A SANS Study of the Conformational Behavior of Linear Chains in Compressed and Uncompressed End-Linked Elastomers

Published

October 1, 2001

Author(s)

N Gilra, C Cohen, R M. Briber, Barry J. Bauer, R C. Hedden, A Z. Panagiotopoulos

Abstract

Small-angle neutron scattering (SANS) experiments were performed to determine the conformational behavior of unattached deuterated linear poly(dimethylsiloxane) (PDMS) chains of Mn = 58,300 g mol-1 in uncompressed and compressed end-linked protonated PDMS networks with a minimal amount of defects. The networks were prepared from low polydispersity precursor chains with Mn = 9,900 g mol-1, 34,800 g mol-1, and 71,500 g mol-1. The mixtures of the 10K network with the linear chains were prepared by crosslinking around the linear chains, while the 35K and 70K network systems were swollen with the linear chains after the network was formed. No significant variation of the radius of gyration of the linear chains was observed as a function of network mesh size. Under compression, the free chains in most of the samples exhibited a crossover from Gaussian to rod-like behavior at length scales comparable to the segment length of the chains. This behavior was quantified by using a Kratky-Porod wormlike chain model to fit the scattering data and to determine model parameters such as the contour length and Kuhn length.

Citation

Macromolecules

Volume

32

Issue

No. 22

Pub Type

Journals

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Keywords

elastomers, Kratky-Porod, networks, PDMS, SANS

Citation

Gilra, N. , Cohen, C. , Briber, R. , Bauer, B. , Hedden, R. and Panagiotopoulos, A. (2001), A SANS Study of the Conformational Behavior of Linear Chains in Compressed and Uncompressed End-Linked Elastomers, Macromolecules, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851862 (Accessed December 1, 2024)