PVA/明胶/淀粉水凝胶的制备及性能

采用反复冷冻一解冻法制备了不同配比的聚乙烯醇／明胶／淀粉水凝胶膜。测试了共混膜的力学性能、脱水率和溶胀度，用扫描电镜观察了共混膜的断面形貌。结果表明：除1：1配比的水凝胶膜成膜性差，其他配比的水凝胶成膜性较好，膜表面比较光滑。m（PVA）：m（明胶）为6：1时力学性能较好。脱水率和溶胀度均随PVA和明胶比例增大而减小。扫描电镜显示，水凝胶膜内部具有多孑L结构，可以用作组织工程支架材料。     

壳聚糖/聚乙烯醇复合水凝胶制备及性能研究

成功制备了壳聚糖/聚乙烯醇(CS/PVA)复合水凝胶。考察了聚乙烯醇与壳聚糖的质量比及戊二醛用量等对水凝胶溶胀度、机械强度等的影响。结果表明:当聚乙烯醇与壳聚糖质量比为2,戊二醛浓度为0.213 mol/L时,水凝胶的综合性能最佳。     

壳聚糖/聚乙烯醇/半胱氨酸复合水凝胶的制备及其性能研究

以壳聚糖(CS)、聚乙烯醇(PVA)和L-半胱氨酸(L-cysteine)为原料,以甲基丙烯酸缩水甘油酯(GMA)为交联剂,通过化学交联和光固化反应合成了壳聚糖/聚乙烯醇/半胱氨酸复合水凝胶。考察了半胱氨酸用量、光引发剂用量等对复合水凝胶性能的影响。试验表明,制备出的水凝胶薄膜溶胀能力和耐溶剂性能均随L-半胱氨酸的增加先增大后减小,加入少量L-半胱氨酸后断裂伸长率由13%增长到200%以上,加入过量的L-半胱氨酸使得断裂伸长率和强度下降。引发剂的加入对材料形貌有一定的影响。在L-半胱氨酸加入量为与GMA摩尔质量比1∶1时性能最优。     

BC/PVA/PEG增强型复合水凝胶的制备及其表征

通过反复冷冻—溶融法制备了细菌纤维素/聚乙烯醇/聚乙二醇(BC/PVA/PEG)复合水凝胶,并采用扫描电镜、红外光谱、X-射线衍射和拉力测试等手段对水凝胶的结构和性能进行表征。拉伸力学性能测试结果表明,随着PEG的加入,水凝胶的力学性能得到显著增强。     

n-HA/I-Col/PVA复合水凝胶材料制备及其性能研究

本研究以纳米羟基磷灰石(n-HA)、聚乙烯醇(PVA)以及I型胶原(I-Col)为原料,通过物理共混法、表面活性剂OP-10发泡致孔法及化学-物理交联法制备纳米羟基磷灰石/I型胶原/聚乙烯醇(n-HA/I-Col/PVA)复合水凝胶,以期用于人工角膜支架材料。实验以化学交联剂戊二醛的用量、胶原用量作为变量来研究最佳配方。结果表明当加入4 m L胶原和2 m L 0.04 mol/L戊二醛时,复合水凝胶含水率为70.41%、孔隙率为58.95%、拉伸强度为3.87 MPa,具有较好的人工角膜综合性能;XRD与IR表明原材料与交联剂之间互相有物理-化学交联作用;SEM观察可见复合水凝胶呈多孔网状结构,孔洞之间相互贯通。     

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。     

壳聚糖/明胶/聚乙烯醇复合水凝胶的溶胀性能研究

以聚乙烯醇(PVA)、明胶和壳聚糖为原料,以戊二醛为交联剂,在醋酸溶液中通过共混交联反应合成了壳聚糖/明胶/聚乙烯醇复合水凝胶,考察了聚乙烯醇/壳聚糖/明胶的质量比、交联剂用量、反应温度、反应时间对复合水凝胶溶胀性能的影响。通过正交实验,确定制备复合水凝胶的优化条件如下:交联剂用量为6 mL、反应温度为75℃、反应时间为70 min、聚乙烯醇/壳聚糖/明胶的质量比为1∶2∶2,在此优化条件下合成的壳聚糖/明胶/聚乙烯醇复合水凝胶溶胀性能良好,对水的平衡溶胀度达到985%。     

