Intramolecular Reaction between Neighboring Substituents of Specially-Designed Alternating Copolymers

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ABSTRACT:The ternary copolymerization of trimethylvinyloxysilane, styrene, and methyl or phenyl acrylate was attempted in the presence of organoaluminum compounds at 0°C. All copolymers had a considerable amount of five-membered lactone structures in their backbone chains following the hydrolysis of the trimethylsiloxy group. These copolymers originally had a I : I composition between acrylate as an electron acceptor and the other two components as electron donors, and therefore could be recognized as copolymers of two alternating units, trimethylvinyland The conversion of lactonization was often beyond 86.5% (Flory's limit) being nearly 100%, especially in copolymers containing the phenyl acrylate component. Additional lactonization of the copolymers did not occur under the same conditions used in the work-up process. Hence, the realized conversion resulted from a statistical intramolecular reaction between trimethylsiloxy and alkoxycarbonyl groups. These terpolymers may thus be regarded as a model of the "specially-designed alternating copolymer" described in the preceding paper.KEY Recently, attention has been directed to the permeation and transport activities of particular ions of membranes of synthetic polymers containing lactone structures. 1 Such polymers can be synthesized either by polymerizing unsaturated lactone monomers or by reacting two neighboring substituents on a copolymer chain so as to form an ester bond. However, misaturated lactone monomers often show low polymerizabilities 2 and the substituents of a simple copolymer are not always arranged in favor of intramolecular lactonization. achieve 100% conversion. Inevitably, 13.5% of the substituents remain unreacted, as was experimentally observed in Hirooka's study. 4

Section: Lactonizationmentioning

confidence: 58%

mentioning

confidence: 99%

Ternary Copolymerization of Trimethylvinyloxysilane, Styrene, and Acrylic Esters Catalyzed by Organoaluminum Compounds

Hirabayashi

Yokota

1981

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“…Thus, the copolymers la in this paper can be regarded as a profitable model for a "specially-designed alternating copolymer". 28 IR analysis of la after desilylation clarified the geometrical structure of the silyloxy diene unit in the copolymer la quantitatively according to the same method…”

mentioning

confidence: 99%

Spontaneous Alternating Copolymerization of 1-Silyloxy-1,3-dienes and Unsaturated Cyclic Anhydrides

Takasu

Inoue

Inai

et al. 2001

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ABSTRACT:1-Silyloxy-1,3-dienes, i.e., 1-butadienyloxytrimethylsilane (BdTMS) or 1-butadienyloxytertbutyldimethylsilane (BdTBDMS) and unsaturated cyclic anhydrides, containing maleic anhydride (MAn), citraconic anhydride (CAn), and itaconic anhydride (!An) were found to form charge transfer complexes (CTC) in benzene. Equilibrium constants, K, of the complexes were calculated by the Benesi-Hildebrand equation using UV spectroscopy to be 0.4 -1.0. Spontaneous copolymerizations of silyloxydienes with unsaturated cyclic anhydrides were established from 25 to 75 mol% of BdTMS in the feed. All polymers obtained had molar composition of 50/50 irrespective of feed molar ratios. Interestingly, molar ratio of 1,4-and 3,4-addtion structure seems to be influenced by K of CTC. Desilylation and successive lactonization of poly(BdTMS-alt-MAn) were conducted. Conversions of lactonization were beyond Flory's limit (86.5%) being nearly 100% due to intramolecular reactions of neighboring hydroxyl groups and cyclic anhydride in alternating copolymers.

“…We have already demonstrated successful cases in which specially-designed alternating copolymers have been employed for this purpose. 5…”

mentioning

confidence: 99%

Copolymerization Behavior of β-Angelica Lactone and Styrene in the Presence of Organoaluminum Chlorides

Hirabayashi

Yokota

1982

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In order to synthesize polymers containing lactone units in the backbone chains and use them as membranes, copolymerization of /3-angelica lactone (/3-AL) with styrene was carried out. Using 0(,0('-azobisisobutyronitrile at 60°C, /3-AL did not copolymerize readily. In the presence of ethylaluminum sesquichloride or diethylaluminum chloride as a complexing reagent in toluene at 20°C, however, /3-AL copolymerized much more readily. Spontaneous initiation took place and a copolymer containing about 50 mol% of /3-AL units was obtained under the most favorable conditions. Nevertheless, it seemed unlikely that regular, highly alternating sequences could be achieved in this manner, in contrast to the well-known Lewis acid-complexed copolymerization of acrylic esters and styrene. NMR studies demonstrated that, while the binary complex between /3-AL and ethylaluminum sesquichloride was formed almost instantly and completely, the ternary complex between styrene, /3-AL and ethylaluminum sesquichloride had a rather low stability constant (,;:; 0.05 dm 3 mol-1) which accounts for the imperfectly alternating sequences.