Photopolymerization of urethane dimethacrylates synthesized via a non-isocyanate route

Urethane dimethacrylate monomers were synthesized via a non-isocyanate route from the reaction of a urethane diol with methacrylic anhydride. The urethane diols were synthesized through the reaction of ethylene carbonate with 1,6-hexanediamine, 3-amino-1-propanol and 2,2-dimethyl-1,3-propanediamine. ¹H NMR, ¹³C NMR and FTIR spectroscopies confirmed the structure of the monomers. Elemental analysis confirmed the purity of the monomers. Photopolymerization of these multifunctional monomers was investigated with respect to polymerization rates and conversions using photoinitiated differential scanning calorimetry. Irgacure 651^® was used as an initiator at 2 mol%. Photopolymerization results indicate high peak polymerization rates, 0.09 s⁻¹ compared to 0.06 s⁻¹ for bis-GMA and 0.07 s⁻¹ for HDDMA polymerized under the same conditions. Overall bulk conversions were 70-78%, compared to 68 and 76% for bis-GMA and HDDMA, respectively.The methodology developed here utilizes diamines and amino-alcohols that are members of commercially available families possessing a large range of structures, thus allowing synthetic flexibility in obtaining new urethane dimethacrylates with desirable properties.     

Adhesion Studies of Mixtures of Ethyl Cyanoacrylate with a Difunctional Cyanoacrylate Monomer and with other Electron-deficient Olefins

Alkyl cyanoacrylate instant adhesives are widely used because of their fast cure speed and versatility on a large number of substrates. Recent performance improvements, such as increased thermal resistance, resulted from the addition of latent acids and polymers, which do not copolymerize with the adhesive monomer, to the adhesive formulations. However, use of these additives can increase fixture time or reduce the final adhesive strength.

Two methods for possibly improving alkyl cyanoacrylate instant adhesives, without loss of cure speed or adhesive properties, could be either crosslinking the alkyl cyanoacrylate monomer with a dicyanoacrylate or copolymerizing it with a second 1, 1 disubstituted electron-deficient olefin. A crosslinker. 1,4 butanediol dicyanoacrylate (BDDCA) and two monofunctional monomers, diethyl methylenemalonate (DEMM) and N,N diethyl-2-cyanoacrylamide (DECA), were prepared, in good purity, for adhesion studies with ethyl cyanoacrylate (ECA). Crosslinking ECA with BDDCA does improve solvent resistance, as determined by solvent swelling experiments. Glass fixture times are approximately the same for ECA, crosslinked ECA, the pure monomers, and monomer mixtures with ECA, while steel fixture times are generally slower. Crosslinking ECA with BDDCA does not improve lap-shear adhesion, either at room temperature or after thermal exposure at 121°C. Lap-shear strength data, before and after heat exposure, revealed that the ECA/DEMM and the ECA/DECA monomer mixtures exhibit weaker lap-shear adhesive strength than ECA alone.     

一种新型耐高温厌氧结构胶的研制

以丙烯酸酯单体作为主要原料、耐热添加剂[如苯乙烯-丁二烯-苯乙烯弹性体(SBS)、聚乙烯丙烯酸酯橡胶(AEM)、氟橡胶(FKM)和氯磺化聚氯乙烯(CSM)等]作为厌氧结构胶的改性剂,制备双组分非混合型耐热厌氧结构胶,并采用单因素试验法优选出制备该厌氧结构胶的最佳工艺条件。结果表明:当混合单体为甲基丙烯酸环己酯/三环癸烷二甲醇二丙烯酸酯、耐热添加剂为AEM且w(AEM)=20%时,厌氧结构胶的综合性能相对最好;该厌氧结构胶可在150℃以下长期使用、200℃时短期使用,并具有良好强度和韧性;此外,该厌氧结构胶的耐溶剂性能优良,可在高温条件下进行粘接,具有良好的应用前景。     

Effects of NCO/OH Ratio and Reactive Diluent Type on the Adhesion Strength of Polyurethane Methacrylates for Cord/Rubber Composites

A series of dual curable polyurethane methacrylate-based oligomers were synthesized by changing the NCO:OH ratio and then were included in adhesive formulations using trimethylolpropane trimethacrylate and tricyclodecane dimethanol diacrylate (TCDDA) as reactive diluents. The effects of NCO:OH ratio and reactive diluent type on the structural properties of UV-cured free films and adhesion properties between polyester cord/rubber surfaces were studied. The highest adhesion strength of the 103?N?cm^?1 was obtained when the NCO:OH ratio was set as 4 and the TCDDA was used as a reactive diluent.     

