Syndiotactic polypropylene copolymer membranes and their performance for oxygen separation

Abstract

Syndiotactic poly(propylene- -olefin) copolymers with controlled microstructure and desired properties for oxygen enrichment have been synthesized via metallocene catalysts. The controlled incorporation of comonomers as pendant branch mainly improved the oxygen permeability, but the oxygen/nitrogen selectivity dropped around 20%. By controlling the amount and length of the branches in the syndiotactic polypropylene, the permeability of the membrane was enhanced up to 12-fold and it is comparable to typical commercial polymers used for this application. In contrast with conventional commercial polypropylene, copolymers with a large amount of comonomer were soluble in cyclohexane, allowing the manufacture of composite membranes with high permeance.The authors acknowledge the financial support of CONICYT (FONDAP Project 11980002 and Término de Tesis Scholarship), and the Ph.D. Scholarship to María Eulalia Vanegas by the Deutscher Akademischer Austauschdienst (DAAD)

Influence of the Polymeric Matrix and Thermal Treatment on the Properties of Polyolefin‐Graphite Nanosheets Nanocomposites

“…Regarding the metallocene catalysts, they are characterized by generating poly(propylene) with narrow molecular weight distribution and excellent control of tacticity, they have also proven to be an excellent route for the synthesis of copolymers. For example, alpha‐olefins having different chain length have been incorporated as comonomers in the PP matrix by using metallocene catalysts to obtain copolymers of different compositions and comonomer incorporation, allowing a very good control of the polymerization reaction, high reproducibility and well defined properties of the final product …”

Preparation and Properties of Low Density Polyethylene Film Modified by Zeolite and Nanoclay

“…Vanegas et al [42] also reported that O 2 =N 2 selectivity, in metallocene catalyst syndiotactic polypropylene copolymers, is affected mainly by diffusivity selectivity. With 3% clay addition permselectivity remained constant, with zeolite loading, compared to that of neat PE-LD (Fig.…”