Accession Number : ADA193390
Title : Spatial Organization of Homopolymer Chains Inside Spherical Polybutadiene Domains of SB Diblock Copolymers.
Descriptive Note : Technical rept.,
Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
Personal Author(s) : Cheng, P ; Berney, C V ; Cohen, R E
PDF Url : ADA193390
Report Date : 16 Mar 1988
Pagination or Media Count : 29
Abstract : Blends of perdeuterated polybutadiene homopolymer and a polystyrene-polybutadiene diblock copolymer were prepared by solution casting techniques. Small angle neutron scattering and transmission electron microscopy experiments on blends containing homopolymer with chain length smaller than the corresponding block sequence showed that homopolymer chains are solubilized by the spherical microdomains up to a homopolymer content of about 15 mole percent. The solubilized homopolymer is distributed in a spatially uniform manner throughout the domain volume and the homopolymer radius of gyration is only slightly larger than that of an unperturbed chain in bulk. At about 18 mole percent pools, of homopolymer appear outside the microdomains; the change in scattering intensities indicate that pool formation is a kinetic phenomenon rather than a thermodynamically controlled event. Experiments on blends containing longer homopolymer chains revealed a lower concentration, between 3 and 6 mole percent, for the onset of homopolymer pool formation.
Descriptors : *POLYBUTADIENE, *BLOCK COPOLYMERS, *MOLECULAR STRUCTURE, *POLYSTYRENE, ANGLES, CASTING, COPOLYMERS, ELECTRON MICROSCOPY, INTENSITY, LENGTH, MIXTURES, NEUTRON SCATTERING, POLYMERS, SCATTERING, SEQUENCES, SPATIAL DISTRIBUTION, TRANSMITTANCE, VOLUME
Subject Categories : Polymer Chemistry
Distribution Statement : APPROVED FOR PUBLIC RELEASE