Plastic Deformation of High Density Polyethylene with Extended-Chain Crystal Morphology.

Samples of polyethylene with extended-chain crystal morphology, obtained by crystallization under high pressure, were subjected to uniaxial compression to various strains. Accompanying structural changes were analyzed using scanning electron microscopy. At the true strain of e = 0.

Deformation of Poly-l-lactid acid (PLLA) under Uniaxial Tension and Plane-Strain Compression.

The ability of PLLA, either amorphous or semicrystalline, to plastic deformation to large strain was investigated in a wide temperature range (T = 70-140 °C). Active deformation mechanisms have been identified and compared for two different deformation modes-uniaxial drawing and plane-strain compression. The initially amorphous PLLA was capable of significant deformation in both tension and plane-strain compression.

Data on bulk rock compositions, geochemical and textural contrasts between central and marginal parts of dykes, and MELTS modeling of lamprophyre dykes in the Kola Alkaline Carbonatite Province (N Europe).

This publication is a series of datasets that accompany a manuscript on petrology of lamprophyre dykes in the Kola Alkaline Carbonatite Province (N Europe) [1]. The datasets served as the basis for interpretation of melt crystallization for lamprophyric and carbonatitic dykes in the crust, to supplement many papers devoted to mantle sources and melting parameters of these rocks based on radiogenic isotopes and trace elements. The first dataset contains bulk major and trace element compositions of the dykes in three areas, Kandalaksha, Kandaguba and Turiy Mys, along with supplementary information on sampling locations and dyke characteristics.

Microbuckling Instability and the Second Yield during the Deformation of Semicrystalline Polyethylene.

Deformation instabilities, such as microbuckling or lamellar fragmentation due to slip localization, play a very important role in the deformation of semicrystalline polymers, although it still not well explored. Such instabilities often appear necessary to modify the deformation path and facilitate strain accommodation in an energy-minimizing manner. In this work, microbuckling instability was investigated using partially oriented, injection-molded (IM) samples of high-density polyethylene, deformed by a plane-strain compression.

Morphology and Plastic Yielding of Ultrahigh Molecular Weight Polyethylene.

The structure, morphology, and mechanical properties of two compression-molded grades of ultrahigh-molecular-weight polyethylene (UHMWPE) and, for comparison, one conventional linear polyethylene (HDPE) were studied. Compression molding resulted in some preferred orientation of lamellae in the compression direction in UHMWPE samples, while no preferred orientation in HDPE. The mean crystal thickness estimated from the size distribution agrees better with those obtained from small-angle X-ray scattering (SAXS) and mechanical yield data than the thickness determined from the melting peak temperature.