Ethylene endcapping

Acetal Resins. Acetal resins (qv) are poly (methylene oxide) or polyformaldehyde homopolymers and formaldehyde [50-00-0] copolymeri2ed with ahphatic oxides such as ethylene oxide (42). The homopolymer resin polyoxymethylene [9002-81-7] (POM) is produced by the anionic catalytic polymeri2ation of formaldehyde. For thermal stabiUty, the resin is endcapped with an acyl or alkyl function. 

Polyoxymethylene polymers, POM, commonly known as polyacetals or Acetal resins are linear thermoplastic polymers containing predominantly the -CH -O- repeat unit in their backbone. There are two types of acetal resins available commercially (1) homopolymers made by the polymerization of formaldehyde, followed by endcapping, (2) copolymers derived from the ring opening polymerization of trioxane (a cyclic trimer of formaldehyde), and a small amount of a comonomer such as ethylene oxide. Acetal resins are... 

Jeong Y-I, Seo S-J, Park I-K, et al. (2005). Cellular recognition of paclitaxel-loaded polymeric nanoparticles composed of poly ([gamma]-benzyl 1-glutamate) and poly(ethylene glycol) diblock copolymer endcapped with galactose moiety. Int. J. Pharm. 296 151-161. 

A polyrotaxane is the counterpart of a pseudorotaxane, as shown in Fig. 1. There are macrocycles threaded on a linear polymer chain, and the macrocycles are prevented from slipping off the chain by the two bulky terminals. Zhao and Beckham [13] reported a polyrotaxane based on poly(ethylene glycol) (PEG). A polypseudorotaxane was obtained from the slipping of a-CD rings to a PEG-Ts2 chain in aqueous solution, the consequent endcapping with dimethylben-zene by etherihcation resulted in the formation of the polyrotaxane. 

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