Polymerization and Fabrication

Kricheldorf and Bier used cesium fluoride as the catalyst for the bulk polymerization of various silylated bisphenols and 4,4 -diflu-orobenzophenone at elevated temperatures from 220 to 320°C (18). The polymerization is essentially a nucleophilic aromatic substitution. Transetherifications were not found during the course of 

Normally, PEEK is a linear molecule. Chen et al synthesized PEEK single size macrocycles and macrocyclic oligomer mixtures (22). The macrocycle monomers can be ring opening polymerized into semicrystalline PEEK with the initiators of a catalytic amount 

The monomers dealt with can be polymerized by various mechanisms, not only by ROMP. For example, a rapid polymerization of norbornadiene occurs using a homogeneous catalytic system consisting of nickel acetylacetonate or a nickel-phosphine complex, such as nickel bis-(tri-n-butylphosphine) dichloride (NiCl2(TBP)2) or nickel bis-(tricyclohexylphosphine) dichloride (NiCl2(TBP)2). Nickel acetylacetonate as catalyst is known to initiate rather a classical vinyl polymerization (7). The classical vinyl polymerization 

A wide variety of PPX have been synthesized, however only a few materials are commercially sold. 

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In addition to wholly aromatic PAs, PAs are termed as aromatic PAs, when at least one constituting component is of an aromatic nature. These types of partially aromatic PAs are in between nylons and aramids. The particular advantages are easier techniques of polymerization and fabrication. So, if the properties of partially aromatic PAs are sufficient for certain particular applications they can be used instead of wholly aromatic PAs. Partially aromatic PAs are dealt with in this chapter only marginally they are summarized in the poly(phthalamide) chapter. 

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