Polyethylene Materials with In-Chain Ketones from Catalytic Copolymerization

The world’s most important plastic, polyethylene, consists of inert hydrocarbon chains. An introduction of reactive polar groups in these chains is much sought-after, to overcome the problematic environmental persistency and enhance compatibility with other materials. However, with state of the art catalytic polymerization processes this has not been possible. Here, we show how a low density of individual in-chain keto groups can be generated in the high molecular weight polyethylene chains by catalytic copolymerization with carbon monoxide. Most importantly, the desirable materials’ properties of high density polyethylene (HDPE) are retained. Processing can be performed by common injection molding and mechanical characteristics are on a par.<br><br>

Polyethylene Materials with In-Chain Ketones from Catalytic Copolymerization

The world’s most important plastic, polyethylene, consists of inert hydrocarbon chains. An introduction of reactive polar groups in these chains is much sought-after, to overcome the problematic environmental persistency and enhance compatibility with other materials. However, with state of the art catalytic polymerization processes this has not been possible. Here, we show how a low density of individual in-chain keto groups can be generated in the high molecular weight polyethylene chains by catalytic copolymerization with carbon monoxide. Most importantly, the desirable materials’ properties of high density polyethylene (HDPE) are retained. Processing can be performed by common injection molding and mechanical characteristics are on a par.<br><br>

A comparison of zwitterionic and anionic mechanisms in the dual-catalytic polymerization of lactide

Two different polymerization mechanisms for lactide are selectivity addressed to illuminate the respective role of organobase and Lewis acid component.

SYNTHESIS AND STUDY OF COPOLYMERS OF ETHYLENE WITH HEXENE-1, MODIFIED WITH FINISHED NANOFIBERS-Al2O3 (NAFEN) WITH INCREASED RESISTANCE TO THERMAL OXIDATIVE DEGRADATION

Here we report the study on synthesis and characterization of nanocomposites obtained by in situ catalytic polymerization of ethylene and hexene-1 on metallocene catalyst in the presence of dispersed surface-functionalized -Al2O3 nanofibers (Nafen). It has been determined that surface treatment of Nafen nanofibers with organosilanes allows to obtain stable nanoscale dispersions under ultrasonication. It has been shown that nanocomposites based on copolymers of ethylene with hexene-1 demonstrate improved resistance to thermal oxidative degradation in comparison with nanocomposites based on copolymers of ethylene with propylene, while the influence of the silane chemistry on the mechanical characteristics in these nanocomposites is less pronounced. The best mechanical characteristics were achieved for nanocomposite with Nafen treated with trimethoxyvinylsilane. The melt flow index drop is observed after moderate heat treatment or combined temperature/humidity.

Compartmentalized polymerization in aqueous and organic media to low-entangled ultra high molecular weight polyethylene

Catalytic polymerization in compartmentalized aqueous or non-aqueous media, respectively, with functional-group tolerant Ni(ii) catalysts yields low-entangled UHMWPE.