Morphology polypropylene

Ferrage, E. Martin, F. Boudet, A. Petit, S. Fourty, G. Jouffret, F. Micoud, P. De Parseval, P. Salvi, S. Bourgerette, C. Ferret, J. Saint-Gerard, Y. Buratto, S. Fortune, J. (2002) Talc as Nucleating Agent of Polypropylene Morphology Induced by Lamellar Particles Addition and Interface Mineral-matrix Modelization. /. Mater. Sci. Vol.37, No.8, pp.1561-1573... 

Wristers J. Nascent polypropylene morphology Polymer flber. J Polym SciB 1973 11 1601. 

Kalay G, Bevis MJ. Processing and physical property relationships in injection molded isotactic polypropylene Morphology and crystallinity. J Polymer Science, Part B PolymPhys. 1997.35 265-291... 

Problems with grafting and morphological changes in the particles are reviewed (117). Vinyl acetate has been grafted onto atactic polypropylene (118) and casein (119). 

Since the last edition several new materials have been aimounced. Many of these are based on metallocene catalyst technology. Besides the more obvious materials such as metallocene-catalysed polyethylene and polypropylene these also include syndiotactic polystyrenes, ethylene-styrene copolymers and cycloolefin polymers. Developments also continue with condensation polymers with several new polyester-type materials of interest for bottle-blowing and/or degradable plastics. New phenolic-type resins have also been announced. As with previous editions I have tried to explain the properties of these new materials in terms of their structure and morphology involving the principles laid down in the earlier chapters. 

In preliminary tests, melt mixed blends of PP and LCP were processed at six different temperatures (Tcyi 230, 240, 250, 260, 270, and 280°C) with a Brabender Plasti-Corder PLE 651 laboratory single-screw extruder. The measured melt temperatures were about 10°C higher than the cylinder temperatures (Tcyi). The objective was to study the influence of temperature on the size and shape of the dispersed LCP phase. Two different polypropylenes were used to ascertain the effect of the viscosity of the matrix on the final morphology. Different draw ratios were obtained by varying the speed of the take-up machine. 

The reactive extrusion of polypropylene-natural rubber blends in the presence of a peroxide (1,3-bis(/-butyl per-oxy benzene) and a coagent (trimethylol propane triacrylate) was reported by Yoon et al. [64]. The effect of the concentration of the peroxide and the coagent was evaiuated in terms of thermal, morphological, melt, and mechanical properties. The low shear viscosity of the blends increased with the increase in peroxide content initially, and beyond 0.02 phr the viscosity decreased with peroxide content (Fig. 9). The melt viscosity increased with coagent concentration at a fixed peroxide content. The morphology of the samples indicated a decrease in domain size of the dispersed NR phase with a lower content of the peroxide, while at a higher content the domain size increases. The reduction in domain size... 

Phinyocheep, P., Axteb, F.H., and Laosee, T., Influence of compatibibzers on mechanical properties, crystallization, and morphology of polypropylene/scrap rubber dust blends, J. Appl. Polym. Sci., 86, 148, 2002. 

The case of isotactic polypropylene (iPP) presents some differences with respect to those just discussed. While both sPP and PET adopt in their mesophases disordered, extended, essentially non-helical conformations, iPP is characterized by a unique, relatively well ordered, stable chain structure with three-fold helical symmetry [18,19,36]. More accurately we can state that an iPP chain segment can exist in the mesophase either as a left handed or as the enantiomeric right-handed three-fold helix. The two are isoener-getic and will be able to interconvert only through a rather complex, cooperative process. From a morphological point of view Geil has reported that thin films of mesomorphic iPP quenched from the melt to 0 °C consist of... 

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