Sorption Behaviour of Acid Dyes by Soybean Protein/Poly （vinyl alcohol） Blend Fibre

The sorption behaviour of acid dyes by soybean protein/poly（vinyl alcohol） blend fibre was studied. The quantity of dye sorbed by the fibre increased markedly with the decrease in the pH of dyebath and reduced with the addition of neutral electrolyte when the pH was below 4.5, Acid dyes exhibited higher sorption rate constant and lower half dyeing time for the fibre than for spun silk and wool, which was related to the special morphological structure of the fibre, At pH 4, the sorption of disulphonated acid dyes with higher molecular weight followed the dual sorption mechanism of Langmuir plus Nernst-type partitioning well as they interacted with the fibre through electrostatic forces, hydrophobic forces and hydrogen bonds. It is considered that soybean protein and PVA components should be simultaneously dyed by disulphonated acid dyes with higher molecular weight.     

Compatibility of Soybean Protein and Poly (vinyl alcohol)

IntroductionTheuseofsoybean ,peanut,zeinandothervegetableproteinsasinexpensivefibermaterialstoreplacewoolandsilkcanbetracedbackto 1930s.Earlyin 1935 ,theItalianfirm ,SniaViscosa ,beganlarge scaleproductionofcaseinfibers[1] .Shortlyafterward ,ICIinEngland produced peanut proteinfibersknownasArdil.CoCornProductRefiningmanufacturedzeinproteinfiberin 1939.Theseusesofseedmealsintoindustryenhancethevalueoftheagriculturematerial.Thelargeintroductionofpetroleum basedfibersduring 194 0sand 195 0s…     

Changes in Structure and Properties of Soybean Protein/Poly （vinyl alcohol） Blended Fibers Subjected to Wet Heat Treatment

The properties of soybean protein/poly（vinyl alcohol） （SP/ PVA） blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope （SEM）, Fourier transform infrared （FTIR） spectroscopy, wide-angle X-ray diffraction （WXD） and differential scanning calorimetry （DSC）. The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1 142 cm^-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.     

Electro-spinning Antimicrobial N-halamine Modified Poly （vinyl alcohol） Nanofibers

Antimicrobial poly( vinyl alcohol)( PVA) nanofibrous composites were prepared by adding 3-( 2,3-dihydroxypropyl)-5,5-dimethylimidazolidine-2,4-dione( N-halamine diol) to the PVA solution using electro-spinning technique upon curing and exposure to diluted sodium hypochlorite. Scanning electron microscopy( SEM) demonstrates that PVA nanofibers formed with diameters of( 255 ±94) nm. Cross-linked PVA nanofibers with N-halamine diol precursor and 1,2,3,4-butanetetracarboxylic( BTCA) showed good water resistance. The chlorinated PVA nanofibrous mats completely inactivated Staphylococcus aureus( Gram-positive) and Escherichia coli O157: H7( Gram-negative) with 7 log reductions( the reduction of the bacterial concentration in logarithm) within 5min and 1 min of contact time,respectively.     

Effect of Added Poly （vinyl pyrrolidone） during Condensation on Properties of Poly（p-phenylene terephthalamide）Pulp

Poly (p-phenylene terephthalamide) (PPTA) pulp was prepared by polycondensation of the p-phenylene diamine (PPDA) with terephthaloyl chloride (TPC) in the completely anhydrous solvent system of N-methyl pyrrolidone (NMP) having calcium chloride, in the presence of poly (vinyl pyrrolidone) (PVP) having a viscosity average molecular weight lower than 40 000. It was confirmed that the polycondensation could be accelerated, the inherent viscosity of the polymer could be increased, and the polymers could be fibrillated more easily by the addition of the PVP. FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps. The morphology of the resultant pulps, the effect of viscosity average molecular weight, amount and adding mode of PVP on inherent viscosity, specific surface area,and mean length of the resultant pulps were discussed in detail. And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.     

Influences of Copolymer Composition upon the Behaviors of Poly（vinyl acetate-co-acrylamide） Sizing Agents

A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetateto acrylamide units were synthesized by emulsionpolymerization for investigating the influences of copolymercompostion upon the performance such as apparentviscosity, film behaviors, and adhesion capacity to fibers forwarp sizing operation. The mole ratios of vinyl acetate toacrylamide were varied from 0 to 4. By using animpregnated roving method, the adhesion was evaluated interms of the maximal strength and work to break of aslightly sized roving. The film behaviors included breakingstrength, breaking elongation, solution time and hygroscopiccapacity. It was found that the viscosity, adhesioncapability, glass transition temperature and film behaviorsof the copolymeric sizing agent strongly depended on themole ratio. Excessively increasing the amounts of vinylacetate or acrylamide units incorporated into the copolymericchains damages much of the performance. A favorable moleratio of vinyl acetate or acrylamide was found to be 45 : 55.Based on this mole ratio, the adhesion capability and filmbehaviors of the sizing agent reach their maximal valuessimultaneously. This demonstrates that the sizing agentshould be synthesized under this copolymer composition fromthe viewpoint of adhesion and film behaviors.     

