Poly‐n‐butyl methacrylate. III. Dilute solution properties by viscosity and light scattering

Abstract

Poly‐n‐butyl methacrylate prepared by the emulsion technique was fractionated three times by the fractional precipitation procedure to obtain eight fractions. Relationships between viscosity and weight‐average molecular weight were obtained in both an ideal solvent, isopropanol, and a nonideal solvent, methyl ethyl ketone. These relationships are represented by equations: The effect of the size of the pendant groups (‐methyl, ‐ethyl, and n‐butyl ester) on the degree of extension of macromolecules in ideal solvents is discussed. It was found that the degree of flexibility of the macromolecule increases as the size of the pendant group increases. These results are believed to be due to the short‐range interference effect of the solvent molecule on the degree of free rotation of the macromolecule.

Mobility of Nonsticky Nanoparticles in Polymer Liquids

“…The root-mean-square end-to-end distance R of 2.5 kDa PBMA chain is approximately 2.5 nm and the size of 180 kDa PBMA chain is about 21 nm as estimated based on data from refs. 4 and 45. The 5 nm gold particles are expected to experience bulk viscosity in 2.5 kDa PBMA melt but in 180 kDa melt they only “feel” effective viscosity, which is predicted by our model to be the viscosity of the PBMA melt with the chain size on the order of the particle size.…”

Reduced and Surface‐Modified Graphene Oxide with Nonlinear Resistivity

“…When Σ < 1, the PBMA grafts are considered to be in the mushroom regime. By assuming an ideal coil in theta state, the height of the coil ( h ) was calculated for the grafts according to Malmström and co‐workers, using the following expression in Equation where C is the characteristic ratio for PBMA in theta state ( C ≈ 7), n is the number of backbone bonds, each with the length of l (1.54 10 −10 m). The coil sizes were h ≈ 5 nm for PBMA10k, h ≈ 12 nm for PBMA50k, and h ≈ 14 nm for PBMA70k.…”

“…where C is the characteristic ratio for PBMA in theta state (C ≈ 7), [28] n is the number of backbone bonds, each with the length of l (1.54 10 −10 m). The coil sizes were h ≈ 5 nm for PBMA10k, h ≈ 12 nm for PBMA50k, and h ≈ 14 nm for PBMA70k.…”

Intrinsic viscosity‐number average molecular weight relationship for poly (n‐Octadecyl acrylate) and poly (N‐n‐octadecylacrylamide)

“…With respect to homologs, however, there is some data available indicating general applicability. Chinai et al (2)(3)(4)(5)21) have found the following values for the parameters of the poly-n-alkyl methacrylates in methyl ethyl ketone at 23-25C, in weight-average relationship: in the order K'X 104, a; methyl 0.71, 0.72; ethyl 0.28, 0.79; n-butyl 0.16, 0.81; 2-ethylbutyl 0.22, 0.77; hexyl 0.21, 0.78. Thus, on the basis of this limited quantity of data, the application of the values in Table III to other polyacrylate or polyacrylamide homologs and homolog mixtures would not be in serious error.…”

“…Constants, related to the thermodynamics of polymer solutions, are obtained as the slopes of the relations between polymer concentration and the characteristics ordinates used for the determination of intrinsic viscosity, and, respectively, number-and weight-average molecular weight. It appears that the only intrinsic viscosity-number average molecular weight relationship previously determined for a long-chain homopolymer was obtained for poly-n-nonyl methaerylate in benzene (1), although weight-average molecular weight relations have been measured for many n-alkyl methacrylate homologs (2)(3)(4)(5)(6)(7)(8)(9). Number-average relationships for n-alkyl acrylate homologs have been limited to whole polymers of methyl acrylate in acetone at 30C (10), and in benzene at 35C (11), and to whole and fractionated polymers of ethyl acrylate at 30C in a variety of solvents (12,13).…”