History and Anthropology

The chemical polymerization of aniline in aqueous solutions was studied as a function of a wide variety of synthesis parameters, such as pH, relative concentration of reactants, polymerization temperature and time, etc. The polymer was synthesized using a number of different oxidizing agents and different protonic acids. It was found that the reaction yield was not sensitive to most variables. By contrast, the inherent viscosity of the polymer, measured in solutions in concentrated sulphuric acid, was strongly dependent on the synthesis parameters. Optimum reaction conditions are outlined for the chemical polymerization of aniline, for post-treatment with aqueous HC1 solutions, and for compensation of the emeraldine salt into its base form. Under such conditions, high-quality polyaniline base was synthesized with an inherent viscosity (0.1% w/w polymer in sulphuric acid) as high as 2.32 dl g-1.

Polyblend fibers of polyaniline (PANI) and ultra high molecular weight polyethylene (UHMW-PE) were prepared by solution blending PANI and UHMW-PE in decahydronaphthalene and gel processing the resulting blend. The use of dodecylbenzenesulfonic acid as a counter-ion for emeraldine base allowed PANI to be solubilized into non polar solvents and to be blended homogeneously into solutions of UHMW-PE and decaline. Fibers were produced with various ratios of PANI to UHMW-PE resulting in materials with excellent mechanical properties as well as good levels of electrical conductivities. The modulus of the fibers ranged from 40 to 0.5 GPa, the tenacity from 2 to 0.02 GPa, and conductivity from 10-12 to 110 S/cm with increasing concenu'ation of polyaniline.

The solubility of polyaniline (PANI) in H2SO4 is investigated with parUr.J.dar emphasis on the stability of the polymer in this strong acid, Very little degradation of polyaniline is observed in these solutions at room temperature. However, it was found that common organic solvents and simple purification methods have a detrimental effect on the SOlUbility of polyaniline in H2SO4. Some evidence of structural change in the polymer is observed which suggest the possibility of crosslinking of the polymer. The processability of these solutions is explored with emphasis on manufacturing composite fibers of PANI with poly (p-phenylene terephthalamidel (PPTA). It was found that these fibers show electronic conductivity at polyaniIine concentrations well below the theoretical percolation threshold.

The preparation of solutions of polyaniline in concentrated sulfuric acid is described. The solutions were characterized by viscosity measurements and by ultraviolet(u.v.)-visible spectroscopy. Polyaniline was successfully processed into monofilaments and films from these solutions. In contrast to previous reports, polyaniline derived from sulfuric acid displays sharp X-ray reflections, indicative of a significant degree of crystallinity. The electrical conductivity of as-spun, washed and dried fibers was in the range 20-60 S/cm.

This essay explores four “big ideas” that swept across the southwest borderlands of North America in the thousand years that span the emergence of social complexity in the ancestral Puebloan world and the consolidation of the Spanish colony of New Mexico in the early eighteenth century, AD 700 to 1700.  The Chaco Phenomenon, the Katsina Religion, Franciscan Catholicism, and Po’pay’s (Pueblo) Revolt each sought, through evangelical methods, to effect a dynamic reorganization of popular religious, cultural, and political beliefs. And each provoked popular resistance or rebellions in which power relations between women and men proved meaningful.  The legacy of their successes and failures continue to resonate in the regional peoples’ memories and lifeways. Cycles of social complexity and disintegration, often attributed to ecological fluctuations, show evidence of tensions among women and men over their respective places in Pueblo socio-religious expression.  Intensification of social complexity among pre-contact Puebloans, as in the rise of the Chaco Phenomenon and the spread of the Katsina religion, often entailed some variety of women’s disenfranchisement from social and ceremonial life.  The advent of Franciscan Catholicism provided descendants of these women new avenues for exploring and expressing social and spiritual power, seldom in complete adherence to orthodox Catholicism, but in forms of experimental piety that resonated with women’s experience.

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