What are Polymers

Thus muscle, collagen (in bone), keratin (in hair, nails and beaks) and albumin are all copolymers of very similar amino acids but have quite different physical properties. In deoxyribonucleic acid (DN A), the genetic template, the sequence of monomers is precise and variations are the cause of genetic mutations. Although the polypeptides are of ultimate importance in life processes they are not important in the context of materials and will not be considered further in this book. However, they have had a significant impact on modern polymer science since the synthesis of the first man-made polyamide fibre. Nylon, by Carothers was modelled on the structure of a silk, a naturally occurring polypeptide. 

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What are polymer composite materials Give two examples that illustrate the importance of polymer composites in the manufacture of consumer products. 

What are polymer lithium ion batteries and how is nanotechnology research improving their performance ... 

Some 500 years ago during Columbuss second voyage to what are now the Americas he and his crew saw children playing with balls made from the latex of trees that grew there Later Joseph Priest ley called this material rubber to describe its ability to erase pencil marks by rubbing and in 1823 Charles Macintosh demonstrated how rubber could be used to make waterproof coats and shoes Shortly there after Michael Faraday determined an empirical for mula of CsHs for rubber It was eventually determined that rubber is a polymer of 2 methyl 1 3 butadiene... 

Currendy, epoxy resins (qv) constitute over 90% of the matrix resin material used in advanced composites. The total usage of advanced composites is expected to grow to around 45,500 t by the year 2000, with the total resin usage around 18,000 t in 2000. Epoxy resins are expected to stiH constitute about 80% of the total matrix-resin-systems market in 2000. The largest share of the remaining market will be divided between bismaleimides and polyimide systems (12 to 15%) and what are classified as other polymers, including thermoplastics and thermoset resins other than epoxies, bismaleimides, cyanate esters, and polyimide systems (see Composites,polymer-matrix-thermoplastics). 

Comment on the implications of your results (e.g. Which commodities have increased by the largest factor How have the relative costs of materials changed What are the implications for the use of polymers ). 

What are the four main generic classes of polymers For each generic class ... 

The classic objective of alloying and blending is to find two or more polymers whose mixture will have synergistic property improvements (Fig. 6-8). Among the techniques used to combine dissimilar polymers are cross-linking to form what are called interpenetrating networks (IPNs), and grafting, to improve the compatibility of the plastics. 

In words, what are weight average molecular weight and number average molecular weight What does the ratio of Mw to Mn tell us about the molecular characteristics of a polymer ... 

Dispersion of polymeric viscosifiers is often difficult because the initial contact of the untreated polymer with water results in very rapid hydration of the outer layer of particles which creates a sticky, rubbery exterior layer that prevents the interior particles from contacting water. The net effect is formation of what are referred to as nfish eyes" or "gel balls." These hamper efficiency by lowering the viscosity achieved per pound of gelling agent and by creating insoluble particles that can restrict flow both into the formation and back out of it. The normal remedy for this behavior... 

E. Bakker, P. Buhlmann, and E. Pretsch, Polymer membrane ion-selective electrodes - what are the limits Electroanalysis 11, 915-933 (1999). 

As with experimental work on polymer adsorption, experiments in the area of dispersion stability in the presence of polymers require detailed characterisation of the systems under study and the various controlling parameters (discussed above) to be varied in a systematic way. One should seek the answer to several questions. Is the system (thermodynamically) stable If not, what is the nature of the equilibrium state and what are the kinetics of flocculation If it is stable, under what critical conditions ( s, T, x> p etc.) can flocculation be induced ... 

What are the main material components needed in the design of a polymer-based ion-selective membrane What is the role of each of these components in the membrane ... 

What are some applications of thermal analysis in the pharmaceutical and polymer industries ... 

One day in Ludwigschafen, the great scientist Mittasch asked me, What are you doing I said I was measuring viscosity. Why he asked. I told him that we desired to determine the molecular weight of a polymer. 

What are the facts of life One of the most striking is that all known living systems involve the same types of polymers, i.e., three varieties of homochiral biopolymers. That is, each variety is composed of unique molecular building blocks having the same three-dimensional handedness. Thus, with rare exceptions, the proteins found in cells are composed exclusively of the 1-enantiomers of 19 optically active amino acids (Fig. 11.1). Similarly, only D-ribose and 2-deoxy-D-ribose sugars are found in the nucleic acid polymers that make up the RNAs and DNAs, which are essential for protein synthesis in the cell and for the transmission of genetic information from one generation to the next. 

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