Monofilaments for artificial turf applications

Lack of resilience and fibrillation are the major problems encountered in the applications of monofilaments. The aim of this study was therefore to develop a bending test to assess the resilience of a monofilament and to correlate this with the results obtained with a newly developed apparatus: a 12m Lisport. The measurements of the ball roll distance with the 12m-Lisport are representative of the resilience and fibrillation resistance of the yarns in artificial turf applications. The density of the polymer, the drawing conditions and the geometry of the monofilaments are important parameters for the resulting resilience and fibrillation behaviour

Three-phase characterization of uniaxially stretched linear low density polyethylene

This study comprises a detailed morphological study of cold-drawn polyethylene monofilaments by Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray measurements. The structure of the three-phase morphology of the linear low density polyethylene monofilaments was investigated by combining these measurements. It was found that the most important structure variation was found in the intermediate or rigid amorphous phase, whereby the amounts of crystalline and amorphous phases were nearly constant and almost independent of the cold draw ratio. The intermediate third phase contains gauche and trans molecules and the amount of trans molecules was increased with the cold draw ratio and was directly related to this 2 cold draw ratio. The resulted mechanical properties of the oriented monofilaments are related to the amount of the trans content in the third phase, a result of the transformation of the gauche molecules into trans molecules due to the cold drawing of the monofilaments. It was found that the two peaks in the Raman spectra, respectively at 1303 and 1295 cm-1, can be correlated to the amount of gauche and trans molecules in the polyethylene monofilaments. A good and new insight into the three phase morphology was obtained by combining the DSC and X-ray measurements with the amounts of trans and gauche molecules from the Raman spectra analysis

Nanostructured polymer coatings for controlling the wettability of fibrous surfaces

In this research we present a new approach for modifying and functionalizing the surface properties of fibrous substrates, especially cellulose-based products, by the deposition of organic nanoparticle coatings. The partial imidisation of high-molecular weight poly(styrene-maleic anhydride) in presence of ammonium hydroxide results in a stable water-borne dispersion of nanoparticles with sizes of 50 to 100 nm. The hydrophobic properties of coated paper surfaces are governed by a unique combination of chemical (degree of imidisation) and topographic (porosity and roughness) effects: it has been found that the contact angle increases at a higher degree of imidisation and higher surface roughness. As such, maximum advancing contact angles in the range of 140 to 150° and receding contact angles of 50° can be obtained on paper surfaces

Morphologies and thermal variability of patterned polymer films with poly(styrene-co-maleic anhydride)

Patterned films of poly(styrene-co-maleic anhydride) copolymers were deposited by dip-coating from acetone solutions. A qualitative study of the film morphologies shows the formation of polymer spheres with smaller diameters at higher amounts of maleic anhydride (MA), and long-fibrous features at higher molecular weights. Upon heating, the films progressively re-assemble with short- and long-fibrous structures as a function of heating time and temperature. In parallel, the film morphologies are quantified by image processing and filtering techniques. The differential scanning calorimetry confirms the higher glass transition temperatures with increasing amount of MA. The analysis with Raman spectroscopy shows interactions between the molecules in solution and effects of ring-opening (hydrolysis) and ring-closure (formation of MA) during drying of the films. The water contact angles on the patterned films are within the hydrophilic range. They mainly correlate with the amount of MA moieties calculated from spectroscopy, while the roughness parameters have a minor effect. The variations in film patterns illustrate the self-assemble ability of the copolymers and confirm a heterogeneous molecular structure, as previously assumed

Nieuws uit de vakgroep textielkunde: semi-industriële co-extrusielijn voor de productie van monofilamenten

De vakgroep Textielkunde heeft sinds kort, door de steun van de Hercules-Slichting, de beschikking over een semi-industriele co-extrusielijn voor de productie van monofilamenten die als basis dienen voor de productie van kunstgrasvelden. Deze opstelling stell ons in staat om wetenschappelijke studies uit te voeren met monofilamenten verkregen onder industriele voorwaarden. Het strekken van de monofilamenten in vaste fase en de daaropvolgende temperatuurbehandelingen kunnen in één continue lijn uitgevoerd worden en met snelheden die de industriële snelheden en condities benaderen. Dit moet ons in staat stellen om een meer gefundeerde wetenschappelijke benadering uit te bouwen van de invloeden van de procesparameters op de uiteindelijke sporttechnische eigenschappen van de monofilamenten en van de uiteindelijke kunstgrasvelden

Novel dressing materials accelerating wound healing made from dibutyrylchitin

Dibutyrylchitin (DBC), a soluble chitin derivative, is a polymer with confirmed biological properties. DBC was obtained in the reaction of shrimp chitin with butyric anhydride, carried out under heterogeneous condition, in which perchloric acid was used as a catalyst of reaction. Production of DBC batches was carried out on a half - technical scale line. If DBC parties were examined by infrared spectrometry, size exclusion chromatography and viscometry. DBC with molar mass of 132 x 10(3) daltons was used for the manufacturing of DBC fibres and DBC non-woven materials. DBC non-woven fabrics after gamma-sterilisation were applied to a group of nine patients with different indications. DBC dressing materials were used exluding the use of other medical products. Satisfactory results of wound healing were achieved in most cases, especially in cases of burn wounds and postoperative/posttraumatic wounds and various other conditions causing skin/epidermis loss

Kunstgras: waardig alternatief voor natuurgras

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