Development and use of a turbidity analyzer for studying the solution crystallization of polyolefins

Abstract

Cooling a solution of a crystalline polyolefin from 1408C to room temperature causes the dissolved polymer to crystallize. If a laser beam passes through this solution, the crystallization will cause the beam to scatter, which thereby decreases the intensity of the beam. With this principle, it is possible to follow the crystallization of polyolefins under controlled cooling. An instrument capable of doing these analyses was manufactured, and several different polyolefins were analyzed. The effect of the experimental parameters are illustrated for both cooling and reheating experiments. In addition, an interesting dependence on molecular weight was also observed for a series of metallocene polypropylenes.

The effect of in-process ethylene incorporation on the evolution of particle morphology and molecular characteristics of commercial heterophasic ethylene propylene copolymers (HEPCs)

“…shown to correlate well with TREF and CRYSTAF [18]. The SCALLS technique was previously used to study the solution crystallization behaviour of a series of different polyolefins and was successful in detecting subtle crystallization differences between samples [19].…”

“…August 2013 [19]. This group published the application of combined AFM and micro-computed tomography (micro-CT) to obtain 3D visualisation of pore distribution (for isotactic PP) and EPR distribution within an HEPC particle ( Fig.…”

“…Despite the many studies that have been conducted on various aspects of HEPC morphology, microstructure, chemical composition etc., [12][13][14][15][16][17][18][19][20][21][22][23][24][25] it is still unclear how the EPR phase evolves in the second reactor and how it interacts with the existing isotactic PP matrix produced in the first reactor to influence the overall particle morphology and product properties. Many of these studies have focused on characterization of the final polymer after melting and crystallization [12][13][14][15][16][17][18][19] [20][21][22][23][24][25].…”

“…Many of these studies have focused on characterization of the final polymer after melting and crystallization [12][13][14][15][16][17][18][19] [20][21][22][23][24][25]. From these, various models (some contradicting)…”

Use of solution crystallization analysis by laser light scattering for studying the solution crystallization of various Ziegler–Natta‐catalysed polypropylenes

“…To fractionate polymers produced using different catalyst systems, a number of methods described in the literature have been used for semi‐crystalline polymers . These methods include solvent extraction, consecutive extraction with different solvents, fractionation with solvent/non‐solvent pairs, consecutive extraction with a solvent at different temperatures and, more recently, TREF and crystallization analysis fractionation (CRYSTAF) .…”