化学交联法制备ZnO/PVA复合水凝胶

以氯化锌为原料制备纳米氧化锌(ZnO),采用化学交联法法制备ZnO/聚乙烯醇(PVA)复合水凝胶,研究ZnO加入量对复合水凝胶拉伸强度、断裂伸长率以及溶胀性能的影响。实验结果表明:ZnO含量为0.1%时,复合水凝胶的拉伸强度和断裂伸长率最大,而ZnO含量为0.4%时,复合水凝胶的溶胀率最大。     

n-HA/Ⅰ-Col/PVA复合水凝胶材料制备及其性能研究

本研究以纳米羟基磷灰石(n-HA)、聚乙烯醇(PVA)以及Ⅰ型胶原(Ⅰ-Col)为原料,通过物理共混法、表面活性剂OP-10发泡致孔法及化学-物理交联法制备纳米羟基磷灰石/Ⅰ型胶原/聚乙烯醇(n-HA/Ⅰ-Col/PVA)复合水凝胶,以期用于人工角膜支架材料.实验以化学交联剂戊二醛的用量、胶原用量作为变量来研究最佳配方.结果表明当加入4mL胶原和2mL 0.04 mol/L戊二醛时,复合水凝胶含水率为70.41％、孔隙率为58.95％、拉伸强度为3.87 MPa,具有较好的人工角膜综合性能;XRD与IR表明原材料与交联剂之间互相有物理-化学交联作用;SEM观察可见复合水凝胶呈多孔网状结构,孔洞之间相互贯通.     

聚乙烯醇/水杨酸/纳米二氧化钛复合水凝胶膜的制备及性能

用纳米二氧化钛(nano-TiO_2)对聚乙烯醇/水杨酸(PVA/SA)水凝胶膜进行改性,考查了不同nano-TiO_2用量的PVA/SA/nano-TiO_2复合水凝胶膜的结构与性能。结果表明:复合膜的透明度随nano-TiO_2用量的增加而降低,而其抗菌性、抗紫外线性及透气性均随nano-TiO_2用量的增加而提高;复合膜的力学性能随nano-TiO_2用量的增加呈先上升后下降的趋势,而其溶胀性却恰好与之相反;当nano-TiO_2用量为5.0%时,复合水凝胶膜的透气系数为0.737 9 m~2/(s·kPa),拉伸强度为8.44 MPa,最大紫外线透过率仅为71.12%,透光率达69.08%,对大肠杆菌与霉菌均具有较好的抑制作用,15℃时溶胀度达19.41%。     

丙烯酰胺改性玉米淀粉/PVA复合膜的制备与表征

为了改善聚乙烯醇（PVA）膜的机械性能,选用玉米淀粉为原材料,50℃条件下以过硫酸铵和尿素为引发剂,同时加入丙烯酰胺对淀粉进行接枝改性,制备得到丙烯酰胺改性的玉米淀粉/PVA复合膜。其中,优化改性淀粉的接枝率确定最佳合成条件为淀粉/丙烯酰胺的质量比为3∶7、引发剂过硫酸铵占单体总质量的0.5%、尿素占单体总质量的0.5%。进一步利用优化的改性淀粉为改性剂,制备了系列改性玉米淀粉/PVA复合膜。采用傅里叶红外光谱、扫描电子显微镜（SEM）对复合膜的组成与结构进行表征,同时测定复合膜的机械性能、耐水性、耐热性等物化特性,结果表明30%ST-0.50%APSU改性淀粉的单体转化率为95.0%,接枝率为85.2%。 30%ST-0.50%APSU/PVA复合膜的耐热性能轻微下降,但断裂伸长率提高了256%,耐水性能提高了43.1%。     

Oxidation of potato starch with NO2: characterization of the carboxylic acid salts

Oxidation of primary hydroxyl groups of potato starch to the corresponding carboxylic acids was performed in a fluidized bed using N₂-diluted NO₂ as oxidant. FT-IR spectrum of the oxidized starch show the presence of two absorption bands at 1743 and 1379 cm⁻¹. The absorption at 1743 cm⁻¹ which normally attributed to carbonyl absorption vanishes after washing the oxidized starch by water. Then two new absorption bands appeared at 1650 and 1400 cm⁻¹ corresponding to the ionized carboxyl groups.

