Tomoaki Matsugi

Microstructure of Highly Syndiotactic “Living” Poly(propylene)s Produced from a Titanium Complex with Chelating Fluorine-Containing Phenoxyimine Ligands (an FI Catalyst)

Highly syndiotactic “living” poly(propylene)s were synthesized at 25°C using a bis[N-(3-tert-butylsalicylidene)-2,3,4,5,6-pentafluoroanilinato]titanium (IV) dichloride/MAO catalyst system, and microstructures of the polymer were analyzed by means of 13C NMR spectroscopy. The syndiotactic poly(propylene) contains isobutyl, isopentyl and propyl end groups, suggesting that the living polymerization of propylene was initiated via 1,2-insertion, followed by 2,1-insertion as the principal mode of polymerization. Pentad distribution analysis revealed that the syndiospecific polymerization proceeds under chain-end control.

Direct modification of polyolefin films by surface-initiated polymerization of a phosphobetaine monomer

The surfaces of polyethylene and polypropylene sheets were modified by grafting with polymeric brushes formed from a phosphobetaine monomer. Pressed sheets of bromo-functionalized polyethylene or polypropylene macroinitiators (PE-MIs and PP-MIs, respectively) were used to initiate the atom-transfer radical polymerization of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) under mild conditions to form a superhydrophilic grafted surface layer. The grafted polyolefin sheets showed excellent wettability and oil-detachment behaviour in water. Even three years after surface grafting had been performed, the PMPC-g-PP sheet retained a water contact angle of less than 10°. Furthermore, the water contact angle of the PMPC-g-PP sheet remained as low as 12° after it had been annealed at 373 K for 60 min under reduced pressure. Dynamic friction tests performed on the PMPC-g-PE sheet by sliding it against a glass ball revealed a marked reduction in the friction coefficient in water at sliding velocities in the range of 10−5 to 10−1 m s−1, possibly as a result of lubrication by water.

Polymer Hybrids Based on Polyolefins – Syntheses, Structures, and Properties

Recent advances in polyolefin chemistry have led to the creation of polymer hybrid linking between different polymer segments to broaden their applications towards use in highly profitable fields. Synthesized polymer hybrids based on polyolefins are expected to possess the properties of each polymer segment. Several methodologies have been reported for the preparation of polyolefin hybrids which employ processes, such as radical, anionic, cationic polymerizations, and post-polymerization reactions, bringing certain improved and unique properties to ordinary polyolefins. These new polymer hybrids can be synthesized using functionalized polyolefins, such as polyolefin (PO) macroinitiator, PO macromonomer, and reactive PO. Synthesized polymer hybrids based on PO, with a well-defined molecular structure, show excellent properties compared to conventional POs, including compatibility and mechanical strength.

Polypropylene-block-poly(methyl methacrylate) and -block-poly(N-isopropylacrylamide) block copolymers prepared by controlled radical polymerization with polypropylene macroinitiator

Polypropylene-block-poly(methyl methacrylate) (PP-b-PMMA) and Polypropylene-block-poly(N-isopropylacryramide) (PP-b-PNIPAAm) block copolymers were successfully synthesized by radical polymerizations of MMA or NIPAAm with polypropylene (PP) macroinitiators. Polypropylene macroinitiators were prepared by a series of end functionalization of pyrolysis PP via hydroalumination, oxidation and esterification reactions. The PP macroinitiators thus obtained could initiate radical polymerizations of MMA or NIPAAm by using transition metal catalyst systems, and 1H NMR analysis and gel permeation chromatography measurement confirmed the formation of PP-b-PMMA and PP-b-PNIPAAm block copolymers. In addition, the length of the incorporated PMMA or PNIPAAm segments in these block copolymers was controllable by the feed ratio between the monomer and the PP macroinitiator, and their molecular weights were estimated to be 35700 and 68700 (PMMA) and 1760 and 13300 (PNIPAAm), respectively. Transmission electron microscopy of the polymers obtained by NIPAAm polymerization revealed specific morphological features that reflected the difference of PNIPAAm segment length.

