Advantages over organic polymeric

Generally these globular dendritic architectures offer several advantages over other kinds of organic polymers, such as the full exposure of the catalytic centers to the environment. In contrast to linear or cross-Hnked polymeric supports, which can partially hide catalytic centers, the functional groups are located on the surface of the dendritic nanoparticle and diffusional Hmitations are less relevant Furthermore the close proximity of the catalytic centers on the surface of the dendritic polymer can enhance the catalytic activity by multiple complexation or even cooperativity. This behavior is described as positive dendritic effect. However, in some cases a negative dendritic effect was observed, which is caused by an undesired interaction or electron transfer between the neighboring catalytic centers on the surface of the dendrimer [70]. 

Introducing chirality into polymers has distinctive advantages over the use of nonchiral or atactic polymers because it adds a higher level of complexity, allowing for the formation of hierarchically organized materials. This may have benefits in high-end applications such as nanostructured materials, biomaterials, and electronic materials. Synthetically, chiral polymers are typically accessed by two methods. Firstly, optically active monomers - often obtained from natural sources - are polymerized to afford chiral polymers. Secondly, chiral catalysts are applied that induce a preferred helicity or tacticity into the polymer backbone or activate preferably one of the enantiomers [59-64]. 

Dowex Optipore is a polymeric adsorbent used to treat chlorinated volatile organic compound (CVOC) contaminated off-gas streams from remediation processes such as air stripping of groundwater and soil vapor extraction. According to the vendor Dowex Optipore adsorbent has the following advantages over activated carbon ... 

In this review results from two surface science methods are presented. Electron Spectroscopy for Chemical Analysis (ESCA or XPS) is a widely used method for the study of organic and polymeric surfaces, metal corrosion and passivation studies and metallization of polymers (la). However, one major accent of our work has been the development of complementary ion beam methods for polymer surface analysis. Of the techniques deriving from ion beam interactions, Secondary Ion Mass Spectrometry (SIMS), used as a surface analytical method, has many advantages over electron spectroscopies. Such benefits include superior elemental sensitivity with a ppm to ppb detection limit, the ability to detect molecular secondary ions which are directly related to the molecular structure, surface compositional sensitivity due in part to the matrix sensitivity of secondary emission, and mass spectrometric isotopic sensitivity. The major difficulties which limit routine analysis with SIMS include sample damage due to sputtering, a poor understanding of the relationship between matrix dependent secondary emission and molecular surface composition, and difficulty in obtaining reproducible, accurate quantitative molecular information. Thus, we have worked to overcome the limitations for quantitation, and the present work will report the results of these studies. 

In contact with catalyst at temperatures higher than those for FCC, heavy petroleum fractions crack to produce propylene and butene, which are useful starting materials for organic synthesis and polymerization. The catalytic cracking has many advantages over the thermal cracking of naphtha to... 

During the past 10 years, in addition to silica-based monoliths [12], a broad range of organic polymeric monoliths has been studied. Their most advantageous attribute is their chemical stability over a wide pH range. The most common organic monoliths were the results of methacrylate [13] and styrene [14] monomers. Some examples that confirm the utility of monolithic columns in IPC are described below. 

---