Preparation and Structure of Poly （ethylene- co-vinylacetate）/Montmorillonite Nanocomposites

Poly(ethylene-co-vinylacetate)/sodium montmorillonite (EVA/MMT) and Poly (ethylene-co-vinylacetate)/arganophilic montmorillonite (EVA/o-MMT) nanocomposite were prepared by solid-state mixing. The morphology and structure of the composites were explored by scanning electron microscopy (SEM),wide-angle X-ray diffraction (WAXD ), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA).The results showed that the intercalated nanocomposite was successfully synthesized for EVA/o-MMT system, while in the EVA/MMT nanocomposite, MMT were poorly dispersed in the order of urn. An unexpected rubbery plateau modulus of EVA/o-MMT nanocomposite above melting point of EVA was explored by DMA. The possible origins of this high-temperature modulus were analyzed.     

pH-Compensation Effect of Lysine on the Acidic Degradation of Electrospun Poly（ lactide-co-glycolide） Fibers in PBS

Electrospun aligned ultrafine fibers of poly（ lactide-coglycolide）（ PLGA） can be used to construct biomimetic scaffolds for engineering those structurally anisotropic and dense tissues（ e. g.,tendon,ligament,etc.）. But the acidic degradation products of the PLGA could result in p H decrease in the vicinity of the scaffolds,which may give rise to biocompatibility concerns. To address the noted problem, this study was designed to evaluate the p Hcompensation capacity of using Lysine（ Lys） —a kind of basic amino acid on the acidic degradation products of PLGA. Ultrafine PLGA（ 50∶ 50） fibers with 0,10%,20%,and 30% by weight of Lys loadings were prepared by a stable jet electrospinning（ SJES）approach. The morphology,structure,and mechanical properties of the electrospun aligned fibrous mats of Lys-incorporated PLGA（ 50∶50） were characterized by scanning electron microscope（ SEM）,Fourier transform infrared spectroscopy（ FTIR）,and tensile testing,respectively. Thereafter,the fibrous PLGA（ 50 ∶50） scaffolds were subjected to degradation by being immersed in phosphate buffered saline（ PBS,p H 6. 86） solution at 37 ℃ for 5weeks. Our results show that the formed Lys / PLGA composite ultrafine fibers have a well-aligned and uniform morphology with a fineness of ca. 1 #m in diameter. Introduction of Lys led to increased mechanical performance; that is,when the Lys loading is less than 30%,tensile strength and Young＇s modulus of the aligned Lys / PLGA fibers reached up to the impressive values of 84. 5 MPa and 2. 4 GPa,respectively. Degradation results show that the p H of the PLGA group fell to 5. 6 in 5 weeks while the p H of the Lys /PLGA groups with 10%,20%, and 30% of Lys loadings was maintained at 6. 3, 6. 5 and 6. 7, respectively. This work demonstrated that incorporation of Lys into electrospun PLGA fibers could be an effective approach in mediating the p H decrease caused by the acidic degradation products of the PLGA.     

Chloromethylation of Poly（ether ether ketone）

Poly（ether ether ketone） （PEEK） is a high-performance engineering thermoplastic with good thermal stability, high chemical resistance and excellent mechanical properties. Chloromethylation reaction is ...     

Preparation and Properties of Poly（Ethylene Terephthalate）/Boehmite Nanocomposite

Colloidal boehmite particles have been included into a polyethylene terephthalate matrix by in situ polymerization. Boehmite nanoparticles were produced by the controlled hydrolysis of aluminium isopropylate. The nanoparticles were characterized using Transmitted Electronic Microscopy （TEM） and X-ray Diffraction （XRD）, which revealed the particles of magnitude about 10 nm. The particles have been used without any surface modification. Characterization of the nanocomposite has been carried out using TEM and differential scanning calorimetry （DSC）. TEM images indicate that the particles have been homogeneously dispersed in the polymer. DSC results show that the presence of boehmite affects the process of crystallization of polyethylene terephthalate.     

