ABSTRACT:In contrast to diethyl fumarate (DEF), diethyl maleate (DEM) did not homopolymerize with 2,2'-azobisisobutyronitrile (AIBN), but was found to undergo radical polymerization in the presence of amines such as morpho line (Mor). From the results of radical polymerization of DEF with AIBN and isomerization of DEM with Mor, the radical polymerization of DEM in the presence of both AIBN and Moris considered to proceed via a new monomer-isomerization radical polymerization mechanism, i.e., DEM is isomerized first to DEF which is then homopolymerized. The most efficient isomerization catalyst was Mor among the amines examined. The apparent activation energies for the monomer-isomerization radical polymerization of DEM was calculated to be 91.9 kJmol-1 and that for this isomerization was also obtained as 24.7 kJmol-1 . Moreover, Mor also acted as a retarder of radical polymerization of DEF. The composition relation of the copolymer to the feed monomer mixture in the copolymerizations of DEM with styrene, isobutyl vinyl ether, and acrylonitrile in the presence of Mor was found to be similar to that of the respective copolymerizations of DEF.KEY WORDS Radical Polymerization I Radical Copolymerization Monomer-Isomerization Radical Polymerization I Diethyl Maleate Diethyl Fumarate I It is known that 1,2-disubstituted ethylenic monomers except vinylene carbonate 1 and maleimide derivatives 2 homopolymerize only to a very small extent in the presence of initiator, because of the steric hindrance of the substituents. However, 1,2-disubstituted olefins such as 2-butene, 2-pentene, and 4-phenyl-2-butene were found to polymerize with the Ziegler-Natta catalyst to give high molecular weight homopolymers consisting of the respective !-olefin monomer unit. 3 In these polymerizations, 2-olefins isomerized first to the corresponding 1-olefins which then homopolymerized, and we termed these polymerizations "monomerisomerization polymerization" for which the data obtained from our laboratory have been reported in detail. dialkyl maleates, did not give any homopolymers under similar conditions. 4 -8 However, when amines such as morpholine (Mor) were added to these systems, dialkyl maleates were also found to polymerize. 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. The results obtained are described in relation to the radical polymerization of diethyl fumarate (DEF). EXPERIMENTAL MaterialsCommercial DEM and DEF were used after fractional distillation under...

We have developed a liquid precursor that can be used in a solution process to form n-type doped silicon films. This precursor is based on phosphorus-doped hydrogenated polysilane synthesized by photo-copolymerizing cyclopentasilane and white phosphorus. By spin-coating this precursor, we have prepared n-type amorphous silicon films and polycrystalline silicon films with resistivities of 6.5–27 Ω·cm and 2.0–10 mΩ·cm, respectively.

Dialkyl fumarates with bulky ester substituents were found to homopolymerize easily in the presence of 2,2'-azobisisobutyronitrile. Among these fumarates, diisopropyl fumarate(DiPF1 homopolymerized with the above initiator(20mol/ 1) in bulk at 40~60'C to give homopolymers with number-average molecular weight of 70 000-221 000. Similar results were also observed for di-t-butyl fumarate (DtBF) and Methyl-t-butyl fumarate (MtBF) .

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

Water-soluble amphiphilic polymers containing styrene (St), acrylic acid (AA), or sulfonic acid moieties were synthesized and evaluated as polymeric surfactants for dye dispersions. 2-Acrylamide-2-methylpropanesulfonic acid (AMPS) was employed as a hydrophilic monomer containing a sulfonic acid moiety. The sulfonic acid moieties are effective hydrophilic molecular components adding moderate redispersion properties. Rheology, particle size distribution, surface tension, surface excess (Γmax), minimum area per molecule (A min), and redispersion properties were examined. This is because these factors are important in controlling the physical properties of an ink solution and the quality of printed materials. After the examination of surface parameters, the copolymer using St, AA, and AMPS shows the highest Γmax, indicating that it is most densely packed at the water/air interface. Aqueous solutions of polymers containing an AA moiety exhibit pseudoplastic properties, whereas those containing only a sulfonic acid moiety show a clear Newtonian fluid property. All color dispersions show unimodal particle size distribution and stable dispersion after thermal aging. However, sedimentation of dye particles was observed for polymers containing AMPS. Incorporation of AA and AMPS moieties in the amphiphilic polymer structure is proven to be suitable for the redispersion of dried or solidified ink into aqueous media. Regarding the rheology and the surface parameters, this study has shown that water-soluble polymers with sulfonic acid groups exhibit different properties from those containing acrylic acid. The introduction of sulfonic acid groups into conventional amphiphilic polymers consisting solely of styrene and acrylic acid was found to improve the redispersion properties of the ink. In this study, we demonstrate the potential of water-soluble amphiphilic polymers containing sulfonic acid groups as dispersants for inkjet inks.