CHAIN CONFORMATION OF ROD-LIKE POLYMERS IN THE MELT - SMALL-ANGLE NEUTRON-SCATTERING OF POLY(BENZOYL PARAPHENYLENE)

The chain conformation of a rigid rod polymer, poly(benzoyl paraphenyl ene), is determined in the melt using small-angle neutron scattering. The coherent scattering cross-section from blends of partially deutera ted and hydrogenous poly(benzoyl paraphenylene) agree well with ideal rod scattering for q > 0.02 Angstrom(-1), indicating that the polymer chains are highly extended. Comparison of the results to a single chai n-scattering function for chains of arbitrary stiffness yield a persis tence length of ca. 130 Angstrom. Pure component scattering at the low est scattering lengths indicate that the melt is not molecularly homog enous, but is comprised of domains, potentially reflecting localized g roupings of chains with similar backbone orientation. Furthermore, thi s mesoscopic structure depends on the processing history of the polyme r in the melt state. (C) 1998 John Wiley & Sons, Inc.