Polyimide adhesives

A process was developed for preparing aromatic polyamide acids for use as adhesives by reacting an aromatic dianhydride to an approximately equimolar amount of an aromatic diamine in a water or lower alkanol miscible ether solvent. The polyamide acids are converted to polyimides by heating to the temperature range of 200 - 300 C. The polyimides are thermally stable and insoluble in ethers and other organic solvents

Process for preparing polyimide adhesives

High bonding strengths are obtained for metals and fiber-reinforced organic resin composites with no significant loss in thermo-oxidative stability of the adhesive resin

Polyimide adhesives

A process of preparing aromatic polyamide-acids for use as adhesives is described. An equimolar quantity of an aromatic dianhydride is added to a stirred solution of an aromatic diamine in a water or alcohol-miscible ether solvent to obtain a viscous polymer solution. The polymeric-acid intermediate polymer does not become insoluble but directly forms a smooth viscous polymer solution. These polyamic-acid polymers are converted, by heating in the range of 200-300 C and with pressure, to form polyimides with excellent adhesive properties

Genetic clustering and parentage analysis of Western Balkan grapevines (Vitis vinifera L.)

A total of 90 grapevine samples collected in five countries of the Western Balkan region were evaluated for trueness-to-type and kinship relations based on comparative analysis with 1,130 grapevine genotypes held at the INRA "Domaine de Vassal" French Grape Germplasm Repository, using 14 microsatellite markers. In the context of the comparative analysis, twenty-four synonyms/counterparts and the putative parents for twelve Balkan accessions were identified. We discovered five pairs of homonyms, subsequently confirming the identity or parentage of three of them. Some of the examined accessions were identified either on the basis of the genotypes found in the literature, or through parentage relationships revealed in this study. For the remaining fifty accessions we were unable to establish either their pedigree or to identify them on the basis of SSR profiles available elsewhere. Finally, the Balkan genotypes that were not well classified by synonymy or parentage analysis were further studied with a Principal Coordinate Analysis to reveal genetic clustering within larger datasets of genotypes. The graphical display of the individual and group distances showed that about forty accessions (85 %) are structured within a group of Balkan and Eastern Europe genotypes and only a minor proportion resulted in admixed population assignment

Stem exclusion and mortality in unmanaged subalpine forests of the Swiss Alps

Understanding the causes and consequences of spatiotemporal structural development in forest ecosystems is an important goal of basic and applied ecological research. Most existing knowledge about the sequence and timing of distinct structural stages following stand origin in unmanaged (not actively managed in \u3e50 years) forests has been derived from forests in North America, which are characterized by particular topographic, climatic, biotic and other environmental factors. Thus, the effects on structural development remain poorly understood for many other forest systems, such as the dense, unmanaged, subalpine Norway spruce forests of the Swiss Alps. Over the past century, land abandonment and reductions in active forest management have led to a substantial increase in the density of these forests types. Consequently, many stands are entering the stem exclusion stage and are currently characterized by associated self-thinning mortality. However, the environmental influences on the rate of this structural development as well as this structural stage itself have not yet been examined. We studied stem exclusion processes based on forest inventory data (National Swiss Forest Inventory; NFI) over three survey periods (1983-1985, 1993-1995 and 2004-2006) using repeated measures statistics. To complement these analyses, we also collected and analysed 3,700 increment cores from 20 field plots within dense subalpine Norway spruce forests dispersed across the Swiss Alps. Over the past decades, basal area (BA) has generally increased, particularly on N-facing and steeper slopes, and within 300 m of potential treeline. The number of dead trees was higher on N-facing compared with S-facing slopes, but the BA of dead wood was higher on S-facing slopes. Tree ring analysis confirmed important differences in growth patterns between N- and S-facing slopes and verified the results of the NFI analysis. This study provides a detailed example of how environmental heterogeneity and management history can influence the spatiotemporal structural development of forest ecosystems. © 2012 Springer-Verlag