The control of hydroxylated polyethylene (PE) structures was investigated in the copolymerization of ethylene with allyl alcohol or 10‐undecen‐1‐ol with a specific metallocene, methylaluminoxane, and trialkyl aluminum catalyst system through changes in the copolymerization conditions. The incorporation of allyl alcohol into the PE backbones was controllable through changes in the trialkyl aluminum, leading to terminally hydroxylated PE or a copolymer possessing hydroxyalkyl side chains. The copolymerization of ethylene with 10‐undecen‐1‐ol gave copolymers with hydroxyalkyl side chains of various contents with a variety of molecular weights through changes in the copolymerization conditions. The obtained copolymers were useful as macroinitiators that allowed polar polymer segments to grow on the PE backbones, leading to the creation of graft copolymers that possessed PE and polar polymer segments. In this way, polyethylene‐g‐poly(propylene glycol) (PE‐g‐PPG) and polyethylene‐g‐poly(ϵ‐caprolactone) (PE‐g‐PCL) were synthesized. The 13C NMR analysis of PE‐g‐PPG suggested that all the hydroxyl groups were consumed for propylene oxide polymerization, and transmission electron microscopy demonstrated nanoorder phase separation and indistinct phase boundaries. 13C NMR and gel permeation chromatography analyses indicated the formation of PE‐g‐PCL, in which 36–80 mol % of the hydroxyl groups worked as initiators for ϵ‐caprolactone polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3657–3666, 2003

Polyethylene‐block‐poly(methyl methacrylate) (PE‐b‐PMMA) was successfully synthesized through the combination of metallocene catalysis with living radical polymerization. Terminally hydroxylated polyethylene, prepared by ethylene/allyl alcohol copolymerization with a specific zirconium metallocene/methylaluminoxane/triethylaluminum catalyst system, was treated with 2‐bromoisobutyryl bromide to produce terminally esterified polyethylene (PE‐Br). With the resulting PE‐Br as an initiator for transition‐metal‐mediated living radical polymerization, methyl methacrylate polymerization was subsequently performed with CuBr or RuCl2(PPh3)3 as a catalyst. Then, PE‐b‐PMMA block copolymers of different poly(methyl methacrylate) (PMMA) contents were prepared. Transmission electron microscopy of the obtained block copolymers revealed unique morphological features that depended on the content of the PMMA segment. The block copolymer possessing 75 wt % PMMA contained 50–100‐nm spherical polyethylene lamellae uniformly dispersed in the PMMA matrix. Moreover, the PE‐b‐PMMA block copolymers effectively compatibilized homopolyethylene and homo‐PMMA at a nanometer level. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3965–3973, 2003

Graft and star copolymers having poly(methacrylate) backbone and ethylene-propylene random copolymer (EPR) branches were successfully synthesized by radical copolymerization of an EPR macromonomer with methyl methacrylate (MMA). EPR macromonomers were prepared by sequential functionalization of vinylidene chain-end group in EPR via hydroalumination, oxidation, and esterification reactions. Their copolymerizations with MMA were carried out with monofunctional and tetrafunctional initiators by atom transfer radical polymerization (ATRP). Gel-permeation chromatography and NMR analyses confirmed that poly(methyl methacrylate) (PMMA)-g-EPR graft copolymers and four-arm (PMMA-g-EPR) star copolymers could be synthesized by controlling EPR contents in a range of 8.6-38.1 wt % and EPR branch numbers in a range of 1-14 branches. Transmission electron microscopy of these copolymers demonstrated well-dispersed morphologies between PMMA and EPR, which could be controlled by the dispersion of both segments in the range between 10 nm and less than 1 nm. Moreover, the differentiated thermal properties of these copolymers were demonstrated by differential scanning calorimetry analysis. On the other hand, the copolymerization of EPR macromonomer with MMA by conventional free radical polymerization with 2,2 0 -azobis(isobutyronitrile) also gave PMMA-g-EPR graft copolymers. However, their morphology and thermal property remarkably differed from those of the graft copolymers obtained by ATRP. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: [5103][5104][5105][5106][5107][5108][5109][5110][5111][5112][5113][5114][5115][5116][5117][5118] 2005

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Structurally well-defined polypropylene-macroinitiator (PP-MI) sheets promoted the surface-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) under the mild conditions. There was no change in visual appearance on the surface during the surface-initiated ATRP. Surface analyses by attenuated total reflection infrared (ATR-IR) spectra and X-ray photoelectron spectra clearly showed the presence of PMMA segment grafting from the initiation sites on the surface of PP-MI sheet. Moreover, a uniform layer (ca. 60 nm) consisted of the grafted PMMA brush was directly observed by cross-sectional surface image of transmission electron micrograph measurement. The thicknesses of PMMA layers were linearly increased corresponding with the molecular weight of the grafted PMMA, and the graft densities of PMMA were estimated to be 0.36 chains/nm 2 . A dynamic friction test of the resulting PMMA-grafted PP sheet was carried out by sliding a stainless ball probe to reveal higher wear resistance to abrasion characteristics compared to a PMMA-coated PP sheet. Utilizing this grafting technique, highly wettable poly(2-methacryloyloxyethyltrimethyl ammonium chloride) (PMTAC) was also successfully grafted from the PP-MI sheet. The contact angle against distilled water reached to 8 , representing that the surface wettability was drastically improved by grafting highly wettable polymer chains. In addition, the sheet showed a high antibacterial property against Escherichia coli and Staphylococcus aureus.