Water sorption of poly(vinyl alcohol)/ poly(diallyldimethylammonium chloride) interpenetrating polymer network hydrogels

Temperature‐responsive interpenetrating polymer network (IPN) hydrogels constructed with poly(vinyl alcohol) and poly(diallyldimethylammonium chloride) using the sequential IPN method were studied. The characteristics of IPN hydrogels were investigated using the dynamic vapor sorption system. IPN hydrogels exhibited a relatively high sorption ratio, 180–360% at room temperature. The sorption ratio of hydrogels depended on temperature. Diffusion coefficients were calculated according to the Fickian Law at several temperatures. The apparent activation energy was 5.43 kJ mol^?1, which corresponds to typical diffusion processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1389–1392, 2003     

魔芋葡甘聚糖接枝聚二甲基二烯丙基氯化胺生物絮凝剂的制备

以过硫酸胺和硫代硫酸钠为氧化还原引发体系,采用L9(34)正交试验法制备魔芋葡甘聚糖接枝聚二甲基二烯丙基氯化胺(KGM-g-PDADMAC)生物絮凝剂。研究结果表明:在反应温度60℃,pH=8的条件下,当引发剂用量为3%,PDADMAC与KGM糖环单元分子质量比为10时,最高接枝率为65.4%,引发剂用量是主要影响因子。     

Electrophoretic deposition of functionalized polystyrene particles for TiO2 multi-scale structured surfaces

Titanium is an interesting material for biomedical implants thanks to its physical and chemical properties. In particular, TiO₂ coatings with a surface characterized by micro-patterning combined with nano-topography are extremely attractive for orthopaedic implants in terms of enhanced osteointegration and consequently improved implant fixation. In the present work, a new method for the preparation of TiO₂ multi-scale structured coatings is presented. This method is based on three steps. Firstly, monodispersed polystyrene (PS) microsized beads are functionalized with TiO₂ submicron particles by a wet process involving a cationic polyelectrolyte. Secondly, the resulting TiO₂-PS composite particles in suspension are used to prepare coatings by electrophoretic deposition (EPD), a simple and flexible electrochemical technique. The EPD is performed cathodically, avoiding uncontrolled oxidation of the substrate. Finally, after removal of the PS spacers during the sintering process, TiO₂ coatings with a combined micro- and nano-topography are achieved from deposits thicker than 100 µm. This achievement presents two relevant aspects: potential applications of the multi-scale structured TiO₂ surfaces (particularly in the biomedical field); the simplicity and flexibility of the process used.     

脱墨浆中胶黏物的絮聚行为研究

利用聚集光束反射测量仪(FBRM)对脱墨浆中胶黏物粒子在阴离子垃圾捕捉剂(PDAD-MAC)作用下的絮聚行为进行了研究,并结合激光粒度仪、浊度仪、Zeta电位仪等对其结果进行了验证.实验结果表明,PDADMAC用量为20 mg/L时,对胶黏物的絮聚效果最佳,此时接近理论电荷等电点,继续增加PDADMAC用量,体系超过等电点,电荷发生逆转,胶黏物粒子重新分散.由FBRM得出的胶黏物絮聚动力学可知,其絮聚过程分为溶解性物质凝聚和胶体性物质絮凝两个阶段.为了得到较好的胶黏物控制效果,提高PDADMAC的使用效率,应避免在过高的碱性条件下进行使用.     

季铵型CPAM组成的复式助留助滤系统对助留助滤作用的研究

研究了季铵型CPAM与其他助剂配合使用对漂白麦草浆滤水性和留着率的影响。用PAC和PDADMAC作为阴离子捕捉剂可显著改善麦草浆的滤水性,提高其留着率。CPAM和膨润土组成微粒系统可提高麦草浆的滤水性和留着率,并且对强度影响不大。     

聚二甲基二烯丙基氯化铵用于控制纸浆中的胶体和溶解性物质

论文对实验室自制的聚二甲基二烯丙基氯化铵(PDADMAC)在胶体和溶解性阴离子物质(DCS)干扰下的环境适应性、对CPAM助留助滤和AKD施胶的增效作用,以及对纸张性能的影响进行了研究,结果表明:PDADMAC的电荷密度不受pH值及无机盐含量的影响,适合作为阴离子DCS的电中和剂、固着剂;对AKD施胶有明显的增效作用;可有效地抑制DCS对CPAM的干扰,协同CPAM发挥更好的对细料的助留助滤效果,提高纸的强度和不透明度,且用量为0.075%时效果最好。     

