聚乙烯醇薄膜的共混改性

从聚合物结构方面分析了聚乙烯醇（PVA）薄膜的水溶性,提出用共混改性方法提高PVA薄膜的溶解性能。研究了聚丙烯酸不同中和度,不同共混组分组成对薄膜水溶性和力学性能的影响,并利用差示扫描量热法（DSC）、傅立叶红外光谱（FTIR）、广角X射线衍射（WXRD）等手段对共混改性机理进行了分析。     

Poly(vinyl alcohol) and poly(vinyl amine) blend membranes for isopropanol dehydration

Blended membranes of hydrophilic polymers poly(vinyl alcohol) (PVA) and poly(vinyl amine) (PVAm) were prepared and crosslinked with glutaraldehyde. The prepared membranes were characterized using infrared (attenuated total reflection mode) spectroscopy, differential scanning calorimetry, X‐ray diffractometry, and scanning electron microscopy measurements. Pervaporation performances of the membranes were evaluated for the separation of water‐isopropanol (IPA) mixtures. As the PVAm content increased from PVAm0 to PVAm1.5, the flux through a 70 μm film increased from 0.023 to 0.10 kg/m² h at an IPA/water feed ratio of 85/15 at 30 °C. The driving force for permeation of water increased due to the temperature but it has no effect on IPA permeation. Activation energies for the permeation of IPA and water were calculated to be 17.11 and 12.46 kJ/mol, respectively. Controlling the thickness of the blend membrane could improve the permeation flux with only a marginal reduction in the separation factor. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45572.     

卤化聚乙烯醇的研究

通过将聚乙烯醇（PVA）直接卤化取代,筛选出Cl,Br等卤化剂,催化剂,并优选出合适的体系,使其既保持PVA的高阻氧性,又能保证加工性时的热稳定性。     

PVA复合薄膜水果保鲜研究

以聚乙烯醇（PVA）复合膜作为生物保鲜膜,分别研究了草莓、香蕉在PVA膜保护下的保鲜效果,分析了PVA膜保鲜作用机理,并与聚乙烯（PE）薄膜的保鲜效果进行了对比。结果表明：PVA薄膜在水果保鲜上可以降低失重率,延缓水果衰老,降低水果的变质率,延长水果贮藏期和维持良好的贮藏质量,PVA薄膜创造了"低氧气,高二氧化碳"环境,将草莓的保鲜期延长了5 d以上,达到了很好的保鲜效果。PVA薄膜对香蕉的保鲜效果不太明显,但在其保鲜期内降低了果实的失重率。     

Surface Modification of Poly(vinyl alcohol) Fibers

The surfaces of PVA fibers prepared by in situ fibrillation were modified by first crosslinking using glyoxal and then attaching cationic and anionic groups by grafting. Crosslinking prior to modification was beneficial in minimizing the solubility of the fibers in the aqueous medium in which they were modified. Heterogeneous modification techniques were employed so that fiber properties could be preserved. PAA and PDMC were grafted from the PVA microfibrils using the KPS/NaS₂O₃ redox initiating system. Grafting was confirmed by FTIR and NMR spectroscopy. The modified PVA fibers were also analyzed by DSC, TGA, and SEM.

     

乙酰乙酰化聚乙烯醇的合成

通过酯交换反应将乙酰乙酰基引入聚乙烯醇(PVA),并采用红外光谱对产物进行了表征。重点讨论了反应温度、反应时间、乙酰乙酸酯用量等因素对酯交换反应的影响。试验发现:随乙酰乙酸酯用量的增加,乙酰乙酰化程度逐渐增大;随反应温度的升高,乙酰乙酰化程度先逐渐提高,后趋于稳定;随反应时间的延长,乙酰乙酰化程度提高,2.5h后趋于平衡。     

肝素化聚乙烯醇性能研究

用聚乙烯醇(PVA)缩醛化方法,共价键结合肝素。用Schiff试剂染色法、红外光谱分析、X射线光电子能谱法(ESCA)、元素分析等测试方法证明醛基和肝素的存在。力学性能测定表明,肝素化聚乙烯醇的拉伸强度达到12 25MPa,断裂伸长率为400%。生物学指标说明,在全血凝固时间实验(CT)中,肝素化聚乙烯醇的抗凝时间达3h,在活性部分凝血时间实验(APTT)中,缩醛化聚乙烯醇共价键结合肝素非常牢固,没有肝素脱落到血液中,证明肝素化聚乙烯醇具有显著的抗凝血性。     

Poly(vinyl alcohol) modified with carboxylic acid anhydrides: crosslinking through carboxylic groups

The reaction of carboxylic acid anhydride with poly(vinyl alcohol) (PVA) leads to vinyl alcohol—vinyl ester copolymers which contain carboxylic acid groups. Esterification enables degrees of modification to be reached which depend on the chemical structure of the anhydride introduced and the ratio of the reagents in the feed. The copolymers obtained were characterized by spectroscopic techniques, elemental analysis, and thermal methods. These half-esters reacted in a second step with aromatic diglycidyl ethers to obtain tridimensional networks. This crosslinking reaction through the carboxylic groups was studied by differential scanning calorimetry. The water absorption of the linear and crosslinked polymers was determined gravimetrically as a function of time at room temperature. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1643–1651, 1997     

