聚乙烯醇(PVA)/聚丙烯酸(PAA)复合水凝胶的合成

本研究采用冷冻—融化方法,正交试验设计考察了聚乙烯醇(PVA)与聚丙烯酸(PAA)复合水凝胶含水率的影响因素(原料配比、交联剂用量、冷冻时间、冻融次数)并得到合成的最佳条件。通过红外光谱分析对产物结构进行了表征。     

羧甲基纤维素接枝丙烯酸制备高吸水性树脂的研究

以羧甲基纤维素(CMC)和丙烯酸(AA)为原料,采用水溶液聚合法制备高吸水性树脂。较优的合成条件为:丙烯酸用量为18g时,羧甲基纤维素2 g,去离子水50 g,NaOH 7.2 g,K2S2O8 0.5 g,1 g/L的N,N’-亚甲基双丙烯酰胺溶液3mL,反应温度60℃,反应时间1.5h,真空干燥温度60℃。此条件下所得1g产品能吸收去离子水474.2g。测定了树脂对去离子水、自来水、模拟尿、模拟血和生理盐水的吸液倍率,并研究了产品的吸水速率、保水性和再生性。     

Release Dynamics of Brufen from a Drug-Loaded Polymer Hydrogel Containing Polyvinyl Alcohol, 2-Acrylamide-2-methylpropane Sulfonic Acid and Acrylamide

A novel AMPS-based hydrogel was synthesized, characterized, and its swelling and drug-release behaviour with brufen as model drug were studied in vitro. The results indicated that the swelling of the hydrogel is pH sensitive and follows the non-Fickian diffusion process. Swelling behaviour of brufen loaded and unloaded hydrogel was similar. The results of in-vitro drug release experiments showed that the hydrogel has sustained release properties and the release rate depends on the equilibrium swelling ratio of the hydrogels, pH of the release medium, and the solubility of the drug. It is believed that this hydrogel could be potentially used for localized drug delivery.     

壳聚糖接枝共聚制备高吸水性树脂的合成与表征

在水溶性氧化还原体系引发剂NaHSO3/K2S2O8的引发下,使丙烯酸(AA),丙烯酰胺(AM)在壳聚糖(CTS)分子链上接枝聚合,并加入N,N′-亚甲基双丙烯酰胺(MBAM)进行一定程度的交联,制得高吸水性树脂。研究了反应条件对所得树脂吸水性能的影响。结果表明,使树脂具有最高吸水性能的最优化反应条件为:m(CTS)∶m(AA)∶m(AM)为1∶3∶1,丙烯酸的中和度为70%,引发剂用量4%,交联剂用量0.04%,反应温度45°C。在此条件下合成的树脂最大吸水倍率可达402 g/g,吸盐水(浓度0.9%)倍率可达102 g/g,定性观察该高吸水性树脂的凝胶强度为良。最后采用SEM和TG对所合成的树脂进行了结构和性能表征。     

Effect of Potassium Methacrylate Content on Synthesis,Swelling, and Diffusion Characteristics of Acrylamide/Potassium Methacrylate Hydrogels

ABSTRACT

Hydrogels based on acrylamide (AAM) and potassium methacrylate (KMA) were synthesized by simultaneous free radical polymerization in aqueous solution using the redox initiator ammonium persulfate (APS) and N,N,N′N′-tetramethylethylenediamine (TMEDA) at room temperature. Eight different compositions of KMA hydrogels were prepared at a fixed concentration of N,N′,-methylenebisacrylamide (MBA) or diallyl phthalate (DP) as crosslinking agents. For all the AAM-KMA hydrogels, the percentage of swelling, swelling kinetics, and diffusion characteristics were investigated. It was found that higher swelling percentage values were obtained for hydrogels crosslinked with DP than for the conventional crosslinker MBA. The de-swelling characteristics of hydrogels were also studied in detail. The power law relationship of hydrogels was evaluated in saline solutions. Hydrogels formation was confirmed by IR spectroscopy. The thermal characteristics of these hydrogels were studied by using differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) and revealed that MBA crosslinked AAM-KMA hydrogels show higher glass transition temperature (Tg) as well as higher decomposition temperatures (Td) than DP crosslinked AAM-KMA hydrogels. It is further confirmed from the studies that the DP crosslinked hydrogels have good swelling as well as de-swelling and salinity characteristics.     

