Melting temperature polypropylene oxide

For using lithium batteries (which generally have high energy densities) under extreme conditions, more durable and better conducting electrolytes are necessary. Salt-in-polymer electrolytes discovered by Angell et al. (1993) seem to provide the answer. Polypropylene oxide or polyethylene oxide is dissolved in low melting point mixtures of lithium salts to obtain rubbery materials which are excellent lithium-ion conductors at ambient temperatures. 

The effects of longer and shorter side chains on the epoxide compared to PBO are shown in Table VII. Polyethylene oxide led to a small improvement in impact strength and melt flow rate, but the heat distortion temperature was decreased. Polypropylene oxide and polyhexene-1 oxide had enhancing effects similar to and even a bit greater than those of PBO. Polyphenylglycidyl ether appeared to be inert when added to modified CPVC. Finally, in this application, the linear PTHF was harmful to properties. 

Stabilizing Activity of Pyrocatechols in Thermal Oxidation and in y-Irradiation of Polypropylene. It is interesting to compare the relationships found on stabilizing isotactic polypropylene oxidized over the melting temperature with the results of our previous study (22, 23) of the stabilizing properties of some derivatives of pyrocatechol in y-irradiated polypropylene. 

This paper describes the theory which permits us to characterize adequately the stereosequence length in stereoregular polymers from the equilibrium percent crystallinity at room temperature and from the melting points of the polymers. Results based on this theory are given on the characterization of the isotactic stereosequence length in the crystalline fractions of polypropylene oxide polymers made from the following catalyst systems (a) ferric chloride (17, 19) (b) diethyl zinc-water (10) (c) diethyl zinc-water-isopropylamine (d) diethyl zinc-water-cyclohexylamine (14). 

High density (HDPE), 52 Irregularities, 52 Linear low density (LLDPE), 52 Low density (LDPE), 52 Molecular weight, 52 Melt flow index, 53 Melting temperature, 51 Moisture absorption, 51 Polymeric forms, 52 Resistance to chemicals, 52 Resistance to oxidation, 52 Shrinkage, 54 Unsaturations, 54 a-transition, 51 P-transition, 51 y-transition, 51 Polyisocyanate, 79 Polylactic acid, 79, 91 Polymer alloys, 48 Polymer processing additives, 646 Polymer rheology, 619 Polymeric forms, 52 Polyphase PlOO, 451 polypropylene (PP), 2, 11 Polypropylene homopolymer, 70... 

When a polymer is irradiated below the melting temperature of crystallites, the polyfunctional monomer remains in the amorphous regions. Gels of polypropylene crosslinked in the presence of butadiene are crystalline which is a manifestation of the formation of crosslinks at the lamellar surfaces [79]. The presence of hexadecane and hexadecene-1 in isotactic polyiroiylene increases the rate of termination of radicals formed in the irradiated polymer and the oxidative post-effect is reduced as well as the deterioration of mechanical properties is less than in a polymer without additives [80]. 

Figure 4 Thermal analysis of polypropylene (PP) and polyethylene (PE). Crystallinities, melting temperatures, T, and oxidation induction temperatures, To, are indicated. (Reproduced with permission from Widman G (1987) Thermal analysis of plastics. American Laboratory 19 98-103.)...

Figure 8.28 Ds (right axis) of ( ) 33.6 kDa polypropylene oxide chains in solutions of 32 kDa PPO chains in a 1 kDa PPO melt, based on measurements of Smith, et a/. (45). Ds (left axis) of 255 kDa deuterated polystyrene in mixtures of (O) 93, (0) 250, or ( ) 20 000 kDa polystyrene and molten 10 kDa polystyrene, using measurements by Tead and Kramer(46). Temperatures were 150, 150, and 175 °C, respectively for clarity, the 150" C data have been shifted upward by a factor of 100.

PHB has a melting temperature (Tm) of 180"C, a glass transition temperature (Tg) of 5 "C and a high molecular weight. It is naturally not crystalline, and is converted in a more crystalline form during the extraction process. Research has been undertaken to avoid this transformation step that causes a decrease in the mechanical properties. The properties of PHB are similar to those of polypropylene, except for its biodegradability. It is also more rigid, more brittle and denser than PP. It resists oxidation but presents low chemical resistance. PHB is insoluble in water and relatively resistant to hydrolysis, the opposite of most biopolymers. 

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