Polypyrrole/poly(N‐isopropylacrylamide‐co‐acrylic acid) thermosensitive and electrically conductive composite microgels

The electrically conductive polypyrrole/dodecylbenzene sulfonic acid/poly(N‐isopropylacrylamide‐co‐acrylic acid) (PPy/DBSA/poly(NIPAAm‐co‐AA)) composite microgels were synthesized by a chemical oxidation of pyrrole in the presence of DBSA as the primary dopant, and poly(NIPAAm‐co‐AA) microgels as the polymeric codopant and template, in which APS was used as the oxidant. It was proposed to prepare “intelligent” polymer microgel particles containing both thermosensitive and electrically conducting properties. The polymerization of pyrrole took place directly inside the microgel networks, leading to formation of composite microgels and the morphology was observed by transmission electron microscope. PPy particles interacted strongly with microgels, as the acid groups of microgels acted as the polymeric codopant. The composite microgels thus formed showed electrically conducting behavior dependent on humidity and temperature. At temperatures lower than lower critical solution temperature, the conductivity decreased with increasing the humidity and a small hysteresis phenomenon was observed. The hysteresis became indistinct when temperature was near volume phase transition temperature. However, after the treatment of high temperature and high humidity, the conductivity increased surprisingly due to the structure reorganization inside the composite microgels. The distinctive functionality of the PPy composite microgels was expected to be utilized in many attractive applications. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1648–1659, 2006     

Cross-linking Copolymerization of Acrylic Acid and Multi-armed Cross-linkers

Polymer gels are of considerable interests in material science1-3. Many theoretical and experimental studies have been made on the cross-linking copolymerization4-6 of these systems. Recently, in situ interferometry is applied in studying this process7-9. As shown in Figure 1, the common two-armed cross-linkers will lead to defects in the network, while multi-armed cross-linkers will enhance the integrity of the network. This paper studies the cross-linkers influence on cross-linking and t…     

HYDROLYSIS TRANSFORMATION OF A POLYSTYRENE-b-POLY(tert-BUTYL ACRYLATE) COPOLYMER AND MICELLIZATION PROPERTIES OF THE HYDROLYZED COPOLYMER

1. INTRODUCTION The association of amphiphilic block copolymers has been the subject of numerous studies for several decades due to the academic interest and industrial applications [1~7]. It is well-known that block copolymers exhibit interesting domain structures in the solid state and form micelle-like aggregates in selective solvent [8]. They have found many potential applications in drug delivery [9], extraction of proteins [10], corrosion protection [11] as well as removal of aromat…     

芘基查尔酮的合成及三阶非线性光学性质

合成了一种新的具有潜在应用价值的非线性光学(NLO)有机材料1-(芘-1-基)-3-(4-二甲氨基苯基)丙烯酮(PMAK),并通过 NMR、IR、MS和元素分析等技术手段进行了表征。 采用溶液Nd:YAG激光技术测定了PMAK的三阶非线性光学性质并确定了相关参数。 纳秒实验结果:折射率n₂=-3.5×10^-17 m²/W,吸收系数β=7.0×10^-10 m/W,极化率χ⁽³⁾=2.54×10^-11 esu,分子超极化率γ=3.44×10^-30 esu;皮秒实验结果:n₂=-2.8×10^-18 m²/W,β=8.3×10^-11 m/W,χ⁽³⁾=2.49×10^-12 esu,γ=3.33×10^-31 esu。     

水溶性丙烯酸聚合物的改性及其应用

叙述了水溶性丙烯酸聚合物的改性及其在涂料、胶粘剂、敏感性水凝胶、皮革涂饰剂等方面的应用新进展。     

丙烯酸改性卤锑阻燃PP的结晶形态

用双螺杆挤出机制备了丙烯酸改性Sb2O3/聚丙烯母料,并注塑成Sb2O3/DBDPO阻燃PP样条.用偏光显微镜和广角X射线研究了阻燃PP中PP的结晶形态.结果表明Sb2O3对PP结晶形态的影响不同于十溴联苯醚（DBDPO）的,根据球晶形态,Sb2O3对PP的异相成核作用比DBDPO的明显,虽然在Sb2O3/PP母料中无β球晶,但在DBDPO/PP和阻燃PP中存在β球晶.对于丙烯酸改性阻燃PP,PP的结晶形态取决于丙烯酸用量,随着丙烯酸用量增加,在高DCP用量条件下,容易形成β球晶.     