Synthesis and Characterization of Poly(acrylic acid)/modified Bentonite Superabsorbent Polymer

A novel poly(acrylic acid)/modified bentonite superabsorbent polymer (SAP) was synthesized through chemical crosslinking by a polymerization technique in a complete aqueous environment. This SAP was fabricated effectively by dispersing modified bentonite in a monomeric solution, using N,N′-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. Fourier transform infrared (FTIR) spectral analysis showed that the XG chains had intercalated into bentonite sheets. The influence of crosslinking density and XG content were investigated. Results showed modified bentonite not only effectively increases water absorbency, but also improves water retention ability. This can be further used as a carrier matrix for the development of a drug delivery system.     

Synthesis,Characterization, and Application of Poly(Acrylamide)/Poly(Vinyl Alcohol) Polyblends

Free radical polymerization of acrylamide (Aam) in the presence of aqueous solution of three commercial grades of polyvinyl alcohol (PVOH), namely, Vinarol FV (containing very few acetyl groups), Mowiol 4-80 (low viscosity-partially hydrolyzed), and Vinarol STH (medium viscosity-partially hydrolyzed), using ammonium persulfate (AP) initiator resulted in three corresponding PVOH/Aam polyblends. Optimum polymerization conditions were PVOH and AP concentrations, 10% and 0.05 mol/L, respectively; Aam concentration, 50% based on the weight of PVOH; polymerization temperature and time, 70°C and 20 min, respectively; rate of stirring, 200 rpm, at which the three polyblends were prepared at very high polymerization extent ranging from 98.2 to 99.9%. Rheological properties of 10% aqueous solutions of the polyblends at 80°C were studied. The extent of film resolubility of PVOH's and their polyblends follows the descending order: Mowiol®4-80/Aam > Mowiol®4-80 > Vinarol®STH/Aam > Vinarol®STH > Vinarol®FV/Aam > Vinarol®FV. Sizing of gauzy cotton fabric with the polyblends and PVOH's showed that (1) their tensile strength follows the order: Vinarol®STH/Aam > Vinarol®STH > Mowiol®4-80/Aam > Mowiol®4-80 > Vinarol®FV/Aam > Vinarol®FV > Unsized and (2) their desizability follows the order: Mowiol®4-80/Aam > Mowiol®4-80 > Vinarol®STH/Aam > Vinarol®STH > Vinarol®FV/Aam > Vinarol®FV.     

Synthesis and Properties of Superabsorbent Hygroscopic Materials Based on Polyacrylamide and Poly(2-acrylamido-2-methyl Propyl Sulfonic Acid) Co-polymer

Polyacrylamide and poly(2-acrylamido-2-methyl propyl sulfonic acid) co-polymer[short as P(AM-co-AMPS)] superabsorbent materials were synthesized using 2-acrylamido-2-methyl propyl sulfonic acid and acrylamide as monomers, and P(AM-co-AMPS)/SiO₂ hybrid superabsorbent materials were prepared using P(AM-co-AMPS) as the organic phase and SiO₂ as the inorganic phase. The absorbent properties of these two kinds of superabsorbent materials were investigated. Fourier-transform infrared (FT-IR) and scanning electron microscopes (SEM) were used to characterize these two kinds of superabsorbent materials. The result shows that the SiO₂ can disperse in P(AM-co-AMPS) polymer networks homogeneously. The water-absorbent ability of P(AM-co-AMPS)/SiO₂ and P(AM-co-AMPS) is similar, but P(AM-co-AMPS)/SiO₂ exhibits better acid, base, salt, organic solvents, and temperature tolerance than the P(AM-co-AMPS) dose. In addition, the swelling speed of P(AM-co-AMPS)/SiO₂ is larger than that of P(AM-co-AMPS).     

