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

A series of experiments were carried out to investigate the photodegradation of lime wood (Tilia cordata Mill.) coated with acrylic copolymer during artificial UV/Vis light irradiation for 600 h. Photodegradation of the Paraloid B72 films and Paraloid B72 treated lime wood samples was evaluated by thermogravimetry throughout the irradiation period of 100 h. The results obtained indicate a shifting of the DTG maxima to lower temperatures, which may be related to a decrease in the stability of the copolymer and wood during photodegradation. The decrease of weight loss with increasing time of exposure was observed, while the global kinetic parameters for the main peak increases when increasing exposure time of wood to the UV light. Even when the surface of the wood was covered with a thin layer of acrylic resin, some photodegradation reactions of the wood surface occurred. The modifications in the wood structure may be influenced by the newly formed structures from acrylic resin photodegradation.

Thermogravimetric analysis of photodegraded acrylic coated lime wood.

Due to their high specific surface area and high porosity, electrospun nanofibers are an attractive choice for a high number of biomedical and biomaterial applications, implying either nonwoven or aligned nanofibrous structures. The applications of the electrospinning technique in this chapter include: drug-releasing systems and stimuli-responsive electrospun meshes (thermo- and pH-responsive) for triggered drug release, wound-dressing nanofibers containing active substances, antimicrobial coatings for biomedical applications, applications of aligned nanofibers for tendon healing, tubular scaffolds, and neural tissue engineering. Particular aspects concerning drug-releasing systems are also presented: effect of drug crystallinity on drug delivery, burst prevention, drug release controlled by hydrophilic and hydrophobic polymers, and effect of the biphasic release.

Electrospun Polymeric Nanostructures With Applications in Nanomedicine

Some Aspects Concerning the Nanomaterials from Renewable Resources Use in Food Packaging

The behavior of the poly(ethylene terephthalate)-co-(ethylene isophthalate)] copolymer/epoxy-modified lignosulfonate (LER) blends has been studied during aging, in the conditions of sewage sludge test. The bulk and surface properties of the aged blends have been followed by electron microscopy, DSC, TG/DTG, IR spectroscopy and contact angle measurements, and compared with undegraded samples. It has been established that the UV-irradiated blends undergo more important changes in their properties after aging than the unirradiated samples. The physical treatment and increase of LER content in the blend could be a way to obtain materials with a good balance of properties and environmental degradation.

Polyester/lignosulfonate blends, 2. Accelerated aging behavior

The swelling behavior of unbleached and bleached softwood Kraft pulp modified with butyric acid and oleic acid in cold plasma conditions, in alkaline solutions, has been studied comparatively with pristine polymers, by gravimetric measurements and optical microscopy. It has been established that the swelling degree depends on the type of cellulose fiber, on the solvent and concentration of the alkaline solution. The treated samples present higher susceptibility in NaOH solutions, in comparison with KOH solutions. Both cellulose fibers modified with oleic acid present a higher swelling degree than those treated with butyric acid. FT-IR spectroscopy of the swollen fibers showed that the modified celluloses present some modifications after swelling in alkaline solutions.

http://www.cellulosechemtechnol.ro/pdf/CCT45,5-6(2011)/p.329-338.pdf

Cornelia Vasile

Papers

Thermogravimetric analysis of photodegraded acrylic coated lime wood.

Electrospun Polymeric Nanostructures With Applications in Nanomedicine

Some Aspects Concerning the Nanomaterials from Renewable Resources Use in Food Packaging

Polyester/lignosulfonate blends, 2. Accelerated aging behavior

Alkaline solution swelling of fatty acids-modified softwood kraft pulp fibers under cold plasma conditions