Abstract: Spherical polyolefin (or modified polyolefin) powders having high bulk density, narrow particle size distribution and good powder flowability are prepared by cooling a polyolefin solution comprising a solvent and nonsolvent for the polyolefin and containing a small amount of an inorganic compound and, if desired, water. The polyolefin powders are suitable for powder coating. Suitable solvents are hydrocarbons, such as hexane, heptane, etc., and a mixture of hydrocarbon and nonsolvent for polyolefin such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. The ratio of a hydrocarbon/nonsolvent is 95/5 - 30/70, preferably 90/10 - 50/50. Suitable inorganic compounds are phosphoric acid, sulfuric acid, sulfurous acid, hydrochloric acid, sodium hydroxide, potassium hydroxide, ammonium hydroxide, inorganic salts thereof, etc. and the most preferable inorganic compound is phosphoric acid.

Abstract: Plastic compositions containing polyolefins and dinaphthylphthalate compounds having the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 independently are from the group hydrogen; a straight or branched chain alkyl group having from 1 to 6 carbon atoms; cyano; nitro; lower alkoxy; fluorine, dialkylamino, phenyl, halo-phenyl, benzyl and halo-benzyl, have been found to be photodegradable plastic materials for use, for example, as wrapping films and agricultural mulching films.

Abstract: Processes for the efficient sulfuric acid hydrolysis of poly(iminoimidazolidinediones) (PIPA) to the corresponding polyparabanic acids (PPA) have been developed. Process conditions can be manipulated to favor the formation of large crystalline particles of ammonium sulfate, a byproduct of the reaction, so that they can be readily separated from the reaction solution.

Abstract: High temperature resistant polymers containing a methylene monoarylene, methylene diarylene, -aromatic ring--CH.sub.2 -- or -aromatic ring--CH.sub.2 --aromatic ring-group are made more effective at even higher temperatures against thermal oxidative degradation by incorporating small quantities of special antioxidant stabilizers therein either singly or in combination to result in novel and unobvious compositions.