Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

A review on polymer–layered silicate nanocomposites

Mechanical and chemical recycling of solid plastic waste.

Analysis of glutathione: implication in redox and detoxification.

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Recycling of PET

Plane strain compression in a channel die is kinematically very similar to drawing; however, the possibility of void formation is limited due to a compressive component of stress. In drawing, voids were detected by small-angle X-ray scattering (SAXS) and density measurements in poly(methylene oxide) (POM), polypropylene (PP), and high-density polyethylene (HDPE), but no voiding was found in polyamide 6 (PA 6), low-density polyethylenes (LDPEs), and ethylene−octene copolymer (EOC). The slope and shape of the initial elastic part of true stress−true strain curves are similar in tension and in channel die compression. When drawn samples of POM, PP, HDPE, and PA 6 already show yielding, the channel die compressed samples still undergo elastic deformation to a much larger deformation and respond with a much larger stress. Channel die compressed POM, PP, HDPE, and PA 6 exhibit strong and rapid strain hardening up to 400 MPa in contrast to their behavior in tension. The difference in strain hardening is related ...

Plastic Deformation of Crystalline Polymers: The Role of Cavitation and Crystal Plasticity

Cavitation during deformation of semicrystalline polymers

Preparation and properties of compatibilized LDPE/organo-modified montmorillonite nanocomposites

The process of cavitation during tensile deformation of polypropylene was studied. It was shown that in injection-molded polypropylene samples cavities appear in the center of a sample shortly before yielding. With increasing deformation the cavities change their size, number, and orientation from elongated perpendicular to parallel to deformation. The cavitation process is visible also as a rapid increase of volume of deformed material. The cavitation could be suppressed by changing internal morphology of polypropylene by fast cooling. The samples prepared by compression molding followed by quenching, with less perfect crystals, were able to deform by plastic deformation of crystals without cavitation. However, for faster draw rate the cavitation in amorphous phase was preferred again due to stronger response of crystals.

Andrzej Pawlak

Papers

Plastic Deformation of Crystalline Polymers: The Role of Cavitation and Crystal Plasticity

Cavitation during deformation of semicrystalline polymers

Preparation and properties of compatibilized LDPE/organo-modified montmorillonite nanocomposites

Cavitation during Tensile Deformation of Polypropylene

Cavitation during tensile deformation of high-density polyethylene