Polymers examples

Synthetic Polymers. Examples of polymers in this class include acrylamide—acryHc polymers and their derivatives, polyamines and their derivatives, poly-(ethylene oxide), and allylamine polymers. 

Predict the type of polymer that a given monomer can form and identify monomers, given the repeating unit of a polymer (Example 19.2). 

Applications Although GD-OES is most popular in metals research, it can also be applied to prepainted steel, coatings and polymers. Examples of analysis of coatings are ... 

The following sections will deal with some polymer examples, for which we tried to confirm the conclusions drawn from these theoretical considerations. 

Fig. 31. Illustration of procedure due to Utiyama124 for determining M of optically anisotropic polymer. Example relates to three concentrations cj, c2, C3 over a range of angles 0...

In the styrene-butadiene polymer example, it is not physically possible to collect spectra of the pure butadiene components (cis-, trans- and 1,2-butadiene) experimentally, because they cannot be synthesized. As a result, only the CLS method that uses estimated pure component spectra basis can be used. Using the concentrations of all four major analytes for all of the calibration samples (obtained by C NMR), it was possible to estimate the pure component spectra of the four known components (see Figure 12.11). When these estimated pure component spectra are then used to estimate the concentrations of the four constituents in the samples (Equation 12.38), it is found that the RMSEE for cA-butadiene is 1.53. 

To illustrate the present rules for naming various kinds of polymers, examples of polymers are given in this section. The key steps in the naming and the corresponding rule numbers are also given. 

The tertiary structure describes the shaping or folding of the polymer. Examples of this are given in Figures 2.16b, 2.17 left, and 2.17 right. 

In principle, one can obtain an unbranched polyethyleneimine by saponifying the amide groups that are located on the polymer (Example 5-4). It is important to note that the ring-opening polymerization of aziridine does not yield linear polyethyleneimines but rather highly branched polymer structmes. 

Other macromolecules are formed by condensing their monomers to form a repeat functional group (e.g., esters, amides, ethers) interspersed by alkyl chains, aromatic rings, or combinations of both. These condensations are characterized frequently, although not always by the loss of some by product (e.g., water, alcohol). The methods of formation of these polymers are far more varied than those of addition polymers. Examples of condensation polymers are (a) poly(esters), (b) poly(urethanes), (c) poly (carbonate), and (d) polyphenylene oxide). 

Interest in the photoconductive properties of the carbazole nucleus has also prompted studies concerned with its incorporation into condensation polymers. Examples of polymers prepared include polyamides (34), polyesters (35) and polyurethanes (36) (80MI11105). Thorough studies on the CT interactions of these polymers with the monomeric acceptor 2,4,7-trinitrofluorenone have been done. In all cases, the formation constant for the CT complex was higher with polymers than for monomeric models. At least two polymer... 

Bioadhesive tablets can be made by the compression of polymers or can consist of a matrix base or bilayers, with an impermeable backing layer covering the layer with the drug and the mucoadhesion polymer. Examples of these systems are discussed below. 

Recently the number of papers about radiation effects of ion beams on polymers has been increasing very rapidly both in the fundamental and applied fields. A fairly large number of papers have been published on the fundamental aspects of radiation effects of ion beams on polymers, including high density electronic excitation effects [1, 2]. A number of papers have been published on the more applied aspects of the ion beam assisted advanced science and technology of polymers examples of these are ion beam modification [1. 2] and lithography [3],... 

Another way to achieve desirable polymer properties is the modification of preformed polymers. This modification may take place on the reactive sites of the polymer chain through alkylation, hydrolysis, sulfonation, esterification, and other various reactions of polymers. Examples of natural polymers and their modifications are cellulose and its derivatives, chitin and chitosan, and polysaccharides. These are still to this day very important polymers for pharmaceutical applications. 

On the other hand, some mechanically compatible blends as well as some dispersed two-phase systems have made respectable inroads into the commercial scene. Many of these are blends of low-impact resins with high-impact elastomeric polymers examples are polystyrene/rubber, poly (styrene-co-acrylonitrile) /rubber, poly (methyl methacrylate) /rubber, poly (ethylene propylene)/propylene rubber, and bis-A polycarbonate/ ABS as well as blends of polyvinyl chloride with ABS or PMMA or chlorinated polyethylene. 

The DHI s may be solution cast with certain polymers. Examples of photochromic plastics prepared this way are poly (methyl methacrylate), poly (n-butyl methacrylate), copoly (vinylidene chloride-acrylonitrile) (e.g., SARAN F), polycarbonate, and polystyrene-butadiene (e.g., Panarez). 

Difunctional. In a polymer-producing reaction, the term applied to a reactant possessing two functional groups in its structure, hence capable of propagating a chain and forming a linear polymer. Example ... 

The 3-stage process involves utilisation of plant sugars derived from photosynthetically fixed C02 as carbon sources in the fermentation of organic acids, alcohols and amino acids. These substances are then used as building blocks for the chemical synthesis of polymers. Examples of polymers using the 3-stage process include polylactic acid and polybutylene succinate. 

Fl-FFF is most attractive for water-soluble polymers [59] and can directly deliver the diffusion coefficient distribution and also a molar mass distribution via the relationship D=AM b. This was exploited for poly(ethylene oxide), poly(styrene sulfonate) and poly(vinyl pyrrolidone) and other polymers using published Mark-Houwink constants [361 ]. Many papers just report on the fractionation of polymers or the determination of the hydrodynamic size distribution of polymers. Examples include poly(styrene sulfonates) [59,165,243],poly(acrylic acid) [243] and poly(2-vinylpyridine) [59]. 

One of the main factors which needs to be considered in PAL analysis of polymers, is the affect which prolonged exposure to the positron source has on the lifetime parameters. It has been found that on prolonged exposure to a positron source, the o-Ps lifetimes are largely unchanged, but that there are significant variations in the o-Ps intensities for some polymers. Examples of these effects for a wide variety of polymers can be found polypropylene (PP), polyethylene (PE) [71], polystyrene [72], polycarbonates [73] poly(a-olefins) [49], poly(vinlyacetate) [74], poly(methyl methacrylate) [74] and a number of copolymers [75]. 

Tb get a better feel for this, let s look at a polymer example that will be relevant to our discussion of crystallization. Essentially, we would like to know what would be the probability that a polyethylene chain in the melt would spontaneously adopt an all-trans extended conformation. Now this is a difficult problem to tackle, in the sense that we would need a precise knowledge not only of the potential function describing bond rotations, but also the calculations would have to... 

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