Properties of isotactic polypropylene

Although very similar to high-density polyethylene, isotactic polypropylene differs from the former in a number of respects of which the following are among the most important  

254 Aliphatic Polyolefins other than Polyethylene, and Diene Rubbers 

As shown in the previous section the mechanical and thermal properties of polypropylene are dependent on the isotacticity, the molecular weight and on other structure features. The properties of five commercial materials (all made by the same manufacturer and subjected to the same test methods) which are of approximately the same isotactic content but which differ in molecular weight and in being either homopolymers or block copolymers are compared in Table 11.1. 

Property Units Test method Random Block Homopolymer 

Melt Flow Ratio 230°C/2.16kg Tensile Yield g/lOmin ISO 1133 30 48 48 

This data indicates that the random copolymer has greater transparency but inferior low temperature impact strength. 

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G. Natta and P. Corradini. Structure and properties of isotactic polypropylene , Nuovo Cimento, Suppl. 15, 40 (1960). 

Fichera, A. and Zannetti, R. Thermal properties of isotactic polypropylene quenched from the melt and annealed. Makromol. Chemie 176, 1885 (1975)... 

The tensile properties of isotactic polypropylene materials reinforced with continuous nylon fibers were measured. Less than 10 vol % of the fibers leads to an increased yield strength and yield elongation. As little as 3 vol % of the nylon fibers increased the elongation at necking from 10 to 20%. This retarded necking arises from the fiber-matrix debonding which delocalizes the microscopic yielding processes. 

Samuels, R. J. Quantitative Structural Characterization of the Mechanical Properties of Isotactic Polypropylene, in Plastic Deformation of Polymers (ed.) Peterlin, A., p. 241, New York, Marcel Dekker, Inc. 1971... 

Mohmeyer, N. Behrendt, N. Zhang, X. Smith, P. Altstadt, V. Sessler, G. Schmidt, H. (2007). Additives to improve the electret properties of isotactic polypropylene. Polymer, Vol.48, pp. 1612-1619... 

Tailoring of Morphology and Mechanical Properties of Isotactic Polypropylene by Processing... 

D AnieUo C, Guadagno L, Gorrasi G, Vittoria V. Influence of the crystallinity on the transport properties of isotactic polypropylene. Polymer 2000 41 (7) 2515-2519. 

SCORIM results in substantial improvements in mechanical properties of isotactic polypropylene and provides an effective route for managing the physical properties of injection moldings. 

Samuels, R.J. (1970) Qualitative structural characterization of the mechanical properties of isotactic polypropylene. J. Macromol. Sci. Phys., B4, 701-59. Uejo, H. and Hoshino, S. (1970) Structure of biaxially oriented polypropylene film. J. Appl. Polymer Sci., 14, 317-23. 

Natta, G. and Corradini, P. (1960) Structure and properties of isotactic polypropylene, Nuovo Cimento Suppl., 15,40-51. 

Yi X, Xu L, Wang Y L, Zhong G J, Ji X and Li Z M (2010) Morphology and properties of isotactic polypropylene/poly(ethylene terephthalate) in situ microfibrillar reinforced blends Influence of viscosity ratio, Eur Polym J 46 719-730. 

Jose S, Aprem A S, Francis B, Chandy M G, Werner P, Alstaedt V and Thomas S (2004) Phase morphology, crystallisation behaviour and mechanical properties of isotactic polypropylene/high density polyethylene blends, Eur Polym J 40 2105-2115. 

There is more to the story of isotactic polypropylene arising from Piero Pino s interest in answering the following question Does the helical property of isotactic polypropylene in the crystalline regions of the sample extend into the amorphous regions, as in the melted state Pino decided to address this question by observing the possibility of chiral optical properties in structural variatiOTis of polypropylene. 

O Kane WJ, Young RJ, Ryan AJ (1995) The effect of annealing on the structure and properties of isotactic polypropylene films. J Macromol Sci Phys B34 427 Padden FJ, Keith HD (1966) Crystallization in thin films of isotactic polypropylene. J Appl Phys... 

Chapter 5 discusses in detail the current application of recycled PET. In particular, the applications of recycled PET are discussed in the fields of food packaging, construction, textile industry, injection moulding and other manufacturing processes, wood-plastic composites and so on. On the other hand. Chapter 6 describes the optical properties of polyolefins upon recycling. Optical properties of different plastics play a key role in packaging applications, so this chapter primarily focuses on the different structural aspects and properties of isotactic polypropylene. 

Krupa I, Luyt AS. Thermal properties of isotactic polypropylene degraded with gamma irradiation. Polym Degrad Stab 2001 72 505-8. 

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