Enhancement of Poly(Vinyl Alcohol)–Poly(Vinyl Pyrrolidone) Blend Properties using Modified Copper (II) Oxide and Ultrasonic Irradiation

Copper (II) oxide nanoparticles supported within poly(vinyl alcohol)/poly(vinyl pyrrolidone) films have been successfully prepared through ultrasonication method. It is discernible that before the preparation of blends, the surface of copper (II) oxide nanoparticles was modified with citric acid and vitamin C as biosafe capping agents. X-ray diffraction scans illustrated the semicrystalline nature of the obtained pure blend and exhibited a good combination between the blend and the modified copper (II) oxide nanoparticles. Also, thermal stability of blends was improved in comparison to the pure polymer blend with increasing modified copper (II) oxide nanoparticles.     

Polymer Nanocomposites based on Modified ZrO2 NPs and Poly(vinyl alcohol)/Poly(vinyl pyrrolidone) Blend: Optical,Morphological, and Thermal Properties

Nanocomposite films were prepared successfully by simple solution casting method from the blend of poly(vinyl alcohol) and poly(vinyl pyrrolidone) as the polymer matrix and functionalized ZrO₂ nanoparticles as nanofiller. To prevent aggregation and improve the dispersion of nanoparticles into the matrix, ZrO₂ nanoparticles were functionalized with citric acid and ascorbic acid. Then, nanocomposites were fabricated by adding different contents of modified nanoparticles into the poly(vinyl alcohol)–poly(vinyl pyrrolidone) matrix. Thermal stability of the obtained nanocomposite films was improved in comparison to the pure blend. Furthermore, optical property of nanocomposites makes them a potential candidate for ultraviolet shielding material.     

Review: Poly(vinyl alcohol) Functionalizations and Applications

Functionalizations of poly(vinyl alcohol) congruent with the desired applications are discussed inthis article. The chemical modifications of poly(vinyl alcohol) with different molecular weights and hydrolysis degrees via conventional chemistries, namely esterification, carbamation, and etherification, and via the modern ones such as click chemistry, led to finished materials with a wide range of applications and uses: membrane fuel cells, biologicals and biomedicals, adsorption of heavy metals and other contaminants, molecular sensing or chemosensor for detection of some useful molecules or toxic ones, separation of mixtures, and catalysis in organic and inorganic syntheses. Different forms of the duly modified poly(vinyl alcohol)s were used in such applications, including hydrogels, films, membranes, and nanoparticles. The incorporated modifying agents onto poly(vinyl alcohol) matrixes brought some changes that were in tune with the projected applications. These modifying agents were not confined to molecular compounds but also to macromolecular ones which are graphene, hyaluronic acid, β-cylcodextrin, polystyrene, poly(4-vinylpyridine), and poly(L-lactic acid).     

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.     

Novel Sepiolite-based Poly(Amide-imide) Nanocomposites: Preparation and Properties

Novel sepiolite-based poly(amide-imide) nanocomposites were prepared by in-situ polymerization via polycondensation of a diamine containing amide groups with hexafluoropropane dianhydride. The process involved dispersion of sepiolite in poly(amic acid) solution followed by thermal imidization to get ultimate nanocomposites. The morphology, thermal and mechanical performances of nanocomposites with various sepiolite contents were studied. Nanoparticles were homogenously dispersed throughout the matrix with 50–65 nm size range. Due to such dispersion, poly(amide-imide)-sepiolite nanocomposite films exhibited improvements on the thermal-mechanical properties. The best results arose from favorable miscibility between polymer and sepiolite in the nanocomposites when 3 wt.% nanoparticles were introduced into poly(amide-imide) matrix.     