AM/AMPS二元吸水树脂的合成与性能研究

以N ,N 亚甲基丙烯酰胺为交联剂、过硫酸钾为引发剂 ,采用溶液聚合制备了AM/AMPS高吸水性树脂 ,并用正交实验及单因素考察法对最佳反应条件进行了研究。得到最佳条件 :w(交联剂 ) =0 0 1 %、w(单体 ) =2 0 %、中和度为 65 %、n(AMPS)∶n(AM ) =1∶1、w (引发剂 ) =0 0 2 %、反应温度 50～ 80℃、反应时间 7h ,在此条件下合成的共聚物于室温下吸蒸馏水最大达2 2 1 5倍 ,吸w(NaCl) =0 9%水溶液最大为 1 1 9倍。     

Electron Beam Synthesis and Characterization of Poly Vinyl Alcohol/Poly Acrylic Acid Embedded Ni and Ag Nanoparticles

Electron beam irradiation was applied to prepare poly (vinyl alcohol) and poly (acrylic acid) P (PVA/AAc) containing nickel and silver nanoparticles. The prepared P (PVA/AAc)–Ni and P (PVA/AAc)–Ag nanoparticles were characterized by Fourier-transform infrared, UV–Visible spectroscopy, X-ray diffraction (XRD) and transmission electron microscope (TEM). The electrical conductivity and thermal gravimetrical analysis (TGA) have been investigated. Bacterial sensitivity toward nickel and silver nanoparticles was studied. The XRD and TEM confirmed that by increasing the Ni or Ag contents from 10 to 150?mmol in the copolymers, the metal particle size increases from 27.6 to 45.6?nm for Ni and from 14.8 to 37.4?nm for Ag. Meanwhile, the mean size particle increases from 33.02 to 45.05?nm for Ni and from 15.5 to 44.03?nm for Ag. The electrical conductivity of the polymer containing Ag is higher than that of Ni and it increased by increasing the metal content. The TGA studies confirmed that, the thermal stability increase by the introduction of metal into polymeric complex. Bacterial sensitivity to metal nanoparticles was found to vary depending on the microbial species. Disc diffusion studies with P. aeruginosa, E. coli and K. pneumoniae revealed greater effectiveness of the silver nanoparticles compared to the nickel nanoparticles, S. aureus depicted the highest sensitivity to nanoparticles compared to the other strains and was more adversely affected by the nickel nanoparticles.     

聚丙烯酸钠/高岭土复合高吸水性树脂的制备、结构与性能

以丙烯酸和高岭土为原料,用反相悬浮聚合法合成了聚丙烯酸钠/高岭土复合高吸水性树脂。研究了加入高岭土的聚丙烯酸钠复合高吸水性树脂合成中反应温度、中和度、交联剂用量、引发剂用量、高岭土添加量等影响树脂吸水性能的主要因素。结果表明,用反相悬浮聚合法合成的复合高吸水性树脂后处理容易,树脂的吸水率达到512g/g,吸盐水率达到81g/g,吸水速度比不加高岭土提高20%,保水能力提高15%,在250℃加热30min仍能保持原吸水率的95%。用IR和TEM研究了复合高吸水性树脂的表面和结构,TEM显示高岭土的加入对树脂颗粒大小和形状有较大的影响,IR初步表明聚丙烯酸与高岭土产生了交联。     

聚丙烯酸钠∕高岭土复合高吸水性树脂的制备、结构与性能

以丙烯酸和高岭土为原料,用反相悬浮聚合法合成了聚丙烯酸钠/高岭土复合高吸水性树脂.研究了加入高岭土的聚丙烯酸钠复合高吸水性树脂合成中反应温度、中和度、交联剂用量、引发剂用量、高岭土添加量等影响树脂吸水性能的主要因素.结果表明,用反相悬浮聚合法合成的复合高吸水性树脂后处理容易,树脂的吸水率达到512 g/g,吸盐水率达到81 g/g,吸水速度比不加高岭土提高20%,保水能力提高15%,在250 ℃加热30 min仍能保持原吸水率的95%.用IR和TEM研究了复合高吸水性树脂的表面和结构,TEM显示高岭土的加入对树脂颗粒大小和形状有较大的影响,IR初步表明聚丙烯酸与高岭土产生了交联.     

