Amphiphilic hyperbranched polyglycerols in a new role as highly efficient multifunctional surface active stabilizers for poly (lactic/glycolic acid) nanoparticles

Amphiphilic hyperbranched polyglycerols synthesized with alkyl alcohol initiators are efficient surfactants and stabilizers for poly(lactic/glycolic acid) nanoparticles, which offer various new possibilities for surface functionalized nanosystems.</p

Synthesis of hyperbranched poly(ethyleneimine) based macromolecular antioxidants and investigation of their efficiency in stabilization of polyolefins

Macromolecular antioxidants with highly sup p ressed leac h ing to the environment, based on hyperbranched poly(ethyleneimine) carrier with bonded sterically hindered phenol and 2 alkyl compatibilizing groups with various chain length were synthesized and tes ted for their efficiency in stabilization of polyolefins. The synthesis of the macromolecular antioxidants was carried out by amidation of the amine groups present in poly(ethyleneimine) with various carboxylic acids containing sterically hindered phenol a nd compatibilizing group s , such as n - butyryl, lauryl or stearyl. The structure of the resulting polymers was analyzed by 1 H NMR and by GPC. The antioxidant content of the samples was determined by UV - Vis spectroscopy. The e fficiency of the synthesized anti oxidants in therm ooxidative stabilization of polypropylene was determined by chemiluminescence. The e fficiency in photostabilization of polypropylene and polyethylene was investigated by using FT IR and UV - Vis spectroscopies. It was found that the macromol ecular antioxidant which did not contain any compatibilizing groups shows the best stabilizing efficiency in both therm ooxidative and photooxidation tests. The extent of extraction of the synthesized macromolecular antioxidants from polypropylene films was investigated as well. Low extent of extraction of the maromolecular antioxidants from the po lypropylene films was observed in contrast to the high level of leaching of commercially used low molecular weight phenolic antioxidant . These results indicate the environmental advantage of the investigated poly(ethyleneimine) based macromolecular antioxidants over the widely applied low molecu l ar weight compounds

Guidelines for Ecosystem Services Based Ecotourism Strategy

The ecosystem services (ESS) based worldview understands that nature contributes to human well-being and society can operate in a way which reduces or enhances nature’s capacity to contribute to our well-being. ESS can be defined as conditions and processes through which ecosystems sustain and enrich human life. Most generally, four types of ESS are differentiated: provisioning, regulating, cultural, and supporting ESS. Tourism in general and ecotourism in particular are usually related to cultural ESS