Total polymer content

In the same way that a low-exclusion-limit column set allows maximum separation of additives in polymer systems, the converse effect applies the polymer appears as a narrow peak at the column exclusion limit and can be 

The latter case is of interest, as the requirement for oil solubility of the polymer inhibits the conventional gravimetric total polymer determination by precipitation with a non-solvent. These experimental conditions (p. 161) have been used to study the changes in the base-oil component of multigrade lubricating oils, for example the degree of oxidation which is shown by increase 

Quantitative results require calibration with a suitable polymer sample, but results were excellent in the three cases quoted  

Nitrocellulose (i) % Present 35.81 by chemical analysis Mean % found 34.9 

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Polymers Nitrile rubber 55 PVC 45 blend, 39 % total polymer content... 

Bound rubber - The bound rubber content was measured with toluene as solvent [48,49]. The nonvulcanized samples (0.2 g) were cut into small pieces and put into a steel-wire basket of very fine mesh, which was immersed in 100 mL of toluene at room temperature for 72 h. The solvent was renewed after 24 h. The extracts were collected and left for 24 h in air and 24 h in vacuo at 105°C to evaporate the solvent. The amount of bound rubber (BdR) is expressed as the percentage of the total polymer content in the compound. 

The formulators wanted to vary the composition of the polymer within the formulation, from consisting entirely of polymer A to containing only polymer B. The total polymer content (A + B) was allowed to vary between 10% and 50% of the mixture excluding the dmg substance and the lubricant. These are given as percentages of the total tablet mass in column 2 of table 10.14, after correction for the proportions of the remaining components (drug substance and lubricant). 

Where the fiber is formed by the interaction of two or more chemically distinct polymers (of which none exceeds 85% by weight), and contains ester groups as the dominant functional unit (at least 85% by weight of the total polymer content of the fiber), and which, if stretched at least 100%, durably and rapidly reverts substantially to its unstretched length when the tension is removed, the term elasterell-p may be used as a generic description of the fiber."... 

To a known amount of latex is added a measured amount of the stabilizer to be tested, and the total pol)rmer content is adjusted to the desired level. Stirring is imposed until complete coagulation occurs. Coagulation is easily detected visually, since it is accompanied by sudden conversion of the fluid latex to a thick paste. Times required for coagulation are determined thus at a few different emulsifier levels. Since no use is made of the absolute values of coagulation times, specific features of the test, such as sample size, total polymer content of the latex, and stirring rate are arbitrary. However, comparisons of one sample with another are necessary, and such comparisons are valid only if these features of the test procedure are standardized. In the work here reported a 40-gram sample of latex adjusted to 27.5 polymer content is stirred at 14000 r.p.m. with a slotted circular disk about 3/4 inch in diameter. 

It is interesting to note that the volume of the gel phase is always equal to that of the supernatant, while the supernatant composition is always the same. Thus the gel is not an equilibrium phase. Nevertheless, preliminary results indicate that the rheological properties of the gel scale with total polymer content. 

Figure 2 shows the incremental surface tension (y - Yq) 0,2% (w/w) polymer solutions as a function of solvent composition for both HEC and HMHEC over the entire composition range in which each polymer was soluble. Also shown is the surface tension of the solvent itself. The incremental surface tension of the control polymer increases with the percentage of ethanol in the solvent. This is expected since the HEC is highly water-soluble. More interesting, however, is the result from the HMHEC solution. A minimum is found in the Incremental surface tension at 50% (v/v) (44% w/w) ethanol, identifying this composition as the "best" EtOH/water solvent for this polymer at room temperature. Note that this optimum solvent composition does not depend on the total polymer content of the solution, since the solution has been optimized with respect to polymer/solvent interactions. Hence 50% (v/v) ethanol/water was used as the solvent for all HMHEC solutions. 

Materials Characterization. 1 mm thick film samples for materials characterization were prepared by compression molding. The blend nomenclature is (w/ )PS/r5 /-SPS0.75/Mmt for the PS/ionomer/Na-Mmt blends, where m/n) denotes the PS/SPS0.75 composition (w/w) based on the total polymer content. The composition of the silicate was fix at 3 wt% of the total polymer mass, except for one sample that had 10 wt% silicate. The composite samples studied are summarized in Table 1. 

The loop formed by the chain as it emerges from the crystal, turns around, and reenters the crystal may be regarded as amorphous polymer, but is insufficient to account for the total amorphous content of most crystalline polymers. 