Synthesis and Characterization of Poly(acrylic acid)/Poly(vinyl alcohol)-xanthan Gum Interpenetrating Network (IPN) Superabsorbent Polymeric Composites

Initially interpenetrating network (IPN) hydrogel was prepared by dispersing xanthan gum (XG) into poly(vinyl alcohol) (PVA) backbone in an aqueous medium. Polyacrylic acid (PAA)/Poly (vinyl alcohol)-Xanthan gum IPN superabsorbent composite were fabricated well by dispersing the prepared IPN hydrogel in acrylic acid and polymerized in a complete aqueous environment through chemical cross-linking method. These superabsorbent polymeric composites were analytically evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared Spectra (FTIR), Thermal analysis (DSC) and X-ray diffraction (XRD) analysis. Simultaneously water absorbency, swelling kinetics and water retention abilities of this prepared superabsorbent polymeric composites were also investigated systematically.     

降滤失剂AMPS/AM/腐植酸钠的合成与评价

本文以褐煤为原料制得腐植酸钠,再以2-丙烯酰胺基-2-甲基丙磺酸、丙烯酰胺和腐植酸钠为单体,采用过硫酸铵和亚硫酸氢钠氧化还原体系作引发荆,运用水溶液聚合法合成了共聚物降滤失剂,在引发温度50℃,引发剂用量为单体质量的0.6%,pH=7.0,m(丙烯酰胺):m(2-丙烯酰胺基-2-甲基丙磺酸):m(腐植酸钠)=30:20:50的反应条件下得到的聚合产物水溶性及降滤失能力较好,用旋转粘度计测得其质量分数1%的水溶液的粘度为10mPa·s.对其结果进行了红外光谱表征,并在淡水基浆中对产品的降滤失性能进行了室内评价,结果表明产物具有良好的降滤失能力.     

淀粉接枝丙烯酸钠高吸水树脂的合成及在食品保鲜中的应用

以过硫酸铵为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,制备了玉米淀粉和丙烯酸的接枝共聚物高吸水性树脂,考察了有关聚合条件对高吸水性树脂性能的影响,并对其在食品保鲜方面进行了试验。结果表明,该树脂具有优良的加压保水能力,在食品保鲜应用上有显著效果。     

Characterization of Poly(Vinyl Alcohol) and Poly(Vinyl Pyrrolidone) Co-polymer Blend Hydrogel Prepared by Application of Gamma Radiation

Hydrogel is prepared from a poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) blend solution by gamma radiation with a ₆₀Co λ source at room temperature. Properties of the prepared hydrogel, such as gel fraction, gel strength swelling ratio, equilibrium water content, and water absorption in room temperature, were investigated. Blending hydrogel with PVP and PVA obviously increased the gel strength and decreased the swelling ratio of hydrogel. It was observed that the gel fraction increased while the swelling ratio and water content decreased with increased radiation dose, but gel strength increased up to a certain radiation dose and then decreased. The percentage of water absorption at room temperature increased with time but after a certain time it became steady and decreased with radiation dose.     

Antibacterial Nanocomposite of Poly(Lactic Acid) and ZnO Nanoparticles Stabilized with Poly(Vinyl Alcohol): Thermal and Morphological Characterization

The effect of polyvinyl alcohol (PVA) as a surface coating agent on the antibacterial and thermal properties of polylactic acid (PLA)/ZnO nanocomposites prepared by melt blending was investigated. The ZnO nanoparticles were coated and stabilized with PVA using a solvothermal method. Nanocomposites were prepared with different ZnO nanoparticle content: 1, 3 and 5 wt.%. Electron transmission microscopy and Fourier transform infrared spectroscopy showed the presence of a layer around the nanoparticles and the interaction between nanoparticles and PVA, respectively. DSC analysis revealed that the thermal properties of the nanocomposites were not affected by the coating of ZnO nanoparticles with PVA. The PLA/ZnO nanocomposites with coated nanoparticles presented better antibacterial activity than those containing uncoated nanoparticles.     