疏水改性聚乙烯醇的黏度行为

以２,４ 二异氰酸甲苯酯作交联剂将十四醇、十八醇作为疏水基引入聚乙烯醇分子中,合成疏水性缔合型增稠剂。当疏水基的摩尔分数仅为０．２５ ％ 时,聚乙烯醇水溶液的黏度就会迅速增高,且水溶液的耐盐能力大大增加。以摩尔分数为０．２５％ 的十八醇疏水基改性聚乙烯醇后,在ｗ（ＮａＣｌ）＝ ６％ 溶液中仍保持黏度的稳定性。     

Effective methodology for the production of novel nanocomposite films based on poly(vinyl chloride) and zinc oxide nanoparticles modified with green poly(vinyl alcohol)

Ultrasonic irradiation and solution dispersion methods were used to organize transparent worthwhile poly(vinyl chloride) (PVC) nanocomposite (NC) films which contain different amounts of modified zinc oxide nanoparticles (NP)s. First, modification of ZnO NPs was accomplished by biocompatible poly(vinyl alcohol) (PVA) to increase NCs compatibility and dispersity in the PVC matrix. The investigation followed by the fabrication and characterization of PVC/ZnO‐PVA NCs which obtained via fast and facile ultrasonication irradiation. The measurements of X‐ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy were used for the characterization of properties, structure and morphology of the obtained NPs and their NCs. Furthermore, thermal and optical properties of the resulting NCs were also carried out by thermogravimetric analysis, ultraviolet‐visible transmission, and absorption spectra. Morphology results demonstrate well‐dispersed characteristics of ZnO‐PVA NPs incorporated in the PVC matrix which resulted from modification. Also, modified ZnO NPs enhanced mechanical properties of prepared NC films. Prepared NCs could be categorized as self‐extinguishing materials on the basis of the limiting oxygen index values. POLYM. COMPOS., 38:1800–1809, 2017. © 2015 Society of Plastics Engineers     

An Efficient Preparation and Characterization of Nanocomposite Films Based on Poly(vinyl chloride) and Modified ZnO Quantum Dot with an Optically Active Diacid Containing Amino Acid as Coupling Agent

The nanocomposites were manufactured by the incorporation of modified ZnO into the poly(vinyl chloride). ZnO nanoparticles were modified with diacid containing alanine amino acid. Ultrasonic irradiation was used for all process. The PVC/ZnO@DA nanocomposites were investigated by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV–visible spectroscopy, thermogravimetric, and mechanical analysis. Results showed the uniform dispersion of particles in the polymer matrix and ZnO@DA nanoparticles in quantum dot size. The optical properties of PVC were affected by the incorporation of modified quantum dot ZnO; also mechanical properties of PVC/ZnO@DA nanocomposites were improved.     

Dispersion of Surface Modified Nanostructure Zinc Oxide in Optically Active Poly(Amide-Imide) Containing Pyromellitoyl-bis-L-isoleucine Segments: Nanocomposite Preparation and Morphological Investigation

Optically active zinc oxide/poly(amide-imide) (PAI) nanocomposites (NC)s were synthesized by using ultrasonic assisted technique. The polymers and zinc oxide (ZnO) nanoparticles were physically and/or chemically connected with each other through different kinds of interactions such as physical van der Waals forces, hydrogen bonding and/or covalent interactions. ZnO/PAI NCs were characterized by Fourier transform infrared spectra, X-ray diffraction patterns, and field emission scanning electron microscopy. The thermal stability studies indicated an enhancement of thermal stability of new NC materials compared with the pure polymer.     

Synthesis and Characterization of Hydroxyapatite/Poly(Vinyl Alcohol Phosphate) Nanocomposite Biomaterials

A hydroxyapatite (HAp)/poly(vinyl alcohol phosphate) (PVAP) nanocomposite has been prepared by a chemical method by varying the HAp content by 10–60% (w/w). The bonding between HAp and PVAP has been investigated through Fourier transform infrared absorption spectra, X-ray diffraction, and thermogravimetric analyses. Transmission electron microscopy study shows a homogeneous dispersion of nanoparticles in the polymer matrix. Scanning electron microscopy study shows enhancement of the surface roughness of the composite with an increase in the nanoparticle content. The mechanical properties of the composites improve significantly with an increase in the HAp content. The HAp/PVAP nanocomposite prepared may have bone–implant applications.     

