Methacryloyloxy Group Research Articles

Preparation and Mechanical Properties of UV-Curable Epoxy Acrylate/Modified Aramid Nanofiber Nanocomposite Films.

In order to enhance the mechanical properties of UV-curable epoxy acrylate (EA)-based coatings, 3-(trimethoxysilyl)propyl methacrylate modified aramid nanofibers (T-ANFs) were synthesized and used as nanofillers to prepare EA/T-ANF nanocomposite films. The morphology of T-ANFs was characterized by transmission electron microscopy. The chemical structure of T-ANFs was analyzed via infrared spectroscopy, confirming successful grafting of methyl methacryloyloxy groups onto the surface of aramid nanofibers (ANFs). Real-time infrared spectroscopy was employed to investigate the influence of ANFs and T-ANFs on the photopolymerization kinetics of the EA film. The results revealed that the addition of ANFs and T-ANFs led to a decrease in the photopolymerization rate during the initial stage but had little impact on the final double bond conversion, with all samples exhibiting a conversion rate of over 83%. The incorporation of ANFs improved the tensile strength of the films while significantly reducing their Young's modulus. In contrast, the addition of T-ANFs led to a substantial increase in both tensile stress and Young's modulus of the films. For instance, the tensile strength and Young's modulus of the 0.1 wt% of T-ANF film increased by 52.7% and 41.6%, respectively, compared to the pure EA film. To further study the dispersion morphology and reinforcement mechanism, the cross-sectional morphology of the films was characterized by scanning electron microscopy.

Preparation and mechanism of toughening and flame retardance of epoxy resin using novel silsesquioxane molecules

To simultaneously improve epoxy resin's toughness and flame retardancy, novel polyhedral oligomeric silsesquioxane with two functional epoxy and methacryloxy groups (EM-POSSs) were synthesized. Various analytical methods showed that caged POSS compounds with T8, T10, and T12 structures were successfully synthesized. The epoxy groups improved the dispersibility of POSS in the epoxy resin matrix and participated in the curing reaction to enhance the mechanical properties and thermal stability. Furthermore, the methacryloyloxy groups polymerized at high temperatures to form longer and more flexible chain groups, thereby improving the toughness of the epoxy networks. It was found that EM-POSSs significantly improved epoxy the resin's toughness and flame retardancy. Compared with pure epoxy resin, the peak heat release rate (PHRR) of epoxy composites was reduced by 45%, while the bending strength, tensile strength, and impact toughness increased by 55%, 50%, and 57.1%, respectively.

Adsorption performance and mechanism of mycotoxin on montmorillonite modified by organosilicon grafting

A series of modified montmorillonites were prepared by acid modification method prior to the organosilicon grafting. Aflatoxin B1, zearalenone and deoxynivalenol (DON) were selected to evaluated the mycotoxin adsorption performance of modified montmorrillonites. The experimental results suggest that under acidic conditions, the higher the charge density in the covalent orbital of the active group, the stronger the interaction between it and the DON molecule, and the better the corresponding modified montmorillonite adsorbs DON. Silicified montmorillonite with active groups of cyano group and methacryloyloxy group has the best adsorption performance for DON, and the adsorption degree are 51.6% and 39.0%, respectively. However, under alkaline terms, due to the hydrolysis of active groups, the adsorption degree of montmorillonite on DON dropped steeply.

Effect of the nature of the reactive group on the electron beam curing of model urethane di(meth)acrylates

In this study, three kinds of model urethane di(meth)acrylates with different radiation-curable groups [one with acryloyloxy (namely H-I-H), one with methacryloyloxy (namely HM-I-HM) and one with half of acryloyloxy and half of methacryloyloxy (namely H-I-HM)] were synthesized. The chemical structures of these products were characterized through attenuated total reflection fourier transformed infrared spectroscopy (ATR-FTIR), proton (1H) nuclear magnetic resonance and elemental analysis. Then, the electron beam (EB) curing process and properties of the synthesized three di(meth)acrylates and a 1:1 mixture of H-I-H and HM-I-HM (namely H-I-H&HM-I-HM) were investigated. ATR-FTIR results showed that the samples containing acryloyloxy groups (H-I-H, H-I-HM, and H-I-H&HM-I-HM) showed a higher polymerization rate and double bond conversion than that containing only methacryloyloxy groups (HM-I-HM). Thermogravimetric analysis indicated that the EB-cured films of H-I-HM and H-I-H&HM-I-HM had relatively good thermal stability, while the film of HM-I-HM with lower double bond conversion and gel content had poor thermal stability. In addition, although acryloyloxy groups have weaker rigidity, benefitting from its improvement of the polymerization degree, the EB-cured coatings with acryloyloxy group had better surface mechanical and basic properties than the coatings containing methacryloyloxy group.

