Polypropylene oxide oligomers

As it was shown in73, 74), methods that can be used to synthesize these copolymers of PAN are those of radical AN block copolymerization in the presence of an oxidation-reduction system in which the hydroxyl end groups of polyethylene oxide) (PEO)73) and polypropylene oxide) (PPO)74- oligomers serve as the reducing agents and tetravalent cerium salts as the oxidizing agents. 

Along with many other low molecular weight organic compormds thermal degradation of PEO and polypropylene oxide (PPO) produces monomers ethylene oxide (3.9% mass) and PPO (0.1-1.16% mass). The molecular masses of oligomer fragments, being volatile at the decomposition temperature, were 400 for PEO and 330 for iPPO. 

Other polymers whose structure has been examined by SEC-MS include poly-3-hexylthiophene [34], styrene oligomers [35], PS [5, 36-38], e-caprolactone [39, 40], polytetrahydrofuran [41] macrocyclic vinyl polymers [42], bis (metholol propionic acid) dendrimers [43], poly-isocyanates [44], isosorbide diols [45], 3,5-diacetoxybenzoic acid polyesters [46], polyethylene and polypropylene oxide condensates and PEG containing a 1,3 disubstituted phenolic group [37]. 

Since 1962, OA polypropylene oxide has been obtained from racemic monomers by asymmetric-selective or a stereoelective polymerization, which was extensively studied by Tsuruta and Furukawa and reviewed recently by these authors [106]. If the epoxide is substituted by an amino group, the polymerization gives only oligomers [110]. Some general observations on this subject are given in Section LB. 

The biodegradation of poly(alkylene glycols) is hindered by their lack of water solubility, and only the low oligomers of polypropylene glycol) are biodegradable with any certainty (179—181), as are those of poly(tetramethylene glycol) (182). A similar exo-oxidation mechanism to that reported for poly(ethylene glycol) has been proposed. 

Oxidation of waste plastics, such as polyethylene, polypropylene, polystyrene, poly (alkyl acrylates), and nylon 6,6, with NO/O2 for 16 h at 170°C, led to mixtures of carboxylic acids, for which uses would have to be developed if this method was applied to large volumes of waste plastics.180 Hydrogenation of polyethylene at 150C>C for 10 h over a sil-ica/alumina-supported zirconium hydride catalysts gave a 100% conversion to saturated oligomers.181 Polypropylene gave a 40% conversion to lower alkanes at 190°C for 15 h. It is not clear what use these materials would have, other than serving as a feedstock for a petroleum refinery. 

About 15.3 million metric tons (16.8 million short tons) of propylene were produced for commercial sale in the United States in 2004. About 39 percent of that amount was used for the production of polypropylene. Almost all of the remaining production was also used for the synthesis of chemical compounds, especially acrylonitrile (14 percent), propylene oxide (11 percent), cumene (10 percent), oxo alcohols (8 percent), isopropyl alcohol (7 percent), oligomers (5 percent) and acrylic acid (3 percent). Acrylonitrile, propylene oxide, oxo alcohols, and acrylic acids are all used primarily for the production of various types of polymers. Cumene is itself used as a raw material in the production of other organic compounds, especially acetone and phenol. 

Isotactic polypropylene (i-PP) Malen J-AOO and chalk of Polish production were used throughout this work. The average size of the chalk particles was calculated from their size distribution known from the previous works, It was assumed that chalk particles are cylinder shaped with diameter h- = 1.2 ym and length h2 = 8 ym. Oligomer of ethylene oxide (OEO) M = 300 was used as chalk modifier. 

I PA, polypropylene, syn. glycerol, acrylonitrile, propylene oxide, heptene, cumene, polymer gasoline, acrylic acid, vinyl resins, 0x0 chemicals, oligomers Manuf./Distrib. Air Prods. http //www.airproducts.com, /VIdrich http //www.sigma-aldrich.com, Atofina Bruxelles... 

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