Nanoinfusion of ZnO and ZnS nanoparticles into ethylene vinyl acetate in situ for improved optical properties

ZnO nanoparticles were successfully synthesized within the free volume of an ethylene vinyl acetate (EVA) polymer sheet. Using a process termed “nanoinfusion,” nanoparticles are created in situ. Vapor phase nanoparticle precursors first filled the polymer free volume. Nucleated components of the precursor molecule within the free volume enabled nanoparticle formation and immobilization within the polymer. Trapped nanoparticles were accessible to gas diffusion and can be modified as was demonstrated by the successful conversion of nanoinfused ZnO to ZnS nanoparticles. Successful nanoparticle formation was confirmed through fluorescence spectroscopy and the amount of material nanoinfused was obtained through thermal gravimetric analysis. The nanoinfused ZnO and ZnS exhibited unexpectedly high fluorescent quantum yields, significantly higher than that observed for comparable materials. © 2013 Society of Plastics Engineers     

Improvement of the Interactions between Modified ZrO2 and Poly(amide-imide) Matrix by Using Unique Biosafe Diacid as a Monomer and Coupling Agent

This research explores the synthesis of a high-performance poly(amide-imide) (PAI) from the polycondensation reaction of N-trimellitylimido-L-leucine as a bioactive diacid with 4,4′-diaminediphenylsulphone using combination of triphenyl phosphite and tetra-n-butylammonium bromide as a condensing agent. ZrO₂ nanoparticle (NP) was used as a filler for the formation of PAI nanocomposites (NC)s. For a unique dispersion of NPs in the PAI matrix, the surface of ZrO₂-NPs was modified with bioactive N-trimellitylimido-L-leucine using ultrasonic technique. The obtained polymer and modified ZrO₂-NPs were used to produce PAI/ZrO₂ NCs under ultrasonic irradiation. The obtained NCs were characterized by different methods.     

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。     

Novel ternary poly(vinyl pyrrolidone)/poly(amide-imide)/ZnO nanocomposite: Synthesis,characterization, thermal and optical performance

The present work describes the synthesis and properties of polymer composites based on poly(vinyl pyrrolidone) (PVP) as polymer shell and poly(amide-imide)(PAI)/ZnO nanocomposite (ZNC) as efficient filler. At first, the alanine amino acid containing dicarboxylic acid was grafted on the surface of ZnO NPs. Then, modified ZnO (12 wt%) was incorporated into the PAI matrix under ultrasonic irradiations. The obtained hybrid ZNC showed high thermal stability and the size of the NPs in the TEM image of ZNC was about 31 nm. Secondly, PVP NCs with different ZNC loadings such as 2, 4 and 6 wt% were prepared via ultrasonication. Transmission electron microscopy (TEM) observations showed that the ZnO NPs were uniformly and highly dispersed in the PVP matrix. The UV–vis results exposed that the high UV-shielding efficiency of the obtained composites. Thermal analysis represented that the onset decomposition temperatures of the obtained PVPNCs had remarkable increasing in compared to the neat PVP due to the presence of both ZnO NPs and PAI.     

Preparation of new polymer nanocomposites based on chiral poly(amide-imide)/surface-modified ZnO nanoparticles containing 4,4′-methylene bis(3-chloro-2,6-diethylaniline) linkages via ultrasonication-assisted process

In the present investigation, a novel chiral poly(amide-imide) (PAI) was synthesized via direct polycondensation reaction of chiral diacid monomer with 4,4′-methylene bis(3-chloro-2,6-diethylaniline) in molten tetrabutylammonium bromide as a green solvent. Then PAI-based bionanocomposites (BNC)s have been successfully prepared via ultrasonic irradiation method using zinc oxide (ZnO) nanoparticles functionalized by γ-aminopropyltriethoxysilane as a coupling agent to decrease aggregation of nanoparticles in polymer matrix. The physicochemical and morphology properties of the neat PAI and BNCs were studied using ¹H-NMR, FT-IR spectroscopy, specific rotation, elemental analysis, X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FT-IR and TEM depicted that the ZnO nanoparticles function as a physical cross-linking agent with PAI through hydrogen bonding between the OH on the ZnO nanoparticles and the C=O of the amide and imide groups. Also, TEM and FE-SEM images revealed that ZnO nanoparticles were dispersed in PAI matrix with particle size between 15 and 25 nm. Thermogravimetric analysis data showed an improvement of thermal stability of new BNCs in comparison with the pure PAI.     