Synthesis of Poly(acrylic acid) Nanogels and Application in Loading and Release of an Oligothiophene Fluorophore and Its Bovine Serum Albumin Conjugate

Summary: Nanometer-sized poly(acrylic acid) (PAA) hydrogels were synthesized by emulsion polymerization of methyl acrylate and subsequent acid hydrolysis, and their pH-dependent swelling behaviour was studied by dynamic light scattering. To determine the suitability of PAA nanogels as pH-sensitive carriers for biomedical applications, loading and release of an oligothiophene fluorophore and its albumin conjugate onto the PAA nanogels were investigated as a function of pH by absorption and photoluminescence measurements. It was observed that loading and release processes of both the oligothiophene and its conjugate could be controlled by changing pH of their solutions.     

丙烯酸酯树脂对泰乐菌素的吸附

通过调节单体、交联剂和致孔剂的种类及数量合成了一系列具有不同孔结构的丙烯酸酯树脂,并从中选出具有典型吸附差异的2种树脂,拥有适合的孔分布结构的三羟甲基丙烷三甲基丙烯酸甲酯(TRIM)聚合树脂(1#)和含酰胺基的三烯丙基异氰尿酸酯(TAIC)与TRIM共聚树脂(5#),与商业化大孔丙烯酸酯树脂XAD-7作比较,研究了丙烯酸酯树脂对泰乐菌素的吸附行为和机理。结果表明,树脂1#表现出了对泰乐菌素有最高的吸附量。3种吸附剂的吸附量随溶液pH值的升高呈增加趋势。吸附剂的吸附能力随溶液NaCl离子浓度的增强而提高,而对CuCl2则呈相反趋势,这是因为疏水作用和孔径排斥效应的贡献。泰乐菌素在3种吸附剂上的吸附动力学均符合准二级动力学模型,吸附等温线符合Langmuir模型。升高温度可以使树脂吸附能力增强,可能是“溶剂替代”效应所致。     

辉光放电电解等离子体引发合成聚丙烯酸钠/腐植酸复合高吸水性树脂

以丙烯酸和腐植酸为原料,N,N-亚甲基双丙烯酰胺为交联剂,在水溶液中采用辉光放电电解等离子体引发聚合反应制备聚丙烯酸钠/腐植酸复合高吸水性树脂。 考察了放电电压、交联剂、丙烯酸中和度、后聚合温度、腐植酸钠和丙烯酸的含量对树脂吸水率的影响,讨论了树脂在0.9%氯化钠溶液中的溶胀速率和不同pH值溶液中的溶胀行为。 用红外光谱和热重分析分别对产物进行了结构表征和稳定性测试,结果表明,最佳的合成条件为：放电电压470 V、交联剂质量分数为0.6%、腐植酸钠质量分数为4%、丙烯酸质量分数为10%、中和度60%、后聚合温度70 ℃。 所得复合树脂对蒸馏水的吸水率为1152 g/g,对0.9%NaCl溶液的吸水率为89 g/g,800 ℃后复合树脂残留率为44.3%。     

In situ ATR-FTIR and SFM Studies on the Influence of Adsorption time on Deposition and Nanostructure of Poly(ethyleneimine)/Poly(acrylic acid) Multilayers

Summary: The deposition and the nanostructure of polyelectrolyte multilayers (PEM) of branched poly(ethyleneimine)/poly(acrylic acid) (PEI/PAC) was studied in dependence of the adsorption time (t_ADS) of the individual steps. PEM were reproducibly deposited applying up to z = 20 adsorption steps at the fixed pH combination of 10/4 and polyelectrolyte concentration c_PEL = 0.005 M in a flow cell using an automated valve system. in situ ATR-FTIR spectroscopy and SFM were used for quantitative determination of deposited amount and thickness, respectively. A linear relation between PEL band integrals and thickness of thin PEM films was found. Varying t_ADS from 0.5 to 5 min in each of the adsorption steps resulted in a steep rise of the deposited PEM amount. For t_ADS > 5 min the deposition did only marginally increase. Evidence for the release of outermost located PEI upon PAC immersion (even step) and of outermost PAC upon PEI immersion (odd step) was obtained. SFM images on consecutively deposited PEM-6 showed a slight increase in structure size and roughness for increasing t_ADS. These studies help to prepare polyelectrolyte based films with controlled thickness for the interaction with biofluids in the biomedical and food field.