Polypropylene parameter

Figure 3.4. H NMR spectrum (simulated at 400 MHz) of isotactic polypropylene. Parameters which are used are the following ones Schj = 0.80 ppm, Schj = 1.20-1.35 ppm, Sch = 1.6 ppm.

There are thus no solvents at room temperature for polyethylene, polypropylene, poly-4 methylpent-l-ene, polyacetals and polytetrafluoroethylene. However, as the temperature is raised and approaches F , the FAS term becomes greater than AH and appropriate solvents become effective. Swelling will, however, occur in the amorphous zones of the polymer in the presence of solvents of similar solubility parameter, even at temperatures well below T. ... 

The effect of these two parameters on mechanical and physical properties of polyethylene and polypropylene are shown in Tables 3.44 and 3.45. The copolymer grade is usually propylene with a little ethylene (5%), wliich considerably improves the impact strength while causing only a slight loss in stiffness. 

A simple, rapid and accurate ICP-AES method was developed for the analysis of Ca, Mg, Fe, Al, Ti in polypropylene [198]. With optimised operating parameters and analytical wavelength, RSD was below... 

We see that the parameter m is constant in the very line of experiments and lies in the limit 0.5-0.75. The energetic barrier of orientation for the studied reactions in polyethylene and polypropylene amounts 5-12 kJ mol-1. 

Danilova-Volkovskaya G.M. The effect of processing parameters and modifiers on the properties of polypropylene and PP-based composite materials. — Doctoral Thesis, (technical sciences). 2005, p. 273. 

F.A. Bovey. Alan Tonelli in our laboratory has been working on the prediction of carbon chemical shifts in polymer chains and he finds what you found for the polyvinyl chloride. I think you first pointed out that the gamma effect can be used to explain such chemical shifts. Polyvinyl chloride can be explcdned if enough variable parameters are used. PVC is not the simplest case. Polypropylene on the other hand can be esplained with a single constant but PVC apparently cannot. Dr. Tonelli hasn t published any of this yet he is still working it out. 

As for container material, polypropylene containers are as satisfactory as glass ones in compound stability and recovery. Since water is more harmful than oxygen to compound degradation and the hygroscopic nature of DMSO favors water uptake, humidity control is a key parameter to ensure compound storage stability. 

In addition to the nature of particulate platelet orientation induced during injection moulding, the associated consequences on molecular orientation and crystalline order of the host thermoplastic matrix have also been reported with particular regard to various flake-filled polypropylenes [174], together with an attempt to interrelate these higher order structural parameters with physical properties of the composites [175]. 

The principal polyolefins are low-density polyethylene (ldpe), high-density polyethylene (hope), linear low-density polyethylene (lldpe), polypropylene (PP), polyisobutylene (PIB), poly-1-butene (PB), copolymers of ethylene and propylene (EP), and proprietary copolymers of ethylene and alpha olefins. Since all these polymers are aliphatic hydrocarbons, the amorphous polymers are soluble in aliphatic hydrocarbon solvents with similar solubility parameters. Like other alkanes, they are resistant to attack by most ionic and most polar chemicals their usual reactions are limited to combustion, chemical oxidation, chlorination, nitration, and free-radical reactions. 

Fig. 10.6. Signals reflected from the top and bottom surfaces of a 40 pm thick layer of polypropylene, with the same acoustic parameters as in Fig. 10.4 (a) bonded to steel (b) unbonded, with air backing (Sinton etal. 1989).

At the pressure P, knowing the interaction parameter, and the vapour pressure of the monomer, Po, the volume-fraction, tj), of the monomer sorbed can be estimated from Equation 5.4-9. Figure 5.4-6 shows the pressure- and temperature dependence of the volume fraction of absorbed propylene in a given amorphous polypropylene [12],... 

The method of incomplete mold filling is effective for investigating injection molding of fiber glass-loaded polypropylene and polystyrene melts.283 After solidification, samples were prepared for microscopic investigation. The authors determined the distribution and orientation of the fibers in different sections of the article and thus were able to clarify the pattern of flow in different parts of the mold as a function of the process parameters. They concluded that the width of the (cavity)... 

The whole-pattern-fitting structure-refinement method is not limited to specimens containing randomly oriented crystallites. The method does permit an orientation parameter to be refined, though it was not done in this work. Crystallites in the molded polypropylene specimen probably were oriented to some small extent nevertheless, the refinement method worked well. The sensitivity of the method to crystallite orientation and the applicability of the method to polymers with oriented crystallites such as in drawn films or fibers are yet to be determined. 

The whole-pattern-fitting structure-refinement method can give correct, refined structural information for linear polymers. Use of generalized coordinates, in which accurately known structural information can be introduced as known parameters, makes the least-squares fitting problem tractable. Excellent fits of x-ray diffraction data for isotactic polypropylene permitted the selection of the correct space group and a preferred model. 

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