The presence of nitrate favor the un-ionized form of carboxyl groups and then the band at 1743 cm⁻¹ can be observed. Furthermore, the ionized carboxyl absorption (1600, 1400 cm⁻¹) are replaced by carbonyl absorption at 1743 cm⁻¹ by adding DCl. By means of ¹³C NMR analysis, oxidized starch, show a band around 200 ppm attributed to carboxylic acid, no formic acid was detected indicating that no cleavage took place under the applied reactions conditions.     

Preparation and characterization of a novel injectable in situ cross-linked hydrogel

A novel injectable in situ cross-linked hydrogel was prepared from α,β-poly(N-hydroxyethyl)-dl-aspartamide (PHEA), which had excellent biocompatibility and biodegradability. PHEA was modified by acryloyl chloride (AC) via the reaction between hydroxyl groups and acryl groups to introduce reactable double bonds into the chain. Two macromers with different degrees of derivatization were prepared. Through NMR and FT-IR characterizations, the structures of the polymers were proposed. Hydrogels were prepared by covalent cross-linking between double bonds with a transition from liquid to gel at body temperature. The effect factors on gelation time, swelling ratio and gel content were investigated in detail. It was found that the grafting ratios of AC, concentrations of macromer and initiator had great influence on the gelation time. And it could be adjusted to meet the requirements of an injectable material.     

Preparation and characterization of the n-HA/PVA/CS porous composite hydrogel

In this paper, a new method combines chemical/physical crosslinking, and emulsification-foaming porogenic was adopted to prepare n-hydroxyapatite (n-HA)/polyvinyl alcohol (PVA)/chitosan (CS) porous composite hydrogel using artificial cornea scaffold materials. The fabricate conditions, including the type and amount of emulsification-foaming porogen, mixing time and speed etc. were researched. The results showed the optimal condition that the alkylphenol polyoxyethylene ether (OP) acted as emulsification-foaming porogen, with the ratio of W_PVA/W_OP as 3.75, and mixing 15 min with a stirring speed of 800 r·min^-1. Additionally, the fabricated composite hydrogel scaffold materials possessed interconnected internal holes, a moisture content of above 65%, and tensile strength of above 6 MPa. In vitro cytotoxicity and acute systemic toxicity assay confirmed that the scaffolds did not show any cytotoxicity. The as-prepared hydrogel could be a promising candidate for artificial cornea scaffold material.     

淀粉/聚乙烯醇/蒙脱土复合材料的制备及性能研究

采用熔融挤出法制备了淀粉/聚乙烯醇/蒙脱土三元复合材料。通过对力学测试、DSC、SEM、维卡软化点的分析,研究了PVA和酸酐的含量对材料的力学性能、热性能、吸水率的影响,并讨论了蒙脱土的加入对体系性能的影响。研究发现,适量的顺丁烯二酸酐能够降低淀粉分子链间的氢键作用,并促使其晶区的破坏,从而改善淀粉的加工性能、力学性能以及耐水性,当加入2.5%顺丁烯二酸酐时,材料的拉伸强度提高了60.54%;随着PVA含量的增加,体系力学性能增强,吸水率降低。蒙脱土的加入改善了其加工性能,并有效地提高了材料的力学性能、耐水性以及热稳定性。SEM显示,复合材料各组分之间的相容性较好,淀粉得到良好的塑化。     

