Amino units were grafted onto the surface of small particle size alumina by reaction with 3‐aminopropyltriethoxysilane. Atactic polystyrene (PS) was sulfonated (1‐14 mol% sulfonation) and mixed with both modified and unmodified alumina at filler loadings varying from 30 to 80 wt %. The resulting composites were characterized by differential scanning calorimetry, Fourier transform infra‐red spectroscopy, and dynamic mechanical spectroscopy in the glass transition region at a frequency of 1 Hz. Whereas mixtures of unsulfonated PS with either filler showed essentially no change in Tg with filler content, sulfonated PS saw its Tg increase as a function of filler loading at a rate which was greater following modification of the alumina. At a fixed filler loading of 30 wt%, the composite rubbery plateau modulus was found to increase with copolymer sulfonic acid content, while the loss tangent maximum corresponding to the glass transition broadened and decreased. These observations were interpreted as a manifestation of the decrease in polymer mobility brought upon by the formation of noncovalent crosslinks resulting from the proton transfer from the sulfonic acid units on the polymer to hydroxyl and/or amino units at the surface of the filler. © 1994 John Wiley & Sons, Inc.

Atactic poly(methyl methacrylate) was partially hydrolyzed in concentrated sulfuric acid to obtain methacrylic acid contents (MAA) of 3–12 mol %. The resulting copolymers were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography. The dynamic mechanical properties of these copolymers were studied in the glass transition region at a frequency of 1 Hz following neutralization with various low‐molecular weight linear (e.g., octylamine) and rigid (e.g., 1‐adamantanamine, ADA) primary amines. While the addition of linear amines to the copolymers was found to depress Tg, the addition of ADA had relatively little effect. FTIR spectra of all these blends indicated that proton transfer occurred from the MAA units to the amines, resulting in H‐bonded ion pairs which behaved mechanically as grafts. Itwas concluded that the ion pairs resulting from protonation of the ADA units by MAA are less effective at reducing free volume than similar ones resulting from the reaction of a sulfonic acid with ADA. © 1993 John Wiley & Sons, Inc.

SYNOPSISMicrobeads possessing amine functionality at the surface have been prepared by two methods: In the first method, poly(4-~inylpyridine/styrene) P(4VP/S) copolymer microbeads containing 13-69 mol % 4-vinylpyridine (4VP) were synthesized from the monomers. In the second method, animated polystyrene (PS) particles were prepared by postpolymerization reactions on cross-linked PS and polychloromethylstyrene particles to obtain poly(aminomethylstyrene/styrene) and polydiethylaminomethylstyrene particles, respectively. Scanning electronic microscopy of P(4VP/S) microbeads showed regular and spherical particles having a diameter between 80 and 200 nm depending on 4VP content. The chemical structure of the various particles made was studied using Fourier transform infrared spectroscopy, electron spectroscopy for chemical analysis (ESCA), and elemental analysis, whereas thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis.

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JOJ 1 RO SYNOPSISComposites of sulfonated polystyrene (PS-SSA) (0-8 mol % sulfonation) mixed with submicronic styrene-4 vinylpyridine (PS-4VP) (31 mol % 4VP content) microspheres were investigated by differential scanning calorimetry, Fourier transform infrared spectroscopy, and dynamic mechanical spectroscopy at 1 Hz in the glass transition region. The resulting proton transfer reaction from the SSA to the 4VP units was confirmed by IR spectroscopy, and led to a significant increase in the post-T, Young's modulus as well as a lengthening of the rubbery plateau. Surprisingly, the addition of sulfonated polystyrene microspheres to styrene-vinyl pyridine copolymers had no such effects, possibly because of steric factors.