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Polymer nanocomposites are particle-filled polymers in which at least one dimension of the dispersed particles is in the nanometer range. Dispersing nanosize particles in a polymer matrix induces superior mechanical properties compared to traditional macro fillers. Nanolevel reinforcement also affects the tribological properties and needs to be clearly understood before using in practical applications. Friction and wear characteristics of Nylon 6 nanocomposites under dry sliding conditions are reported in this paper. Nylon 6 with 5% organoclay was prepared by melt intercalation technique. The tensile behaviour is evaluated according to ASTM standards. A pin-on-disc type tribometer is used for evaluating the friction and wear behaviour. It is found that the Nylon 6 nanocomposites have superior tribological properties than unfilled polymer. Formation of uniform tenacious transfer layer by Nylon 6 nanocomposite on the counterface contributes to the reduction in coefficient of friction and specific wear rate. Nylon Nancomposites exhibited high wear resistance compared with the neat Nylon. [ABSTRACT FROM AUTHOR]

The tear resistance of polyethylene terephthalate film is characterized by the essential work of fracture method in mode I as a function of test speed and temperature. Attempts to extrapolate tearing resistance found by the method of essential work to commercial slitting processes are discussed. Limitations of the essential work of fracture method with regards to specimen size are evaluated. Based on the findings modifications to the test protocol are suggested. [ABSTRACT FROM AUTHOR]

The reinforced and toughened PP/PA66 in situ composites were prepared via extrusion-drawing-injection method. The relationship among composition, phase morphology and mechanical properties, together with their functional mechanism, was investigated. The results show that in the range of PA66 weight fraction (fw) from 0 to 20% and under the experimental processing conditions, the main changes in phase morphology of the composites with fw are that the number of in situ formed PA66 microfibers and remained PA66 particles increases with fw whereas the fiber transverse size and its dispersity decrease till fw = 15% and then increase. This can be attributed to the combined effect of break-up, coalescence and deformation of the PA66 phase in the PP phase in the course of extrusion and drawing. The tensile strength of composites has a maximum value at fw of 15% and Young's modulus increases with fw up to a plateau level, while impact strength continuously rises with fw, an effect which can be ascribed to the distinct dependence of these properties on the phase-morphological factors mentioned above. [ABSTRACT FROM AUTHOR]

The relation between flaw density and strength of ceramic or brittle materials were derived and applied to a commonly used testing method of four-point bending for determining the strengths of ceramic or brittle materials. Previous analysis failed to include the failures outside or at the inner loading positions for four-point test data. The present approach elevates such a constrain so that the relation applies to failures occurs at any points between the outer loading positions for four-point test data. [ABSTRACT FROM AUTHOR]