The synthesis of several difunctional monomers, derived from the introduction of two 4-styrene-substituted moieties into a covalent skeleton, is described. The more rigid ones, built around malonate ...moieties and more preorganized to give 3,3′-cyclophane repeating units, failed completely to give soluble, ordered cyclopolymers. The introduction of a certain degree of flexibility in the tethering moiety afforded, by using free-radical initiation, structurally stable cyclopolymers with a high degree of cyclization and good degrees of polymerization. Theoretical calculations detail and strongly support the experimental results. Further chemical elaboration of the obtained cyclopolymeric backbones, by means of the removal of a ketal group, is possible in mild conditions to give systems which can be easily cross-linked thermally, with the loss of H2O, at temperatures higher than 100 °C.
A new dental dimethacrylate monomer containing phosphonic acid functionality, 2,5-bis(methacryloyloxy)-1,4-phenylenediphosphonic acid (1), was synthesized by silylation of ...2,5-bis(diethoxyphosphoryl)-1,4-phenylene bis(2-methylacrylate) (2) with trimethylsilyl bromide (TMSBr)
followed by the hydrolysis of the silyl ester. The monomer was solid and soluble in ethanol and water. The structure of this monomer was characterized by
1
H-,
13
C-,
31
P-NMR and FT-IR spectroscopy. The aqueous solution of 1 is acidic (pH 1.65), so that
it is expected to etch enamel and dentin, but is prone to hydrolysis over long storage periods. The co-polymerization behavior of this monomer with 2-hydroxyethyl methacrylate (HEMA) was investigated in water using photodifferantial scanning calorimeter at 40°C with bis(2,4,6-trimethylbenzoyl)phenylphosphine
oxide (BAPO) as photoinitiator. It was observed that the addition of monomer 1 to HEMA slightly decreased both the maximum rate of polymerization and conversion. The thermal solution co-polymerization of this monomer with acrylamide (AAm) and HEMA gave cross-linked polymers, indicating
its incorporation into the co-polymers. The interaction of this monomer with hydroxyapatite was observed using FT-IR spectroscopy. This monomer was found to be more suitable for dental composites than dental adhesives.
Development of reactive phosphonated methacrylates Edizer, Seda; Sahin, Gorkem; Avci, Duygu
Journal of polymer science. Part A, Polymer chemistry,
1 November 2009, Letnik:
47, Številka:
21
Journal Article
Odprti dostop
Five novel phosphonated mono- and dimethacrylate monomers have been synthesized by two different routes. Monomers 1 and 2 were synthesized by reactions of methacryloyl chloride with diethyl ...(2-hydroxyphenyl) phosphonate or tetraethyl (2,5-dihydroxy-1,4-phenylene) bisphosphonate; monomers 3 and 4 by reactions of α-(chloromethyl)acryloyl chloride (CMAC) first with dimethyl (2-hydroxyethyl) phosphonate and then with benzoic or formic acids. The reaction of CMAC with two moles of dimethyl (2-hydroxyethyl) phosphonate gave monomer 5. Thermal homopolymerization of monomers 1, 3, 4, and 5 and copolymerization of monomer 1 with methyl methacrylate (MMA) were investigated using azobisisobutyronitrile (AIBN) at 60 °C. Glass transition temperatures were observed for poly-1, poly(MMA-co-1) (50:50), poly(MMA-co-1) (90:10), PMMA, poly-3, and poly-5 at 52, 90, 99, 129, 50, and 70 °C, respectively. TGA analysis of these polymers indicated formation of char on combustion. Homo- and/or copolymerization behavior of the synthesized monomers with 2,2-bis4-(2-hydroxy-3-methacryloyloxy propyloxy) phenyl propane (Bis-GMA) were investigated with photodifferential scanning calorimetry. The maximum rate of polymerizations decreased in the following order: Bis-GMA~3 > 1 > 4 > 5. The conversions of monomers 1, 3, 4, and 5 (73.9, 85.9, 98.2, and 62.2%) were very high compared with Bis-GMA (40.5%).
The synthesis and characterization of a series of polystyrene (PS)-based copolymers, bearing 2-ureido-4
1H
-pyrimidinone (UPy) units pendant from the polymer backbone, is reported. The PS-based ...copolymers are efficiently synthesized by RAFT-mediated free radical polymerization performed on styrene and protected 4-vinylbenzylamine, and post-modification with suitable UPy-derived isocyanates to give the target polymers. Analysis of the samples in solution reveals that the polymer chains aggregate to give organic nanoparticles of discrete and uniform dimensions, whose direct visualization when deposited on surfaces can be achieved using AFM.
Six methacrylate monomers have been synthesized for use as reactive diluents in dental composites and evaluated to investigate the relationship between molecular structure and monomer reactivity. ...Four were synthesized by reactions of glycidyl methacrylate (GMA) with various acids, 2-(2-methoxyethoxy)acetic acid (1), 2-(2-(2-methoxyethoxy)ethoxy)acetic acid (2), cyanoacetic acid (3), and benzoic acid (4); others were synthesized by reactions of GMA with diethyl hydrogen phosphate (5) or methanol (6). Monomers 1 and 2 are novel, 3 seems to be novel, 4 and 6 were synthesized via a novel method, and the synthesis of 5 was described in the literature. The monomers showed high crosslinking tendencies during thermal bulk polymerizations. The photo-, homo-, and copolymerization behavior of the monomers with 2,2-bis4-(2-hydroxy-3-methacryloyloxy)phenylpropane (Bis-GMA) were investigated. The maximum rate of polymerizations of monomers 2-6 was found to be greater than triethyleneglycol dimethacrylate, Bis-GMA, 2-hydroxyethyl methacrylate, and glycerol dimethacrylate. For the more reactive monomers (2, 3, and 4), the oxygen sensitivity of polymerization was found to be low due to a hydrogen abstraction/chain transfer reaction. The computationally calculated dipole moment and lowest unoccupied molecular orbital energies indicated that there seems to be a correlation between these quantities and reactivity for ester linked monomers (1-5), which was also supported by ¹³C NMR data.
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