Monomers for Adhesive Polymers, 3. Synthesis,Radical Polymerization and Adhesive Properties of Hydrolytically Stable Phosphonic Acid Monomers

2‐(Dihydroxyphosphoryl)ethyloxy‐α‐methyl‐substituted methacrylic acids were synthesized by hydrolyzing ethyl 2‐[4‐(dihydroxyphosphoryl)‐2‐oxa‐butyl]‐acrylate. Methacrylonitrilo‐ or N,N‐diethylmethacrylamido‐phosphonic acids were obtained by ether formation of α‐chloromethacrylonitrile with hydroxyalkyl phosphonates or aminolysis of 2‐[4‐(dimethoxyphosphoryl)‐2‐oxa‐butyl]acrylic acid and subsequent hydrolysis to produce the corresponding phosphonic acid. The structure of the new monomers was characterized by IR and by ¹H, ¹³C and ³¹P NMR spectroscopy. The monomers dissolve well in water and are hydrolytically stable. They demonstrate a different behavior during radical polymerization in water with 2,2′‐azo(2‐methylpropionamidine) dihydrochloride (AMPAHC). This behavior may be attributed to the different reactivity of the starting radicals. Furthermore, adhesive properties of the phosphonic acid monomers were measured.     

Monomers for Adhesive Polymers, 4

Hydrolytically stable, crosslinking bis(acrylamide)s 1a – 1l or bis(methacrylamide)s 2a – 2c were synthesized by reaction of acryloyl or methacryloyl chloride using primary or secondary amines. In addition, monomers 3a and 3b were obtained by amidation of 2,6‐dimethylene‐4‐oxaheptane‐1,7‐dicarboxylic acid (DMOHDA) with propylamine and diethylamine, respectively. The structures of the monomers were characterized by IR, ¹H, and ¹³C NMR spectroscopy. All monomers containing N,N′‐monosubstituted carbamide groups were solids. Those containing N,N′‐disubstituted carbamide groups were water‐soluble liquids. Water‐soluble bis(acrylamide) 1d (N,N′‐diethyl‐1,3‐bis(acrylamido)propane) shows a radical polymerization reactivity in the presence of 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (AMPAHC) similar to that of glycerol dimethacrylate, as revealed by gelation experiments in water. 1d is hydrolytically stable in 20 wt.‐% phosphoric acid and can be used to substitute dimethacrylates in self‐etching dentin adhesives. Furthermore, this monomer was also suitable as a reactive diluent in composites.

     

耐高温型结构厌氧胶黏剂的研究进展

本文综述了耐高温厌氧胶的发展状况，根据其单体的特点将耐高温厌氧胶进行分类，并着重阐述了耐高温结构厌氧胶的单体合成及以该单体配制成厌氧胶的性能特点。     

紫外光(UV)固化胶黏剂收缩率与强度的研究

UV胶黏剂的固化收缩率与固化后的残留应力乃至粘接强度有着密切关系。对比UV胶黏剂中不同丙烯酸单体、几种低聚物和阳离子单体的收缩率和相应的粘接强度。讨论了单体和树脂类型对收缩率和粘接强度的影响。介绍了以低收缩丙烯酸酯树脂和阳离子树脂为主体树脂,以低收缩单体为稀释剂、配合填料和适当增强剂制备出混合型UV胶黏剂。该胶黏剂粘接强度和耐久性好,其固化收缩率为3．5％,远低于普通自由基型UV胶黏剂。经湿热老化试验后,粘接强度保持率仍保持在80％。     

Synthesis, Characterization and Reactivity Ratios of Phenylethyl Acrylate/Methacrylate Copolymers

2-Phenylethyl acrylate (PEA) and 2-Phenylethyl methacrylate (PEMA) were synthesized by reacting 2-Phenyl ethanol with acryloyl and methacryloyl chloride respectively. Homopolymers and copolymers were prepared by free radical polymerization technique using benzoylperoxide as initiator. Copolymers of PEA and PEMA with methyl acrylate (MA) and N-vinyl pyrollidone (NVP) of different compositions were prepared. The monomers and polymers were characterized by IR and NMR techniques. Thermal stability of the polymers were determined by TG analysis. The composition of the copolymer was determined using ¹H-NMR analysis. The reactivity ratios of the monomers were determined by the application of Finemann–Ross and Kelen–Tudos methods. The prepared copolymers were tested on leather for their pressure sensitive adhesive property.     

