Small-angle neutron scattering study of amorphous polycarbonate

Conformational Analysis, RIS Models and Single-Chain Properties of Structurally Modified Polycarbonates, 1. Effect of Cyclohexyl and Phenyl Ring Substitutions

“…[10] Our RIS model predicts a value of 0.187 2 N mol N g -1 for a chain with 1 000 repeat units, which is in close agreement with the experimental value. pS 2 P values for substituted PC's as listed in Table 2 and 3 again point towards compact conformations of the structurally modified PC's with DMPC having the lowest value of 403 nm 2 when compared to 476 nm 2 for BPAPC.…”

“…By increasing the molecular weight corresponding to that of 1 000 repeat units, the value obtained is 1.12 2 N mol N g -1 at 300 K. These values are in close agreement with the earlier RIS models [6,8] and experimental values from dilute-solution measurements on BPAPC. [5,[9][10][11] The reported values are in the range 0.75-1.28 2 N mol N g -1 . The averaged chain dimensions as a function of chain length are shown in Figure 10.…”

“…(The repeat unit was considered to be made up of six bonds, four virtual and two real). Experimental results from light scattering, [5,9] intrinsic viscosity [5] and neutron scattering [10] are in the range 8 l 2. For other PC's the experimental values are not available for comparison.…”

“…The calculated pR 2 P was in close agreement with the experimental values from light scattering and small-angle neutron scattering measurements. [5,[9][10][11] This model was also extended to poly(thiocarbonates), in which the methyl group at the C a atom is replaced by the chlorophenyl group. [12] Conformational characteristics of structurally modified PC's have received little attention except for the RIS models derived for a series of C a -substituted polycarbonates, [7] and also the studies on the effect of articulated side groups at the C a atom on the main-chain flexibility of PC's.…”

Morphology and properties of melt-spun polycarbonate fibers containing single- and multi-wall carbon nanotubes

“…The diameter of 1.1 nm for the SWNTs used in this work corresponds to a channel diameter of w0.17 nm. This value is nearly two orders of magnitude less than the radius of Table 2 Tensile and electrical properties of PC nanocomposite fibers based on MWNT, SWNT-soln, and SWNT-dry gyration for the present PC which is estimated to be w13 nm [35,36], suggesting that polymer is essentially incapable of inter-diffusion into the ropes comprised of single wall tubes. Therefore, based on diffusion alone, exfoliation of the small diameter nanotubes, unlike MWNTs, is geometrically limited by polymer melts.…”