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

Renewable resources are used increasingly in the production of polymers. In particular, monomers such as carbon dioxide, terpenes, vegetable oils and carbohydrates can be used as feedstocks for the manufacture of a variety of sustainable materials and products, including elastomers, plastics, hydrogels, flexible electronics, resins, engineering polymers and composites. Efficient catalysis is required to produce monomers, to facilitate selective polymerizations and to enable recycling or upcycling of waste materials. There are opportunities to use such sustainable polymers in both high-value areas and in basic applications such as packaging. Life-cycle assessment can be used to quantify the environmental benefits of sustainable polymers.

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Sustainable polymers from renewable resources

Chemical modification of lignins: Towards biobased polymers

Synthesis, properties, and applications of magnetic iron oxide nanoparticles

A review on pyrolysis of plastic wastes

Among the promising sustainable materials of modern times, biopolymeric nanocomposites have received an increased interest for orthopedic applications due to their excellent mechanical, biocompatibility, bioactivity properties, and special architecture for the cells proliferation, differentiation, and migration in bone tissue regeneration. The aim of this chapter is to summarize the recent research results on the development and applications of various types of biopolymeric nanocomposites utilized in prosthetic devices to bone grafts, for cell delivery, with a special focus on material type, formulations, current design, and performance in bone tissue engineering. Important challenges related to the degradation of biopolymeric nanocomposite scaffolds, wide range of properties, and benefits for bone healing are addressed.

Biopolymeric Nanocomposites for Orthopedic Applications

Behavior of polypropylene/epoxidized lignosulfonate blends has been tested in conditions of accelerated aging both in the pres * ice of microorganisms and in soil burial. It has been established that increase of the epoxidized lignosulfonate concentration is not sufficient to create materials with satisfactory environmental/ biodegradation rate.

Polyolefins/lignosulfonates blends. V. Bio- and environmental degradation

Amiodarone low solubility and high permeability is the limiting step for its bioavailability, therefore new formulations are needed to improve the solubility of amiodarone either to increase its oral bioavailability or to reduce its toxic effects. Complexation of amiodarone with cyclodextrin results in improved dissolution rate, solubility, and allows for a more controlled drug release. We characterized the acute toxicity of a new amiodarone 2-hydroxypropyl-β-cyclodextrin complex (AMD/HP-β-CD) as powdered form and as a matrix based on Kollidon® and chitosan, administered intraperitoneally in laboratory animals. There were developed two formulations of matrix: one containing only pure AMD as a control sample (Fc) and one containing the inclusion complex with the optimal solubility (F). AMD was equitoxic with HP-β-CD after intraperitoneal administration (289.4 mg/kg for AMD and 298.3 mg/kg for AMD/HP-β-CD), with corresponding histopathological changes. The matrix based formulations presented higher LD50 values for acute toxicity, of 347.5 mg/kg for Fc and 455.6 mg/kg for F10, conducting to the idea of a safer administration because KOL and CHT matrix modified the solubility and controlled the AMD release. The LD50 is 1.5 higher for AMD/HP-β-CD included in a KOL and CHT based matrix compared to the pure AMD, administered intraperitoneally.

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Study on Acute Toxicity of Amiodarone New Complexes With Cyclodextrin.

This paper presents the synthesis of some new theophylline derivatives with potential bronchodilatatory properties. The compounds were synthesized starting from theophylline and 8-R-theophyllines (R=Br, NO(2), pyrrolidinyl, piperidinyl, morpholinyl, imidazolyl) that were reacted with 4-(2,3-epoxy-propyloxy)-acetanilide. The new compounds, which have not been mentioned in the literature concerning this domain, have been characterized by their physical constants (melting point, solubility) and the chemical structure was confirmed by elemental and spectral (FT-IR, (1)H-NMR, (13)C-NMR) analysis. The DL(50) values of new synthesized theophylline derivatives have been also established.

Synthesis and Characterization of Some New Theophylline Derivatives

The processing behaviour and mechanical and thermal properties of the polystyrene/polyethylene or polystyrene/polypropylene blends containing block copolymers of KRATON type as compatibilizing agents have been studied. It has been established that the compounding on a twin screw extruder followed by γ-irradiation assures satisfactory homogeneity of the blends and also good mechanical properties. A thermomechanical method was developed to characterize the blends. The variation of the α-relaxation or glass transition temperatures with blend composition as well as the variation of the other thermal characteristics such as melt flow rate, melting and crystallization temperatures, Vicat temperatures, etc. exhibit the important differences in respect to the average values indicating a good compatibilization of the components.

Cornelia Vasile

Papers

Biopolymeric Nanocomposites for Orthopedic Applications

Polyolefins/lignosulfonates blends. V. Bio- and environmental degradation

Study on Acute Toxicity of Amiodarone New Complexes With Cyclodextrin.

Synthesis and Characterization of Some New Theophylline Derivatives

Compatibility of the Polystyrene/Polyolefin Blends Containing Block Copolymers I. Processing Behaviour and Characterization