Polypropylene Growth rate-crystallization

Polypropylene has a crystal growth rate some one hundred times lower than that of high density polyethylene for example. It therefore responds well to heterogeneous nucleation by well dispersed additives present in the crystallizing melt. 

Figure 3.52 AFM images of an edge-on lamella of imperfectly isotactic polypropylene growing at room temperature. Overall crystallization times are 55 minutes, 73 minutes, 169 minutes, and 190 minutes. The first two images show that the growth rate is about 6 nm/min. In frames (c) and (d) the formation of a screw dislocation with its axis in the plane of the image can be seen. From Franke and Rehse [73] with permission from the American Chemical Society.

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