Paul L. Kronick

Organic Semiconductors. V. Comparison of Measurements on Single‐Crystal and Compressed Microcrystalline Molecular Complexes

Utilizing specialized micromanipulative techniques, measurements of conductivity, activation energy of conduction, and Seebeck coefficient have been performed on charge‐transfer complex single crystals. The results are compared with previous measurements on compressed microcrystalline materials.

Composition of Some Conducting Complexes of 1,6‐Diaminopyrene

The absorption spectra of solid complexes of 1,6‐diaminopyrene with quinones exhibiting high electrical conductivity show them to be mostly radical‐ion salts. The mole fractions of ionic component for complexes with bromanil, chloranil, and 2,3‐dichloro‐5,6‐dicyano‐benzoquinone are 0.65, 0.90, and 0.95, respectively. This is the order of the estimated electron affinities of the acceptors but not of the conductivity of the complexes. The iodanil complex, with much higher resistivity, shows little ionic component.

Construction and properties of hydrogel-graft-coated copper-bearing intrauterine devices for rabbits.

The method for grafting blood and tissue compatible hydrogel coatings to polymeric substrates and the applicability of this method in constructing rod-shaped rabbit intrauterine devices (IUDs) consisting of polyethylene splints with copper wire are discussed. Dry hydrogel-graft-coated IUDs, with and without copper, were installed without suture fixation in 1 or both uterine horns of more than 50 rabbits. None of the IUDs removed (or expelled) after or during several 31- and 61-day experiments revealed fragmentation of the copper wire and/or hydrogel. Scanning electron micrographs were consistent with the results obtained with the bare copper-bearing 7- device. These observations suggest that the reactions on a copper surface in utero and in vitro are similar whether the copper is hydrogel-coated or not. However, in addition to greater tolerance of an IUD and minimizing inflammatory responses and the potential dangers of the release of copper or copper oxide fragments, this grafted hydrogel cover can be expected to contribute to better conservation of copper with a longer lasting efficacy.

Viscoelasticity of calf hide impregnated with radiation-polymerized polyhydroxyethyl methacrylate

In order to combine the desirable properties of synthetic polymers (elasticity and water, chemical, and biological resistance) with those of animal hide (strength, flexibility, and dyability), composites can be formed between the two types of material. Actually, adding materials to hide has long been an aspect of traditional leathermaking, usuaslly to increase thermal stability and to make the hide more hydrophobic. Newer uses for hide material require it to be stable but compatible with aqueous environments. Appropriate compositions can be formed from leather and hydrophilic polymers. Composites of collagen with poly(hydroxyethyl methacrylate) (polyHEMA or pHEMA) (1), with starch (2), or with Polyacrylamide (3) have been described for surgical implants with blood compatibility and lack of tissue inflammatory reactions. Other uses for these compositions may be found as substrata for cells and enzymes in biotechnology.

Radiation Polymerized Graft Copolymers for Leather

Radiation cured coatings for leather have been discussed in a series of publications (1–10). Somewhat less attention has been focused on the use of radiation polymerization of vinyl monomers within the leather to modify its properties in spite of an early suggestion by Buechler (1, 3) that this should also be possible and should be considered for full grain (unbuffed) leathers.