瓜胶/聚丙烯酸互穿聚合物网络水凝胶对模型药物的负载与控制释放

考察了以牛乳清蛋白(BSA)为模型药物,通过相平衡分配法制备载药瓜胶(GG)/聚丙烯酸(PAA)互穿聚合物网络(IPN)水凝胶的工艺条件.借助紫外可见光谱仪研究了载药水凝胶在结肠酶存在下的控制释放行为.结果表明:载药容量(CM)随瓜胶、丙烯酸用量的增加而下降,半IPN水凝胶的Cm较全IPN的略大;结肠酶能明显提高半IPN与全IPN中的BSA释放速率,且提高幅度随GG含量的增加而加快,GG/PAA IPN水凝胶具有结肠定位降解的特性,有望成为靶向结肠给药的理想载体材料.     

High Solid Acrylic–Melamine Latexes with Tunable Crosslinking Capability

Miniemulsion polymerization is employed to produce high solid content (50%) acrylic/melamine latexes with varied crosslinking capability, for their potential application as waterborne crosslinkable coatings. This synthesis strategy allows the efficient incorporation of a hydrophobic crosslinker, iso‐butylated melamine (iBMF), into polymer particles, and to obtain latexes with different iBMF concentrations and acrylic polymer with varied content of hydroxylic groups (OH–). The involved crosslinking mechanisms and the physical transformations during film thermosetting of acrylic/iBMF nanocomposite are exhaustively investigated by combining thermal, spectroscopic, and thermo‐mechanical analyses. The influence of reactive groups concentration (iBMF and OH– content in the acrylic polymer) on the rate of curing, the crosslinking degree, and consequently onto the sensitive properties of cured films are discussed here.     

1-二茂铁基-3-[(9-乙基)咔唑-3-基]丙烯酮的合成及三阶非线性光学性质

合成了一个新的非线性光学(NLO)有机材料1-二茂铁基-3-[(9-乙基)咔唑-3-基]丙烯酮(FCAK),并通过NMR、IR、MS和元素分析等技术手段进行了表征。 采用粉末Nd∶YAG激光技术测定了标题化合物的三阶非线性光学性质并确定了相关参数。 激光脉冲为4 ns时,非线性折射率n₂=-3.5×10^-18 m²/W,非线性吸收系数β=-2.7×10^-11 m/W,三阶非线性极化率χ⁽³⁾=2.04×10^-12 esu,三阶非线性分子超极化率γ=1.1×10^-30 esu。 激光脉冲为21 ps时,n₂=0.55×10^-18 m²/W,β=-0.6×10^-11 m/W,χ⁽³⁾=3.4×10^-13 esu,γ=0.13×10^-30 esu。     

Inverse Suspension Polymerization of Partially Neutralized and Lightly Cross-Linked Acrylic Acid: Effect of Reaction Parameters

An inverse suspension polymerization was carried out in laboratory in one Liter Buchi glass reactor to produce superabsorbent polymers (SAPs) based on acrylic monomers for hygiene applications. Strongly water absorbing polymers, based on acrylic acid, sodium acrylate were prepared by copolymerization using potassium per sulfate as initiator and N-N′ methylene-bisacrylamide (MBA) as crosslinking agent. The effect of varying monomer, crosslinker, initiator, dispersant concentration, time of reaction and degree of neutralization, on absorption capacities was investigated. In the present studies, the continuous hydrocarbon phase was taken as 50:50 mixture of n-heptane and cyclohexane (aliphatic-alicyclic) because the availability of crosslinker in the aqueous phase is controlled by the partition coefficient of the crosslinker between the aqueous phase and the continuous hydrocarbon phase. The SAPs were evaluated for their free absorption capacities in distilled water, saline (0.9% NaCl), and also absorption under load (AUL). The experimental results show that these SAPs have good absorbency both in water and NaCl solutions. It was observed that SAP synthesized from acrylic acid with about 70% degree of neutralization, containing 1% cross-linker, and 0.5–1.0% initiator concentration with 10% dispersant exhibited absorption capacities in water, saline and AUL as 220 g/g, 70 g/g and 27 g/g respectively.     

Mo-V-Te-Nb-O催化剂上丙烷选择氧化制丙烯酸Ⅰ.催化剂的制备条件及稳定性

 研究了催化剂的制备条件(焙烧方式、焙烧气氛和焙烧温度)对Mo-V-Te-Nb-O上丙烷选择氧化制丙烯酸反应的影响. 结果表明,制备条件对催化剂的催化性能具有很大的影响. 与敞开式焙烧制得的催化剂相比,封闭式焙烧制得的催化剂具有较高的丙烯酸选择性,但丙烷转化率较低. 在空气中焙烧制得的催化剂对丙烯酸无选择性,但在氮气和氩气中焙烧制得的催化剂具有很高的丙烷转化率和丙烯酸选择性. 随着焙烧温度的升高,丙烷转化率降低,丙烯酸选择性升高,适宜的焙烧温度为600 ℃. 催化剂制备条件对催化剂的晶相结构也具有重要的影响. 在惰性气氛中采用600 ℃下封闭式焙烧制得的Mo-V-Te-Nb-O催化剂经210 h反应后,丙烷转化率保持为19%,而丙烯酸选择性持续升高,由32%升至50%.     

