A super‐hydrophobic surface (see Figure), possessing a microscale and nanoscale hierarchical structure similar to the surface structure of the lotus leaf, was prepared in one step from a micellar solution of polypropylene‐block‐poly(methyl methacrylate).

This paper describes the first example of consecutive chain transfer reaction, first to p-methylstyrene (or styrene) and then to hydrogen, during metallocene-catalyzed propylene polymerization by rac-Me(2)Si[2-Me-4-Ph(Ind)](2)ZrCl(2)/MAO complex. The PP molecular weight is inversely proportional to the molar ratio of [p-methylstyrene]/[propylene] and [styrene]/[propylene] with the chain transfer constants of k(tr)/k(p) = 1/6.36 and 1/7.5, respectively. Although hydrogen does not influence the polymer molecular weight, it greatly affects the catalyst activity. Each PP chain formed contains a terminal p-methylstyrene (or styrene) unit. The terminal p-MS unit can be metalated to form a stable polymeric anion for living anionic polymerization to prepare new PP diblock copolymers, such as PP-b-PS, which are very difficult to prepare by other methods. The overall process resembles a transformation reaction from metallocene to living anionic polymerization.

This paper discusses an effective route in the functionalization of s-PS polymer that involves the direct copolymerization of styrene with a borane-containing styrenic monomer, i.e., 4-[B-(n-butylene)-9-BBN]styrene (B-styrene). The reactivity ratios of the two comonomers are quite close, with r1 ) 0.9 for styrene and r2 ) 1.2 for B-styrene in the Cp*Ti(OMe)3/MAO catalyst system. A broad composition range of syndiotactic poly(styrene-co-B-styrene) copolymers has been prepared with narrow molecular weight and composition distributions. The random copolymer structure was further evidenced by DSC and 13 C NMR analyses. With increasing B-styrene concentration, the copolymers show a systematic decrease in glass transition temperature, melting point, crystallization temperature, and crystallinity. At above 8.4 mol % B-styrene content, the crystallinity of the copolymer completely disappears. In turn, the borane groups in the copolymer are very versatile and can be quantitatively converted to other functional groups, such as hydroxy and anhydride groups, or transformed to free radical initiators for in situ free radical graft polymerization to prepare s-PS-g-PMMA graft copolymers.

This paper discusses an effective method to prepare cross-linked isotactic polypropylene (PP-X) with high purity (almost 100% gel content and no contamination) and high melting temperature and crystallinity. The reaction scheme involves a linear poly(propylene-co-p-(3-butenylstyrene)) copolymer (PP-BSt) containing few pendent styrene groups and the subsequent thermal treatment without any external reagent. The intermediate PP-BSt copolymers were prepared by a specific rac-CH2(3-tert-butyl-Ind)2ZrCl2/MAO catalyst that not only performs iso-specific propylene insertion but also incorporates BSt units with a preferred α-olefin insertion over styrene moiety. The combined features permit the preparation of linear PP-BSt copolymers with high molecular weight and high catalyst activity, without the presence of hydrogen. The resulting PP-BSt copolymers having some flexible pendent styrene moieties are completely soluble in xylene at elevated temperatures, and the solution case films show active cross-linking activity at temperatures >160 °C by engaging in a Diels−Alder [2 + 4] interchain cycloaddition reaction between the pendent styrene units. Evidently, the flexibility of styrene units is important, which enhances the interchain cyclization to form a complete 3-D network, even with a very small amount of BSt units. In contrast, the corresponding poly(propylene-co-p-divinylbenzene) (PP-DVB) prepared by the same metallocene catalyst only shows moderate cross-linking efficiency under similar conditions.

This paper discusses a direct (one-pot) polymerization process to prepare isotactic polypropylene (i-PP) having a terminal functional group including Cl, OH, and NH2. The chemistry involves metallocene-mediated propylene polymerization using rac-Me2Si[2-Me-4-Ph(Ind)]2ZrCl2/MAO complex in the presence of styrene derivatives (St-f), carrying a Cl (St-Cl) or a silane-protected OH (St-OSi) or a silane-protected NH2 (St-NSi2), followed by hydrogenation. Apparently, the propylene propagating chain end engages in a facile consecutive chain transfer reaction, reacting with St-f and then hydrogen, with high catalyst reactivity under the proper St-f and hydrogen concentrations. The polymer molecular weight was inversely proportional to the molar ratio of [St-f]/[propylene] with a chain transfer constant (ktr/kp) of 1/21 for St-Cl, 1/34 for St-NSi2, and 1/48 for St-OSi, respectively. Both silane protecting groups were hydrolyzed in acidic aqueous solution during the sample workup step to obtain the desirable i-PP polymers with a terminal OH and NH 2 group (i.e., PP-t-St-OH and PP-t-St-NH2). The terminal functional group was confirmed by end group analysis and chain extension reaction. Despite the high molecular weight, the terminal functional group in PP engages a coupling reaction with polycapolactone (PCL) in solution and melt to form PP-b-PCL diblock copolymers that are very effective compatibilizers in PP/ PCL polymer blends.

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This paper discusses a novel polymerization process for preparing polyethylene having a terminal p-methylstyrene (p-MS) group. The chemistry involves metallocene-mediated ethylene polymerization in the presence of p-MS and hydrogen. Apparently, the reaction mechanism, including the copolymerization and chain transfer reactions, can be controlled with a favorable combination of metallocene catalyst and hydrogen concentration. Under some specific reaction conditions, the Cp2ZrCl2/MAO catalyst selectively forms PE with a terminal p-MS terminal group (PE-t-p-MS) via a consecutive chain transfer reaction to p-MS and then hydrogen. The catalyst activity increases with the hydrogen concentration, and the polymer molecular weight is inversely proportional to the p-MS concentration. In contrast, [C5Me4(SiMe2N t Bu)]TiCl2/MAO initiates a copolymerization reaction between ethylene and p-MS, and hydrogen has little effect on the catalyst activity. The terminal p-MS unit at the PE chain end is a valuable reactive group that can be metalated to form a stable polymeric anion, which can be used to prepare functionalized PE polymers containing a polar terminal group or diblock copolymers.

Summary: Copolymerization of propylene and 1,4‐divinylbenzene was successfully performed by a MgCl2‐supported TiCl4 catalyst, yielding isotactic poly(propylene) (i‐PP) polymers containing a few pendant styrene groups. With a metalation reaction with butyllithium and a hydrochlorination reaction with dry hydrogen chloride, the pendant styrene groups were quantitatively transformed into benzyllithium and 1‐chloroethylbenzene groups, respectively, which allowed the synthesis of i‐PP‐based graft copolymers by living anionic and atom transfer radical (ATRP) polymerization mechanisms.The incorporation of styrene pendant groups into isotactic poly(propylene) using a Zeigler–Natta catalyst gave functionalized polymers able to undergo living anionic and atom transfer radical (ATRP) polymerizations.imageThe incorporation of styrene pendant groups into isotactic poly(propylene) using a Zeigler–Natta catalyst gave functionalized polymers able to undergo living anionic and atom transfer radical (ATRP) polymerizations.