Effect of Surface Modification on the Synthesis of Pore‐Filling Polymeric Monoliths in Microfiltration Membranes Made from Poly(propylene) and Poly(ethylene terephthalate)

The effect of pre‐modification on the interaction of macroporous substrates (membranes) with mainly micro‐ and mesoporous polymer monoliths has been studied. Bulk, porous polymer monoliths were synthesized to optimize the synthesis conditions and their pore morphology, and the data were used as benchmark for this study. Pre‐modification of the entire pore surface of PP microfiltration membranes and PET track‐etched membranes by UV‐initiated grafting with PEGMA was performed using well‐established methods, including coating with the photo‐initiator, benzophenone. Subsequently, these membranes were functionalized by filling the pores with porous polymer monoliths from MAA and EDMA and compared with membranes that had been functionalized without the pre‐modification step. The materials were characterized mainly by the degree of grafting, SEM and by the gas‐adsorption‐isotherm method. The DG values, after composite‐membrane preparation under identical conditions, were not influenced by the pre‐modification. However, it could be clearly seen from the SEM images that the pre‐modification step prevents the formation of voids at the monolith‐membrane pore interface. Larger specific surface area and pore volume values for composite membranes, prepared after pre‐modification, fully support the SEM results. Especially large differences in pore structure between the two different composite membranes were found in the mesopore range. The results of this study indicate that it is possible to prepare porous, composite membranes where the trans‐membrane transport is exclusively controlled by the pore and surface structure of a functional polymeric monolith, for example, made from a molecularly‐imprinted polymer.

     

聚（丙烯酸-醋酸乙烯酯）- 聚乙烯醇互穿网络高吸水性树脂的合成

以丙烯酸(AA)、醋酸乙烯酯(VAc)、聚乙烯醇(PVA)为原料,过硫酸钾为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,环己烷作为油相,span60为分散剂,采用反相悬浮法制备出聚(丙烯酸-醋酸乙烯酯)-聚乙烯醇互穿网络(IPN)高吸水性树脂。研究了丙烯酸中和度、单体物料比、引发剂用量、交联剂用量、反应时间以及聚乙烯醇用量对高吸水性树脂吸液倍率的影响。筛选出了最佳工艺条件为:丙烯酸中和度为70%,丙烯酸与醋酸乙烯酯质量比为3∶1,引发剂质量分数为0.4%,交联剂质量分数为0.035%,反应温度为70℃,PVA质量分数为8%。在最佳工艺条件下,树脂对蒸馏水和质量分数0.9%生理盐水的吸液倍率分别为1 889 g/g和124 g/g,具有良好的吸水性。并用红外光谱仪、扫描电镜、热重分析仪对其结构进行了表征。     

Synthesis and Characterization of a Conducting Composite of Polyaniline,Poly(o-Anisidine), and Poly(Aniline-co-o-Anisidine)

A conducting composite of polyaniline, poly(o-anisidine), and poly(aniline-co-o-anisidine) using incorporation of TiO₂ and SiO₂ was prepared by electrochemical polymerization. The films were electropolymerized in a solution containing 0.1 M monomer(s), 1 M sulfuric acid as supporting electrolyte, and 10^?5 M TiO₂ and SiO₂ by applying a sequential linear potential scan rate of 50 mV/s between ? 0.2 and 1.0 V versus an Ag/AgCl electrode. The composites were characterized by cyclic voltametry, UV-visible spectroscopy, electrical conductivity, and thermogravimetric analysis. It was observed that the UV-visible peaks appeared in the region of the conducting emerladine salt phase. In an overall study, the polymers prepared using TiO₂ had a higher conductivity than those prepared with SiO₂; however, higher conductivity was observed for the polyaniline-TiO₂ conducting composite than for the other polymers. The composites did not lose their color at higher temperature and hence can be utilized as the conductive pigments required for antielectrostatic applications.