Poly spherulite radius

To illustrate In drawn poly ethylene) fibers, the speed of light is less in the direction of the fibers than in the direction perpendicular to this. Here, light parallel to the fiber direction shows a higher refractive index. In drawn poly(ethylene) fibers, the molecular axes are largely parallel to the fiber axis. Since poly(ethylene) forms negative spherulites, the molecular axes must be at right angles to the spherulite radius. 

Fig. 11.45 Plot of spherulite radius of poly(ethylene terephthalate) in a blend with poly(ether imide) as a function of time at indicated crystallization temperatures. Blend composition poly(ethylene terephthalate)/poly(ether imide) 70/30. (From Chen etal. (103))...

Fig. 11.46 Plot of spherulite radius as a function of time for poly(ethylene oxide) in blends with either ethylene-methacrylic acid or styrene-hydroxy styrene copolymer. With ethylene-methacrylic acid poly(ethylene oxide)/ethylene-methacrylic acid A 80/20, = 52.5 °C X 70/30, = 48 °C. With styrene-hydroxy styrene ...

Fig. 11.47 Plot of spherulite radius of poly(3-hydroxy butyrate) as a function of time in a 50/50 blend with cellulose acetate butyrate at three crystallization temperatures A 65 °C, 95 °C, o 130 °C. (From Pizzoli et al. (2))...

Andrews76 gave results of the work of Reed and Martin on cis-polyisoprene specimens crystallized from a strained cross linked melt and on solid state polymerized poly-oxymethylene respectively, explaining the results by simple two phase models. He also summarized the studies of Patel and Philips775 on spherulitic polyethylene which showed that the Young s modulus increased as a function of crystallite radius by a factor of 3 up to a radius of about 13 n and then decreased on further increasing spherulite size. 

Fig. 4.25. A plot of the radius of spherulites of isotactic poly(styrene) as a function of time. From [153].

Figure 10.17 Etched surface showing lamellar detail in a banded spherulite of poly(vinylidene fluoride). Moving outwards along the radius (arrowed) the lamellar orientation changes from being seen close to flat on [B] to being edge on [A]. In region [A] the very dark radial features are a consequence of material being stripped from the specimen surface during replication.

Fig. 11.42 Plot of radius of isothermally growing spherulite as a function of time, at 135 °C, in a blend of isotactic poly(propylene), M = 178000, and atactic poly(propylene), M = 540. (From Keith and Padden (55))...

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