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Structure and properties of high-speed spun fibers of nylon 6 were studied in the range of take-up speeds from 5 to 12 kdmin. With increasing take-up speed, Young's modulus increased uniformly, while tenacity passed through a maximum at 8 km/min. WAXD data demonstrated the increase in the perfectness of the crystalline state with increasing take-up speed. First, the y-form crystal structure predominated up to 9 kdmin along with increase in its crystal size; second, in the range of 9 to 12 km/min, the a-form crystal structure appeared and developed as reflected by the increase in its crystal perfection. The structure-properties relationships are discussed, and it is indicated that the increasing tendency of Young's modulus over 9 kdmin can be attributed to the development of the a-form crystals.

An overview of advances of the amorphous wire magnetics over the past 27 years with discoveries of extremely sensitive magnetic effects such as the large Barkhausen effect, the Matteucci effect and the magnetoimpedance effect and their successive applications to security sensor tags, pen‐inputting computer tablets and electronic compasses for mobile phones in commercial productions is presented. An important new topic of biocell magnetic field sensing in vitro and human physiological magnetic field sensing in vivo using a 10 pT amorphous wire magnetoimpedance sensor is also shown that would be improved using thinner glass‐covered amorphous wires. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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ABSTRACT:The microstructure (crystallinity, long spacing) and the micromechanical properties (microhardness H) of two series of nylon 6 and nylon 66 monofilaments and their blends were investigated as a function of annealing temperature T A and uniaxial deformation in a wide composition range. In case of the homopolymers, the gradual rise of microhardness with T A is interpreted in the light of the increasing values of the crystallinity ␣ and the hardness of the crystals H c . The depression of the hardness values of the blends from the additive behavior of the hardness of individual components is discussed in the basis of the crystallinity depression of one component by the second one and viceversa. Finally, the influence of drawing and pressing the blends at 130°C which leads to a hardness increase is also explained in the light of an increase in the H c value of nylon 66 due to orientation.