Search results for "Adhesion"
showing 10 items of 1165 documents
Biological evaluation of PLLA membranes, with different pore diameters, to stimulate cell adhesion and growth in vitro
2015
Polymeric membranes prepared via DIPS (Diffusion Induced Phase Separation) are widely studied and utilized as scaffolds for the regeneration of tissue. In this work, poly (L)-lactide membrane are prepared through a DIPS protocol starting from a ternary solution made of polymer, dioxane (solvent) and water (non-solvent). A three-dimensional, porous and mechanically stable membrane is desirable for ingrowth of human bronchial epithelial cells. Polymeric membranes prepared via DIPS (Diffusion Induced Phase Separation) are widely studied and utilized as scaffolds for the regeneration of tissue. In this work, poly (L)-lactide membrane are prepared through a DIPS protocol starting from a ternary …
Epoxy resins as a matrix material in advanced fiber-reinforced polymer (FRP) composites
2013
Abstract: This chapter discusses the epoxy resins which, thanks to their good and versatile properties, can be considered nowadays the most important class of thermosetting polymers. In particular the chapter first reviews both the epoxy resins commonly available on the market, including a new class of bio-derived epoxy resins, and the most-used curing agents. it then describes the principal characteristics of the epoxy resins and how it is possible to enhance them by adding several fillers to the epoxy system. Finally, the chapter analyzes the main engineering fields in which epoxy resins find application today and their possible future utilization.
Evaluation of interfacial shear strength by tensile tests of impregnated flax fiber yarns
2011
Adhesion of flax fibers and polymer matrix as well as mutual bonding of elementary fibers in a technical fiber are among the principal factors governing the mechanical response of flax fiber-reinforced polymer–matrix composites. A method for evaluation of adhesion is proposed based on tension tests of impregnated fiber yarns, with subsequent characterization by optical microscopy of length distribution of fibers pulled out of the yarn fracture surfaces. An elementary probabilistic model is derived relating aspect ratio distribution of the pulled-out fibers to the fiber tensile strength distribution and the effective interfacial shear strength (IFSS). The method was applied to flax fiber/vi…
Flexural Behavior of Glass Beams with T and I Shape Cross Sections
2017
AbstractGlass beams having T or I cross sections can be obtained as glass panels or laminated glass (LG) panels assembled with polymer adhesives of different types, such as semirigid (silicones, mo...
Modulation Theory of Adhesion: Role of the Ectoenzymes Glycosidase and Glycosyltransferase
1986
It is amazing, but still plausible, that in all animal systems hitherto studied there is only one basic principle by which cell-cell recognition occurs. From sponges to higher eukaryotes there is only a small number of cell adhesion molecules which are involved in cell-cell adhesion. Specificities and histogenetic patterning are achieved by modulating processes acting on cell adhesion molecules. In sponges (secondary aggregation system) and in other eukaryotes, the activity and function of cell adhesion molecules are assumed to be modulated by enzymatic processes (glycosylation and deglycosylation). Strong evidence from experiments with sponges is available which indicates that modulation c…
Improving the properties of polypropylene–wood flour composites by utilization of maleated adhesion promoters
2007
Polymer composites filled with natural organic fillers have gained a significant interest during the last few years, because of several advantages they can offer compared with properties of inorganic-mineral fillers. However, these composites (based, in most cases, on polyolefins) often show a reduction in some mechanical properties. This is mainly due to the problems regarding dispersion of the polar filler particles in the non-polar polymer matrix and their interfacial adhesion with polymer chains. In this work, polypropylene-wood flour composites were prepared and the effect of the addition of a maleated polypropylene was investigated. The two materials were compounded by an industrial c…
Demixing and polymerization in systems of anisotropic globular particles: A molecular dynamics simulation study
1991
We report a first set of results of Molecular Dynamics simulations of phase separation in a two-dimensional system of identical particles bearing attachment sites at their surface. Morphology of regions of aggregation so obtained appear similar to images of biologically self-assembled structures. Also, they evidence the relevance of the region of thermodynamic instability and of the presence and range of interaction of specific attachment sites. Particles of our system are apt to represent indifferently, though grossly, globular proteins or rigid cells, bearing specific and fixed adhesion sites at their surface. Results illustrate some basic aspects of the origin of the morphology of extend…
Kultivierung humaner Zellen auf polymerbeschichteten Bioimplantaten?ein neues Konzept zur Verbesserung der Implantateigenschaften
2004
BACKGROUND AND PURPOSE Calcific degeneration with the resulting need for operative replacement remains the major drawback of bioprostheses. Previous studies have shown that cellular surface seeding decreases calcium uptake in vitro and in vivo, but complete coverage remains difficult to achieve. A new approach is presented, masking glutaraldehyde residues with a covalently bound polymer layer thus facilitating cell seeding. The aim of this study was to evaluate different polymers for their ability to promote surface cell adhesion and formation of complete monolayers. MATERIAL AND METHODS Ten ultrathin polymers, covalently bound to glass and exhibiting different physicochemical characteristi…
ChemInform Abstract: Glycopeptide Synthesis Using O-Pentafluorophenyluronium Salts as Novel Condensing Reagents.
2010
Pentafluorophenyluronium salts and related coupling reagents for the solid-phase synthesis of peptides and glycopeptides have been developed and employed in the synthesis of a glycopeptide sequence from the cell adhesion molecule E-CAD 1.