Creation of New Polyolefin Hybrids on the Surface of Molded Polypropylene Sheet

Abstract Surface polymerization of 2-hydroxyethyl methacrylate (HEMA) at the initiation sites on the molded sheet of polypropylene macroinitiator (PP-MI) was performed by a CuBr mediated controlled radical polymerization (CRP). The obtained sheet was coated with poly(HEMA), then analyzed by attenuated total reflection infrared (ATR/1R) and transmission electron microscopy (TEM) to investigate the structure and the morphology. It was revealed that PP-graft-poly(HEMA) was successfully synthesized on the sheet and showed unique morphological features.

Controlled radical polymerization with polyolefin macroinitiator: a convenient and versatile approach to polyolefin-based block and graft copolymers

This paper introduces the new synthetic methodology of polyolefin-based block and graft copolymers with polar segments [e.g., polystyrene and poly(meth)acrylates]. Various brominated polyolefins were prepared by bromination of polyolefins with N-bromosuccinimide. The resulting brominated polyolefins were able to initiate the controlled radical polymerization of polar monomers, such as methyl methacrylate, ethyl acrylate, t-butyl acrylate, styrene and 2-(dimethylamino)ethyl acrylate, using a CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system, leading to a variety of polyolefin-based copolymers with a different content of the corresponding polar segment. Because of the accessible synthesis of polyolefin macroinitiators, this synthetic methodology is expected to result in the preparation of a wide range of polyolefin-based block and graft copolymers.

133 II catalysts: New titanium complexes having two indolide-imine chelate ligands for ethylene polymerization

Publisher Summary This chapter introduces a series of transition metal complexes possessing non-symmetric bidentate ligand(s) which show high catalytic performance for olefin polymerization including living olefin polymerization. The chapter introduces new titanium complexes bearing two indolide–imine chelate ligands, named II Catalysts. Four II Catalysts were synthesized and investigated for their potential as ethylene polymerization catalysts using methylaluminoxane (MAO) as a cocatalyst. Among them, three II Catalysts showed very high activities at room-temperature and produced polyethylenes having extremely narrow molecular weight distributions. The transmission electron microscopy (TEM) micrograph of the block copolymer shows well-defined morphology of micro phase separation, in which white domains corresponding to the polyethylenes (PEs) segment form a fine nanostructue. While those of the blend polymer display the grown lamellar crystals of PE and the stained poly(ethylene-co-propylene). Therefore, the well-defined block copolymer prepared via living polymerization is expected to have a potential as modifier, compatibilizer, or new elastomer.

131 Creation of new polymers using terminally unsaturated polyolefins prepared with FI catalysts

Publisher Summary This chapter describes new zirconium complexes, which can promote the polymerization of ethylene for vinyl-terminated low molecular weight polyethylenes (PEs) with high activities, and the examples of their applications to create a new class of polymers. The ethylene polymerization behavior of complexes is investigated with methylalumoxane (MAO) cocatalyst at 25 °C under atmospheric pressure. Although there is no clear relationship between the catalytic activity and the substituent on the imine-nitrogen, it appears that the steric bulk of the substituents play a role and that extremely high activities are thus achieved. This is probably because that the bulky substituents would enhance the polymerization rate by increasing the separation between the cationic active site and the anionic cocatalyst. A comparison of polyethylene molecular weights (M w ) for the resultant Pes reveals that the substituent on imine–nitrogen affects the M w values, ranging from 2100 to 13800. It is also demonstrated that complexes promote the polymerization of ethylene to produce vinyl-terminated low molecular weight linear PEs having narrow molecular weight distributions with high activities.

Unique Flowability Behavior of Ethylene Copolymers Produced by a Catalyst System Comprising Ethylenebis(indenyl)hafnium Dichloride and Aluminoxane

This paper relates to novel ethylene copolymers and a process for preparing the same and more particularly to novel ethylene copolymers excellent in flowability in spite of the fact that they are narrow in molecular weight distribution (Mw/Mn) in comparison with conventionally known ethylene copolymers, and to a process for preparing the same. In another aspect, this paper relates to olefin polymerization catalysts capable of polymerizing olefins with excellent comonomer incorporation and capable of giving olefin polymers having high molecular weights.