Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure: I.3-hydroxyneopentyl acrylate

The synthesis of new unsaturated monomers containing functional groups has been theoretically analyzed by considering a simple kinetic scheme. In the reactions between acetyl and acryloyl chloride with neopentylglycol, it was shown that the comparison between theoretical and experimental results, does not allow us to conclude that the two rate constants controlling the reactions are equivalent. Kinetic experiments of the polymerization of 3-hydroxyneopentyl acrylate were carried out in benzene and 1,4-dioxane solution at different temperatures. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. The values of $k_p /k_t^{1/2}$ for this monomer were found higher in dioxane than in benzene due, probably, to the fact that in the last solvent the polymerization is heterogeneous. The activation energy, determined by using different values of $k_p /k_t^{1/2}$ was found 7.6 kcal/mol. The stereostructure of the polymers derived from 3-hydroxyneopentyl acrylate and 3-acetoxyneopentyl acrylate was determined by ¹³C-NMR spectroscopy from the analysis of the resonance signals belonging to the carbonyl groups, obtaining values for the fraction of isotactic dyads in the range 0.36 ± 0.03 for both polymers. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were found 281 and 255 K, respectively. © 1994 John Wiley & Sons, Inc.     

Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure. II. 3-hydroxyneopentyl methacrylate

The synthesis of unsaturated monomers containing one or more hydroxyl groups by reaction between polyalcohols (number of OH, n≥2) and monoacid chlorides has been theoretically analyzed. The difficulties were shown involved in the preparation of these monomers with a high degree of purity even in the most favorable case of the completely substituted compound. The calculated mole fractions of the two monomers that can be obtained by reaction between neopentylglycol and methacryloyl chloride were compared with the experimental ones. Kinetic experiments of the polymerization of 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate were carried out at different temperatures in 1,4-dioxane for the former monomer and dioxane and absolute ethanol for the latter. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. In homogeneous solution the values of k_p/k^1/2_t for the 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate was determined by ¹³C-NMR spectroscopy and the molar fractions of tactic triads and dyads were calculated from different resonance signals. The polymers are predominantly syndiotactic and follow a Bernoullian distribution of tactic sequences. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were 145 and 89°C, respectively. © 1995 John Wiley & Sons, Inc.     

Radiation postpolymerization in devitrifying matrices: Different polymerization activity of acrylic and methacrylic monomers

Investigation of the effect of the α-CH₃-group on low-temperature postpolymerization in devitrifying matrices leads to the following conclusions. 1. The low-temperature postpolymerization in supercooled alcohol solutions (T_g ～ 102 K) is quite efficient with acrylic monomers. Inactivity of their methacrylic analogues under these conditions is attributed to steric screening of the unpaired electron in the growing radicals. 2. As the temperature is raised and the CH₃-group vibration intensity increases, the screening effect fades. Thus in devitrifying water-alcohol solutions of NaAA and NaMAA, at higher temperatures the postpolymerization is efficient in both cases. Data on copolymerization of NaAA and NaMAA indicate that at ～ 170 K the steric limitations due to the CH₃-group are eliminated. 3. In a glycerine matrix ($\text{T}{}_{\mathrm{g}}\text{? 195 K}$), all the acrylic and methacrylic monomers studied show efficient polymerization over virtually the same temperature range. It is concluded that the a-CH₃-group in methacrylic monomers appreciably affects their polymerization activity only at low temperatures, where steric screening of the growing polymer radical becomes important.     

Synthesis of new hybrid monomers and oligomers containing cationic and radical polymerizable vinyl groups and their photoinitiated polymerization

New hybrid vinyl monomers with both cationic- and radical-polymerizable vinyl groups were synthesized by the reaction of bis[1(chloromethyl)-2-(vinyloxy)ethyl]terephthalate ( 3 ) with unsaturated carboxylic acids using 1,8-diazabicyclo[5.4.0]-undecene-7 (DBU) as a base. The reaction of 3 with methacrylic acid 4a was carried out using DBU in DMSO at 70°C for 24 h to give an 86% yield of the hybrid vinyl monomer ( 5a ). Polycondensation of 3 with unsaturated dicarboxylic acids was also performed using DBU to give hybrid vinyl oligomers with radical polymerizable C (DOUBLE BOND) C groups (V_R) in the main chain and cationic polymerizable vinyl ether moieties (V_C) on the side chain. The photopolymerization of these hybrid vinyl compounds proceeded smoothly in bulk using either a cationic photoinitiator such as a sulfonium salt or a radical photoinitiator such as acyl phosphine oxide under UV irradiation. © 1996 John Wiley & Sons, Inc.     

Comparative study of mechanical and dielectric properties of glassy acrylic polymers containing 1,3-dioxane rings in their structures

A comparative study of mechanical and dielectric relaxation behaviour in the glassy region of some acrylic polymers containing 1,3-dioxane rings in the side chain is reported. Earlier results for similar polymers containing cycloaliphatic rings are used to interpret the results obtained. This study suggests that simple mechanisms based on chair-to-chair inverse conformational transitions are not able to explain in a unified way the responses of these polymers in the glassy region to mechanical and electric perturbation fields.     

Synthesis of di‐ and tri‐tertiary amine containing methacrylic monomers and their (co)polymerization via RAFT

The synthesis, reversible addition‐fragmentation chain transfer (RAFT) (co)polymerization, and aqueous phase behavior of three methacrylic monomers containing two or three pendent tertiary amine functional groups are described. Homopolymerizations were conducted with 1‐methyl‐1‐cyanoethyl dithiobenzoate (CPDB) under bulk conditions following standard RAFT procedures. All three monomers, 1,3‐bis(dimethylamino)propan‐2‐yl methacrylate ( M1 ), 1‐(bis(3‐(dimethylamino)propyl) amino)propan‐2‐yl methacrylate ( M2 ), and 2‐((2‐(2‐(dimethylamino)ethoxy)ethyl) methylamino)ethyl acrylate ( M3 ), polymerized in a controlled manner as evidenced by the kinetic and molecular weight profiles. Homopolymerizations conducted at a lower ratio of CPDB:AIBN proceeded faster than those at a higher ratio. Subsequently, the facile copolymerization behavior of M1 and M3 was demonstrated via the synthesis of a range of statistical copolymers with hexyl and lauryl methacrylate comonomers containing 10–90 mol % hydrophobic comonomer. Finally, the aqueous‐solution characteristics of the M1 – M3 homopolymers were briefly examined. All three homopolymers were shown to undergo phase transitions in aqueous media in response to changes in both temperature and pH. Specifically, 1 wt % solutions of poly M1 were shown to possess an LCST of ～22 °C, that of poly M2 at ～33 °C, and for poly M3 the observed cloud point was ～63 °C. Additionally, all homopolymers became hydrophobic and phase separated at high solution pH. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1877–1890, 2009     

Study of polymerization kinetics of acrylic and methacrylic acid esters at low conversions

The kinetics of high-energy radiation initiated polymerization of acrylate and methacrylate monomers were studied in dilute cyclohexane solutions. The absorption spectra of the intermediates were obtained by pulse radiolysis with optical detection. In solutions of acrylates at longer times after the pulse the presence of oligomer radicals was observed. In solutions of methacrylates the beginning of the oligomerization reaction was detected at higher monomer concentrations. From the kinetic curves the rate coefficients of termination were calculated.     

Synthesis of phosphorescent iridium-containing acrylic monomers and their room-temperature polymerization by Cu(0)-RDRP

A series of acrylic monomers based on cyclometalated iridium(III) complexes have been synthesized based on common phosphorescent emitters for organic light-emitting diodes. A simple room-temperature polymerization procedure for these materials was developed using Cu(0) reversible deactivation radical polymerization, providing polymers with low dispersities of 1.08–1.14 at conversions from 81 to 93% when the Ir complexes are copolymerized with a carbazole-based acrylic host. These methods were also found to be suitable for the preparation of high-molecular-weight polymers with M _n approaching 40,000 Da, as well as block copolymers formed in one pot from the chain extension of methyl acrylate. This scalable room-temperature synthesis of iridium-containing copolymers and block copolymers provides a useful route to optoelectronic materials, which we anticipate can be readily adapted to a broad range of acrylic metallopolymers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2539–2546     

Cationic polymerization of 2-vinyl-1,3-dioxane

The cationic polymerization of 2-vinyl-1,3-dioxane initiated with triethyloxonium tetrafluoroborate was studied with particular emphasis on elucidation of the structure of the polymer. The polymer was a light yellow powdery material with a molecular weight of several thousands which was soluble in most organic solvents. The infrared and NMR investigations on the polymer, together with chemical analyses, showed that the polymer consisted of the three structural units I, II, and III, the contents of which were estimated to be 5–10%, 20–25%, and 65–70%, respectively. The formation of the structural units I and II was discussed in detail.     

Preparation and polymerization of some vinyl monomers containing the 1,3-dioxolane group

The synthesis and structure determinations of (2,2-dimethyl-1,3-dioxolan-4-yl)-methyl acrylate, 4-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl itaconate, and [(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] methyl fumarate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization study of the effects of ultraviolet light and heat on these polymers and copolymers is presented. The 1,3-dioxolane group when appended to the polymer chain performs as an internal ultraviolet sensitizer. A mechanism is offered to explain the crosslinking behavior of these polymers when treated with ultraviolet light.     

Vinyl monomers bearing chromophore moieties and their polymers. XI. Synthesis and photochemical behavior of carbazole‐containing methacrylic monomers and their polymers

Three carbazole‐containing methacrylic monomers, 2‐(N‐carbazolyl)ethyl methacrylate(CzEMA), 6‐(N‐carbazolyl)hexyl methacrylate(CzHMA), and 11‐(N‐carbazolyl)undecyl methacrylate (CzUMA), and their saturated model compounds, 2‐(N‐carbazolyl)ethyl isobutyrate, 6‐(N‐carbazolyl)hexyl isobutyrate, and 11‐(N‐carbazolyl)undecyl isobutyrate, were synthesized and polymerized. UV absorption spectra showed that there was either negligible or no interaction between the carbon–carbon double bond of the methacrylic group and the carbazolyl chromophore moiety in the ground state for these monomers. Fluorescence spectra of the monomers, their model compounds, and the polymers were recorded in the solvents with different polarities. CzEMA exhibited the fluorescence structural self‐quenching effect (SSQE), but CzHMA and CzUMA did not. In addition, the SSQE of CzEMA depended strongly on the polarity of the solvents. That is, the stronger the polarity of a solvent was, the more obvious the SSQE was. Therefore, the SSQE of CzEMA mainly was caused by the intramolecular charge‐transfer interaction between the excited electron‐donating carbazolyl chromophore moiety and the electron‐accepting carbon–carbon double bond of the methacrylic group. This was confirmed by the fluorescence‐decay curves and the fluorescence lifetimes of the monomers, their model compounds, and the polymers. The monomers, their model compounds, and the polymers initiated the photopolymerization of methyl methacrylate (MMA) upon UV irradiation. CzEMA showed greater initiation ability than the other two monomers and their model compounds; this was ascribed to the photoinduced intramolecular charge‐transfer interaction. The higher initiation efficiency of the homopolymers compared to that of the copolymers with MMA was interpreted as the result of singlet energy migration of the excited carbazolyl chromophores along the polymer chains. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 679–688, 2000     

Bis(fluoroalkyl)acrylic and methacrylic phosphate monomers, their polymers and some of their properties

Ten fluoromonomers of structure (R_FO)₂P(O)OCH₂CH₂OC(O)CRCH₂ were made in 30-64% yield by treating the chloridates (R_FO)₂P(O)Cl with HOCH₂CH₂OC(O)CRCH₂ in chloroform in the presence of triethylamine [R_F=CF₃CH₂, C₂F₅CH₂, C₃F₇CH₂, C₄F₉CH₂, C₄F₉CH₂CH₂ or C₆F₁₃CH₂CH₂; R  H or Me]. The chloromonomer (CCl₃CH₂O)₂P(O)OCH₂CH₂OC(O)CHCH₂ was obtained analogously in 29% yield. Polymerisation of the acrylate monomers, but not the methacrylate monomers, could be effected using α-azoisobutyronitrile as a radical initiator. Acrylic polymers having CF₃CH₂O, CCl₃CH₂O and C₆F₁₃CH₂CH₂O side-chains were obtained as translucent rubbers. Specimens of cotton fabric were treated with solutions of the polymers, and average water and oil repellency ratings measured. Fabric coated with the polymer with the C₆F₁₃CH₂CH₂O side-chain afforded protection from penetration of the test liquids. Treated fabrics were subjected to the limiting oxygen index (LOI) test according to BS EN ISO 4589-2 (1999): this test determines the point at which a material just burns in a volumetric flow of oxygen and nitrogen. The treated fabrics were more fire-resistant (LOI 22-29%) than the untreated fabric (LOI 18%). Fabric coated with the CCl₃CH₂O-based polymer can be considered fire-retardant (LOI 29%). The fluoromonomers were tested for anti-acetylcholinesterase activity and were found to be poor enzyme inhibitors; they are predicted to possess low acute toxicity.     

