Poly p-Xylylene PPX

Moreover, where i r-acetjldi- -xyljlene [10029-00-2]( is pyroly2ed, by adjusting temperatures in the deposition region, it is possible to isolate two different polymeric products, ie, poly(acetyl-/)-xylylene) [67076-72-6] (8) and poly(p-xylylene) (PPX) (2). This of course requires the cleavage of the original dimer into two fragments. 

The linear polymer of PX, poly(p-xylylene) (PPX) (2), is formed as a VDP coating in the parylene process. The energetics of the polymerization set it apart from all other known polymerizations and enable it to proceed as a vapor deposition polymerization. 

Crystal structure analysis of poly(p-xylylene) (PPX) P-form [2,25]... 

Another striking example concerns the polymer poly(p-xylylene) (PPX). It is obtained by condensation at room temperature of the gaseous monomer. A clear foil may be obtained in that way. The melting point of PPX is 427 °C and it crystallises immediately after polymerisation, so that entanglement cannot be formed. Van der Werff and Pennings (1988, 1991) have shown that hot drawing of such a material at 420 °C yields a material with a tensile strength of 3 GPa and a tensile modulus of 100 GPa. 

Organometallic derivatives of poly-p-xylylene (PPX) with Ge and Sn atoms covalently bonded to polymer chains have been synthesized by a vapor deposition technique using bridged [2,2]-paracyclophanes with corresponding organometallic groups [32, 33]. Pyrolysis of these cyclophanes, along with polymerization of the /7-xylylene monomer mixture, is shown in Scheme 2.2. 

J. H. P. Utley and C. Z. Smith. Electroorganic reactions. Part 53. The electrosynthesis of novel water-soluble poly-(p-xylylene)(PPX) and poly(p-phenylenevinylene)(PPV) polymers and co-polymers. J. Mater. Chem., 10 2642-2646, 2000. 

Utley JHP, Gruber J. Electrochemical synthesis of poly(p-xylylenes) (PPXs) and poly(p-phenylenevinylenes) (PPVs) and the study of xylylene (quinodimethane) intermediates an underrated approach. J Mater Chem 2002 12 1613-24. 

Poly(p-xylylene), PPX, was first prepared via the reactive intermediate p-xylylene by Szwarc in the 1940s. In the 1960s Union Carbide developed a synthetic route based on the dimer di-p-xylylene ([2.2]paracyclophane). These PPXs are commonly referred to as parylene and are available under the GALXYL trade name from Specialty Coating Systems, Inc [63,64]. A general structure of PPX is depicted in Fig. 1.38. 

Poly(p-phenylene benzobisthiazole) PBZT Poly(p-phenylene terephthalamide) PPTA Poly(p-xylylene) PPX... 

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