Enhancing and Toughening Effect

Nanoparticles are able to provide PP with stiffening, reinforcing and toughening effects at rather low filler concentration. The influence of processing conditions on the nanocomposite structure, i.e. intercalated or exfoliated, and on the enhancement of mechanical properties of PP nanocomposites was studied by different researchers." " Most polymer/clay nanocomposites studies report... 

Wilfong et al. (1986) reported on the effects of blending low concentrations (1-10 wt%) polyolefin with PET on the crystallization and toughening behavior of the latter. The authors studied blends of PET with LLDPE, HDPE, PP, and poly (4-methylpentene-l), all of them having a lower melting point than PET (Table 3.15). Polyolefin melts did not enhance the nucleation of PET, although the spherulite size of the PET matrix was found to be 2.5-3 times larger than for the homopolymer, with a broader spherulite size distribution. Both the crystallization... 

D-B transition temperature, and the effect of elastomer MFI on the D-B transitirMi temperature becomes less prominent with the increased PP molecular weight as seen in Fig. 17.18. The nanocomposites based on the high-octene-content elastomer ( 39 wt%) also lead to a lower D-B transition temperature compared with nanocomposites based on the elastomer with low octene content ( 28 wt%). The toughening mechanism was not explored for this system a more detailed study in this area would further enhance the understanding of the role of organoclay in elastomer-toughened nanocomposites with partially exfoliated clay particles. 

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