Liquid crystalline copolyesters of high molecular weight were obtained by polycondensation of aromatic diols, diacyl dichlorides, oligolactides, and poly(ethylene glycol)s. Hydrophilicity of the copolyesters was controlled by the content of ethyleneoxy moieties as verified by contact angle measurements. Copolyesters with ethyleneoxy moieties showed significant enhancement of degradability under physiological conditions in comparison to copolyester without ethyleneoxy moieties, which makes these copolyesters promising materials for bone tissue engineering as also verified by hardness testing and mechanical testing.

The picture shows compression-molded tensile bars of melt-processable high-density poly(tetrafluoroethylene) (HD-PTFE), colored with high-temperature dyes, compounded using a conventional co-rotating twin-screw extruder. Upon tensile-deformation, a macroscopic neck can be observed which runs across the interface, indicative of both deformation behavior comparable to that of common thermoplastic materials, as well as outstanding welding characteristics of these materials.

Despite widespread and growing use of polymers in applications where abrasion is present, ranging from gearboxes to prosthetic joints, abrasive wear of these materials is ill-understood. We present a study that for commercially relevant polyethylene (PE) points to the effective number of physical cross-links per macromolecular chain as the principalremarkably simplefactor that dictates the intrinsic abrasive wear resistance. This new insight has permitted us, among other things, to identify a polyethylene of a hereto unknown matrix of desirable properties, i.e., ultra-wear-resistant andunlike the commonly used ultrahigh molecular weight version (UHMW PE)melt-processable, which should open a host of novel applications.

The identification of a window of viscosities of poly(tetrafluoroethylene)s is described that :permits standard melt-processing of this unique polymer into mechanically coherent, tough objects-a polymer that, heretofore, has been characterized as "intractable" and "not melt-processable".

Using differential scanning calorimetry (DSC) and X-ray analysis it is shown that binary systems of perfluorinated alkanes form solid solutions or exhibit eutectic phase behaviour, depending on their difference in chain length. A simple model, which successfully correlated experimental results for this aspect of phase behaviour of binary n-alkane systems, is demonstrated to quantitatively describe the behaviour of perfluorinated alkanes as well. From the model parameters and experimental observations, it appears that, at equal number of carbon atoms, binary perfluorinated alkane systems allow for a larger chain difference than their hydrogenated analogues, before eutectic phase behaviour sets in.

High molecular weight liquid crystalline copolyesters were obtained by copolycondensation of aromatic diols and diacyl chlorides with oligolactides. The molecular structure of these copolyesters was verified by NMR studies. The copolyesters form nematic melts, which can be frozen in into a nematic glass. Unexpectedly, a fibrillar structure was observed exclusively on the surface of solution cast films. In spite of a significant content of lactide moieties of the copolyesters their films and fibers are characterized by exceptional mechanical properties. Initial experiments indicated excellent biocompatibility based on cell seeding experiments and microscopic evidence.