Immobilization of cobalt disulfophthalocyanine complex on polypropylene

Procedures were developed for chemical activation of polypropylene materials and subsequent immobilization on them of the cobalt disulfophthalocyanine complex. Factors affecting these processes were examined, and the state of the phthalocyanine on the surface of the polypropylene fiber was determined.     

Multi-Hollow Surface Dielectric Barrier Discharge for Bacterial Biofilm Decontamination

The plasma-activated gas is capable of decontaminating surfaces of different materials in remote distances. The effect of plasma-activated water vapor on Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli biofilm contamination was investigated on the polypropylene nonwoven textile surface. The robust and technically simple multi-hollow surface dielectric barrier discharge was used as a low-temperature atmospheric plasma source to activate the water-based medium. The germicidal efficiency of short and long-time exposure to plasma-activated water vapor was evaluated by standard microbiological cultivation and fluorescence analysis using a fluorescence multiwell plate reader. The test was repeated in different distances of the contaminated polypropylene nonwoven sample from the surface of the plasma source. The detection of reactive species in plasma-activated gas flow and condensed activated vapor, and thermal and electrical properties of the used plasma source, were measured. The bacterial biofilm decontamination efficiency increased with the exposure time and the plasma source power input. The log reduction of viable biofilm units decreased with the increasing distance from the dielectric surface.     

Tetra-tert-butylphthalocyanine and Its Copper Complex in Surface Modification of Nonwoven Polymer Materials

Russian Journal of General Chemistry - Immobilization of tetra-tert-butylphthalocyanine and its copper complex on a chemically activated surface of nonwoven polypropylene and Dacron materials was...     

Control of the Sorption Properties and Wettability of a Nonwoven Polypropylene Material by Direct Gas Fluorination

The effect of direct gas fluorination on the surface properties of a nonwoven polypropylene material was studied. Direct gas fluorination with mixtures of different compositions allows directional variation of the surface properties of the nonwoven polypropylene material. The surface becomes more hydrophobic when using a mixture of fluorine and nitrogen but less hydrophobic when using a mixture of fluorine, oxygen, and nitrogen. The modification leads to changes in the chemical composition of the surface and in the roughness of the material. The nonwoven polypropylene materials thus obtained exhibit increased sorption capacity for spent oil or water, respectively. Variation of the properties of the nonwoven polypropylene material allows expansion of its applications.

     

Improvement of bonding between cellulose and polypropylene by plasma treatment

Plasma treatments can be utilized to upgrade the value of lignocellulosic materials for applications such as biobased composites. Poor adhesion in biobased composites is caused by incompatibility between polar cellulosics and non-polar thermoplastics. Plasma modification of both cellulose and polypropylene was evaluated by a T-peel test for improved compatibility and adhesion between these materials. Oxygen and argon plasmas were used to modify the surface of polypropylene films, while a cyclohexane plasma was used to modify the cellulose surface through deposition of a hydrophobic polymer layer. For plasma treatment of polypropylene, changes in power input had a greater effect on adhesion than changes in pressure. Surface oxidation and increased acid/base characteristics were found on both argon- and oxygen-plasma-treated polypropylene based on ESCA and wetting measurements. With the non-reactive argon plasma the persistence of reactive species, such as free radicals, was very important for enhanced adhesion. The amount of polar carbonyl groups introduced onto the surface was also an important factor for adhesion improvement. Modification of the cellulose (filter paper) surface to a hydrophobic character with a cyclohexane plasma did not improve adhesion to polypropylene.     

Surface modification of polypropilene by gentamicin

A possibility of the immobilization of gentamicin on the surface of the polypropylene materials activated by the aqueous solution of hydrogen peroxide is studied. The polymers modified by biologically active materials are mainly the polymers of medical designation. Their basic function is exerting a complex of therapeutic actions in all phases (inflammation, regeneration and epitalization). Such materials in essence are used for preparing surgical seam threads, ambulance means, fixing bandages, prostheses of internal organs and tissues, etc.     

