Polymethylene oligomer

Utterback and co-workers [54] determined oligomers of polyoxymethylene glycols and ethers by derivatisation with ammonia then determination by capillary column GC. Okada [55] used temperature programmed GC to determine polymethylene oligomers. High temperature capillary GC has also been used to determine separate Novoloc phenolic and epoxy novolac oligomers [56]. 

Mention may also be made of the controlled ozonolytic or oxidative degradations of high MW iso tactic poly(oxypropylene), poly(vinyl chloride), and poly(isobutene-co-2,3-dimethylbuta-diene) " to give oligomers with functional end groups. However, no effective synthesis has yet been devised for a, co-difunctional polymethylene oligomers which would be of considerable interest as precursors of block copolymers. 

Polymethylene-co-Guanidine Hydrochloride, Oligomer 654 0.2-2.0 Scientific Polymer Products, Ontario, NY... 

The donor-acceptor distance may not be unique, especially when the donor and acceptor are linked by a flexible chain (e.g. end-labeled oligomers of polymethylene or polyethylene oxide, oligopeptides, oligonucleotides, polymer chains). 

The ratio is of diagnoslic value if kt kj, essentially low molecular weight products such as methane or Cj —C4 are formeduf ki ki, the reaction will yield oligomers in a wider distribution, e.g., Ci, Cis. and if 2 > the reaction will yield high molecular wei i products like waxes or polymethylene [12]. 

Our efforts to make polyolefin-supported soluble catalysts require synthetic routes to terminally-functionalized ethylene oligomers. Such oligomers can be prepared by our approaches (Figure 2),(P) newer catalytic routes(/0) or by polymethylenation.(7 7)... 

Chapter 3 is a guided tour of molecular dynamics and infrared and Raman frequency and intensity spectroscopy of polymethylene chains, from oligomers to polymers, in their perfect and disordered states. The reader is exposed in the easiest possible way to the basic theoretical concepts and to the numerical techniques which can be applied to such studies. Many references are provided for the spectro-scopist who wants to develop his or her own independent skill and judgment. 

The method used most in the present work to estimate amorphous polyethylene properties consisted in using oligomer (ra-alkane) properties to calculate limiting properties (Pcx>, properties of an infinite-length homolog) sueh limiting properties resemble the corresponding properties of amorphous, linear polyethylene (or amorphous polymethylene) (Table 11). 

On the other hand, because TDM and dimethylsulfoxonium methylide 11 react with organoborane in a similar mechanism (formation of borate followed by 1,2-migration), organoborane-initiated copolymerization of TMD with 11 proceeded to give poly(TMSmethylidene-co-methylene), which is a partially TMS-substituted polymethylene [69]. Although the composition of TMSCH in the products was lower than that expected from the feed ratio of [TDM]/[11], oligomers with a relatively narrow MWD were obtained as shown in Scheme 47. 

Side chain crystallisation or side chain interactions ( with partial and/or full intercalation) occur and play a dominant role in the determination of the structure of many organic polymethylenic systems such as liquid crystal oligomers and polymers etc. X ray structure determinations on polyalkylthiophenes are presently being performed by various groups [164-165]. 

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