Modified castor oil (MCO)
was prepared by transesterification selleck inhibitor of glycerol and CO at the molar ratio of 2.0. The waterborne polyurethane-dispersed polyol (PUDp), one component of the 2K-WPU, was synthesized from MCO, dimethylol propionic acid (DMPA) and isophorone diisocyanate (IPDI) by the acetone process to provide a prepolymer with a carboxyl and hydroxyl groups. Then the prepolymer was neutralized by triethylamine (TEA) and dispersed into water. After vacuum distillation to remove acetone, the PUDp was obtained and then mixed with four different hardeners: IPDI, hexamethylene diisocyanate(HI), polyethylene glycol (PEG) modified PIPDI (polymeric IPDI) and PEG-modified see more PHDI (polymeric HDI). The NCO/OH molar ratio of 1.5 was used and a 2K-WPU coating was obtained. The results showed that the film of the 2K-WPU coatings obtained from IPDI hardener had excellent gloss and hardness. On the contrary, the film containing PEG-modified PIPDI hardener (PEG-PIPDI) had lower hardness and gloss but higher tensile strength. The film containing PEG-modified PHDI hardener (PEG-PHDI) showed the best elongation at break, abrasion resistance and impact resistance,
though it had the worst hardness. The film with HDI hardener had the best hardness and highest tensile strength and superior water resistance among all the films with different hardeners, and it was suitable for wood coatings. (C) 2012 Elsevier B.V. All rights reserved.”
“Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy
dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied Lazertinib solubility dmso patches was relatively stable from 2000 to 2010 (1524% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability.