Kinetic studies on light-induced cationic ring-opening reactions on 2,3-epoxypropyl phenyl ether

Light-induced cationic ring-opening reactions of 2,3-epoxypropyl phenyl ether (phenyl glycidyl ether, PGE) in acetone, methanol and bulk were studied. Cations are produced by electron transfer from excited sensitizers (anthracene, An; 9,10-phenanthrenequinone, PQ; benzophenone, BP) or from photolytically cleaved sensitizer (benzoin isoproyl ether, BIPE) to diphenyliodonium hexafluorophosphate. With excess of acetone and methanol, addition reactions take place resulting in 2,2-dimethyl-4-phenoxymethyl-1,3-dioxolane and 1-methoxy-3-phenoxy propan-2-ol as main products. The efficiency of the sensitizers taken from the quantum yields of PGE conversion, follows the order An ? BIPE > PQ > BP in acetone and An ～ BP > BIPE ? PQ in methanol. Unlike bulk polymerization, in these addition reactions no steady-state concentration of cations exists and the reaction accelerates with time. When alcohol is added in only small proportions, the initial addition reactions goes over into a linear oligomerization. The relatively higher basicity of methanol over PGE influences the nature of the active center, and the course of reaction depends on methanol concentration. Kinetic expressions, which account for all possible types of active centers, have been derived to express the rate of PGE reactions in methanol.     

Development of reactive methacrylates based on glycidyl methacrylate

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‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy)phenyl]propane (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. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3787–3796, 2010     

New thermo-crosslinking reactions of polymers containing pendant epoxide groups with various polyfunctional active esters

New thermo-crosslinking reactions of poly(glycidyl methacrylate), copolymers of glycidyl methacrylate with methyl methacrylate, styrene or ethyl acrlate with various active esters such as di[S-(2-benzothiazoly)] thioadipate (BTAD), di(S-phenyl) thioadipate (PTAD), di(4-nitrophenyl) adipate (NPAD), diphenyl adipate (PAD), and di(S-phenyl) thioisophthalate (PTIP), and other polyfunctional esters were carried out in the film state using various catalysts such as quarternary ammonium or phosphonium salts, tert amines, or the crown ether 18-crown-6 = potassium salts system. Addition reactions of pendant epoxide groups in the polymer with the active esters such as NPAD and PTAD proceeded selectively to give gel compounds without other side reactions. The rates of reaction with the thioesters such as BTAD and PTAD were relatively faster than those with the phenyl esters such as PAD and NPAD at 70°C. The rates of reactions with the esters having flexible segments such as PTAD were also faster than those with the esters having rigid skeletons such as PTIP. Furthermore, it was found that the rate of reaction was affected strongly by reaction temperature, catalyst concentration, length of alkyl chain in the catalyst, kind of counterion of quarternary ammonium salts as a catalyst, content of pendant epoxide groups in the polymer, and kind of copolymer unit in the polymer, respectively.     

Synthesis and photopolymerizations of new phosphonated monomers for dental applications

Three novel phosphonated methacrylate monomers have been synthesized and studied for use in dental applications. Two of the monomers were synthesized from the reactions of glycidyl methacrylate (GMA) with (diethoxy‐phosphoryl)‐acetic acid (monomer 1 ) and (2‐hydroxy‐ethyl)‐phosphonic acid dimethyl ester (monomer 2 ). These monomers showed high crosslinking tendencies during thermal bulk and solution polymerizations. The third monomer (monomer 3 ) was prepared by the reaction of bisphenol A diglycidylether (DER) with (diethoxy‐phosphoryl)‐acetic acid and subsequent conversion of the resulting diol to the methacrylate with methacryloyl chloride. The homopolymerization and copolymerization behaviors of the synthesized monomers were also investigated with glycerol dimethacrylate (GDMA), triethylene glycol dimethacrylate (TEGDMA), and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane (bis‐GMA) using photodifferential scanning calorimetry at 40 °C using 2,2′‐dimethoxy‐2‐phenyl acetophenone (DMPA) as photoinitiator. Monomer 1 showed polymerization rate similar or greater than dimethacrylates studied here but with higher conversion. The maximum rate of polymerizations decreased in the following order: 1 ～TEGDMA>GDMA～bis‐GMA～ 3 > 2 . A synergistic effect in the rate of polymerization was observed during copolymerizations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2290–2299, 2008     

Oligomerization of Substituted Phenyl Glycidyl Ethers with Tertiary Amine

The oligomerization of substituted phenyl glycidyl ethers was studied kinetically in the presence of dimethylbenzylamine using toluene or dioxane as a solvent. The infrared spectra of the resultant oligomers suggest that the reaction products have the internal carbon-carbon double-bond un-saturation, which is confirmed by the catalytic hydrogenation. The molecular weights of the oligomers also suggest that γ-phenoxy allyl alcohol produced by the initial reaction step, in which the γ-proton of phenyl glycidyl ether is attracted by a base, amine, reacts with other phenyl glycidyl ether and thus proceeds further, yielding the oligomer. The value of the reaction constant ρ is obtained positive for this reaction, which indicates that electron-withdrawing substituents of phenyl gylcidyl ethers increase the rate of oligomerization. A kinetic analysis shows that the proposed reaction sequence accounts for all the characteristics of the polymerization including sigmoidal shapes of monomer consumption curves, reaction rates, and induction periods.     

A novel insertion reaction of epoxy compounds into phenyl ester linkages in polymer chains

The insertion reaction of various epoxy compounds such as phenyl glycidyl ether (PGE), methyl glycidyl ether, butyl glycidyl ether (BGE), and styrene oxide into the phenyl ester linkage in the polymer chain was investigated using quaternary ammonium salts as catalysts in diglyme, anisole, sulfolane, o-dichlorobenzene, or DMSO at 100–150°C. The reaction of PGE with poly[4-(4-nitrobenzoyloxy)styrene] (polymer 1a ) proceeded almost quantitatively to give the corresponding polymer using tetrabutylammonium bromide (TBAB) as catalyst in diglyme at 100°C for 24 h. The reactions of BGE with poly(4-nitrophenyl methacrylate), and copolyarylate derived from 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane and iso- and terephthaloyl chlorides also produced the corresponding polymers with 86 and 89 mol% new structural units, respectively, using TBAB in sulfolane at 150°C for 24 h. Furthermore, it was found that the degree of insertion of the epoxy compound into the ester linkage in the polymer chain was affected by the kind of epoxy compound, reaction solvent, catalyst concentration, substituent group on the phenyl ester, and structure of the polymer. Chiral polymers were also synthesized with high degrees of insertion by the reaction of chiral epoxides such as (R)-1,2-epoxyhexane, (R)-1,2-epoxyheptane, and (R)-1,2-epoxydecane with polymer 1a and poly(2,4-dichlorophenyl methacrylate) using TBAB in diglyme at 120°C for 24 h.     

Synthesis and characterization of dimethacrylate monomer with high molecular weight for root canal filling materials

A new dimethacrylate monomer 9,9'-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl] fluorene (3) with a molecular weight of 634 was synthesized in 51.4% yield by addition of a glycidyl ether group to 9,9'-bis(4-hydroxyphenyl) fluorene (1) by the reaction of compound 1 with epichlorohydrin, and then introducing the methacrylate moiety by the reaction of the epoxy group with methacrylic acid. The structure of monomer 3 was confirmed by FT-IR, (1)H-NMR, mass spectra and elemental analysis.     

Photochemical addition reaction of a polymer-bearing pendant vinyl ether with various thiol compounds

Photochemical addition reaction of the pendant vinyl ether group in the polymer ( P-1 ), which was synthesized by the alternate ring-opening copolymerization of glycidyl vinyl ether with phthalic anhydride, with various thiol compounds such as benzenethiol, phenylmethanethiol, 2-mercaptoacetic acid, ethyl 2-mercaptoacetate, N-acetyl-L -cysteine (AcCys), and 1,4-phenylenedi(methylthiol) was carried out using benzophenone (BP) as the photosensitizer in the THF solution. Each reaction proceeded very smoothly to give the corresponding polymers with high conversion, although the degree of reaction of the pendant vinyl ether group in P-1 was affected by the molar ratio between the thiol compounds and the vinyl ether group, and the amounts of photosensitizer BP added. Furthermore, it was also found that optically active polymer containing pendant N-acetyl-L -cysteine residue was synthesized by the photochemical addition reaction of P-1 with AcCys. The reactions of P-1 with dithiol or bisazide compounds occurred effectively to give gel products in the film state, and it was found that the polymer film containing P-1 and those compounds can be applied as negative-type photoresists with high practical photosensitivity. © 1993 John Wiley & Sons, Inc.     

Hydroxyl Functionalized Uniform‐Porous Beads,Synthesis and Chromatographic Use

Uniform‐porous poly(dihydroxypropyl methacrylate‐co‐ethylene dimethacrylate), poly(DHPM‐co‐EDM) particles were synthesized as an alternative packing material for reversed phase chromatography. In the synthesis, poly(glycidyl methacrylate‐ethylene dimethacrylate), poly(GMA‐co‐EDM) particles were obtained by a multi‐stage swelling and polymerization protocol, the so called “modified seeded polymerization”. For this purpose, 2.4 µm polystyrene seed particles were first swollen by dibutyl phthalate (DBP) and then by a monomer mixture including glycidyl methacrylate and ethylene dimethacrylate. The repolymerization of monomer phase in the swollen seed particles provided porous uniform particles approximately 7 µm in size. Poly(DHPM‐co‐EDM) particles were obtained by the acid hydrolysis of the particles synthesized with different GMA feed concentrations. These particles were used as column‐packing material in the reversed phase separation of alkylbenzenes. The retention factor‐acetonitrile concentration diagrams clearly showed that the polarity of packing material could be controlled by changing the GMA feed concentration in the “modified seeded polymerization”. The packing materials with more hydrophobic character (i.e., poly(EDM) and poly(DHPM‐co‐EDM) particles produced with the GMA feed concentrations up to 20%) exhibited better chromatographic performance in the reversed phase mode.     

Graft copolymers having hydrophobic backbone and hydrophilic branches. III. Synthesis of graft copolymers having oligovinylpyrrolidone as hydrophilic branch

Graft copolymers were synthesized by the esterification reaction between acrylic copolymers and carboxyl group terminated vinylpyrrolidone oligomer using phase transfer catalysts. Acrylic copolymers were obtained by the radical copolymerization of β-bromoethyl methacrylate, chloromethylstyrene or glycidyl methacrylate with methyl methacrylate. Hydrophilic oligomers were prepared by the radical oligomerization of vinylpyrrolidone using β-mercaptopropionic acid as chain transfer agent. The degree of esterification increased with decreasing the molecular weight of oligomer and with increasing the number of potential grafting sites on polymer backbones. The water dispersibility of graft copolymers increased with increasing the nitrogen content and was therefore dependent on the branch oligomer content.     

Synthesis of silicon-containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Silicon-containing divinyl ether monomers were synthesized by the addition reaction of glycidyl vinyl ether ( 1 ) with various silyl dichlorides using tetra-n-butylammonium bromide (TBAB) as a catalyst. The reaction of 1 with diphenyl dichlorosilane gave bis-[1-(chloromethyl)-2-(vinyloxy)-ethyl]diphenyl silane ( 3a ) in 89% yield. Polycondensations of 3a with terephthalic acid were also carried out using 1,8-Diazabicyclo[5.4.0]-7-undecene (DBU) to afford silicon-containing polyfunctional vinyl ether oligomers ( 5 ). A multifunctional Si-monomer with both vinyl ether and methacrylate groups ( 7 ) was prepared by the reaction of 3a with potassium methacrylate using TBAB as a phase transfer catalyst. Photoinitiated cationic polymerizations of these vinyl ether compounds proceeded rapidly using the sulfonium salt, bis-[4-(diphenyl-sulfonio)phenyl]sulfide-bis-hexafluorophoshate (DPSP), as the cationic photoinitiator in neat mixtures upon UV irradiation. Multifunctional monomer 7 with both vinyl ether and methacrylate groups showed “hybrid curing properties” using both DPSP and the radical photoinitiator, 2,4,6-trimethylbenzoyl diphenylphoshine oxide (TPO). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3217–3225, 1997     

Metal-free synthesis of reactive oligomers by ring-opening oligomerization of glycidyl phenyl ether initiated with tetra-n-butylammonium fluoride in the presence of various protic compounds

Metal-free ring-opening oligomerizations of glycidyl phenyl ether (GPE) were performed with tetra-n-butylammonium fluoride (n-Bu₄NF) as an initiator in the presence of protic compounds (RHs) as chain transfer agents (CTAs). The RHs having pKa between 4.66 and 15.5 enabled to serve as the CTA in this oligomerization system, leading to reactive oligomers with relatively controlled molecular weights having narrow molecular weight distributions bearing functional groups such as alkene, benzyl ether, alkyne, ester and methacrylate groups at initiating end.     