Nylon-11. Nylon-11 [25035-04-5] made by the polycondensation of 11-aminoundecanoic acid [2432-99-7] was first prepared by Carothers in 1935 but was first produced commercially in 1955 in France under the trade name Kilsan (167) Kilsan is a registered trademark of Elf Atochem Company. The polymer is prepared in a continuous process using phosphoric or hypophosphoric acid as a catalyst under inert atmosphere at ambient pressure. The total extractable content is low (0.5%) compared to nylon-6 (168). The polymer is hydrophobic, with a low melt point (T = 190° C), and has excellent electrical insulating properties. The effect of formic acid on the swelling behavior of nylon-11 has been studied (169), and such a treatment is claimed to produce a hard elastic fiber (170). 

Neoprenes. Of the synthetic latices, a type that can be processed similarly to natural mbber latex and is adaptable to dipped product manufacture, is neoprene (polychloroprene). Neoprene latices exhibit poor initial wet gel strength, particularly in coagulant dipped work, but the end products can be made with high gum tensile strength, oil and aUphatic solvent resistance, good aging properties, and flame resistance. There are several types of neoprene latex, available at moderately high (ca 50 wt %) and medium soHds content. Differences in composition between the types include the polymer s microstmcture, eg, gel or sol, the type of stablizer, and the total soHds content (Table 22). 

More recently Fina Chemicals have introduced linear SBS materials (Finaclear) in which the butadiene is present both in block form and in a mixed butadiene-styrene block. Thus comparing typical materials with a total styrene content of about 75% by weight, the amount of rubbery segment in the total molecule is somewhat higher. As a result it is claimed that when blended with polystyrene the linear block copolymers give polymers with a higher impact strength but without loss of clarity. 

Different levels 5, 8, 15, 25, and 33% divinylbenzene content based on total polymer and monomers. 

Im summary, it was not possible to achieve all analytical goals in this study of AN/S polymerizations. We were unable to approximate total solids contents directly because of presence of insoluble polymer. Circumstantial evidence sug-... 

Hydrolysis of amide groups to carboxylate is a major cause of instability in acrylamide-based polymers, especially at alkaline pH and high temperatures. The performance of oil-recovery polymers may be adversely affected by excessive hydrolysis, which can promote precipitation from sea water solution. This work has studied the effects of the sodium salts of acrylic acid and AMPS, 2-acrylamido-2-methylpropanesulfonic acid, as comonomers, on the rate of hydrolysis of polyacrylamides in alkaline solution at high temperatures. Copolymers were prepared containing from 0-53 mole % of the anionic comonomers, and hydrolyzed in aqueous solution at pH 8.5 at 90°C, 108°C and 120°C. The extent of hydrolysis was measured by a conductometric method, analyzing for the total carboxylate content. 

The word protein describes only one type of polymer involving mainly a-amino acids and yet it includes many thousands of different molecules. It is possible to measure the total protein content of a sample despite the fact that relatively simple preparative techniques may be capable of demonstrating the presence of different proteins. However, if interest lies in only one of these proteins, then a measure of the total protein content would be completely inappropriate. Methods for the quantitation of proteins are either suitable for all proteins or designed to measure individual proteins. Such specific methods may depend on either a preparative stage in the analysis or the use of a specific characteristic of the protein in question. 

We seek to determine an effective fixed-charge density which influences ion uptake and transport. This may be different from an analytical determination of total carboxyl content because some groups may not be in swollen regions of the polymer and so may not... 

Latexes are usually copolymer systems of two or more monomers, and their total solids content, including polymers, emulsifiers, stabilizers etc. is 40-50% by mass. Most commercially available polymer latexes are based on elastomeric and thermoplastic polymers which form continuous polymer films when dried [88]. The major types of latexes include styrene-butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyacrylic ester (PAE) and epoxy resin (EP) which are available both as emulsions and redispersible powders. They are widely used for bridge deck overlays and patching, as adhesives, and integral waterproofers. A brief description of the main types in current use is as follows [87]. 

Such effects increase with an increase in the polymer content or the polymer-cement ratio (the weight ratio of total solids in a polymer latex to the amount of cement in a latex-modified mortar or concrete mixture). However, at levels exceeding 20% by weight of the cement in the mixture, excessive air entrainment and discontinuities form in the monolithic network structure, resulting in a reduction of compressive strength and modulus [87, 94, 95]. 

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