Nascent polypropylene morphology: Polymer fiber

Abstract

Abstract A new morphological structure has been shown to be a general feature of polyolefin powders. This feature is a fiber approximately 0.5 μ in diameter and is common to a large number of samples of polyethylene, ethylene‐propylene copolymer, polypropylene, polybutene‐1, and poly‐4‐methylpentene‐1 samples. Polymer particles prepared with different catalysts under different conditions are composed of these fibers. The fibers grow from globules formed during the initial phase of polymerization, and their formation at high catalyst efficiency suggests that not all primary catalyst particles have equivalent activities. The fiber structure is one of at least six levels of order prevailing in the polypropylene particle. While the catalyst particle is responsible for some of the distinctive morphological arrangements, polymer morphology is the primary cause for the other structures. The primary catalyst particle is thought to be the determinant for the fiber.