Novel functional copolymers based on glycidyl methacrylate: Synthesis,characterization, and polymerization kinetics

A new methacrylate monomer 2-(4-nitrophenyl)-2-oxoethyl-2-methacrylate (NFM) was synthesized and its radical copolymerization with glycidyl methacrylate (GMA) was studied in 1,4-dioxane solution at 65°C using 2,2′-azobisisobutyronitrile as an initiator. The synthesized monomer and copolymers were characterized by FTIR, ¹H and ¹³C-NMR spectroscopy. The analysis of reactivity ratios revealed that NFM is less reactive than GMA, and copolymers formed are statistically in nature. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increasing in the mole fraction of NFM in the copolymers. Glass transition temperatures of the copolymers decreased with an increasing of NFM molar fraction in copolymers. In addition, according to the results obtained from the contact angle and zeta potential measurements the hydrophobic character of the polymer decreases (it means surface free energy increases) and its zeta potential becomes more negative with increase of NFM ratio in the copolymer. Polymers with carbonyl functional groups have been particularly interesting because of their use as photoresists.     

Preparation of methyl methacrylate and glycidyl methacrylate copolymerized nonporous particles

Particles of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) copolymer having narrow size distributions were prepared by the method of dispersion polymerization. Results from the analysis of particle porosity and the correlation of specific surface area with the reciprocal of particle diameter suggest that the prepared particles were nonporous. The particle size was found to decrease from 4.2 to 2.1 μm with increasing the mass ratio of GMA/MMA from 0.1 to 0.75. Polymer particles having an average diameter falling in this range are suitable for being employed as the stationary phase in protein chromatography. The decrease in particle size when GMA was present could be due to the increase in adsorption rate of poly(vinyl pyrrolidone). The oligomer chains that were rich in GMA were more active for adsorbing and grafting PVP, compared with the moiety of MMA. An increase in the GMA/MMA ratio also leaded to a decrease in epoxy‐group density on the particle surface, since the reactivity of GMA was greater than that of MMA. Results of this work suggest that the influence of GMA/MMA mass ratio on the particle size and surface functionality of the nonporous particles was very significant. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1457–1463, 1999     

Synthesis of well‐defined glycidyl methacrylate based block copolymers with self‐activation and self‐initiation behaviors via ambient temperature atom transfer radical polymerization

Well‐defined glycidyl methacrylate (GMA) based di‐ and triblock copolymers, with self‐activation and self‐initiation behaviors by incorporation of 2‐(diethylamino) ethyl methacrylate (DEA) blocks, were synthesized via ambient temperature atom transfer radical polymerization (ATRP). The stability of the GMA pendant oxirane rings in tertiary amine environments at ambient temperature was investigated. More importantly, both self‐activation behavior in oxirane ring opening addition reaction and self‐initiation behavior in post‐cure oxirane ring opening crosslinking of these block copolymers were evidenced by ¹H NMR studies. The results demonstrated that the reactivity of pendent oxirane rings was strongly dependant on the nucleophilicity and steric hindrance of tertiary amine moieties and temperature. This facilitated the synthesis of well‐defined block copolymers of GMA and DEA via sequential monomer addition ATRP, particularly for polymerization of GMA monomer at ambient temperature. Moreover, these one‐component GMA based block polymers have novel self‐activation and self‐initiation properties, rendering some potential applications in both enzyme immobilization and GMA‐based thermosetting materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2947–2958, 2007     

Methacrylate-based monolithic layers for planar chromatography of polymers

A series of macroporous monolithic methacrylate-based materials was synthesized by in situ free radical UV-initiated copolymerization of functional monomers, such as glycidyl methacrylate (GMA), butyl methacrylate (BuMA), 2-aminoethyl methacrylate (AEMA), 2-hydroxyethyl methacrylate (HEMA) and 2-cyanoethyl methacrylate (CEMA), with crosslinking agent, namely, ethylene glycol dimethacrylate (EDMA). The materials obtained were applied as the stationary phases in simple and robust technique - planar chromatography (PLC). The method of separation layer fabrication representing macroporous polymer monolith bound to the specially prepared glass surface was developed and optimized. The GMA-EDMA and BuMA-EDMA matrixes were successfully applied for the separation of low molecular weight compounds (the mixture of several dies), as well as poly(vinylpyrrolidone) and polystyrene homopolymers of different molecular weights using reversed-phase mechanism. The materials based on copolymers AEMA-HEMA-EDMA and CEMA-HEMA-EDMA were used for normal-phase PLC separation of 2,4-dinitrophenyl amino acids and polystyrene standards.     

