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Surface and morphological characterization of poly[styrene‐ co ‐(Boc‐ p ‐aminostyrene)] microspheres
Author(s) -
Covolan Vera L.,
Volpe Pedro L. O.,
de Castro Sandra G. C.,
Landers Richard,
Fernandes Elizabeth G.,
Ruggeri Giacomo
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200207)203:10/11<1454::aid-macp1454>3.0.co;2-2
Subject(s) - comonomer , copolymer , dispersity , styrene , polymer chemistry , particle size , chemistry , monomer , gel permeation chromatography , polymer , materials science , analytical chemistry (journal) , chromatography , organic chemistry
Poly[styrene‐ co ‐(Boc‐ p ‐aminostyrene)] microspheres were obtained by dispersion copolymerization of styrene (ST) and Boc‐ p ‐aminostyrene (Boc‐AMST) monomers. The polymer microspheres obtained were soluble in chloroform. The copolymer composition was determined by NMR, average molecular weight and polydispersity by gel permeation chromatography. Copolymers with different comonomer molar content were synthesized with molecular weights ranging from 40 000–125 000, and polydispersity indices ranging from 2.0–3.5. Particle size by Coulter‐counter measurements and surface area analysis by BET method were performed; the mean diameter of the particles ranged from 0.7 to 1.2 μm, the surface area ranged from 1.3 to 5.7 m 2 · g −1 and the mean pore dimension was around 100 Å. By scanning electron microscopy it was verified that the particles were spherical with a homogeneous size distribution. The relative surface density of NH groups on the particle surface, determined by X‐ray photoelectron spectroscopy, was between 2.62 · 10 15 and 1.48 · 10 16 nitrogen atoms/cm 2 ; this value increased with increasing content of aminated comonomer in the monomeric feed. Particle‐water interactions, investigated by differential scanning calorimetry measurements, suggest that the presence of NHCOOC(CH 3 ) 3 groups increases the capacity of water adsorption by the microspheres.Typical photomicrograph of the Boc‐AMST/ST copolymer microspheres obtained by SEM (Boc/ST 5/95 sample).