Heat-resistant adhesive resins derived from bismaleimides and bisnadimides containing amide linkages

A novel class of bismaleimides and bisnadimides containing amide linkages in their backbones were synthesized and characterized. The synthesis of these polymer precursors was carried out by reacting a diamine containing amide linkages with maleic/nadic anhydride. They were alternatively prepared by reacting the monomaleamic/monoadiamic acid of an aromatic diamine (1 mol) with terephthaloyl chloride (0.5 mol) and subsequent cyclodehydration. The latter new preparation method circumvented the hydrogeneration necessary in the first method of synthesis. The monomers were characterized by infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Differential thermal analysis (DTA) of monomers showed that bisnadimide and bismethylnadimide were polymerized at lower temperatures than the corresponding bismaleimide. Thermogravimetric analysis (TGA) in nitrogen and air atmosphere revealed that all polymers were stable up to 321–363°C. Their char yield at 800°C under anaerobic conditions was 49–67%.     

Synthesis of novel antibacterial monomers (UDMQA) and their potential application in dental resin

To prepare antibacterial dental resin, a series of novel urethane dimethacrylates quaternary ammonium methacrylate monomers (UDMQAs) with different substituted alkyl chain length were synthesized, and their structures were confirmed by FTIR and ¹H‐NMR spectra. The obtained UDMQAs were used to replace 2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloyloxypropyl)‐phenyl]propane (Bis‐GMA) totally as base monomers of dental resin and mixed with Tri‐ethyleneglycol dimethacrylate (TEGDMA) at the mass ratio of 50/50. The properties of these prepared resins like antibacterial activity, double bond conversion (DC), polymerization shrinkage, flexural strength (FS), and modulus (FM), water sorption and sol fraction were investigated. The most commonly used dental resin Bis‐GMA/TEGDMA (50wt/50wt) was chosen as a reference. The results showed that UDMQAs could endow dental resin with antibacterial activity. Compared with Bis‐GMA‐based dental resin, UDMQAs‐based resin had the same or higher DC, lower polymerization shrinkage, lower flexural strength and modulus, and higher water sorption and sol fraction. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Improvement of corrosion protection of steel by incorporation of a new phosphonated fatty acid in a phosphorus-containing polymer coating obtained by UV curing

Six formulations containing diacrylate monomers (from 89 to 92.5% (w/w)) as well as a phosphonated methacrylate monomer (from 1 to 10% (w/w)) were prepared. All formulations were UV-cured and the corrosion performance of the resulting coatings applied onto a steel substrate was assessed by electrochemical impedance spectroscopy (EIS). It was first shown that the coatings containing phosphonic acid methacrylate (MAPC1(OH)₂) instead of methacrylate phosphonic dimethyl ester (MAPC1) presented higher corrosion protection related to the strong adhesive properties of phosphonic acid on the metal substrate. A minimum MAPC1(OH)₂ content of 2.5% was determined to provide the highest impedance values (best efficiency). Then, a new bio-based compound, i.e. phosphonic acid-bearing oleic acid (phosphonated fatty acid), was synthesized and added as an inhibitor to the formulations. In the presence of this compound, the corrosion protection was notably improved. The beneficial effect of phosphonated fatty acid was explained by its inhibitive action at the steel/coating interface and by the improvement of the barrier properties.     

