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A procedure is described of grafting the acrylic acid onto an oxygen/ozone-activated metallocene poly(ethylene-co-propylene). Consequently, the grafted copolymer is applied as a component in a metallocene polyolefin-based hot-melt adhesive composition with increased adhesion. The surface properties and adhesion strength of the prepared hot-melt adhesive (HMA) were determined and used to account for the effect of grafting. The application of grafted polyolefin as one of the components of the HMA mixture provides significant increase in adhesive strength, and it also results in increased compatibility and negligible effects on the technological parameters of the final composition. The obtained results may have significant impact for the practical application of prepared HMA for book bonding. [ABSTRACT FROM AUTHOR]

Alginic acid coated polyethylene films were examined in terms of surface properties and bacteriostatic performance against two most representative bacterial strains, that is, Escherichia coli and Staphylococcus aureus. Microwave plasma treatment followed by brush formation in vapor state from three distinguished precursors (allylalcohol, allylamine, hydroxyethyl methacrylate) was carried out to deposit alginic acid on the substrate. Surface analyses via various techniques established that alginic acid was immobilized onto the surface where grafting (brush) chemistry influenced the amount of alginic acid coated. Moreover, alginic acid was found to be capable of bacterial growth inhibition which itself was significantly affected by the brush type. The polyanionic character of alginic acid as a carbohydrate polymer was assumed to play the pivotal role in antibacterial activity. The cell wall composition of two bacterial strains along with the substrates physicochemical properties accounted for different levels of bacteriostatic performance. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is one of the most widely used polymers in many industrial applications. Biomedical uses seem to be attractive, with increasing interest. However, PE it prone to infections and its additional surface treatment is indispensable. An increase in resistance to infections can be achieved by treating PE surfaces with substances containing antibacterial groups such as triclosan (5-Chloro-2-(2,4-dichlorophenoxy)phenol) and chlorhexidine (1,1'-Hexamethylenebis[5-(4-chlorophenyl)biguanide]). This work has examined the impact of selected antibacterial substances immobilized on low-density polyethylene (LDPE) via polyacrylic acid (PAA) grafted on LDPE by low-temperature barrier discharge plasma. This LDPE surface treatment led to inhibition of Escherichia coli and Staphylococcus aureus adhesion; the first causes intestinal disease, peritonitis, mastitis, pneumonia, septicemia, the latter is the reason for wound and urinary tract infections. [ABSTRACT FROM AUTHOR]

Medical-grade polyvinyl chloride was coated by polysaccharides through a novel physicochemical approach. An initial surface activation was performed foremost via diffuse coplanar surface barrier discharge plasma in air at ambient temperature and pressure. Then, radical graft copolymerization of acrylic acid through grafting-from pathway was directed to render a well-defined brush of high density, and finally a chitosan monolayer and chitosan/pectin alternating multilayer were bound onto the functionalized surfaces. Surface characteristics were systematically investigated using several probe techniques. In vitro bacterial adhesion and biofilm formation assays indicated that a single chitosan layer was incapable of hindering the adhesion of a Staphylococcus aureus bacterial strain, while up to 30% reduction was achieved by the chitosan/pectin layered assembly. On the other hand, chitosan and chitosan/pectin multilayer could retard Escherichia coli adhesion by 50% and 20%, respectively. Furthermore, plasma treated and graft copolymerized samples were also found effective to diminish the degree of adherence of Escherichia coli. [ABSTRACT FROM AUTHOR]

Poly(lactide) (PLA) films obtained by thermoforming or solution-casting were modified by diffuse coplanar surface barrier discharge plasma (300 W and 60 s). PLA films were used as hot-melt adhesive in joints in oak wood. It was demonstrated that lap shear strength increased from 3.4 to 8.2 MPa, respectively, for the untreated and plasma-treated series. Pull-off tests performed on particleboard for the untreated and treated PLA films showed 100% cohesive failure. Pull-off strength tests on solid oak demonstrated adhesion enhancement from 3.3 MPa with the adhesion failure mode to 6.6 MPa with the cohesion failure mode for untreated and treated PLA. XPS revealed that carbonyl oxygen content increased by two-to-three-fold, which was confirmed in the Fourier-transform infrared spectroscopy experiments of the treated PLA. The water contact angle decreased from 66.4° for the pristine PLA to 49.8° after treatment. Subsequently, the surface free energy increased from 47.9 to 61.05 mJ/m2. Thus, it was clearly proven that discharge air plasma can be an efficient tool to change surface properties and to strengthen adhesive interactions between PLA and woody substrates. [ABSTRACT FROM AUTHOR]