Changes in the surface structure of oriented polypropylene (PP) films in conditions of graft copolymerization of acrylamide, vinylpyridine, and styrene on a PP surface preliminary subjected to plasmochemical activation in oxygen plasma or in a plasma-electrolyte solution system are investigated by atomic-force microscopy. It is shown that the latter soft conditions of activation are superior to the hard conditions with oxygen plasma in retaining original lamellar structure of oriented PP films. It is established that the subsequent graft copolymerization of the vinyl and acryl monomers on the PP surface yields amorphous phases of respective polymers. 相似文献
Polypropylene (PP) films were modified in 1,2-dichloroethane (DCE) plasma. Surface energy measurement and rate of deposition showed two-step surface modification. First, incorporation of chloride ions on PP surface followed by deposition of cross-linked layer. DCE plasma modified PP films were subsequently compared with earlier reported work on carbontetrachloride (CCl4) and chloroform (CHCl3) plasma modification. Modified films were characterized using ATR-FTIR technique by monitoring the relative changes in intensities of C–H stretch vibrations. The nature of deposition on PP film was characterized using FTIR technique and solubility test. Peel strength measurements of DCE, CCl4, and CHCl3 plasma modified films showed improvement in bonding strength. Durability of plasma modified PP film was studied by calculating surface energy and peel strength of samples aged for two months. 相似文献
Nonporous films were formed on polypropylene (PP) films using 3-aminopropyltriethoxysilane (APTEOS) as the only precursor.
The PP film was modified by corona-plasma treatment to provide appropriate adhesion between coating layer and substrate. Gas
permeation properties of coating films were evaluated, and the influences of water ratio and film storing time on the gas
permeability were investigated. Structural and surface properties of coating layers were characterized by 29Si-NMR, FT-IR, and contact angle analyzer. The APTEOS coating films exhibit much higher barrier properties than PP film. The
permeability coefficient of APTEOS coating film with water ratio of 3 is 0.011Barrer for nitrogen, 0.044Barrer for oxygen,
and 0.002Barrer for carbon dioxide, while each permeability coefficient of PP bare film is 0.233, 0.858, and 2.886Barrer,
respectively. The gas permeability coefficient is increased slowly along with storage time. Although additionally formed siloxane
network may lead to a higher inorganic network density, the enhancement of gas permeability during storing period is largely
attributed to film-swelling effect by the water vapor from atmosphere. 相似文献
In an attempt to modify the hydrophobic surface properties of polypropylene (PP) films, this study examined the optimum process parameters of atmospheric pressure plasma (APP) using Ar gas. Under optimized conditions, the effects of a mixed gas (Ar/O2) plasma treatment on the surface-free energy of a PP film were investigated as a function of the O2 content. The polar contribution of the surface-free energy of the PP film increased with increasing O2 content in the gas mixture. However, slightly more oxygen-containing polar functional groups such as CO, CO, and COO were introduced on the PP film surface by the Ar gas only rather than by the Ar/O2 gas mixture. In addition, AFM analysis showed that the Ar plasma treatment of the PP film produced the smoothest surface as a result of the relatively homogeneous etching process. 相似文献
Graft polymerization of acrylamide (AAm) was performed onto the surface of a poly(ethylene terephthalate) (PET) film with the simultaneous UV irradiation method but using no photosensitizer and without degassing. To examine whether polyacrylamide (PAAm) was introduced into the bulk place of PET film by the surface graft polymerization, an x-ray photoelectron spectroscopic (XPS) study was performed on the PAAm-grafted PET films. The distribution of grafted PAAm chains on and in the PET films was estimated from the PAAm/PET ratio calculated from the XPS spectra of PET films with different amounts of grafted PAAm. The results clearly demonstrate that graft polymerization has actually occurred not merely on the outermost surface but also within the thin surface region of the PET film. In addition, the XPS analysis revealed that the PET component was always present in the grafted surface region by a mole fraction of 0.1 to 0.05 even when the amount of PAAm grafted was larger than 10 μg/cm2. 相似文献
High-speed surface modification of polypropylene (PP) and polyethylene (PE) films has been achieved by liquid phase photograft polymerisation of acrylic acid (AA) and hydroxypropyl acrylate (HPA). Benzophenone was used as photoinitiator to generate polymer radicals at the surface of the polyolefin film. The grafting reaction was carried out in aqueous solution or with the neat monomer, which was laminated between two PP films, in the presence of air. Under the intense illumination of a UV-curing line, acrylic acid was grafted within seconds to polypropylene films or fabrics, which were thus made hydrophilic. Direct evidence of surface grafting was obtained through infrared spectroscopy analysis and surface energy measurements. This continuous photografting process proved to be very efficient to improve the adhesion of UV-cured acrylate coatings on polyolefin-made materials. 相似文献
Plasma surface modification is widely used to tailor the surface properties of polymeric materials. Most treatments are performed
using low pressure plasma systems, but recently, atmospheric dielectric barrier discharges (DBDs) have appeared as interesting
alternatives. Therefore, in this paper, an atmospheric He + CF4 DBD is used to increase the hydrophobicity of a polypropylene (PP) film. The surface characterization of the PP film is performed
using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results show that
the hydrophobic properties of the polymer films are greatly enhanced after plasma treatment as evidenced by an increased contact
angle. The incorporation of fluorine on the surface is significant (45 at%), demonstrating the ability of the used DBD set-up
to generate fluorine-containing functional groups on the PP surface. 相似文献
Summary: A responsive polymer composite film was generated by the use of reversibly switchable surface morphology of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) films in response to different block selective solvents on the rough isotactic poly(propylene) (i‐PP) substrate. The maximum difference of the water contact angle of the composite films increased from 22.6° of PS‐b‐PMMA films on the smooth substrate to 42.6° when they were treated by PS and PMMA selective solvents, respectively. The mechanisms of the responsive extent enhanced and the superhydrophobicity of the composite films were discussed in detail.
