In vitro evaluation of cellulose acetate hemodialyzer immobilized with heparin

In this study, heparin was immobilized onto cellulose acetate hollow fibers to improve the anticoagulation performance during hemodialysis. In vitro evaluation was carried out using mini‐hemodialyzer circulating with fresh porcine whole blood to simulate kidney therapy. The dialysis performance and hemocompatibility were estimated. The results showed that heparinized hemodialyzer could be used through out the whole dialysis time (4 hr) without injecting additional heparin to prevent coagulation in the dialysis system. In addition, the hemocompatibility was evaluated by measuring activated partial thromboplastin time (APTT), prothrombin time (PT), and fibrinogen time (FT). The complete blood count (CBC) including red blood cell (RBC), hemoglobin (Hgb), hematocrit (Hct), white blood cell (WBC), and platelet were determined. The results showed that heparinization could keep the CBC stable during dialysis, whereas unmodified cellulose acetate hemodialyzer would cause a decrease in RBC unless heparin was injected during dialysis. Heparinized hemodialyzer showed longer APTT, PT, and FT than unmodified hemodialyzer. Heparinized hemodialyzer also showed slightly higher clearance than unmodified hemodialyzer. These results indicated that the dialysis performance and hemocompatibility of cellulose acetate hemodialyzer could be improved by the immobilization of heparin. Copyright © 2006 John Wiley & Sons, Ltd.     

Preparation and Adsorption Properties of PAM Based Adsorbents for Plasma Lipoproteins

Crosslinked macroporous polyacrylamide (PAM) was prepared with inverse phase suspension polymerization technique.After treatment with hydrazine,the polymer was functionalized with chloroacetic acid,trifluoroacetic acid diethylenetriaminepentaacetic acid (DEPAA),and maleic acid,respectively,and PAM based adsorbents beating carboxyl functional groups for low density lipoprotein (LDL) apheresis use were obtained.The blood compatibility and the adsorption properties for plasma lipoproteins of PAM based adsorbents were investigated.     

聚砜/聚醚砜相容性对合金膜结构和性能的影响

通过混合焓法预测并用相差显微镜表征了PSF/PES合金体系的相容性,表明二者为相容性比较差的部分相容体系.合金膜中聚合物的组成影响PSF/PES间的相容性,进而影响合金膜的结构和性能.随合金体系相容性下降,膜的平均孔径显著增加,水通量增大而相应的截留率下降;研究表明,改变PSF/PES间的相容性是调节膜结构、提高膜性能的有效方法.     

Aqueous biphasic systems formed by nonionic polymers II. Concentration effects of inorganic salts on phase separation

Concentration effects of KSCN, KClO₄, KI, KBr, KNO₃, KCl, KF and K₂SO₄ on the compatibility of dextran with ficoll, polyvinylpyrrolidone and poly(ethylene glycol) at fixed polymer concentration ratios were studied in aqueous solution. The results obtained are considered in terms of the Patterson theory of-effect. It is assumed that phase separation in an aqueous solution of two nonionic polymers results from the appearance of two different water structures in the vicinity of the phase polymers. The data obtained are considered in terms of the concept of salting-in-salting-out effects of neutral salts on aqueous solubility of biopolymers. The salt effects observed are attributed to two antagonistic influences of salts on the electrostatic (dipole-dipole) polymer-water interactions and on the water-water interactions in the vicinity of the phase polymers.     

具有血液相容性的嵌段聚酯-聚醚接枝共聚物的合成

本文研究了嵌段聚酯-聚醚膜经紫外光活化后,于水溶液中铈盐引发亲水性单体丙烯酰胺在其表面上接枝共聚合反应。同时对接枝物进行了证实和表征。并通过活体动物血液灌流实验表明,此接枝共聚物具有良好的血液相容性。     

Interaction parameters of crystalline/crystalline polypropylene/poly(butene‐1) blends: Effect of molecular fractionation