State of water in chitosan–PVA hydrogel

The bound water fraction (X_BW) of a newly‐ developed pH‐sensitive, biodegradable chitosan‐polyvinyl alcohol (PVA) hydrogel crosslinked with glutaraldehyde (GA) was investigated as a function of the chitosan/PVA molar ratio, GA concentration (C_GA), and ionization state. Differential scanning calorimetry (DSC) was used to determine the X_BW of the initial hydrogel, and of the hydrogel equilibrated in pH 3 and pH 7 buffers. Changes in X_BW during swelling and shrinking of hydrogel were also investigated. In the initial state of hydrogel, X_BW increased with increasing PVA concentration (C_PVA), without being significantly affected by C_GA. In the buffer‐equilibrated hydrogels, X_BW decreased with increasing C_PVA and decreasing C_GA. The amount of bound water based on dry mass (C_BW) was substantially higher when the hydrogel was in the ionized (swollen) state compared to its unionized counterpart. This may be due to the association of a large quantity of water molecules with ? NH₃⁺ groups of chitosan when the gel swelled in the acidic environment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3227–3232, 2006     

淀粉/丙烯酸/PVA互穿网络高吸水性树脂的合成

以淀粉、丙烯酸(AA)和聚乙烯醇( PVA)为原料,N,N-亚甲基双丙烯酰胺为交联剂,采用水溶液聚合法制备了淀粉/丙烯酸/聚乙烯醇互穿网络高吸水性树脂;探讨了淀粉、PVA、引发剂、交联剂用量及丙烯酸中和度对产物吸水倍率的影响;用红外光谱对产物进行了表征.结果表明,所制备的互穿网络高吸水性树脂的吸蒸馏水和生理盐水能力最高...     

Preparation and characterization of PVA/SA composite nanofiltration membranes

Nanofiltration (NF) composite membranes based on poly(vinyl alcohol) (PVA) and sodium alginate (SA) were prepared by coating PVA/SA (95/5 in wt %) mixture solutions on microporous polysulfone (PSF) supports. For the formation of a defect free thin active layer on a support, the PSF support was multi‐coated with a dilute PVA/SA blend solution. The PVA/SA active layer formed was crosslinked at room temperature by using an acetone solution containing glutaraldehyde as a crosslinking agent. The prepared composite membranes were characterized with a scanning electron microscopy (SEM), a Fourier transform infrared spectroscopy (FTIR), an electrokinetic analyzer (EKA) and permeation tests: The thicknesses of the active layers were about 0.25 μm and 0.01 μm depending on the preparation conditions. The crosslinking reaction of the active layers were completed in less than three minutes via the formation of acetal linkage. The surface of the PVA/SA composite membrane was found to be anionic. The permeation properties of the composite membrane were as follows: 1.3 m³/m² day of flux and > 95% of rejection at 200 psi for 1000 ppm PEG600 solution. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 347–354, 2000     

退浆废水中聚乙烯醇和淀粉浓度的测量

论文对测定退浆废水中聚乙烯醇(PVA)和淀粉的浓度进行了研究.利用普通分光光度仪,通过双波长分光光度法进行了分析和讨论,得到了适宜的实验条件:2.5%的硼酸5mL,1.27%的碘溶液2 mL,显色时问为15～20min.还得到了双波长分光光度法测定PVA和淀粉浓度的计算式.实验表明:用该方法同时测定双组分含量,既简便又准确.     

Synthesis and characterization of nanostructured PZT encapsulated PVA–PAA hydrogel

Hydrogel/PZT composite was prepared by encapsulating, Pb(Zr_0.52Ti_0.48)O₃ (PZT) nanoparticles in an electroactive (PVA–PAA) hydrogel. The XRD studies confirmed the presence of pure tetragonal phase in PZT with crystallite size of 13 nm in the composite matrix. PZT nanoparticles were found to be embedded in the micro pores of PVA–PAA hydrogel as indicated by the SEM images. The composite shows three step degradation process in the TG/DTA measurements. Dielectric properties were studied from room temperature to 120 °C within wide frequency range of 100 Hz–600 kHz. At room temperature and intermediate frequency range, the composite shows a high dielectric constant of ~225 to 600 and low dielectric loss of 0.08.