静电纺丝法制备聚乙烯醇纳米纤维膜及其交联处理

用化学方法和物理方法对聚乙烯醇(PVA)纳米纤维膜进行交联处理,并且用SEM、DSC和XRD分别对不同的纳米纤维膜样品进行表征。结果表明:煅烧处理的PVA纳米纤维膜的结晶度提高,抗溶解性能良好。     

改性魔芋葡甘聚糖纳米晶对聚乙烯醇薄膜性能的影响

通过硫酸水解魔芋葡甘聚糖(KGM)得到魔芋葡甘聚糖纳米晶(NKGM),再表面接枝3-(三甲氧基硅丙基)十八烷基氯化铵,与壬基酚聚氧乙烯醚硫酸钠反应等过程得到改性KGM纳米晶类流体(NKGMf);然后采用溶液流延法制备了含NKGM和NKGMf的聚乙烯醇(PVA)薄膜;通过傅里叶变换红外光谱仪、透射电子显微镜、扫描电子显微镜、热失重分析仪、拉伸测试仪等对NKGM、NKGMf的结构和PVA薄膜的性能进行表征。结果表明,经改性后,NKGM的片状结构得以保留,在PVA基质中的分散性增加,薄膜的起始分解温度提高了23℃,拉伸强度提高了34.7%,其中,NKGMf的最佳含量为3%(质量分数,下同)。     

水溶性聚乙烯醇的熔融纺丝

用共混的方法,在聚乙烯醇中加入复配增塑剂,通过共混仪探究其可纺性,通过差示扫描量热仪、热失重分析仪、强力仪等对纤维的熔点、分解温度以及强度进行测试,通过测定纤维在热水中的溶解时间探究其水溶性的好坏。结果表明:在满足材料强度要求的前提下,当复配增塑剂的质量分数达到43.6%时,改性聚乙烯醇具有很好的可纺性,且具有很好的水溶性。     

高相对分子质量聚乙烯醇的研究进展

综述了高相对分子质量聚乙烯醇的发展及其用途。从聚合方法和引发方式两方面介绍了国内外合成高相对分子质量聚乙烯醇研究进展。简述了高强高模PVA的使用场合及其应用前景,并对今后我国高相对分子质量聚乙烯醇工业的发展提出了建议。     

Properties of branched and network poly(vinyl alcohols) prepared with poly(vinyl alcohol) having aldehyde groups at the chain ends

Branched and network poly(vinyl alcohols) (PVAs) were prepared with inter-acetalization of the PVA with aldehyde groups at the chain ends which was prepared by the cleavage of 1,2 glycol bonds in commercial PVA. The numbers of branches estimated from molecular weights were compared with those estimated by theory. Huggins' constant and crystallinity decreased with increasing branch number. Dissolution of branched PVAs into dimethylsulphoxide was not so easy compared with commercial PVA. The colour of branched PVA–iodine complex decreased rapidly with standing while that of commercial PVA decreased gradually. Network PVAs with Young's modulus of 1–8 MPa were prepared.     

四种聚乙烯醇的特性粘度（浓度与比浓粘度）研究

通过对聚乙烯醇17-99H、100．37H、100-50H及100-60L的特性粘度（浓度与比浓粘度）进行研究,发现比浓粘度与浓度不成直线关系,出现了“w”折线图,即得不到聚乙烯醇的特性粘度。图中的“峰”“谷”与聚乙烯醇的组成关系,有待下一步分离、纯化后实验研究求证。     

聚乙烯醇改性及降解研究进展

从材料学的改性技术和环境学的相容性两个角度综述了国内外聚乙烯醇生物降解的研究概况。通过聚乙烯醇溶液及薄膜的降解过程的介绍,指出化学改性和微生物降解的结合将是今后处理含聚乙烯醇类废水和固体废弃物的主要方法。     

聚乙烯醇降解特性研究

采用凝胶色谱法（GPC）和紫外分光光度法（UV）研究了聚乙烯醇（PVA）微生物降解和化学氧化降解效果。GPC实验表明，PVA经过本实验室筛选的微生物菌株降解后，保留9min左右产生了一个小相对分子质量的峰，其峰面积约占总面积的一半；UV实验也表明了PVA在降解菌株的作用下，其浓度呈下降趋势；采用Fenton试剂（FR）对PVA进行预先氧化处理，然后再进行微生物降解。结果表明FR预处理有利于PVA的快速有效降解。     

拉伸对熔纺聚乙烯醇纤维结构形态的影响

采用含水的复合改性剂增塑聚乙烯醇(PVA),制备熔纺PVA纤维原丝。经冷拉伸3倍后,分别在160、220℃下进行热拉伸。研究了拉伸对纤维结构和表面、截面形貌的影响。结果表明:拉伸使纤维分子取向,结晶度升高;熔纺PVA纤维截面为圆形,拉伸后在纤维表面产生沿轴向的微孔,增加了纤维表面的粗糙度。     

聚乙烯醇改性固体淀粉胶粘剂的研制

介绍新型固体淀粉胶的制备方法。以淀粉为主要原料，经加热催化分步氧化，再加入聚乙烯醇合成树脂改善其性能，然后用硬脂酸钠作为赋型剂。制得的淀粉胶剪切强度比泡花碱高0.01MPa。