels are a class of injectable hydrogel solids with significant potential use in injectable therapies. β-hairpin peptide hydrogels can be injected as preformed solids, because the solid gel can shear-thin and consequently flow under a proper shear stress but immediately recover back into a solid on removal of the stress. In this work, hydrogel behavior during and after flow was studied in order to facilitate fundamental understanding of how the gels flow during shear-thinning and how they quickly recover mechanically and morphologically relative to their original, pre-flow properties. While all studied β-hairpin hydrogels shear-thin and recover, the duration of shear and the strain rate affected both the gel stiffness immediately recovered after flow and the ultimate stiffness obtained after complete rehealing of the gel. Results of structural analysis during flow were related to bulk rheological behavior and indicated gel network fracture into large (>200 nm) hydrogel domains during flow. After cessation of flow the large hydrogel domains are immediately percolated which immediately reforms the solid hydrogel. The underlying mechanisms of the gel shear-thinning and healing processes are discussed relative to other shear-responsive networks like colloidal gels and micellar solutions.     

Electroactive response of mesoporous silica and its nanocomposites with conducting polymers

Electroactive response of suspensions of mesoporous silica and its nanocomposites with conducting polyaniline and copolyaniline inside its channels were examined under an electric field, mainly focusing on their rheological characteristics. Initially these conducting polymer/mesoporous silica nanocomposites were synthesized and their physical properties were studied by scanning electron microscopy, transmission electron microscopy and N₂-adsorption isotherm. Then, mesoporous silica and its nanocomposites were dispersed in silicone oil as an electrorheological (ER) material. Typical ER behaviors of shear stress and shear viscosity curves as a function of electric field and shear rate were observed. Without an electric field, the suspensions behaved almost like a Newtonian fluid. However, under an electric field, their shear stresses increased with shear rate, demonstrating a yield stress. Compared with mesoporous silica and polyaniline, polyaniline/mesoporous silica-based ER fluid showed enhanced ER performance due to the anisotropic characteristics. In addition, it was found that a suggested shear stress model (Cho–Choi–Jhon model) well described the flow curves.