Poly(acrylamide‐co‐vinyl alcohol)—Superabsorbent materials reinforced by modified clay

A series of copolymeric superabsorbent materials comprising polyacrylamide (PAM), polyvinyl alcohol (PVA) reinforced with variable wt% of modified clay were prepared. The copolymer/clay composite was characterized by Fourier transformed infrared, transmission electron microscopy, and scanning electron microscopy. The water absorbencies of poly(acrylamide‐co‐vinyl alcohol)/clay composites were measured by calculating their percentage swelling ratio. The effects of copolymerization, type of clay, and clay content on the water absorbencies were studied. The swelling was measured in acidic, alkaline, and saline condition to ensure its versatility. The results indicated a remarkable increase in swelling ratio by incorporation of modified clay having higher hydrophilicity and optimum clay loading. The poly(acrylamide‐co‐vinyl alcohol)/clay composite hydrogel was found to have better re‐swelling ability and water retention capacity compared to the virgin copolymer. The substantial enhancement of swelling properties enables the superabsorbent poly(acrylamide‐co‐vinyl alcohol)/clay suitable for agricultural and horticultural application. POLYM. COMPOS., 34:1794–1800, 2013. © 2013 Society of Plastics Engineers     

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。     

The utilization of poly(amide-imide)/SiO2 nanocomposite as nanofiller for strengthening of mechanical and thermal properties of poly(vinyl alcohol) nanocomposite films

The present investigation reports the preparation and characterization of the thermally stable poly(vinyl alcohol)/(poly(amide-imide)-SiO₂) nanocomposite (PVA/PAI-SiO₂ NC) films. For this reason, the surface of SiO₂ nanoparticles (NPs) was modified with N-trimellitylimido-l-methionine and subsequently, 5 wt.% of modified SiO₂ NPs were dispersed in the PAI matrix via sonochemical reaction. The resulting NC was studied by different techniques. Finally, the PAI-SiO₂ NC was employed as nanofiller and was incorporated into the PVA matrix for the enhancement of its mechanical and thermal properties. The synthesized NCs were studied by Fourier transform infrared and X-ray diffraction spectroscopy analysis. The surface topography and morphology of the NCs were studied by atomic force microscopy techniques, field emission scanning electron microscopy and transmission electron microscopy. The micrographs demonstrated that the nanofillers were homogeneously dispersed in the PVA matrix. The thermo gravimetric analysis curves indicated that the thermal decomposition of the PVA/PAI-SiO₂ NC films shifted toward higher temperature in comparison with the pure PVA. The effect of nanofiller on the mechanical properties of NC films was also explored.     

Ultrasonic attenuation and mobility in polymer solutions and dispersions. Poly(vinyl alcohol) and poly(vinyl acetate)

Summary To obtain informations about molecular processes, poly(vinyl alcohol) solutions and poly(vinyl acetate) solutions and dispersions have been studied by ultrasonic methods in the frequency range from 200 kHz to 150 MHz. The measured excess attenuations are qualitatively discussed in terms of cooperative and local mode motions of the macromolecules. In poly(vinyl alcohol) solutions with different residual vinyl acetate content a mixing of normal and local mode motions has been observed. In poly(vinyl acetate)/toluene solution two discrete relaxation processes have been detected which are probably related to a local mode and a coupling of local and normal mode motions, respectively. The frequency-temperature dependence of the absorption maximum of the poly(vinyl acetate) dispersion follows the WLF relation.     

光学活性聚酰胺酰亚胺的合成研究进展

介绍了光学活性聚酰胺酰亚胺的3种主要合成方法,即酰氯法、二异氰酸酯法及亚胺二羧酸法,讨论并总结了三种方法的优缺点,综述了以D–氨基酸和L–氨基酸为手性源的光学活性聚酰胺酰亚胺的合成研究现状,介绍了光学活性聚酰胺酰亚胺的性能如旋光性、热稳定性及可生物降解性等。