New chiral liquid crystal materials based on menthol: Synthesis and phase behavior

ABSTRACTTo study structure-mesomorphism relationships of chiral materials based on menthol, a series of chiral compounds containing menthyl group were synthesized. Their chemical structures, formula, and the purity were characterized by Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), and elemental analyses. The corresponding phase behavior was investigated with differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The effect of the mesogenic core, flexible spacer, and terminal groups on the mesophase formation and type was discussed. The compound 4-menthyloxyacetoxybenzoyloxy-4′- (6-bromohexyloxy)biphenyl showed the smectic A (SA) and cholesteric phases on heating cycle, and a cubic Blue Phase, chiral smectic C (SC*), SA and cholesteric phases on cooling cycle. However, the compound 4-menthyloxyacetoxybenzoyloxy-4′-(4-bromobutoxy)biphenyl showed enantiotropic SC*, SA and cholesteric phases, moreover, the platelet texture of a cubic Blue Phase was also observed on cooling cycle. The methacrylate monomer with six flexible methylene units and three phenyl rings as mesogenic core only showed cholesteric phase, while the methacrylate monomer with four methylene unit and three phenyl rings showed the SC* and cholesteric phases. However, when the terminal methacryloyloxy groups in the monomers were substituted by thiophenylacryloyloxy groups, the corresponding monomers all show no mesophase. With increasing the rigidity of mesogenic core or decreasing the flexible methylene spacer length, the corresponding melting temperature (Tm) or isotropic temperature (Ti) increased.

Microparticles for Drug Delivery Based on Functional Polycaprolactones with Enhanced Degradability: Loading of Hydrophilic and Hydrophobic Active Compounds

Microparticle drug carriers made of biodegradable functional polyesters were produced. The polyesters consist of a poly(ε-caprolactone) backbone bearing pendant acryloyloxy and methacryloyloxy groups. Stable microparticles were prepared via an oil/water emulsion-solvent evaporation technique eventually combined with a simultaneous crosslinking procedure. Crosslinked particles were obtained via photo-crosslinking and Michael type addition using diamines as crosslinking agents. Encapsulation of a hydrophobic fluorescent dye and a hydrophilic protein, as model drugs, were performed and confirmed by optical microscopy and Raman spectroscopy. The presence of the functional groups allow for not only the tuning of the degradation rate, but also for further processing and (bio)functionalization.

3-Acetyl-4-hydroxyphenyl acrylate

In the title compound, C12H12O4, the hydr­oxy O and the C and O atoms of the acetyl group are almost coplanar [maximum deviation = 0.0356 (1) Å] with the benzene ring. The dihedral angle between the benzene ring and the plane through the non-H atoms of the methacrylo­yloxy group is 86.1 (1)°. In the crystal structure, mol­ecules are linked by two C—H⋯O hydrogen bonds, forming dimers with graph-set descriptor R 2 2(16). A strong intra­molecular O—H⋯O hydrogen bond is also observed.

Synthesis and characterization of photosensitive methacrylates to give heat-resistant polymers

New photosensitive monomers having multiple methacryloyloxy groups were synthesized by the reaction of naphthalene and biphenyl derivatives containing two or more glycidyloxy groups with methacrylic acid. The obtained photosensitive monomers were mixed with polymerization initiators (1 wt% AIBN and/or BIPE) and a reactive diluent (20 wt% DPCA60). The mixtures were termed as compounds. The compounds were converted into the insoluble gel products by heating or photo-irradiation with an ultra high-pressure mercury lamp. We also measured the heat resistance of the insoluble gel products by thermogravimetry and investigated the correlation between the heat resistance and the chemical structures of photosensitive methacrylate composites. All of the insoluble gel products showed the heat-resistance over 260 8C and particularly the compound having the largest number of methacryloyloxy groups had the highest heat-resistance among them. This compound exhibited the highest consumption rate of the photosensitive group and it was in accordance with the result of the reactive photo-polymerizability measured by the gray scale method.

Photophysical and lasing properties of new analogs of the boron-dipyrromethene laser dye pyrromethene 567 incorporated into or covalently bounded to solid matrices of poly(methyl methacrylate).

