|Macromolecules 2011, 44, 3062-3072 Macromolecules ARTICLE (7) There is substantial band broadening caused by some factors not well understood at this moment. An in-depth investigation is needed in order to improve TGIC resolution capability.

Despite the commercial importance of maleic anhydride grafted polypropylene (PP-g-MAH), it has long been a scientific challenge to prepare this polymer with a wellcontrolled molecular structure. This paper discusses a new chemical route that can form PP-g-MAH with desirable MAH content, a single MAH incorporated unit, white color, high molecular weight, and narrow molecular weight and composition distributions. The chemistry involves a unique PP-co-p-BT copolymer as the "reactive intermediate" that can be effectively prepared by metallocene-mediated copolymerization of propylene and p-(3-butenyl)toluene (p-BT), with narrow molecular weight and composition distributions, high molecular weight, and a broad range of p-BT contents. The incorporated p-BT comonomer units provide the reactive sites for the subsequent free radical MAH graft reaction under a suspension condition at a low reaction temperature. The resulting PP-g-MAH polymers were carefully examined by a combination of NMR and GPC measurements, which shows almost no change in polymer molecular weight and distribution and a single MAH incorporation (no oligomerization). The incorporated MAH units increase with the increase of initiator concentration, p-BT content, and reaction time. Evidently, the combination of high reactivity of φ-CH 3 moiety, a favorable mixing condition between the reactive sites and chemical reagents in the swollen amorphous phases, and low reaction temperature results in MAH grafting reaction selectively taking place at the φ-CH 3 moieties without side reactions (i.e., chain degradation and MAH oligomerization). In addition, this suspension reaction process presents an economic method to prepare PP-g-MAH with high polymer content and easy product purification.

This paper discusses the synthesis of a new family of well-controlled isotactic polypropylene ionomers (iPP-NH 3 + Cl − ) containing up to 5 mol % of NH 3 + Cl − ionic groups, with high molecular weight and narrow molecular weight and composition distributions, as well as good processability in melt and solution. A systematic study was conducted using various isospecific Ziegler−Natta and metallocene catalysts in the copolymerization of propylene and a high α-olefin comonomer containing a silane-protected amino group and the subsequent work-up procedures that can prevent undesirable side reactions in forming iPP-NH 3 + Cl − ionomers in a one-pot process. The resulting copolymers were carefully monitored by polymer solubility and a combination of NMR, GPC-triple detectors, DSC, and mechanical property measurements. Evidently, the most suitable reaction process requires a combination of the rac-Me 2 Si[2-Me-4-Ph(Ind)] 2 ZrCl 2 metallocene catalyst system with a purified d-MAO (TMA-free), 6bis(trimethylsilyl)amino-1-hexene comonomer during the copolymerization reaction and a work-up procedure to directly interconvert the silane-protected amino groups (−N(SiMe 3 ) 2 ) into −NH 3 + Cl − ionic groups before exposing to air. The attempt of isolating both iPP-N(SiMe 3 ) 2 and iPP-NH 2 intermediates resulted in the insoluble (cross-linked) products. On the other hand, the resulting iPP-NH 3 + Cl − ionomers were melt processed in air and showed a systematic increase of mechanical properties and high-temperature stability with the increase of NH 3 + Cl − content.