Compatibility of crystalline/crystalline polypropylene (PP)/poly(butene‐1) (PB‐1) blends was investigated via the method of equilibrium melting temperature depression followed by determining the polymer–polymer interaction parameter (χ) using the Nishi–Wang equation. The composition variation of the equilibrium melting temperatures of blends (T) was determined with the Hoffman–Weeks plot. The T and its variation with the blend composition depended on the crystallization temperature range. The morphological effect of the blend composition was not a contribution factor for the T depressions of PP and PB‐1 in the blends. The interplay of the dilution effect and molecular fractionation effect of the amorphous component on crystallization of the crystalline component in the blends governed the relation of T with the blend composition. The calculated χ values were negative depending on the blend composition. The negative χ values suggested that PP and PB‐1 in the amorphous region were compatible. The composition variation of the χ values was attributed to the molecular fractionation effect during crystallization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 638–648, 2002; DOI 10.1002/polb.10125     

环氧树脂／酚酞聚醚醚砜共混物的相行为

酚酞聚醚醚砜(PES-c)同未交联的双酚A二缩水甘油醚(DGEBA)环氧树脂的共混物呈单一的玻璃化转变温度,其相容性主要归因于混合熵的贡献。PES-C同交联的环氧树脂之间的相容性与所用的固化剂有关。以胺类作DGEBA的固化剂时,共混物不发生相分离;以酸酐作固化剂时,共混物发生相分离。     

聚醚聚酯嵌段共聚物的表面性质对血液相容性的影响

聚合物的表面性质和结构对血液相容性具有很大的影响。本文通过接触角、吸水率和电子能谱研究了聚醚聚酯嵌段共聚物混合物的表面组成及微相分离结构。电子能谱的测试表明:试样空气面的氧碳元素比高于试样本体,表明醚键向空气面扩散,并以此来估量试样空气面的组成分布。试样的血液相容性与试样空气面氧碳比的提高程度随试样中聚乙二醇对苯二甲酸酯(PEGT)组成的递增呈相似的变化趋势,在共混物中软链段的组分比:聚四亚甲基二醇对苯二甲酸酯/聚乙二醇对苯二甲酸酯(PTMGT/PEGT)=60/40时,试样的接触角最大、氧碳比的提高率最大、血液相容性最好,且试样呈现最为细微的相分离结构。由此表明聚醚聚酯嵌段共聚物混合物的血液相容性主要受表面组成、各链段的表面自由能及微相分离程度的影响。     

Stabilized liposomes with phospholipid polymers and their interactions with blood cells

To stabilize a phospholipid liposome, addition of various water-soluble polymers into a liposomal aqueous suspension was investigated. The water-soluble polymers were poly(ethylene oxide) (PEO), poly(N-vinyl pyrrolidone) (PVPy) and poly[2-methacryloyloxyethyl phosphorylcholine(MPC)], and poly[MPC-co-n-butyl methacrylate(BMA)]. The gel–liquid crystal transition temperature (T_c) of the diparmitoylphosphatidylcholine (DPPC) liposome was not changed by addition of these polymers significantly. However, membrane fluidity of DPPC liposome treated with water-soluble polymers, which was measured with fluorescence probe, depended on the chemical structure of the water-soluble polymers. In the case of PEO and PVPy, the temperature dependence of membrane fluidity was the same as that of the original DPPC liposome, on the other hand, poly(MPC) and poly(MPC-co-BMA) induced a rise in the temperature where an increase in the membrane fluidity was observed. The release of carboxy fluorescein from the DPPC liposome was suppressed by the addition of the MPC polymers. The liposomes in the MPC polymer solution were stable compared with those in water when plasma was added into the suspension. Interactions with stabilized liposome with blood cells such as platelets and erythrocytes were evaluated. Activation of platelets in contact with liposome covered with poly(MPC) or poly(MPC-co-BMA) was less than PEO-stabilized liposome. On the other hand, no hemolysis of erythrocytes was observed when every polymer-treated liposome was added in the suspension of erythrocytes. Based on these results, the MPC polymers could interact with the liposome surface, adsorb on the liposomes and stabilize them, and had no adverse effect to the blood cells even when they were in a physiological environment.     

Thermal analysis of thermoplastic elastomers based on recycled polyethylenes and ground tyre rubber

Thermal stability and phase structure of thermoplastic elastomers (TPEs) based on post-consumer materials such as recycled lowor high-density polyethylene and ground tyre rubber (GTR) were investigated by using TG, DSC and DMTA analysis. Preliminary reclamation of GTR leads to enhancement of compatibility between polyethylene matrix and dispersed GTR particles.