季铵型两性PAM对麦草浆的助留助滤作用

用水溶液共聚法合成了一系列季铵型两性聚丙烯酰胺（LPAM）。分别考察了阳离子化度和用量对麦草浆滤水性、填料留着率和动态条件下一次留着率的影响，发现季铵型两性PAM可显著提高漂白麦草浆的滤水性和填料留着率，两性PAM与PAC、PDADMAC和膨润土配合使用可进一步改善漂白麦草浆的留着和滤水。     

Preparation and characterization of konjac glucomannan/poly(diallydimethylammonium chloride) blend films

A novel preservative film was prepared by blending konjac glucomannan (KGM) and poly (diallydimethylammonium chloride) (PDADMAC) in aqueous system. The effects of PDADMAC content on the miscibility, morphology, thermal stability, and mechanical properties of the blend films were investigated by density determination, scanning electron microscopy (SEM), attenuated total reflection infrared spectroscopy (ATR‐IR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile tests. The results of the density determination predicted that the blends of KGM and PDADMAC were miscible when the PDADMAC content was less than 70 wt %. Moreover, SEM and XRD confirmed the result. ATR‐IR showed that strong intermolecular hydrogen bonds interaction occurred between the negative charge groups of KGM and the quaternary ammonium groups of PDADMAC in the blends. The tensile strength and the break elongation of the blends were improved largely to 106.5 MPa and 32.04%, when the PDADMAC content was 20 wt %. The thermal stability of the blends was higher than pure KGM. Results from the film‐coating preservation experiments with lichi and grapes showed that the blend film had excellent water‐holding and preservative ability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Centrifugal Polyelectrolyte Enhanced Ultrafiltration for Removal of Copper‐Citrate Complexes from Aqueous Solutions

Abstract

To replace the conventional dead‐end polyelectrolyte enhanced filtration (PEUF), which is a time consuming process in the optimization of process variables, centrifugal polyelectrolyte enhanced ultrafiltration was investigated to remove copper‐citrate complex in aqueous phase with a cationic polyelectrolyte, poly(diallydimethylammonium chloride) (PDADMAC). Effects of concentration ratios between polyelectrolyte, copper, and citrate and pH were observed. Below pH 3, copper was not removed by centrifugal PEUF. At the same concentration (1 mM) of citrate and copper, removal of copper at pH 5 was the highest value of 54%, 90%, and 98% with 5, 10, and 20 mM PDADMAC, respectively. Removal of copper decreased with the logarithmic ionic strength. Since the centrifugal PEUF is very economical in time compared with conventional dead‐end PEUF, the present method should be a valuable tool in the optimization of process variables.     

Self-assembly behavior of polymer-assisted clays

Layered silicate clays are natural crystallites that are well recognized for their practical uses, but little is known about their self-assembly behavior. In this review, we summarize the recent literature on clay interactions with organic polymers as well as clay self-assembly with organic involvement. We place emphasis on two aspects of these non-covalent interactions: first, plate-like clays can have a considerable impact on polymer properties such as hydrogels and clay films, and also on the encapsulation of bio-molecules. Second, through ionic intercalation with polymeric amine-salts, the clay layered structure units can be modified and enabled to self-assemble into ordered arrays such as rod-, dendrite-, and fiber-like microstructures. The silicate self-assembled morphologies such as worm-like and hollow microspheres were obtained in epoxy matrices and during spray drying, respectively. A mechanism was proposed for the clay self-assembly in two orientations, platelet face-to-face (ionic attraction) and edge-to-edge (organic hydrophobic effect). Further, the layered clays after the exfoliation into random platelets (1 nm in thickness) had strong propensity toward self-piling without any organic influence. Formation of lengthy rods or fibrils up to 5 μm in length and their hierarchical transformation under transmission electron microscope (TEM) electron beam bombardment and ultrasonication were observed. The clay thin-platelet geometric shape and surface ionic charge are two important parameters for the self-assembling tendency. The high surface of clay platelet has a significant impact on polymer interactions and drives the self-organization of inorganic-organic structures.