Surfactant-modified polypropylene as a catalyst for oxidation of mercaptans

Surface modification of polypropylene by soluble metallophthalocyanine was performed. The effect of pretreatment of polypropylene on the degree of surface anchoring of the macrocycle was shown. The catalytic activity of the hybrid materials produced in the oxidation reaction of sodium diethyldithiocarbamate was determined.     

Surface properties of plasma-modified polypropylene and propylene-hexene-1 copolymer films

The surface properties of polypropylene and propylene and hexene-1 copolymers synthesized on the rac-Me₂SiInd₂ZrCl₂-polymethylalumoxane isocpecific metallocene system and the Ph₂C(Cp)(Flu)ZrCl₂-polymethylalumoxane syndiospecific system were studied. It was found that syndiotactic polypropylene films were less hydrophobic than isotactic polypropylene films, whereas the films of propylene and hexene-1 copolymers were less hydrophobic than the films of corresponding homopolymers. The hydrophobicity of samples decreased with the hexene-1 content of the copolymer. Treatment in a dc discharge resulted in noticeable surface hydrophilization in all of the test polymer samples. There is a correlation between the surface parameters and the density of surface charge induced in the polymers by dc discharge treatment.     

Immobilization of 5,10,15,20-tetrakis(4’-carboxyphenyl)porphyrin on the surface of a modified polypropylene film

The immobilization of 5,10,15,20-tetrakis(4’-carboxy-phenyl)porphyrin on the surface modified polypropylene films was investigated. To activate the surface of the polypropylene the method of structural-chemical modification of the acrylamide and polyvinyl alcohol developed, which can increase the number immobilizing porphyrin 15–20 times. Modified materials possess of antimicrobial activity.     

Effect of polystyrene-grafted multi-walled carbon nanotubes on the viscoelastic behavior and electrical properties of polypropylene-based nanocomposites

In this work, a free-radical grafting method was used to modify multi-walled carbon nanotubes (MWNT) to improve their dispersion in a polymer matrix by use of a compounding technique. By free-radical grafting for in-situ polymerization, MWNT agglomerates are turned into a networked micro-structure, which in turn builds up a strong interfacial interaction with the polymeric matrix during the mixing procedure. Polystyrene (PS)-MWNT with a hairy rod nanostructure were synthesized by in-situ free-radical polymerization of styrene monomer on the surface of MWNT. PS-MWNT/polypropylene (PP) nanocomposites were prepared by melt mixing. The effect of polystyrene-grafted multi-walled carbon nanotube (PS-MWNT) content on the rheological properties of the polypropylene (PP)-based nanocomposites was investigated. Surface characteristics of PS-MWNT were investigated by infrared spectroscopy, Raman spectroscopy (FT-Raman), thermogravimetric analysis, and transmission electron microscopy. The rheological properties of the PS-MWNT/PP composites were confirmed by rheometry. The complex viscosity of the PS-MWNT/polypropylene (PP) nanocomposites increased with increasing PS-MWNT content, primarily because of an increase in the storage modulus G??. In-situ-polymerized PS-MWNT were uniformly distributed in the PP matrix. In addition, the PS-MWNT were interconnected in the PP matrix and then formed PS-MWNT networks, resulting in the formation of a conducting network. Therefore, compared with samples with pristine MWNT, PS-MWNT-reinforced samples have lower conductivity as a resulting of PS grafting on the surface of MWNT.     

Effect of surface chemistry and topography of sulphite fibres on the transcrystallinity of polypropylene

In the present study the effect of chemically and mechanically treated cellulose materials on the degree of polypropylene transcrystallisation was investigated. The cellulose materials which were sulphite fibres, microcrystalline cellulose (MCC) and knife milled sulphite fibre, were either chemically treated by esterification or mechanically treated by beating. The esterified cellulose materials did not induce a transcrystalline layer, however, all unesterified cellulose materials clearly induced a transcrystalline layer. The fibres which were mechanically treated by beating gave a higher degree of transcrystallisation than the untreated ones. Our results show the importance of the surface chemistry of the added fibres on the growth of transcrystallisation in polypropylene composite materials.     