螺噁嗪化合物在丙烯酸聚氨酯清漆膜中的光致变色性能

制备了含有螺噁嗪(SO)化合物的紫外光固化丙烯酸聚氨酯清漆(UV-PUA)膜, 研究了SO在该清漆中的光致变色性能, 并与其在聚甲基丙烯酸甲酯(PMMA)中的光致变色性能进行了比较. 结果发现, 紫外光固化螺噁嗪丙烯酸聚氨酯清漆(UV-SO-PUA)膜在紫外光固化过程中逐渐由无色变为蓝色和紫色, 撤去紫外光源, 漆膜退色至粉色, 且固化后的漆膜在粉色和紫色之间可逆变化; 而SO-PMMA膜在无色和蓝色之间可逆变化. 紫外光激发的UV-SO-PUA膜的紫外-可见吸收光谱可见光区出现了明显的双重吸收峰(520和600 nm), 而在PMMA中仅出现单峰. SO开环体在UV-PUA 中室温稳定性优于其在ＰＭＭＡ中的稳定性. SO在UV-PUA膜中的抗疲劳性能与其在PMMA中相比显著提高, 紫外光照射16 h, UV-SO-PUA漆膜未出现疲劳现象. SO在UV-PUA膜中表现出了优良的光致变色行为.     

硫酸钙晶须催化合成三羟甲基丙烷三丙烯酸酯

以三羟甲基丙烷(TMP)、丙烯酸(AA)为原料,硫酸钙晶须为催化剂,环己烷和甲苯混合物为带水剂,合成三羟甲基丙烷三丙烯酸酯(TMPTA).考察了原料配比、催化剂用量等因素对产品酯化率的影响.结果表明:以对苯二酚和吩噻嗪做混合阻聚剂,n(AA)∶n(TMP)=3.40,硫酸钙晶须的质量分数(以三羟甲基丙烷用量为基准)为2.0%,、环己烷用量20%、甲苯用量30%;酯化反应温度为98 ℃,反应时间为5 h,在此条件下合成的三羟甲基丙烷三丙烯酸酯酯化率大于96.8%,纯度达到97.6%.     

Acrylic fibers processing with ionic liquid as solvent

Ionic liquid, 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl), was used as solvent for the polymerization of acrylonitrile (AN) and the resulting polymer solution was directly applied for spinning to produce polyacrylonitrile (PAN) fiber for the first time. Acrylic polymers with high content of AN, large molecular weight, and low polydispersity index (PDI) were prepared. The PAN macromolecules have little degradation during dissolution of PAN in [BMIM]Cl, which is completely different from the dissolution of biopolymers such as cellulose in ionic liquids. The PAN fiber with round profile and good mechanical properties was successfully spun from the PAN/[BMIM]Cl solution using dry–jet wet spinning technology. It suggests that an environmental friendly process for the acrylic fiber would be developed and the high performance PAN fiber would be obtained when the spinning conditions are optimized further. Copyright © 2008 John Wiley & Sons, Ltd.     

Hydrophobically modified poly (acrylic acid) using calix[4]arene derivative. Ionophoric properties and extraction abilities toward alkali metal cations

p‐t‐Butyl calix[4]arene diol (distal cone) (1) was grafted with poly (acrylic acid) (PAA) to obtain hydrophobically modified PAA (PAA‐C) bearing calixarene moieties. The grafting method includes the direct esterification reaction of PAA with calixarene diol 1 which was carried out in a system of tosyl chloride (TsCl), pyridine (Py), and N,N‐dimethylformamide (DMF). The grafting yield was studied using different molar ratios of PAA to calix[4]arene diol 1, temperature, and reaction time. The chemical composition of the PAA‐C was studied by IR and ¹H NMR spectroscopy. Also, the morphology of PAA‐C was evaluated by scanning electron microscopy. The PAA‐C had different solubility and thermal properties. The extraction ability measurements of modified PAA toward alkali metal cations (Na⁺, K⁺, Cs⁺) and Ag⁺ showed a remarkable efficiency and selectivity of PAA‐C toward Na⁺. The main goal of this work was to design hydrophobically modified PAA with binding ability that is suitable for ion selective membranes and chemical sensor devices such as ion‐specific electrodes, semipermeable membranes, and quartz microbalances. Copyright © 2009 John Wiley & Sons, Ltd.     

Safety and Quality Aspects of Acrylic Monomers

Summary : Acrylic monomers are important intermediates for the chemical industry. Especially acrylic acid (AA) is the basis for various reactions, such as polymerizations and esterifications and is, therefore, responsible for high product diversity. Spontaneous polymerization is a safety problem during the transportation and storage of acrylic monomers. In the production process, polymerization leads to blockages in the apparatus. For the prevention of these issues, special stabilizer systems are used such as hydroquinone monomethyl ether (MeHQ)/oxygen and phenothiazine (PTZ). The reactions of these stabilizer systems are not well understood at the moment. Therefore a lot of expertise and experience are necessary to guarantee safe handling. In this paper some methods for the investigation of stability related reaction kinetics are presented. A better comprehension of the mechanism of the polymerization inhibition is generated by the kinetic simulation with these data.