甲基丙烯酸缩水甘油酯与甲基丙烯酸甲酯的共聚合及竞聚率测定

以N,N-二甲基甲酰胺(DMF)为溶剂,实施了甲基丙烯酸缩水甘油酯(GMA)与甲基丙烯酸甲酯(MMA)的溶液共聚合,测定了共聚物P(GMA-co-MMA)的红外光谱(FT-IR),对其化学结构进行了表征,并采用差示扫描量热法(DSC)测定了共聚物的玻璃化转变温度(Tg).改变两单体投料比进行共聚合,采用化学分析法测定低转化率下(<7%)共聚物组成,重点研究了两单体的竞聚率.结果表明:GMA与MMA的共聚合易于进行,P(GMA-co-MMA)的玻璃化转变温度(Tg)介于均聚物PGMA(72℃)与PMMA(106℃)之间,当n(GMA)/n(MMA)=4/6时,共聚物的Tg为9l℃.采用FR和KT 2种作图法及YBR计算法对单体的竞聚率进行了计算和比较,结果表明:KT和YBR法较为准确,以DMF为溶剂时,GMA与MMA的竞聚率分别为2.14与0.69.     

在聚合物微球 GMA/MMA 表面同步合成与固载卟啉及固载化金属卟啉的催化氧化性能

 制备了甲基丙烯酸缩水甘油酯 (GMA) 与甲基丙烯酸甲酯 (MMA) 共聚微球 GMA/MMA, 并通过键合有对羟基苯甲醛 (HBA) 的改性微球 HBA-GMA/MMA 与苯甲醛 (或取代苯甲醛) 以及吡咯间的 Adler 反应, 实现了卟啉在共聚微球 GMA/MMA 表面的同步合成与固载, 制得了固载有苯基卟啉 (PP)、对氯苯基卟啉 (CPP)、对硝基苯基卟啉 (NPP) 的功能化微球 PP-GMA/MMA, CPP-GMA/MMA 和 NPP-GMA/MMA. 重点考察了影响卟啉同步合成与固载过程的因素. 制备了固载有钴卟啉的催化剂, 并以分子氧氧化乙苯为模型反应, 考察了催化剂的活性. 结果表明, 苯甲醛取代基的结构、催化剂的酸性和溶剂的极性对卟啉的同步合成与固载都有较大的影响; 钴卟啉催化剂对分子氧氧化乙苯反应具有较高的催化活性, 且当钴卟啉外环上含有强吸电子基团硝基时, 催化剂活性最高.     

Coffee Beverage: A New Strategy for the Synthesis of Polymethacrylates via ATRP

Coffee, the most popular beverage in the 21st century society, was tested as a reaction environment for activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) without an additional reducing agent. Two blends were selected: pure Arabica beans and a proportional blend of Arabica and Robusta beans. The use of the solution received from the mixture with Robusta obtained a high molecular weight polymer product in a short time while maintaining a controlled structure of the synthesized product. Various monomers with hydrophilic characteristics, i.e., 2-(dimethylamino)ethyl methacrylate (DMAEMA), oligo(ethylene glycol) methyl ether methacrylate (OEGMA₅₀₀), and glycidyl methacrylate (GMA), were polymerized. The proposed concept was carried out at different concentrations of coffee grounds, followed by the determination of the molar concentration of caffeine in applied beverages using DPV and HPLC techniques.     

聚-4-氧杂-6,7-双二苯膦基庚基硅氧烷铑配合物的合成及其催化硅氢化性能

4-氧杂-6,7-二氯庚基三甲氧基硅烷依次与二苯膦钾、气相法二氧化硅、三氯化铑作用,合成了聚-4-氧杂-6,7-双二苯膦基庚基硅氧烷铑配合物。它对烯烃与取代烯烃的硅氢化反应具有良好的催化活性。