The photophysical, lasing and thermostability properties of newly synthesized analogs of the commercial dye pyrromethene 567 (PM567) have been measured in polymeric matrices of poly(methyl methacrylate) both when used as a dopant and when covalently bounded to the polymeric chain. These analogs have an acetoxy or a polymerizable methacryloyloxy group at the end of a polymethylene chain at Position 8 of the PM567 chromophore core. Clear correlations between photophysical and lasing characteristics are observed. Linking chain lengths with three or more methylene units give the highest fluorescence quantum yields (as high as 0.89) and lasing efficiencies (as high as 41%). The covalent linkage of the chromophore to the polymeric chain via the methacryloyloxy group improves the photostability of the PM567 chromophore.

Methacrylate-tethered analogs of the laser dye PM567--synthesis, copolymerization with methyl methacrylate and photostability of the copolymers.

The synthesis and characterization of new analogs of the laser dye PM567 (4,4-difluoro-1,3,5,7,8-pentamethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indacene) with the 8-position substituted by a linear chain with n methylenes (n = 1, 3, 5, 10 or 15) tethered with an acetoxy or methacryloyloxy group (PnAc and PnMA, respectively) is described. The monomeric dyes PnMA have been successfully copolymerized with methyl methacrylate (MMA), yielding linear copolymers of high optical quality where the covalently bonded chromophore is separated from the polymeric main chain by a spacer of variable length. The photostability of the solid polymeric materials under UV (310 nm) irradiation (method ASTM G 53-77) has been compared with those of the model dyes PnAc and PM567 as solid solutions in poly-MMA (PnAc-PMMA and PM567-PMMA, respectively). In all the cases, the chromophore bound to the polymer is more photostable than that simply dissolved in the same polymer, with photodegradation quantum yields in the range 2.3 x 10(-5) to 4.8 x 10(-5), which was interpreted as due to additional modes for the dissipation of the absorbed energy along the polymeric chain. In both polymer solutions and copolymers, the length of the polymethylene chain has low or null influence on the photostability. In ethanol solution, PnAc model dyes with polymethylene chains with three or more methylene groups show about the same photostability; this is of an order of magnitude higher than that of the parent dyes P1Ac and PM567 in the same solvent.

Preparation of poly(tert-butyl acrylate-g-styrene) as precursors of amphiphilic graft copolymers. 1. Kinetic study and thermal properties

Free radical copolymerizations of tert-butyl acrylate and a polystyrene macromonomer carrying a methacryloyloxy group at the chain end have been performed in benzene solution using 2,2′-azobis(isobutyronitrile) (AIBN) as initiator at 70°C. The estimated values of the ‘lumped’ kinetic constant, kp/kt1/2, have shown a clear dependency on the macromonomer concentration in the reaction medium. The obtained poly(tert-butyl acrylate-g-polystyrene) graft copolymers were characterized by size exclusion chromatography (SEC), and differential scanning calorimetry (DSC). In addition, the thermal behavior of these copolymers was studied by thermogravimetric analysis (TGA). Subsequently, hydrolysis of precursor graft copolymer was performed to afford an amphiphilic graft copolymer. Characterization using FT-IR confirmed total hydrolysis of the ester group.

Synthesis of hybrid resins via polysiloxane with methacryloyloxy groups

A polysiloxane derivative with methacryloyloxy groups (MPS) that was obtained from the reaction of polymeric tributylstannyl ester of silicic acid and (3-methacryloyloxypropyl)dimethylchlorosilane was demonstrated to be a useful inorganic component for the preparation of organic–inorganic hybrid resins as nanocomposites. The copolymerizations of MPS with common monomers such as styrene, acrylonitrile, and methyl methacrylate proceeded readily at room temperature under UV irradiation to give the corresponding resins in good yields. The resins obtained from MPS and methyl methacrylate showed good transparency, hardness in a scratch test, and resistance to toluene but had poor flexibility. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1–7, 2001

Characterization and thermal properties of poly(n-butyl acrylate-g-styrene) graft copolymers

Poly(butyl acrylate-g-styrene) graft copolymers were prepared by free-radical polymerization using a polystyrene macromonomer carrying a methacryloyloxy group at the chain end and they were characterized by size-exclusion chromatography, and Fourier transform infrared spectroscopy. Glass transition temperatures and degradation behavior were determined by thermal analysis. Only a single glass transition temperature was observed for the resulting graft copolymers, indicating the miscibility between the poly(styrene) phase and poly(butyl acrylate) (pBA) phase in the graft copolymer. The incorporation of polystyrene segments in the graft copolymer improved the thermal stability of pBA and enhanced the apparent activation energy for the thermal degradation of pBA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 783–789, 2001