Preparation of 5-benzotriazolyl-4-hydroxy-3-sec-butylbenzenesulfonate anion-intercalated layered double hydroxide and its photostabilizing effect on polypropylene

An organic UV absorber has been intercalated into a layered double hydroxide (LDH) host by ion-exchange method using ZnAl-NO₃-LDH as a precursor with an aqueous solution of the sodium salt of 5-benzotriazolyl-4-hydroxy-3-sec-butylbenzenesulfonic acid (BZO). After intercalation of the UV absorber, the interlayer distance in the LDHs increases from 0.89 to 2.32 nm. Infrared spectra and thermogravimetry and differential thermal analysis (TG-DTA) curves reveal the presence of a complex system of supramolecular host-guest interactions. The thermostability of BZO is markedly enhanced by intercalation in the LDH host. ZnAl-BZO-LDHs/polypropylene composite materials exhibit excellent UV photostability.     

The role of specific nucleation in polypropylene photodegradation

The paper focuses on the effects of polymorphism on photodegradation of isotactic polypropylene. The starting polymer was modified by a specific α-nucleating agent, 1,3;2,4-bis(3,4-dimethylbenzylidene)sorbitol, by a specific β-nucleating agent, N,N′-dicyclohexylnaphthalene-2,6-dicarboxamide, or their combination. Samples prepared by compression moulding were then exposed to UV-irradiation in the interval from 0 to 240 h. The differences in morphology were reflected in different photooxidative behaviour. Infrared spectroscopy showed that neat polypropylene was the most sensitive to photooxidation and the sample modified solely by the β-nucleating agent was the least sensitive. The remaining two samples exhibited an intermediate sensitivity. Differential scanning calorimetry revealed that the UV-exposure led to gradual changes in crystallization mechanism specifically asserting in individual materials. This behaviour was ascribed to homogeneous nucleation of partly degraded macromolecules. Possible changes of the nucleating agent itself during UV-exposure were also discussed.     

Antibacterial HPL-DOSS surface coating for commercial plastics

Bacterial colonization and biofilm formation on the surface of materials can lead to serious bacterial infections and are highly detrimental to our health. Here, we prepared a water-insoluble HPL-DOSS complex by compounding hyperbranched polylysine (HPL) with docusate sodium salt (DOSS) and coated HPL-DOSS onto the surfaces of the commercial polypropylene (PP) and thermoplastic polyurethane (TPU) plastics to afford antibacterial PP-HD and TPU-HD plastics. PP-HD and TPU-HD showed excellent antibacterial activities against both Escherichia coli and MRSA. In addition, the bacterial residues on the PP-HD and TPU-HD surfaces were significantly reduced compared with the pristine PP and TPU surfaces, indicating that the HPL-DOSS surface coating had good anti-adhesive property against bacteria and helped to reduce the formation of biofilms. Meanwhile, both PP-HD and TPU-HD exhibited excellent biocompatibility, indicating that the HPL-DOSS complex could be used as a safe antimicrobial coating material to reduce bacterial infections on plastic surfaces.     

Biodegradability of conventional and bio-based plastics and natural fiber composites during composting,anaerobic digestion and long-term soil incubation

Plastics are a major constituent of municipal solid waste that pose a growing disposal and environmental pollution problem due to their recalcitrant nature. To reduce their environmental impacts and allow them to be transformed during organic waste recycling processes, various materials have recently been introduced to improve the biodegradability of plastics. These include conventional plastics amended with additives that are meant to enhance their biodegradability, bio-based plastics and natural fiber composites. In this study, the rate and extent of mineralization of a wide range of commercially available plastic alternative materials were determined during composting, anaerobic digestion and soil incubation. The biodegradability was assessed by measuring the amount of carbon mineralized from these materials during incubation under conditions that simulate these three environments and by examination of the materials by scanning electron micrography (SEM). The results showed that during a 660 day soil incubation, substantial mineralization was observed for polyhydroxyalkanoate plastics, starch-based plastics and for materials made from compost. However, only a polyhydroxyalkanoate-based plastic biodegraded at a rate similar to the positive control (cellulose). No significant degradation was observed for polyethylene or polypropylene plastics or the same plastics amended with commercial additives meant to confer biodegradability. During anaerobic digestion for 50 days, 20–25% of the bio-based materials but less than 2% of the additive containing plastics were converted to biogas (CH₄ + CO₂). After 115 days of composting, 0.6% of an additive amended polypropylene, 50% of a plastarch material and 12% of a soy wax permeated paper pulp was converted to carbon dioxide. SEM analysis showed substantial disintegration of polyhydroxyalkanoate-based plastic, some surface changes for other bio-based plastics and coconut coir materials but no evidence of degradation of polypropylene or polypropylene containing additives. Although certain bio-based plastics and natural fibers biodegraded to an appreciable extent in the three environments, only a polyhydroxyalkanoate-based resin biodegraded to significant extents during the time scale of composting and anaerobic digestion processes used for solid waste management.     

