Polypropylene(PP) is a polymer of the propylene monomer. PP is a highly crystalline, easily processed on conventional processing machines and an important commodity polymer. It, also, has a low processing temperature and low cost but poor toughness, average modulus and thermal-resistant properties. Cao, Feng and Wu, Polym. Eng. Sci., 50 #2 p222-231 (2010)

                                —(CH2—CH)—
                                                CH3 

“Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Polypropylene is normally tough and flexible, especially when copolymerized with ethylene. This allows polypropylene to be used as an engineering plastic, competing with materials such as ABS. Polypropylene is reasonably economical, and can be made translucent when uncolored but is not as readily made transparent as polystyrene, acrylic, or certain other plastics. It is often opaque or colored using pigments. Polypropylene has good resistance to fatigue.” (Wikipedia, Polypropylene, 2/9/2011)

Crystalline polypropylene occurs in alpha, beta, gamma, and delta crystal forms as well as in the smectic crystal form which is formed on quenching of melted polypropylene. “The beta-crystal form differs from the form found in the conventional natural pellet in that it is lower in melting point and in density and exhibits differences in the mode of crystallization and fracture.” Beta nucleated PP has outstanding toughness and 15 to 20 degree higher heat deflection temperature. Unfortunately this form only occurs under special crystallization conditions. The most effective method is the use of beta nucleating agents.
(Ma et al, Chemtura Corporation, US Patent 7,569,630 8/4/2009) Polypropylene Pipes PP/LLDPE Blends PP/LDPE Blends PP/Carbon Black Nanocomposites

EPDM
Maleic Acid Grafted Polypropylene (mPP) 
Polymers /Resins  
Polyolefins   
Polypropylene (PP) /Clay Nanocomposites  
Polypropylene (PP) Composites   
Polypropylene (PP) Crystallization
Polypropylene (Pp) /Hemp Nanocomposites
Polypropylene (PP) Nanocomposites   
Polypropylene (PP) Nucleating Agents    
Polypropylene (PP) /Polylactic Acid (PLA) Copolymers  
Polypropylene (PP) /Silica Nanocomposites  
Polypropylene (PP) for Thermoforming
Polypropylene (PP)/Wood/Clay Nanocomposites   
Recycling Polypropylene (PP)
 

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