Synthesis of hybrid resins via polysiloxane with methacryloyloxy groups

A polysiloxane derivative with methacryloyloxy groups (MPS) that was obtained from the reaction of polymeric tributylstannyl ester of silicic acid and (3-methacryloyloxypropyl)dimethylchlorosilane was demonstrated to be a useful inorganic component for the preparation of organic–inorganic hybrid resins as nanocomposites. The copolymerizations of MPS with common monomers such as styrene, acrylonitrile, and methyl methacrylate proceeded readily at room temperature under UV irradiation to give the corresponding resins in good yields. The resins obtained from MPS and methyl methacrylate showed good transparency, hardness in a scratch test, and resistance to toluene but had poor flexibility. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1–7, 2001

Synthesis of Polysiloxane Having Methacryloyloxy Group from Tributylstannyl Ester of Silicic Acid and Silane Coupling Agent

Polysiloxane derivative (MPS), obtained from the reaction of polymeric tributylstannyl ester of silicic acid (PTBS) and (3-methacryloyloxypropyl)dimethylchlorosilane (1a), was shown to be a useful inorganic component for the preparation of organic-inorganic hybrid resin as a nanocomposite. Copolymerization of MPS containing methacryloyloxypropyl groups with the common monomer such as styrene, acrylonitrile, or methyl methacrylate proceeded readily at room temperature under UV irradiation to give the corresponding resins (HR). The resins obtained from MPS and methyl methacrylate showed a good transparency and resistance in scratch test, but a poor flexibility. The gels consisted of analogous structure to HR were obtained from PTBS, 1a, and the monomer by one-pot procedure, in which substitution and polymerization proceeded simultaneously.

Synthetic application of tributylstannyl ester of silicic acid: Synthesis and polymerization of polysiloxane having methacryloyloxypropyl groups

Polymeric tributylstannyl ester of silicic acid (PTBS) was demonstrated to be a useful intermediary compound for the preparation of polysiloxane derivative (MPS), which possessed methacryloyloxypropyl groups. The reaction of PTBS and (3-methacryloyloxypropyl)dimethylchlorosilane (1a) proceeded readily at room temperature under neutral conditions to give MPS with the elimination of tributyltin group. The reaction conducted in the presence of 1a and trimethylchlorosilane (1b) was effective for the preparation of MPS containing the both silyl groups, in which the content of methacryloyloxy groups could be controlled. The obtained MPS polymerized readily under UV irradiation to afford the organic–inorganic hybrid resin (MSR) as a kind of organically modified silica gel. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4226–4232, 1999

Synthetic application of tributylstannyl ester of silicic acid: Synthesis and polymerization of polysiloxane having methacryloyloxypropyl groups

Polymeric tributylstannyl ester of silicic acid (PTBS) was demonstrated to be a useful intermediary compound for the preparation of polysiloxane derivative (MPS), which possessed methacryloyloxypropyl groups. The reaction of PTBS and (3-methacryloyloxypropyl)dimethylchlorosilane (1a) proceeded readily at room temperature under neutral conditions to give MPS with the elimination of tributyltin group. The reaction conducted in the presence of 1a and trimethylchlorosilane (1b) was effective for the preparation of MPS containing the both silyl groups, in which the content of methacryloyloxy groups could be controlled. The obtained MPS polymerized readily under UV irradiation to afford the organic–inorganic hybrid resin (MSR) as a kind of organically modified silica gel. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4226–4232, 1999

ケイ酸のトリブチルスタンニルエステル高分子体，クロロシランおよび有機モノマーを用いたハイブリッドゲルの一段階合成

Organic-inorganic hybrid gels were obtained efficiently by one-pot procedure from tributylstannyl ester of polymeric silicic acid (PTBS), chloro (3-methacryloyloxypropyl) dimethylsilane (1a), and cornmon monomers such as styrene, acrylonitrile, and methyl methacrylate. In the reaction system, substitution of tributylstannyl groups of PTBS by silyl groups of la and copolymerization of methacryloyloxy group of la with a monomer proceeded simultaneously under UV irradiation at room temperature. The resulting gel should be consisted of covalently bonded three components and regarded as a nanocomposite material. The use of another chlorosilane lb, which had cyanopropyl group, with la led to formation of a multifunctional hybrid gel.

Polymerizable azo dyes

AbstractA series of new polymerizable azo dyes containing the methacryloyloxy group were prepared. Their melting points, yield, colour, solubility and absorption in the UV‐visible range were characterized, and the relationship between their properties and structure was evaluated. The characteristics of radical homopolymerization of one of the azo dyes, N‐methyl‐N‐[4‐(2,5‐dichlorophenyl) azophenyl]‐2‐aminoethyl methacrylate, and of its copolymerization with a number of vinyl monomers were determined. By using the seeded polymerization of the azo dye in the industrially produced butadiene‐styrene (35/65) latex a colour latex was obtained.