Stereocontrol in radical polymerization of acrylic monomers

A clear effect of Lewis acids, such. as scandium trifluoromethanesulfonate [Sc(OTf)₃], on stereocontrol during the radical polymerization of a designed monomer, benzyl α-(methoxymethyl)acrylate was found. This Lewis acid also influenced the stereochemistry in the radical polymerization of methyl methacrylate giving a less syndiotactic and more isotactic polymer, although many Lewis acids were not effective. A catalytic amount of Lewis acids, such as Y(OTf)₃ and Yb(OTf)₃, also significantly enhanced isotactic-specificity during the radical polymerization of acrylamide and its derivatives, N-isopropylacrylamide (NIPAM) and N,N-dimethylacrylamide. Obvious solvent and temperature effects on tacticity were observed in these polymerizations, and poly(NIPAM) with >80% triad isotactic content has been obtained in the presence of Lewis acids.     

Synthesis of phosphorus‐containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Divinyl ether monomers containing phosphorous residues were synthesized by the addition reaction of glycidyl vinyl ether (GVE) with various phosphonic dichlorides or dichlorophosphates with quaternary onium salts as catalysts. The reaction of GVE with phenylphosphonic dichloride gave bis[1‐(chloromethyl)‐2‐(vinyloxy)ethyl]phenylphosphonate ( 1a ) in a 77% yield. The polycondensation of 1a with terephthalic acid was also carried out with 1,8‐diazabicyclo[5.4.0]undecene‐7 (DBU) as a condensing agent to afford the corresponding phosphorus‐containing polyester. A multifunctional monomer containing both vinyl ether groups and methacrylate groups was prepared by the reaction of 1a with methacrylic acid with DBU. The photoinitiated cationic polymerization of these vinyl ether compounds proceeded rapidly with bis[4‐(diphenylsulfonio)phenyl]sulfide‐bishexafluorophosphate as the cationic photoinitiator without a solvent upon ultraviolet irradiation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2031–2042, 2004     

Kinetic behavior in free-radical polymerization of isomer methacrylic monomers with active functional groups as side substituents

The kinetic behavior of the free-radical polymerization of 2-hydroxy-4-N-methacrylamidobenzoic acid (4-HMA) and 2-hydroxy-5-N-methacrylamidobenzoic acid (5-HMA) in a solution of N,N-dimethylformamide is described. The methacrylic monomers 4-HMA and 5-HMA were isomers in which the phenolic and carboxylic functional groups were in different positions on the side aromatic ring with respect to the methacrylamide group. Semiempirical (AM1 and PM3 treatments) and ab initio (6-31G**) quantum mechanical calculations indicated the existence of intramolecular H-bonding between the phenolic and carboxylic groups. These calculations also indicated a slightly higher reactivity of 4-HMA with respect to 5-HMA under the same experimental conditions as obtained from the frontier orbital interactions between the highest molecular orbital of the monomers and the singly occupied molecular orbital of the radical obtained by the reaction of a methyl radical with the corresponding monomer. Gravimetric study of the free-radical polymerization of 4-HMA and 5-HMA at several temperatures ranging from 50 to 150 °C demonstrated this behavior. The kinetic results obtained and the average molecular weights of the polymers prepared at different temperatures indicated that the monomer 4-HMA had a slightly higher reactivity at low temperatures (50–90 °C), whereas at higher temperatures (120–150 °C), the reactivity of both monomers became similar as a consequence of the “dead-end” radical polymerization. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4528–4535, 1999     

Polymerization of asymmetric polyfunctional monomers. III. Ionic polymerization of acrylic and methacrylic esters of 2-allylphenol

The polymerization of acrylic and methacrylic esters of 2-allyphenol with different anionic, cationic and coordination catalysts was studied. The polymerization occurs exclusively or predominantly through (meth)acrylic C?C double bonds in all the studied cases. With anionic catalysts the allylic groups are not polymerizable and the polymers have linear structure. Polymerization with catalysts based on dialkylaluminum chloride (alone or associated with some metal salts) yields soluble or partially crosslinked polymers, depending on the reaction conditions. The crosslinking is due to the participation of allylic groups in the polymerization reactions. Copolymers of acrylic and methacrylic esters of 2-allylphenol with styrene, acrylonitrile, methyl methacrylate, N-vinylcarbazole and 1,3-pentadiene were synthesized by copolymerization in the presence of anionic catalysts and of systems based on dialkylaluminum chloride.     

