Copolymers ratio

Miller, R. A., Brady, J. M., and Cutright, D. E., Degradation rates of oral resorbable implants (polylactates and poly-glycolates) Rate modification with changes in PLA/PGA copolymer ratios, J. Biomed. Mater. Res., 11, 711, 1977. 

In number of labs, the NIR is a rapid, non-destructive test. It is used (everywhere) for water determination. For the petroleum industry, it is routinely used for octane and betaine values, to determine levels of additives, and as a test for unsaturation. The polymer companies, in addition to identification, use NIR for molecular weight, cross-linking, iodine value (unsaturation) block copolymer ratios, and numerous... 

The value in units of incident dose per unit area for either a positive or negative resist system is of little value unless accompanied by a detailed description of the conditions under which it was measured. This description should include, at the minimum, the initial film thickness, the characteristics of the substrate, the temperature and time of the post- and pre-bake, the characteristics of the exposing radiation, and the developer composition, time and temperature. The structure, copolymer ratio, sequence distribution, molecular weight, and dispersity of polymers included in the formulation should also be provided. 

Feed Ratio Mole J Wtl Raman (Wt ) ) Copolymer Ratio Elemental Analysis (Wt %)... 

The random copolymer (ratio of vinyl alcohol to vinylsulfonic acid units, 22... 

Poly(amino acids) are usually copolymers due to the difficulty of producing polyamide sequences poly(glutamic acid-glutamate). The degradation of poly(glutamic acid-glutamate) is dependent on the copolymer ratio, as shown in Figure 7.26, which controls the hydrophi-licity of the polymer. 

The freeze/thaw (F/T) stability of a polymer emulsion serves as a macroscopic probe for investigating the properties of the average particle in a polymer emulsion. A review of the factors which contribute to this stability is included. A study of styrene-ethyl acrylate-methacrylic acid polymers shows the existence of a minimum in the plot of minimum weight percent acid required for F/T stability vs. the minimum film formation temperature (MFT) of the polymer. This is considered to be a function of both the amount of associated surfactant and the minimum acid content. Thus, both the type of surfactant and the copolymer ratio—i.e., MFT—play major roles. Chain transfer between radicals and polyether surfactant resulting in covalently bonded surfactant-polymer combinations is important in interpreting the results. 

Ogawa, Y., Yamamoto, M.,Takada, S., and Shimamoto, T. (1988), Controlled release of leuprolide acetate from polylactic acid or copolymer ratio of polymer, Chem. Pharm. Bull, 36,1502-1507. 

The copolymerization of ethylene and chlorotrifluoroethylene is performed as a free radical suspension process in aqueous media at low temperatures. Lowering the temperature reduces the number of ethylene blocks in the polymer backbone that are susceptible to thermal degradation. A commercial polymer with an overall CTEE-to-ethylene ratio of 1 1 contains ethylene blocks and CTFE blocks in the proportion lower than 10 mol% each [85], Reaction pressure is adjusted to give the desired copolymer ratio [86]. Typical pressures during the process are on the order of 3.5 MPa... 

Salt rejections by the NS-300 membrane toward synthetic seawater improved as the isophthalamide content of the barrier layer increased. Surprisingly, membrane flux peaked rather than simply declining as a function of increasing isophthalamide content. This is illustrated by the data in Table II. Maximum water permeability characteristics were found at an approximate copolymer ratio of 67 percent isophthalic and 33 percent trimesic groups. The differences in the magnesium sulfate versus sodium chloride rejection appear to be due to the anionically charged nature of the membrane barrier layer, which is rich in carboxylate groups. 

It should be noted that this ratio is significantly lower than that usually applied in polymcr/C tll bulk heterojunction devices, where the Copolymer ratio is typically 4 1 to allow the formation of C50 percolation paths for electron collection [59]. 

Bigg, D. M. (1996). Effect of copolymer ratio on thecrystallinityand properties of polylactic acid copolymers,/. Eng. Appl Set, 2,2028-2039. 

Filament wound flat strip composites of PE fibie-rrinforced ethylene-butane copolymer have been used for diff oit biomedical applications. Composites of three difierent matrix compositions and two winding angles were reported. The matrix composition varied with the copolymer ratio raidering the composite material softening and it is more compliant and suitable for different biomedical application [75]. 

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