Polymers from 1,2‐disubstituted ethylenic monomers, 2. Homopolymers from dialkyl fumarates by radical initiator

Abstract

It has been generally accepted that mono and 1,l-disubstituted ethylenes are homopolymerized in the presence of initiators, but the homopolymerizations of 1,2-disubstituted ethylenes, except vinylene carbonate') and maleimide derivatives", occur very hardly, because of the steric hindrance of the substituents.In 1975, Bengough et al.3) reported that diethyl fumarate (DEF) homopolymerized by radical initiator to give a relatively high number-average molecular weight homopolymer (& = 15000). At almost the same time, a similar observation was made in our laboratory in the alternating copolymerization of DEF with ethylene in order to obtain the head-to-head poly(ethy1 a~rylate)~). Furthermore diethyl maleate, cisisomer of DEF, was also homopolymerized in the presence of both radical azo initiator and isomerization catalyst such as morpholine') .Recently we found that various dialkyl fumarates @RF) could undergo radical homopolymerization, and that in some DRFs such as diisopropyl fumarate the polymerization proceeded easily to yield high molecular weight polymers. The present paper describes the results of radical homopolymerizations of various DRFs and of characterization of the polymers. Experimental PartThe commercial dimethyl fumarate (DMF), diethyl fumarate (DEF), dibutyl fumarate (DBF), and bis(2-ethylhexyl) fumarate (DEHF) were used after fractional distillation i. vac. The other DRFs, dipropyl fumarate (DPF), diisopropyl fumarate (DiPF), bis(sec-butyl) fumarate (DsBF), and diisobutyl fumarate (DiBF) were prepared by diesterification of fumaric acid with the respective alcohols in the presence of p-toluenesulfonic acid as catalyst. The resulting DRFs were also purified by repeated distillation. All DRF monomers were confirmed by gas chromatography to have purities > 99%. The radical initiators, 2,2'-azoisobutyronitrile (AIBN) and 2,2 '-azocyclohexanecarbonitrile (ACN) were recrystallied from methanol. Bulk polymerizations of the DRF monomers were carried out in a degassed glass tube in the presence of a radical initiator at 60°C. After polymerization for a given time, the content of the tubes was poured into a large amount of watedmethanol (vo1.-ratio 1/5) for DMF, DPF, and DBF, hexane for DEF, and methanol for other DRFs as precipitants. The resulting polymers were washed several times with the above precipitants, and then dried i. vac. a) Part 1: cf.9. 0173-2803/81/OOO2/0725/%03.00

Polymers from 1,2-Disubstituted Ethylenic Monomers VI. Monomer-isomerization Radical Polymerization of Diethyl Maleate

“…The TGA thermogram of the polymer obtained from DEM was also similar to that obtained by DEF, 5 i.e., the initial and maximum degradation temperatures were determined as 248° and 378°C, respectively. These results provide some supports that the polymers obtained from both DEM and DEF have identical structures and that DEM is polymerized through a monomer-isomerization radical polymerization mechanism.…”

“…4 • 6 Recently, various dialkyl fumarates, trans-! ,2-disubstituted monomers, were found to undergo homopolymerization in the presence of a radical initiator to give relatively high molecular weight homopolymers, but the respective cis isomers, i.e., In previous papers, the results of the radical homopolymerization of dimethyl fumarate 7 and dimethyl maleate 8 in either the presence or absence of amines were reported. In order to clarify further the detailed mechanism of the monomerisomerization radical polymerization of dialky'l maleates, the radical polymerization of diethyl maleate (DEM) was undertaken in this study.…”

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“…Glass transition temperatures ( T g ) of the poly( 1b ) and the poly( 1c ) were observed at −35.4 and −46.5 °C, respectively. The values are considerably lower than T g value of the poly(DEF), which are reported to be 62–72 °C 31. This is considered that both flexible alkoxyethyl and siloxy groups as the side chain induce the T g to lower.…”

“…The temperatures at maximum degradation for the poly( 1b ), the poly( 1c ), and the poly(DEF) are to be 384, 385, and 382 °C,31 respectively. Thermal stability of these polymers are found to be almost same.…”

Multi‐Component Kinetic Modeling for Controlling Local Compositions in Thermosensitive Polymers

“…[31][32][33] Direct data are also available for the homopolymerization of the cationic monomers. [29] FA data are estimated from the polymerization of fumaric acid diethyl ester in benzene; [34] the tabulated data are corrected for the kinetic impact of the esterification and the organic solvent according to effects tabulated in the corresponding acrylic acid data. [35] MA is considered essentially unreactive in homopolymerization such that k 33 ¼ 0 for this system.…”