Phenolic rigid organic filler/isotactic polypropylene composites. I. Preparation

Abstract

A novel phenolic rigid organic filler (KT) was melt-mixed with an isotactic polypropylene (iPP) to prepare a series of PP/KT composites, with or without maleic anhydride grafted polypropylene (MAPP) as compatilizer. The evolution of filler morphology during melt-mixing and melt-pressure processes was monitored by scanning electron microscope (SEM) and polarized optical microscope (POM). The influences of shear force, pressure time, filler content and MAPP concentration on the final filler dispersion were studied. We found that this rigid organic filler readily melted and dispersed homogenously into the iPP matrix through a fission-fusion process during the melt-mixing process. Thus a balanced dispersion, which was closely related to shear force and MAPP concentration, can be achieved. During the meltpressure process, parts of the filler particles combined gradually through a coalescence process. However, the incorporation of MAPP can effectively inhibit the tendency to coalesce and refine the filler particles sizes into nanoscale. Thus, a series of PP/KT composites with controllable filler particles size and narrow size distribution can be obtained just by adjusting process conditions and MAPP concentration. In addition, due to the in-situ formation mechanism, the filler phase possessed a typical solid true-spherical shape.

Phenolic rigid organic filler/isotactic polypropylene composites. III. Impact resistance property

“…Thus, there is a critical ligament thickness (T c ). However, in this system, it is worth noticing that the interparticle distance (IPD) values of all PP/KT composites are very similar (≈1.8 μm) due to the in-situ formation of filler particles under the same preparation conditions [13], but the toughen effect of filler particles is very different. It implies that IPD is not the unique determinant for BDT.…”

“…Filler dispersion parameters and PP crystallinity in PP/KT blends a) counted from SEM micrographics according to the measuring methods described in the first paper[13] b) observed from POM micrographics directly c) calculated from DSC curves…”