Macromolecular Rapid Communications

Uyama, Hiroshi; Inada, Kojiro; Kobayashi, Shiro

doi: 10.1002/(SICI)1521-3927(19990401)20:4<171::AID-MARC171>3.0.CO;2-2pmid: N/A

The lipase‐catalyzed regioselective polymerization of divinyl sebacate and triols has been carried out. Immobilized lipase derived from Candida antarctica induces the polymerization of divinyl sebacate and glycerol, yielding a soluble polymer of relatively high molecular weight. NMR analysis showed that 1,3‐diglyceride is a main unit and the branching unit (triglyceride) is contained in the resulting polymer. These data indicate that the polymerization proceeds regioselectively to give the reactive polyester having a pendant hydroxy group.

Kim, Keon Hyeong; Jo, Won Ho; Kwak, Soonjong; Kim, Kwang Ung; Kim, Jungahn

doi: 10.1002/(SICI)1521-3927(19990401)20:4<175::AID-MARC175>3.0.CO;2-Npmid: N/A

Poly(styrene‐co‐4‐tert‐butyldimethylsilyloxystyrene) as a precursor of hydroxyl‐functionalized syndiotactic polystyrene was successfully synthesized via (η5‐indenyl)trichlorotitanium (IndTiCl3)‐catalyzed copolymerization of styrene with 4‐tert‐butyldimethylsilyloxystyrene in toluene at 25°C in the presence of methylaluminoxane (MAO) ((Al)/(Ti) = 2 000). The amount of styrene derivative incorporated into the polymeric chain for a 20,7 : 1 mole feed ratio of styrene to 4‐tert‐butyldimethylsilyloxystyrene was found to be 1,8 mol‐% from a 1H NMR analysis. The styrene derivative was successfully prepared from 4‐hydroxybenzaldehyde via first protecting the hydroxyl group using tert‐butyldimethylchlorosilane followed by the ‘Wittig‐type’ reaction with the ‘Tebbe’ reagent. The yield was about 82 wt.‐% on the basis of the initial amount of 4‐hydroxybenzaldehyde used.

Tamai, Toshiyuki; Ichinose, Nobuyuki; Agari, Yasuyuki

doi: 10.1002/(SICI)1521-3927(19990401)20:4<179::AID-MARC179>3.0.CO;2-7pmid: N/A

Pyrolytic conversion of poly(4‐((trimethylstannyl)methyl)styrene) (1) film to SnO2 was studied. The pyrolysis at 500°C of the polymer film which was crosslinked by 248 nm light or electron beam irradiation afforded a SnO2 film. The crosslinking network formation is necessary for the conversion of 1 into SnO2 through the encapsulation of the low molecular weight intermediates to prevent their escape from the polymer film.

Takeuchi, Daisuke; Aida, Takuzo; Endo, Takeshi

doi: 10.1002/(SICI)1521-3927(19990401)20:4<182::AID-MARC182>3.0.CO;2-Vpmid: N/A

2,2′‐Methylenebis(6‐tert‐butyl‐4‐methylphenolate) titaniumdichloride (1 a) brought about the living polymerization of 1,3‐dioxepan‐2‐one (7CC) to give polymers with narrow molecular weight distributions. The molecular weight of the obtained polycarbonate could be controlled by changing the initial mole ratio of 7CC and 1 a. The polycarbonate thus formed has hydroxymethylene terminal units at both ends.

Antipov, Evgueni M.; Vasnev, Valeri A.; Stamm, Manfred; Fischer, Erhard W.; Platé, Nikolai A.

doi: 10.1002/(SICI)1521-3927(19990401)20:4<185::AID-MARC185>3.0.CO;2-Jpmid: N/A

A comparison of the structure and phase composition of a recently synthesized carborane‐containing copolymer and its wholly organic analogue was carried out by DSC and X‐ray analysis in a wide temperature range between 20–300°C. It is found that the incorporation of 10 mol‐% of m‐carboranedicarboxylic units in the polymer prepared from 4,4′‐dihydroxybiphenyl and sebacic acid, acting as mesogen and flexible spacer, respectively, leads to the formation of a columnar mesophase at elevated temperatures. This newly observed phase occurs in addition to the crystalline and liquid crystalline smectic phases known for the wholly organic analogue.

