Polymers historical background

The use of various polysaccharides for pharmaceutical purposes has a long historical background and increased considerably during the last decades. This is not only the case for polysaccharides used as excipients, which are essential for specific formulations and constitute the most widely used form of polysaccharides, but also for a series of carbohydrate polymers which have proven to be most useful as direct drugs. 

Abstract The morphology of polyethylene has been an important theme in polymer science for more than 50 years. This review provides an historical background and presents the important findings on five specialised topics the crystal thickness, the nature of the fold surface, the lateral habit of the crystals, how the spherulite develops from the crystal lamellae, and multi-component crystallisation and segregation of low molar mass and branched species. 

In this chapter, a selective overview of technological and historical background is followed by a general discussion of the microscopic details of the transport phenomenon and experimental techniques. Key results of earlier studies on carbon-based systems are presented and then compared with corresponding data on poly(methylphenylsilylene) (PMPS), which has been taken as the prototype for studies of transport system in polymers with silicon backbones. Key points are then summarized. Those wishing to omit the extensive background section may proceed directly to the section on electronic transport in polysilylenes (page 492). 

However, in order to facilitate students and "non-silicon" scientists an easier access to the ongoing research on the basis of the relevant historical background, we decided to split this volume in two parts, each with a comprehensive introduction, one on molecular and one on polymer and solid state (organo)silicon chemistry. 

Caseri, W., Nanocomposites of polymers and metals or semieonductors historical background and optical properties, Macromol. Rapid Corrmum., 21, 705-722 (2000). 

The present paper reviews the principles of process technology for concrete-polymer composites, the historical backgrounds, and the past important achievements, recent trends and future trends in the research and development activities of the concrete-polymer composites and the major standardization work on the concrete-polymer composites. 

Historical Backgrounds and the Past Achievements in Research and Development Activities Historical Backgrounds. The history of the research and development of concrete-polymer composites is considerably different in various countries because of the differences of scientific and technological backgrounds, and the types of concrete-polymer composites. 

In this review article, after a description of the historical background of the present subject, some general features of reactions in amorphous polymer solids are summarized and then specific features of photo-physical processes, photoisomerization, photodimerization, chain scission, and crosslinking reactions are discussed separately. Typical theoretical treatments of solid-state reactions are reviewed in relation to the interpretation of experimental results. 

G. Inzelt. 2008. Historical background (Or There is nothing new imder the sun). In Conducting Polymers A New Era in Electrochemistry, Chapter 8. Berlin Springer Verlag. 

On the other hand, the historical perspective and operation of supercritical extraction was intended to supply the background to serve as an aid in appreciating the motivation for the current activities, not just in flavors extraction and characterization but for the process development being carried out in the chemical, food, pharmaceutical, and polymer industries. 

Historically, Equation 14.6 has been an important method for estimating the thermal conductivities of amorphous polymers at room temperature [6]. Although Equation 14.6 will he discussed here as a part of the background information of scientific interest, we emphasize (since erroneous statements to the contrary have been published recently by some authors) that it is not used as a component of the final method developed for the thermal conductivity in this book. The heat capacity Cp at constant pressure, Poisson s ratio v, and molar volume V, must all be calculated at room temperature for use in Equation 14.6. UR is the molar Rao function,... 

It is easier to characterize unknown material if its historical and technological backgrounds are known. The development of semi-synthetic polymers in the second half of the nineteenth century can be followed using patents (Fernandez-Villa and Moya, 2005). Development of cellulose nitrate was prompted by the need to find substitutes for natural materials including tortoiseshell, ivory and ebony, which were very expensive. By 1858, approximately 8 per cent of British patents concerned the synthesis or moulding of semi-synthetics. 

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