Multi functionalization of polypropylene with controlled degradation and its structure characterization

Abstract

The multi functionalization of isotactic polypropylenes (iPP) with glycidyl methacrylate (GMA) was carried out by in situ chlorinating graft copolymerization (ISCGC), in which chlorine (Cl 2 ) is used as a radical initiator as well as a radical scavenger. The molecular weight measurement indicates that functionalized iPP with controlled degradation could be obtained because the unstable radicals that induce iPP degradation could be terminated quickly by chlorine. Owing to the unique allyl-containing structure of GMA, multi functionalized iPP could be synthesized under the effect of chlorine, which contained both epoxy groups and C=C double bonds as well as trace amount of chlorine atoms in the functionalized polymer structure. The structure of both the functionalization polymer and homopolymer formed in this system were analyzed by FTIR and 1 H NMR. The mechanism of grafting reaction, iPP chain degradation, and GMA homopolymer formation scheme in ISCGC were proposed. The thermal properties of the functionalized polymer are also discussed.

Preparation of epoxy functionalized PP with unique structure and its post‐ring open reaction

“…The FTIR spectra of the purified PP‐ cg ‐St‐co‐GMA and PP‐ cg ‐GMA are given in Figure 5. The absorptions at 1720 cm −1 corresponding to the carbonyl stretch vibration and absorptions at 1640 cm −1 corresponding to CC stretching vibration, respectively, which indicate both epoxy groups and CC double bonds are located at the grafted side chains of PP‐ cg ‐St‐co‐GMA as well as PP‐ cg ‐GMA and the reasons are discussed in detail in Ref 26…”

“…The schematic diagram of ISCGC reaction system is depicted in detail in our previously published work 24. The chlorine content of PP‐ cg ‐GMA prepared was controlled at about 3–4 wt %, and its calculated method can consult reference 26…”

“…Our laboratory has been interested in polyolefins modified by ISCGC for many years 23–26. In fact, this chemical approach has taken advantage of the high chemical reactivity of the chlorine.…”

“…We attempt to apply this chemical approach in PP modification for the purpose of obtaining modified PP with higher grafting level and limited PP chain degradation. Some preliminary research has got some progress 24–26…”

“…Multi functionalization PP with both epoxy groups and CC double bonds located at the graft side chains has been gained by ISCGC 26. The goal of this study is to obtain functionalized PP with higher grafted GMA levels by exploring the preparation conditions, such as GMA initial concentration, chlorine concentration, reaction temperature, and the addition of a second comonomer.…”