Polypropylene and copolymers

An alternative approach to preparing i-PP standard reference materials has been suggested by Fetters etal [37], using narrow-distribution atactic polypropylenes, a-PP. The anionic polymerization of 2-methyl-1, 3-pen-tadiene with s c-butyl lithium occurs exclusively by 1,4-addition to produce poly(l,3-dimethyl-l-butenylene). The polymers are monodisperse in molecular mass distribution. Hydrogenation transforms them into a-PP. Light scattering and osmometry were carried out, as well as viscosity measufements in tetrahydrofuran and 2-octanol, a 0-solvent, and the intrinsic viscosity were related to the mass average molecular mass  

Coll and Gilding [39] reviewed the theoretical justification for comparing M[rj] values for different polymers at the same retention volume, i.e. the universal calibration procedure, in analysing the SEC of i-PP samples in TCB at 135°C. The universal calibration line for polypropylene was derived from polystyrene and linear polyethylene standard materials, and molecular mass averages determined from viscosity measurements in decalin solutions and the 

Similarly, Ogawa et al. [40] obtained a molecular mass-elution volume calibration curve for polypropylene from a plot of log(My) against elution volume curve for fractionated polystyrene. The relations [rj i M against elution volume and were compared. When both curves were converted into 

Atkinson and Dietz [41], using 12 fractions of i-PP and a set of polystyrene standard samples, obtained the universal calibration for polypropylene in ODCB at 135°C. The Mark-Houwink relation and the unperturbed dimensions were determined for polypropylene. The previous studies were compared and the following points made  

Rudin and Hoegy [43] have considered the assumption, inherent in the universal calibration procedure, that the hydrodynamic volume of a polymer at the concentration range adopted in SEC analysis is that which pertains at infinite dilution, and discuss whether this can account for apparent failures in some instances. A model is presented to estimate hydrodynamic volumes of polymers at finite concentrations and provide a universal calibration. Polypropylene is one of the examples used to illustrate the size of the effect. 

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In spite of this early work showing the successful use of TREE for polypropylene analysis, the value of the technique does not seem to have been as well recognized as in the polyethylene area. Most studies involving stereoregularity separation have been conducted using successive solvent extraction with n-alkane solvents [32], [33]. Recently, however, Kakugo, Miyatake, Mizunuma and Kawai [34] successfully used TREE to characterize polypropylene and copolymers with ethylene and 1-butene in terms of their isotacticity. 

Figure 2.3 WAXS diffraction curves of (a) plain iPP (isotactic polypropylene) and copolymers, crystallized at Tc=90 °C (b) ethylene-propylene and propylene-) 1-butene) copolymers (coded here as EPS and BPS, respectively) BPS/EPS and (c) BPS/EP2 (isotactic propylene-ethylene (EP)) blends at various composition, crystallized at Tc=90 °C. 

The degree of crystallinity of swollen polyfvinyl alcohol) has been measured by laser Raman spectroscopy from the relative intensity of the amorphous band at 1124 cm . The crystalline band, at 1147 cm, was not considered quantitative. Polyacetylene,poly(vinylidene fluoride), polyfdiphenyl siloxane), poly-(butylene terephthalate), poly(decamethylene oxide), polypropylene and copolymers, poly(methyl methacrylate), poly(ethylene terephthalate), polystyrene, polycarbonate, polyalkylene, poly(oxymethylene), and poly (ethylene oxide) have all been studied either by WAXS or thermal analysis. 

Polymer laminate technology is a rapid prototyping technique using standard film lamination for the fabrication of microfluidic devices. Polymeric materials (eg, PMMA, PET, PS, polypropylene and copolymers such as Zeonor) in thin sheets or... 

Just recently a new polyolefin wax family had been developed by using metallocene catalyst technology. The family of waxes includes polyethylenes and specialty grades of polypropylenes and copolymers. These low viscosity and low softening point resins have already been successfully used as dispersing aids in the production of master-batches, in adhesives and sealants as well as in fibre glass coatings for composites [2],... 

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