Schematic illustration of how to fabricate a wettability‐responsive composite film: (a) on the flat Si substrate, (b) on the rough PP substrate. 相似文献
In order to prepare a new-type adsorbent with an affinity ligand, polypropylene films modified with amino acid groups such as
-phenylalanine (Phe),
,
-Phe,
-cysteine (Cys), and
,
-tryptophane (Try), were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) films and subsequent amination of poly-GMA graft chains. The physical and chemical properties of the GMA-grafted PP film and the PP film modified with amino acid groups were investigated by IR and XPS. The adsorption of urokinase for the PP films modified with four kinds of amino acid groups were examined under various conditions, such as the contents of the amino acid group and pH value. The adsorption of urokinase increased with the increasing content of the amino acid group. The adsorption of the PP film modified with four kinds of amino acid groups was in the following order:
-Phe>
,
-Phe>
,
-Try>
-Cys. The adsorption amounts of urokinase by the PP film modified with four kinds of amino acid groups at pH 7.4 was higher than that at pH 9.0. 相似文献
To improve the low water wettability of poly(ethylene terephthalate) (PET), graft polymerization of acrylamide (AAm) by UV irradiation was performed onto the surface of a PET film with the simultaneous irradiation method without using a photo sensitizer. The PET film immersed in a 10 wt % deaerated aqueous solution of AAm was found to become highly hydrophilic upon UV irradiation. Optical microscopy on cross sections of grafted films showed that localization of the graft polymerization was restricted to a thin surface region of the film. Both the low concentration of polymer radicals formed by UV irradiation and the monomer penetration limited to the film surface would be responsible for localization of the grafted layer to the film surface region. Pretreatment of the PET film with benzyl alcohol was effective for enhancement of the graft polymerization. Retention of high hydrophilicity of the surface even after rigorous extraction of homopolymer and a comparative study of polymerization without UV irradiation strongly suggested that UV irradiation of the PET film under immersion in the deaerated AAm aqueous solution would lead to formation of the true graft copolymer. 相似文献
The novel film structure of corn-zein coated on polypropylene (PP) synthetic film for packaging industry was developed to
examine the feasibility of resulting coated films as an alternative water barrier performance for food packaging. The effects
of coating formulation (solvent, corn-zein, plasticizer concentration and plasticizer type) on final properties of films were
observed. Corn-zein is the most important protein of corn and has good film forming property. Composites structures of PP
films coated with corn-zein were obtained through a simple solvent casting method. Polyethylene glycol (PEG) and glycerol
(GLY) were used as plasticizer to increase film flexibility. Statistical analysis based on full factorial design was performed
to observe coating formulation effects. The high water vapour barriers were obtained for films coated with coating formulation
consisting of higher amounts of corn-zein plasticized by GLY. The lower glass transition temperatures (Tg) of films were obtained by plasticization of films and Tg decreased by increasing plasticizer content. The statistical analysis defined the key parameters of coating formulation that
had major effects on the final properties of coated PP films as corn-zein, plasticizer concentration and plasticizer type.
In conclusion, corn-zein coatings could have potential as an alternative to conventional synthetic polymers used in composite
multilayer structures for food packaging applications. 相似文献
Emulsion polymerization of styrene/vinyl acetate/methyl methacrylate with butyl acrylate, acrylic acid and acrylamide is investigated using conventional and polymerizable surfactants. The effect of different surfactants on the water resistance, adhesion and surface properties of the polymer films was studied. The performance of films obtained from latexes using conventional surfactants is compared with that of latexes using polymerizable surfactants. The study showed that polymerizable surfactants are bound to the polymer backbone in such a way that their migration to film surfaces during drying is inhibited which helps in achieving better water resistivity with good adhesive performance. 相似文献