By polymerizing phenyl or n‐butyl isocyanate in various solvents in the presence of anionic catalysts such as lithium or sodium alkyls, crystalline polymers were obtained. For both polymers, the I.R. spectra, the X‐ray diffraction spectra and other physical properties are reported. The possible structures of the two crystalline polymers are discussed. By cationic catalysts (e.g. AlBr3) amorphous polymers were obtained from phenylisocyanate, but no polymers from n‐butylisocyanate.

synopsis T h i s study was undertaken to measure quantitatively the flammability characteristics of cotton and polyester fibers. The smoke density generated during the burning of these fabrics was also studied a t various temperature conditions. A mathematical relationship was established between the results obtained in an oxygen-depleted atmosphere chamber and those obtained in a chamber in which there was constant repIenishing of an oxygen and nitrogen atmosphere. Three commercially available flame-retardant treatments were utilized in this study. The effect of temperature as well as the influence of fabric weight on the flammability behavior and the smoke density of these fabrics were investigated. A novel instrument built according to ASTM standards was employed throughout this study; it was found to be versatile, convenient, and highly reproducible in the generation of the data. It was found that polyester fabrics generate far more smoke than cotton fabrics without the phenomenon of afterglow. It was found also that aa the temperature increases, the smoke density of cotton fabrics increases as well, but in the case of polyester fabrics the opposite relationship was obtained.

This study was undertaken to measure quantitatively the effect of temperature on the oxygen index values of several fabric samples of cotton, polyester, and their blends. The smoke density generated during the burning of these fabric samples at their oxygen indices was also studied at various temperature conditions. The results indicate a definite rela tionship of burning behavior with temperature, fabric weight, and composition of the blends. Two commercially avail able flame-retardant finishes were employed in this comparative flammability study of treated and untreated specimens. A novel instrument, which complies with standard laboratory procedures, was employed throughout this study, and it was found to be versatile, convenient, and highly reproducible in the generation of the data.

The reaction of two molecules of AlRCl2 with an electron donor molecule D, gives rise to the practically quantitative formation of AlR2Cl and AlCl3.D. This can explain the catalytic activity in the stereospecific polymerization of propylene to isotactic polymer of the systems prepared from violet TiCl3, AlRCl2, and an electron‐donor substance. These systems have the same degree of stereospecificity as the systems consisting of AlR2ClTiCl3 (violet).