Influence of nanodispersed boehmite on polypropylene photooxidation

Nanocomposites containing pure or organically modified nanoboehmites of different sizes were prepared by melt compounding with polypropylene. The samples were UV light irradiated in artificial accelerated conditions representative of solar irradiation (λ > 300 nm) at 60 °C in air. The chemical modifications resulting from photooxidation were followed by IR and UV-visible spectroscopies. The presence of pristine nanoboehmites was shown to change the rate of oxidation of polypropylene by reducing the oxidation induction period due to the presence of residual processing antioxidant. The differences of the oxidation induction periods between the nanocomposites and the pristine polymer disappear after solvent extraction of the antioxidant. The inefficiency of traditional antioxidant in retarding the photooxidation of polypropylene containing nanodispersed boehmite is proved. Antioxidant migration to the boehmite surface induced by the preferential interaction with the polar filler is proposed as an explanation. The oxidative behaviour of the organically modified boehmites was shown to depend on the type of organic substituent. p-Toluenesulfonate reduces the adsorption of antioxidants while the presence of a long-chain alkyl benzensulfonate increased the oxidation rate by generation of radical initiators.     

Surface modification of polypropylene materials by the cobalt complex of 5,10,15,20-tetrakis-(4-methylpyridyl)porphyrin tetratosylate

The process of immobilization of cobalt(II) 5,10,15,20-tetrakis(4-methylpyridyl)porphyrin tetratosylate on chemically activated surface of polypropylene materials was studied using infrared spectroscopy of multiple frustrated total internal reflection, electron spectroscopy, and atomic force microscopy. The modified materials were shown to have a sorption activity with respect to nitrogen bases, the structural analogs of blood toxines.     

Surface modification of polyolefins by photografting of acrylic monomers

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.     

Accelerating role of clay in photo-oxidation of polypropylene/clay multifilament yarns

Photo-oxidative degradation of polypropylene/clay multifilament yarns containing different amounts of clay was investigated. These samples and pure polypropylene(PP) multifilametns were exposed to long wavelength radiations(λ 300 nm) under atmospheric condition of constant temperature and relative humidity. The photo-oxidative stability was studied using FTIR spectroscopy, tensile testing and microscopy. The results indicate that the addition of clay particles decreases the stability of PP/clay composites to photo-oxidative degradation according to comparison with pure PP. From FTIR study and tensile properties, it was also found that the multifilaments with higher clay loading reveals a faster loss of mechanical properties, higher photo-oxidative product formation and more reduction in the induction time of photooxidation. Moreover, the crack formation on surface of irradiated filaments corresponds well to the conclusions in tensile properties and FTIR characterization.     

Polyelectrolyte-surfactant complexes and their influence on the wettability of different polymer surfaces

A novel method to modify the wettability of polymer surfaces is presented. It was found that the surface properties of polymers with different surface-free energies—polyamide 6.6, polypropylene, polyethylene and polystyrene—can be easily changed by a simple modification with premixed polyelectrolyte-surfactant complexes (PSCs). The modification effect can be significantly affected by the complex properties which are influenced by the type of surfactant and polyanion and their charge ratio in a mixture. Complexes having positive charge and low surface tension are most effective. All the complexes investigated show an interaction with polymer surfaces; however, the most effective modification was obtained with hydrophobic substrates such as polypropylene and polystyrene. In contrast to modification with the ‘pure surfactant’, the modification with PSC is persistent also after rinsing.