Synthesis and cationic photopolymerization of electroactive monomers containing functional groups

The synthesis and cationic photopolymerization of different cationically polymerizable monomers containing electroactive groups are reviewed with 98 references. The preparation of various compounds containing electron‐donor or electron‐acceptor moieties and photopolymerizable functional groups is described. After a short discussion of basic principles of cationic polymerization, photoinduced cationic polymerizations of various cationically polymerizable monomers containing both electron‐donor or electron‐acceptor chromophores and the functional groups such as epoxy, vinyl, thiiranyl, oxetanyl and others are reviewed. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and polymerization of various vinyl-type monomers containing the pyrrole ring

Vinyl-type monomers containing the pyrrole ring, such as 2-vinylpyrrole (2-VPyrr), N-(pyrrol-2-yl)methylacrylamide (PMA), N-methyl, N-(pyrrol-2-yl)methylacrylamide (MPMA), 2-allylpyrrole (2-AP), β-(pyrrol-1-yl)ethyl vinyl ether (PEVE), 2-diallyl-aminomethylpyrrole (DAMP), and 3-(2-pyrrolylmethyleneimino)propene-1 (PIP) were synthesized by various reactions involving characteristic properties of the pyrrole ring. Radical homopolymerizations and copolymerizations of these monomers were studied. In the homopolymerization of conjugated monomers such as 2-VPyrr and PMA, chain transfer to the pyrrole-containing monomer was remarkable but not degradative. The copolymerization parameters, that is, the values of r₁, r₂, Q₁, and e₁ of 2-VPyrr, were determined to be 0.066, 0.69, 5.53, and ?1.36, respectively in the copolymerization of 2-VPyrr (M₁) with MMA (M₂). The Q and e values of the monomers containing a heteroaromatic ring such as 2-vinylpyrrole, 2-vinylfuran, and 2-vinylthiophene were evaluated by the molecular orbital theory. The e value of PMA was found to be negative (?0.64) in the copolymerization with styrene, although e for acrylamide derivatives is generally positive. This may be explained by the intermolecular hydrogen bonding between the carbonyl group and NH group of PMA. That is, attraction or polarization of π-electrons in the vinyl group of PMA is weakened by such hydrogen bonding. From the results of copolymerization of 2-AP with various comonomers, the comonomers could be classified into three categories: class a monomers, in which both Q and e values are largely positive, can copolymerize with 2-AP; class b monomers, having small e values, homopolymerize and can not copolymerize with 2-AP; class c monomers, in which both Q and e values are small. The Q and e values of the comonomer must be largely positive in order to permit copolymerization with an allyl-type monomer.     

Synthesis,structure and properties of new chiral liquid crystalline monomers and homopolysiloxanes containing menthyl groups

The synthesis is described of four new chiral liquid crystalline monomers (M₂–M₅ ) and their corresponding side‐chain homopolysiloxanes (P₂–P₅ ) containing menthyl groups. Chemical structures were characterised using FT‐IR or ¹H NMR spectra, and specific optical rotations were evaluated with a polarimeter. The phase behaviour and mesomorphic properties of the new compounds were investigated by differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy, UV/visible/NIR spectrocopy and X‐ray diffraction. The monomers and homopolymers with more aryl segments showed noticeably lower specific optical rotation value. The monomers M₂–M₅ formed a cholesteric or blue phase when a flexible spacer was inserted between the rigid mesogenic core and the terminal menthyl groups by reducing the steric effect. M₂–M₅ revealed enantiotropic cholesteric phase. Moreover, M₂ also exhibited a monotropic smectic A (SmA) phase, and M₄ also exhibited a cubic blue phase on cooling. The selective reflection of light shifted to the long wavelength region with increasing rigidity of the mesogenic core for M₂–M₅ . P₂–P₅ exhibited SmA phases, and the mesogenic moieties were ordered in smectic orientation with their centres of gravity in planes. Melting or glass transition temperature and the clearing temperature increased, and the mesophase temperature range widened with increasing rigidity of the mesogenic core.