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The purpose of this study was to evaluate the mechanical properties of experimental silicone elastomers, Silastic® MDX 4-4210 reinforced with silica fillers, to assess its potential as a denture soft lining material. The mechanical properties measured included tensile strength, percentage elongation, tear strength, and Shore A hardness. Using one-way ANOVA and Tukey's HSD test, the results indicated that silicone elastomers with filler loadings of 6, 8, and 10 phr had significantly greater tensile strength, percentage elongation, tear strength with a softer surface compared with commercial materials (p<0.001). In conclusion, the experimental silicone elastomers revealed acceptable mechanical properties to be used as denture soft lining materials. [ABSTRACT FROM AUTHOR]

Abstract: Artificial turf surfaces with “soft” yarns are increasingly used because of haptic attractiveness and player friendliness. Linear low density polyethylene (LLDPE) with low density is preferred to achieve the desired softness. The choice of LLDPE material is guided by the performance requirements outlined in the FIFA Quality Concept for football turf . Different LLDPE materials were extruded into fibrillated tape yarns on pilot and production scale machinery. A key mechanical property of fibrillated yarns is the tear resistance in machine direction influencing the fibrillation process and the ultimate yarn splitting and resulting wear in the field. A high tear resistance makes fibrillating the yarn difficult however improves the ultimate split and wear resistance in the field. Unfibrillated oriented yarns of different composition were analyzed for tear and other mechanical properties. The results are related to previous work on durability of certain yarn compositions which demonstrate the benefits of low density LLDPE resins in terms of durability and wear resistance . As proof of concept one metallocene LLDPE resin with one of the highest tear resistance values currently commercially available was extruded into oriented yarn and subsequently fibrillated. Processing conditions and choice of particular LLDPE greatly influence yarn fibrillation and performance. As already demonstrated in monofilament yarns , shrinkage is identified as an important measure to characterize residual stress in low density LLDPE yarns. We discuss strategies to minimize shrinkage for fibrillated tape made with low density LLDPE and refer to its relation to performance in the Lisport test used to determine the durability of an artificial turf yarn. [Copyright &y& Elsevier]

The possibility of modifying the structure and properties of fibrous papermaking pulps with bacterial cellulose was investigated. For this purpose, three ways of obtaining specific composites were developed. The first one consisted in making the biosynthesis of bacterial cellulose in Acetobacter xylinum culture in the presence of fibres of papermaking semiproducts; the second one involved the addition of suitably disintegrated bacterial cellulose film to different papermaking pulps; and the third one consisted of joining semi-product paper sheets with bacterial cellulose film by putting the bacterial cellulose film on a sheet of paper and drying it in laboratory apparatus of the Rapid-Koethen type. The most important structural and strength properties of fibrous semi-products and their composites with bacterial cellulose were determined and compared. It was observed, among others, that composites produced according to the first two methods (i.e. in acetobakter xylinum culture and as a result of the addition of bacterial cellulose to a fibrous semi-product) in general show higher static and dynamic strength indices than semi-products used for composite production. The joining of sheets of two kinds of cellulose (i.e. fibrous semi-product and bacterial cellulose) gives a two-layered composite characterised above all by higher static strength properties than unbeaten pulps and, at the same time, a higher tear resistance in comparison with bacterial cellulose. Joining bacterial cellulose with pulp fibres, irrespective of the joining method, increases the apparent density of the semi-product. [ABSTRACT FROM AUTHOR]