Study Of Functionalization Of Polypropylene And Its Molecular Structure

13C-enriched Maleic Anhydride ([2.3-13C2] MAH) grafted isotactic polypropylene (iPP) samples were prepared via solution-grafting. Dicumyl peroxide (DCP) was used as initiator. The grafted rate, molecular weights and molecular structure of MAH grafted PP (PP-g-MAH) were studied by Chemical titration, FTIR spectroscopy, Gel Permeation Chromatography (GPC) and NMR, respectively. In addition, the morphology, formation and evolution of PP/PA6 blending was studied.The FTIR spectra of PP-g-MAH samples show intense absorption bands at 1700-1900cm-1, indicating that MAH monomers have been grafted onto the chains of the Polypropylene. The results from the chemical titration suggested that the grafted degree increases with increasing initial MAH content. The GPC results showed that the molecular weight decreases with increasing initial MAH content. Similar result was obtained from rheometer measurements.NMR results showed that: (1) The signals of MAH attached to the tertiary carbons of the iPP chains increased considerably with increasing MAH content, whereas the signals of MAH onto the radical chain ends (with single bond) arising from P scission did not. This result was consistent with the previous simulation study; (2) the signals of MAH onto the radical chain ends with double bonds increased markedly with increasing MAH content, indicating that P scission occurred after MAH attached to the tertiary carbons. As a result, the PP molecular weight decreased with increasing MAH content; (3) the fraction of "mm" construction along PP chains increased with increasing MAH content, whereas the fraction of "mr" and "rr" constructions decreased with increasing MAH content.According to the experiment of PP/PA6 blending, we believe that (1) keeping the shear rate at 20s-1, the diameter of PA6 particle reduces gradually and becomes constant with the increase of shear time. With theshear rate increasing, the time becomes short, which the diameter of PA6 particle becomes the constant (2) Keeping the shear time at 80s, the diameter of PA6 particle reduces gradually with the increase of shear rate. (3) The experiment of PP-g-MAH/PA6 blending shows that the compatibility of PP-g-MAH/PA6 is better than PP/PA6.