甲壳胺与聚乙烯醇共混纤维

将甲壳胺与聚乙烯醇进行湿法纺丝得共混纤维,并将纤维进一步缩醛化. 缩醛化增加了共混纤维的强度,这是由于缩醛化使分子间形成亚甲基桥键以及减少了纤维内空洞所致. 扫描电镜观察还表明缩醛后的共混纤维有较好的断裂韧性. 实验表明强度和密度最大值的共混比为(10%～20%)/(90%～80%)(甲壳胺/聚乙烯醇).     

聚乙烯醇渗透汽化分离膜的研究进展

在描述聚乙烯醇(PVA)成膜工艺制取不同类型的分离膜以及PVA膜的改性处理技术的基础上,给出了PVA膜渗透汽化(PV)分离有机物/水、有机物/有机物混合物的性能,讨论了交联剂、复合膜的支撑膜、高分子网络结构等对膜分离性能的影响,并分析了PV操作参数如料液浓度、操作温度等对分离性能的影响。提出了PVA膜在今后研究开发中的3个方向。     

超支化聚(酰胺-酯)/聚丙烯/聚氯乙烯共混体系的相容性研究

用扫描电子显微镜(SEM),X射线能谱仪(EDS)对聚丙烯/聚氯乙烯(m(PP):m(PVC)=80:20)二元体系和超支化聚(酰胺-酯)/聚丙烯/聚氯乙烯(HBP/PP/PVC)三元体系的相容性进行了研究.通过X射线能谱微区分析得到了共混物中氯元素面分布图,对氯元素面分布进行了粒径分布统计和平均粒径计算.实验结果表明:在PP/PVC(质量比为80:20)共混物中加入3份HBP,增容的效果最好;当HBP达到4份时, PP/PVC(质量比为80:20)的相容性反而降低.     

Fabrication of Chitosan/Poly (vinyl alcohol) Porous Membrane for Wound Dressing

A porous,biocompatible,and modifiable chitosan (CS)/poly (vinyl alcohol) (PVA) hybrid membrane, which can be evaluated as wound dressing,has been prepared by lyophilization method and using the low toxicity solvents. Experiments illustrated that the moisture regain and porosity rate of polymer blend membranes had the similar variation tendency and got the maximum value at the case of CS/PVA weight ratio of 6∶4. And the value of water vapor transmission rate( WVTR) is conductive to the healing of wound and desirable for the application as a wound dressing.Mechanical performance test of blend membrane showed that the presence of PVA could effectively improve the interaction between CS molecules. The scanning electron microscopy( SEM)photograph confirmed the porous surface on top-layer supported by a macroporous sponge-like sub-layer of this novel type of CS blend membrane. Besides, Fourier transform infrared spectroscopy( FTIR) revealed the facts that the two polymers were physically bended and certain chemical actions took place,which illustrated the good compatibility between them. Differential scanning calorimetry(DSC) results showed that decomposition reaction occurred in CS at about 210℃. Introducing of PVA to CS made the decomposition temperature of blend membrane decrease. The good properties,such as moisture regain,porosity rate,and WVTR,of this kind of CS/PVA blend membranes suggested a potential application as a wound dressing in the future.     

聚乙烯醇缩丁烯醛初探

对聚乙烯醇缩丁烯醛进行的初步研究表明，聚乙烯醇不难进行缩丁烯醛化．高缩醛度的聚乙烯醇缩丁烯醛较易凝胶化，说明其分子间交联程度较高，可能的原因是作为α，β不饱和醛的丁烯醛与聚乙烯醇进行缩醛化反应时存在着１，２加成与１，４加成两种方式     

聚乙烯醇水凝胶的制备及应用进展

综述了PVA水凝胶的制备进展,详细介绍了PVA水凝胶的最新应用研究。     

聚氯乙烯中环氧大豆油的迁移

测定了时间、温度、接触介质等对增塑聚氯乙烯(PVC)中环氧大豆油(ESO)迁移的影响,并拟合计算得到120℃下增塑剂的迁移扩散系数。结果表明,ESO在低温迁移过程中出现"诱导期","迁移诱导期"随温度升高而缩短。在40℃时,ESO的整个迁移过程处于"诱导期",在96h内未测出质量损失;在80℃时,"迁移诱导期"小于6h;在120℃时,ESO向活性碳和PVC粉末等介质的迁移则没有观察到"迁移诱导期"。通过对迁移扩散系数的拟合发现,在120℃下ESO向PVC粉末以外的其他介质的迁移符合费克定律。此外,在偏苯三酸三辛酯(TOTM)中加入ESO可以降低增塑剂的迁移量。