Eighty years of macromolecular science: from birth to nano-, bio- and self-assembling polymers—with slight emphasis on European contributions

A definition of macromolecular science (as opposed to polymer science and engineering) is given, from which the year 1930 is derived as the year of its birth. The scope of treatment of this paper will be limited to solid technical polymers. Some important discoveries of polymer technology in the nineteenth century are reviewed together with the reason why the concept of macromolecules and the theory of rubber elasticity did not emerge earlier. The role of chain backbones in structure formation and mechanical loading of technical polymers has been heavily discussed ever since and has attracted this author for most of his scientific work. He offers a personal perspective of the most important achievements in three domains of macromolecular science: the synthesis of well-designed chain molecules, structural characterization and the understanding of the micro-mechanics of (nano-structured) polymer materials. Progress is generally documented by citing individual references from the discussed periods—well knowing that the development of science is due to the contributions of many more people. In conclusion, a critical outlook will be attempted on future trends in the design and application of well-adapted—and frequently complex—polymer systems towards growing human need

Eighty years of macromolecular science: from birth to nano-, bio- and self-assembling polymers-with slight emphasis on European contributions

A definition of macromolecular science (as opposed to polymer science and engineering) is given, from which the year 1930 is derived as the year of its birth. The scope of treatment of this paper will be limited to solid technical polymers. Some important discoveries of polymer technology in the nineteenth century are reviewed together with the reason why the concept of macromolecules and the theory of rubber elasticity did not emerge earlier. The role of chain backbones in structure formation and mechanical loading of technical polymers has been heavily discussed ever since and has attracted this author for most of his scientific work. He offers a personal perspective of the most important achievements in three domains of macromolecular science: the synthesis of well-designed chain molecules, structural characterization and the understanding of the micro-mechanics of (nano-structured) polymer materials. Progress is generally documented by citing individual references from the discussed periods-well knowing that the development of science is due to the contributions of many more people. In conclusion, a critical outlook will be attempted on future trends in the design and application of well-adapted-and frequently complex-polymer systems towards growing human needs

Biological Flora of the British Isles: Sorbus torminalis

1.This account presents information on all aspects of the biology of Sorbus torminalis (L.) Crantz (Wild Service-tree) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation.2.Sorbus torminalis is an uncommon, mostly small tree (but can reach 33 m) native to lowland England and Wales, and temperate and Mediterranean regions of mainland Europe. It is the most shade-tolerant member of the genus in the British Isles and as a result it is more closely associated with woodland than any other British species. Like other British Sorbus species, however, it grows best where competition for space and sunlight is limited. Seedlings are shade tolerant but adults are only moderately so. This, combined with its low competitive ability, restricts the best growth to open areas. In shade, saplings and young adults form a sapling bank, showing reproduction and extensive growth only when released. Sorbus torminalis tolerates a wide range of soil reaction (pH 3.5-8.0) but grows best on calcareous clays and thin soils over limestone.3.Sorbus torminalis is a sexual, diploid, non-apomictic species that has hybridised with a number of other Sorbus species to form microspecies. The hermaphrodite flowers are primarily insect pollinated. Seed production is reliable only in warm years, especially at the edge of its range, although even then seed viability is low. The fruits are primarily dispersed by carnivorous mammals. Seeds display embryo dormancy but most will germinate the first spring after falling.4.This tree is very tolerant of short droughts but only moderately tolerant of frost, hence its southerly and lowland distribution. It faces no particular individual threats although the small size of most populations makes it susceptible to habitat loss and fragmentation, particularly through the loss of open coppiced areas. As a consequence it appears to be declining throughout Britain and Europe despite its wide range of historical uses and the high value of its timber. The extent to which these losses will be offset by increases due to climate change is unknown.This article is protected by copyright. All rights reserved

The physics and micro-mechanics of nano-voids and nano-particles in polymer combinations

In this article the role of voids or particulate inclusions of different sizes on mechanical properties and particularly on toughness in several polymers is discussed. With decreasing void sizes and intervoid distances, the influence of the interphase material around the voids becomes more important and characteristic changes in the nano- and micro-deformation mechanisms appear. These mechanisms are revealed by several techniques of electron microscopy within rubber modified polymers, nanocomposites and nanofibres respectively. Three nanoscopic toughness enhancing mechanisms are described in detail: thin layer yielding, nanovoid-modulated craze-formation, and the core flattening mechanism. The action of these mechanisms constitutes a distinct advantage of nanovoids over microvoids. (c) 2013 Elsevier Ltd. All rights reserved