Schäfer, Oliver; Brink‐Spalink, Friedel; Greiner, Andreas

doi: 10.1002/(SICI)1521-3927(19990401)20:4<190::AID-MARC190>3.0.CO;2-Zpmid: N/A

Phenylethyl‐substituted poly(p‐xylylene) (PEPPX) was prepared by base‐induced 1,6‐dehydrohalogenation of the corresponding 4‐chloromethyltoluene. Very high degrees of polymerization of about 3150 were obtained already at low conversions. Several standard retarders for radical polymerizations failed to limit the degree of polymerization significantly. However, best control was accomplished by the addition of dibenzoyl peroxide. The degree of polymerization of PEPPX was depressed to about 110 by addition of 10–15 mol‐% of dibenzoyl peroxide.

Neffgen, Stephan; Keul, Helmut; Höcker, Hartwig

doi: 10.1002/(SICI)1521-3927(19990401)20:4<194::AID-MARC194>3.0.CO;2-Jpmid: N/A

Di‐ and triblock copolymers with tetramethyleneoxy and trimethylene urethane repeating units were prepared by sequential polymerization of tetrahydrofuran (THF) and trimethylene urethane (TU) with the monofunctional initiator methyl trifluoromethanesulfonate (TfOMe) and the bifunctional initiator trifluoromethanesulfonic acid anhydride (TfOTf), respectively. The block copolymers obtained after purification show a uniform A‐B resp. A‐B‐A microstructure as was deduced from NMR and GPC analyses. The block copolymers are semicrystalline materials with distinct melting points of the poly(THF) and the poly(TU) domains.

Hagihara, Hideaki; Shiono, Takeshi; Ikeda, Tomiki

doi: 10.1002/(SICI)1521-3927(19990401)20:4<200::AID-MARC200>3.0.CO;2-Upmid: N/A

Propene polymerization was conducted with the (t‐BuNSiMe2Flu)TiMe2/B(C6F5)3 catalyst at –50°C at various concentrations of propene. The polymerization proceeds in a living manner regardless of the propene concentration employed. Molecular weight of polymer obtained in a certain polymerization time with low monomer conversion increases with increasing concentration of propene. The logarithmic plot of molecular weight against propene concentration gives a straight line with a slope of 1.8, which indicates that the propagation rate is almost of second order with respect to propene concentration.

Baumert, Martin; Fröhlich, Jörg; Stieger, Markus; Frey, Holger; Mülhaupt, Rolf; Plenio, Herbert

doi: 10.1002/(SICI)1521-3927(19990401)20:4<203::AID-MARC203>3.0.CO;2-Ipmid: N/A

TEMPO‐mediated free radical polymerization was employed for homo‐ and copolymerization of vinylferrocene (Vfc). Homopolymerization of Vfc resulted in relatively narrow polydispersities (Mw/Mn = 1.24–1.8), however, molecular weights were limited to 4 800. Copolymerization with styrene afforded random copolymers with molecular weights (Mn) up to 10 000, narrow polydispersity (1.2 > Mw/Mn > 1.4) and up to 42 mol‐% Vfc. Block copolymers with PS block and P(S‐co‐Vfc) block with molecular weights (Mn) in the range of 9 000 to 17 600 (Mw/Mn > 1.3) were also prepared with up to 17 mol‐% vinylferrocene. DSC revealed two glass transition temperatures (Tg) evidencing phase separation.

Stork, Martin; Koch, Matthias; Klapper, Markus; Müllen, Klaus; Gregorius, Heike; Rief, Ursula

doi: 10.1002/(SICI)1521-3927(19990401)20:4<210::AID-MARC210>3.0.CO;2-Qpmid: N/A

In this paper we report on a zirconocene dichloride/methylaluminoxane catalyst system supported on a crosslinked polystyrene in order to provide ethylene polymerization catalysts for gas phase or slurry processes. Our novel approach uses the Diels‐Alder reaction of cyclopentadiene functions as the final, cross‐linking synthetic step. This provides polymer supported zirconocene catalysts with a homogeneous distribution of active sites. The catalysts were shown to be highly active and to form spherical beads as proven by scanning electron microscopy.