Copolymerization of N‐substituted maleimide with alkyl acrylate and its industrial applications

A series of new copolymers with desired thermal stability and mechanical properties for applications in leather industry were synthesized from various substituted maleimides and alkyl acrylates. Polymerization was carried out by a free‐radical polymerization using benzoyl peroxide (BPO) as initiator. The monomers and polymers synthesized were characterized by elemental analysis, IR, and nuclear magnetic resonance (NMR). Interestingly, these polymers were soluble in common organic solvents. Copolymer composition and reactivity ratios were determined by ¹H‐NMR spectra. The molecular weights of the polymers were determined by gel permeation chromatography. The homo‐ and copolymer of maleimide showed single‐stage decomposition (ranging from 300–580°C). The initial decomposition temperatures of poly[N‐(phenyl)maleimide] [poly(PM)], poly[N‐4‐(methylphenyl)maleimide] [poly(MPM)] and poly[N‐3‐(chlorophenyl)maleimide] [poly(CPM)] were higher compared to those of the copolymers. Heat‐resistant adhesives such as blends of epoxy resin with phenyl‐substituted maleimide‐co‐glycidyl methacrylate copolymers with improved adhesion property were developed. Different adhesive formulations of these copolymaleimides were prepared by curing with diethanolamine at two different temperatures (30°C and 60°C). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1870–1879, 2001     

Viscosity effects in the photopolymerization of two‐monomer systems

Photopolymerization kinetics and viscosity behavior of five different two‐monomer systems forming hydrogen bonds and composed of mixtures of a high viscosity monomer (HVM) and a low viscosity monomer (LVM) at various molar ratios were investigated at six polymerization temperatures. The monomers used were mono‐ or dimethacrylates. Detailed viscosity measurements of the monomer mixtures showed significant negative deviations from the theoretical values (characterized by excess logarithm viscosities) indicating that interactions between the molecules of the same type (in individual monomers) are stronger than those between two molecules of different types (HVM and LVM). The photopolymerization kinetics were analyzed from the point of view of the appearance, viscosity and temperature behavior of the most reactive composition (MRC), the one showing the highest value of the maximum polymerization rate within a range of the HVM: LVM ratios. It was found that MRC appearance is determined mainly by the initial viscosity of the two‐monomer system, whereas the functionality of the monomers (and network formation) is much less important (MRC is observed even in linear systems). The initial viscosity of all the monomer mixtures showing MRC lay in the range of 0.06–2 Pa s, which is narrow compared to the range of viscosities of the monomers (approximately 10^?3–10³ Pa s). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Copolymerization kinetics of dental dimethacrylate resins initiated by a benzoyl peroxide/amine redox system

The copolymerization of four dental dimethacrylates initiated by a benzoyl peroxide/4-N,N-dimethylamino phenethyl alcohol redox system at 37°C was studied with differential scanning calorimetry. The studied dimethacrylates were viscous bisphenol A glycidyl dimethacrylate (Bis-GMA), bisphenol A ethoxylated dimethacrylate (Bis-EMA), and urethane dimethacrylate (UDMA), which were characterized as base monomers, and low-viscosity triethylene glycol dimethacrylate (TEGDMA), which was characterized as a diluent. Also, three series of dimethacrylate copolymers were prepared by incremental additions (12.5 wt %) of TEGDMA to a base comonomer (Bis-GMA, UDMA or Bis-EMA). The maximum rate of homopolymerization of the dimethacrylates followed the order of Bis-GMA > UDMA > TEGDMA > Bis-EMA, and the final degree of conversion of the corresponding homopolymers followed the order of TEGDMA > UDMA > Bis-EMA > Bis-GMA. A reaction–diffusion-controlled termination region was clear in all monomers and started earlier in bulky and rigid Bis-GMA and Bis-EMA (followed by the more flexible UDMA and TEGDMA) but lasted longer in the Bis-EMA polymerization. The maximum rate of copolymerization and degree of conversion of copolymers of a base monomer with TEGDMA changed monotonically with an increase in the TEGDMA content in the initial comonomer mixture. A synergistic effect was clear only in the final double-bond conversion of Bis-GMA/TEGDMA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

一种专用厌氧胶的研制

通过改善厌氧胶主体树脂的合成条件,在配方中添加耐水/耐热树脂及单体,有机硅烷偶联剂作为增强剂,制备了一种石英晶体行业专用厌氧胶.检测结果表明该厌氧胶能完全满足石英晶体的加工要求.     

