Structure of amorphous poly-(ethylmethacrylate): A wide-angle x-ray scattering study

Abstract

The local, temperature dependent structure of poly-(ethylmethacrylate) was studied with wide-angle x-ray scattering. The results were set into context to recent wide-angle neutron scattering results as well as to the results from a multitude of studies of the dynamics of this polymer. The temperature dependence of the wide angle x-ray results point to the development of local order which is backed by the neutron scattering results and which is connected to characteristic temperatures of the relaxation dynamic T(g) and T(c). The poly-(ethylmethacrylate) was studied in its predominantly syndiotactic as well as predominantly isotactic state displaying vastly different local structures as manifested in the x-ray results.

Self- and Collective Dynamics of Syndiotactic Poly(methyl methacrylate). A Combined Study by Quasielastic Neutron Scattering and Atomistic Molecular Dynamics Simulations

“…It was interpreted as the genuine mechanism for the structural relaxation. [15][16][17] We note at this point that the interchain collective dynamics, which have been measured by NSE techniques at the first maximum of S(Q) in different polymers, was always interpreted as the actual structural R-relaxation. 34 At Q ) 1.9 Å -1 , with the exception of the MC/SG and MC/ MC correlations, basically all the relaxation times are within a factor of 2.…”

“…7,8 Furthermore, other subglass and glass relaxation processes in PMMA have been studied for a long time mainly by dynamic mechanical analysis, dielectric spectroscopy, and advanced NMR spectroscopy. [9][10][11][12][13][14][15][16][17] Especially in the temperature range close to and above the glass-transition temperature (T g ≈ 400 K), PMMA exhibits a complicated dynamics. A complexsand likely cooperativessecondaryrelaxation has been reported, which masks the pure R-process when techniques such as mechanical or dielectric spectroscopy (e.g., ref 13) are used.…”

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

“…This peak is roughly in the same position as the "prepeak" in the x-ray pattern, reinforcing the idea that in polymers with bulky side groups such a "prepeak" is representative of the polymer backbone distance. 11,12,14,50,51 This average distance could be estimated from the peak position as 2π/0.6 Å −1 = 10.5 Å. S MC/MC (Q) smoothly decreases toward higher Q but still shows a small shoulder around 1.2 Å −1 , i.e., around the "main" peak.…”

“…In particular, the hypothetic presence of two types of α relaxation is discussed in poly(n-alkyl-methacrylates) and poly(di-n-alkyl itaconates). [12][13][14] Two structural relaxations have also been reported for poly(isobornyl methacrylate), a polymer with a bulky bicyclic isobornyl side group. 15 In order to clarify the role played by side groups dynamics, it can be useful to reduce the complexity herited a) Electronic mail: a.arbe@ehu.es.…”

“…[1][2][3] Moreover, it has been shown that increasing the size of side groups has a deep impact on the structure and dynamics of polymers. Of particular interest is the family of poly(nalkyl-methacrylates), 2,[4][5][6][7][8][9][10][11][12] where x-ray and neutron diffraction analysis show that nanosegregation occurs between backbone and side groups. The effects of these nanosegregated domains on the local dynamics remain however unclear.…”