Modification of cotton,rayon, and silk with urethane acrylate under ultraviolet radiation

Ten different formulations were developed with Ebcryl 264, a urethane acrylate in combination with other monofunctional monomers in the presence of some additives and coadditives. Thin films prepared from these formulations under ultraviolet (UV) radiation were characterized. Natural fibers such as cotton, rayon, and silk were treated with the formulations and cured under UV radiation. Their physical and mechanical properties were studied. It was found that the tensile strength (TS) of cotton, rayon, and silk was significantly increased as a result of this treatment under UV radiation (TS_cotton = 150%, TS_rayon = 30%, and TS_silk = 40%). Elongation of cotton and silk increased to 380 and 50%, respectively. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1703–1711, 1997     

Polyhydroxyesterimides from Renewable Resources: Synthesis,Characterization, Properties

Novel polyhydroxyesterimides were prepared by the reaction between diglycidyl monomers and diimidodiacids at the molar ratio 1/1 in the presence of triethylbenzylamonim chloride as catalyst. Diimidodiacids (DIMDA) were obtained from Diels-Alder adduct of resin acids with maleic anhydride and two aromatic diamines, at the molar ratio 1:2. The chemical reactions between the diglycidyl monomers (diglycidylether of bisphenol A -DGEBA and diglycidyl ether of hydroquinone–DGEHQ) and diimidodiacids were monitored by using differential scanning calorimetry (DSC). The chemical structures of the obtained monomers and polymers were established by means of elemental analysis, FT-IR, ¹H-NMR, and ¹³C-NMR methods. Thermal stability of the obtained polymers was also investigated and showed that they are reasonably thermostable.     

Shear strength of calabrian pine (Pinus brutia Ten.) bonded with polyurethane and polyvinyl acetate adhesives

In this study, the change in shear strength on radial and tangential surfaces of Calabrian pine (Pinus brutia Ten.) wood having different roughness values as the result of sawing with a circular ripsaw, planning, and sanding, and bonded with polyurethane (PU) and polyvinyl acetate (PVAc) adhesives at the pressure levels of 3, 6, and 9 kg f/cm² were studied. A total of 360 specimens of each, prepared with the objective of being able to determine the effect of the variables on bond performance, were subjected to the shear test in the universal test machine in accordance with the ASTM D 905–98 standard. The values obtained were analyzed statistically and the results were interpreted. The highest shear strength (11.83 N/mm²) for plane of cut was obtained on the tangential surface after sanding and applying PVAc adhesive with a pressing pressure of 9 kg f/cm². The lowest shear strength (6.01 N/mm²) was obtained in the joinings made on the planed surfaces by using PU adhesive and a pressing pressure of 3 kg f/cm². The highest shear strength (9.10 N/mm²) on the radial surface was obtained after sanding and applying PVAc adhesive and pressing with a pressure of 6 kg f/cm². The lowest shear strength (3.76 N/mm²) was obtained in the specimens whose surfaces were sanded and by using PU adhesive and with a pressing pressure of 3 kg f/cm². In general, in the radial surfaces, just like in the tangential surfaces, the specimens bonded with PVAc produced a higher shear strength compared to those glued with PU. According to these results, it is definitely necessary to sand the surfaces prior to the bonding process to have a higher shear strength. The bonding process should be made on the tangential surfaces with higher pressures. The PVAc adhesive should be preferred instead of the PU adhesive. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4856–4867, 2006     

A reactive acrylic adhesive for bonding polyolefins

An acrylic adhesive was developed for forming strong, water resistant structural joints with polyolefins. This two-component, lightly crosslinked, methyl methacrylate (MMA) based adhesive consisted of an anaerobic curing system in one part with a copper (II) salt catalyst in the other. Bonds formed with low density polyethylene (LDPE) resulted in substrate failure upon block shear testing throughout the open time of the adhesive (45 min). The interdiffusion of the monomers into the substrates, and their subsequent polymerization was followed using several infrared spectroscopy (IR) techniques. The interphase of mixed LDPE and adhesive was determined to be as thick as 1.7 mm using IR microscopy. It was concluded that the strong adhesion in the aforementioned joints was the result of the interpenetration of the adhesive into the substrates.