Synthesis and copolymerisation of fluorinated monomers bearing a reactive lateral group : Part 21. Radical copolymerisation of vinylidene fluoride with 2-hydroperfluorooct-1-ene

The synthesis and the radical copolymerisation of 2-hydroperfluorooct-1-ene (HPO) with vinylidene fluoride (VDF), initiated by tertio-butyl peroxypivalate (TBPPI) at 75 °C, are presented. That fluorinated alkene (HPO) was synthesised in two steps starting from the thermal or redox telomerisation of VDF with C₆F₁₃I (after purification of the monoadduct compound by rectification) followed by a dehydroiodination in the presence of various alkalies. Their influences are discussed toward the yield of the reaction. The compositions of the resulting random-type copolymers were calculated by means of ¹⁹F NMR spectroscopy and allowed one to quantify the respective amounts of each monomeric unit in the copolymer. From the Tidwell and Mortimer method, the reactivity ratios (r_i) of both comonomers for this copolymerisation were determined showing a higher incorporation of VDF: r_VDF = 12.0 ± 3.0 and rF₂CCHC₆F13=0.9±0.4 at 74 °C.     

Radical solution copolymerisation of vinylidene fluoride with hexafluoropropene

The radical copolymerisation in solution of vinylidene fluoride (or 1,1-difluoroethylene (VDF)) with hexafluoropropylene (HFP) initiated by di-tert-butyl peroxide is presented. A series of eight copolymerisation reactions was investigated with initial [VDF]_o/[HFP]_o molar ratios ranging from 5.0/95.0 to 85.2/14.8. Both co-monomers copolymerised in this range of copolymerisation. Moreover, only VDF homopolymerised in these conditions. The copolymer compositions of these random-type copolymers were calculated by means of ¹⁹F NMR spectroscopy which allowed the respective amount of each monomeric unit in the copolymer to be quantified. The Tidwell and Mortimer method led to the assessment of the reactivity ratios, r_i, of both co-monomers showing a higher incorporation of VDF in the copolymer (r_HFP = 0.12 ± 0.05 and r_VDF = 2.9 ± 0.6 at 393 K). Alfrey-Price's Q and e values of HFP were calculated to be 0.002 (from Q_VDF = 0.008) or 0.009 (from Q_VDF = 0.015) and +1.44 (versus e_VDF = 0.40) or +1.54 (versus e_VDF = 0.50), respectively, indicating that HFP is an electron-accepting monomer. The thermal properties of these fluorinated copolymers were also determined. Except for those containing a high amount of VDF, they were amorphous. Each showed one glass transition temperature (T_g) only, and from known laws of T_g, that of the homopolymer of HFP was assessed. It was compared with that obtained from the literature after extrapolation and is discussed.     

Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group 13. Copolymerization of vinylidene fluoride with 2-benzoyloxypentafluoropropene

The synthesis of 2-benzoyloxypentafluoropropene (BPFP) and its radical copolymerization with vinylidene fluoride (VDF), initiated by tert-butyl peroxypivalate is presented. In a first step, the preparation of two monomers [F₂CC(CF₃)OCOR were R stands for CH₃ or C₆H₅] was attempted. In contrast to the acetoxy derivative that could not be isolated, the benzoyl monomer was purified and then copolymerized with VDF. A series of 11 copolymerization reactions was achieved starting from initial [VDF]₀/([BPFP]₀+[VDF]₀) molar ratios ranging from 19 to 99 mol%. The molar compositions of the obtained copolymers were assessed by means of ¹⁹F nuclear magnetic resonance spectroscopy. From the Tidwell and Mortimer method, this kinetics of copolymerization led to the determination of the reactivity ratios, r_i, of both comonomers (r_VDF=0.77±0.40 and r_BPFP=0.11±0.32). Hence, the Alfrey and Price equation enabled one to assess the Q and e parameters of BPFP as follows: 0.019 (from Q_VDF=0.008), 0.043 (from Q_VDF=0.015) or 0.182 (from Q_VDF=0.036) and 1.97 (vs e_VDF=0.40), 2.07 (vs e_VDF=0.50) or 2.77 (vs e_VDF=1.20), respectively. These Q-e parameters and r_i were compared to those of other fluoroalkenes and are discussed.     

Radical copolymerization of vinylidene fluoride with 1‐bromo‐2,2‐difluoroethylene

The radical copolymerization of vinylidene fluoride (VDF) and 1‐bromo‐2,2‐difluoroethylene (BDFE) in 1,1,1,3,3‐pentafluorobutane solution at different monomer molar ratios (ranging from 96/4 to 25/75 mol %) and initiated by tert‐butylperoxypivalate (TBPPI, mainly) is presented. Poly(VDF‐co‐BDFE) copolymers of various aspects (from white powders to yellow viscous liquids) were produced depending on the copolymer compositions. The microstructures of the obtained copolymers were characterized by ¹⁹F and ¹H NMR spectroscopy and by elementary analysis and these techniques enabled one to assess the contents of both comonomers in the produced copolymers. VDF was shown to be more incorporated in the copolymer than BDFE. From the extended Kelen and Tudos method, the kinetics of the radical copolymerization led to the determination of the reactivity ratios, r_i, of both comonomers (r_VDF = 1.20 ± 0.50 and r_{BDFE =} 0.40 ± 0.15 at 75 °C) showing that VDF is more reactive than BDFE. Alfrey‐Price's Q and e values of BDFE monomer were calculated to be 0.009 (from Q_VDF = 0.008) or 0.019 (from Q_VDF = 0.015) and +1.22 (vs. e_VDF = 0.40) or +1.37 (vs. e_VDF = 0.50), respectively, indicating that BDFE is an electron‐accepting monomer. Statistic cooligomers were produced with molar masses ranging from 1,800 to 5,500 g/mol (assessed by GPC with polystyrene standards). A further evidence of the successful copolymerization was shown by the selective reduction of bromine atoms in poly(VDF‐co‐BDFE) cooligomers that led to analog PVDF. The thermal properties of the poly(VDF‐co‐BDFE) cooligomers were also determined and those containing a high VDF amount exhibited a high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3964–3976, 2010.     

Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. XIV. Radical copolymerization of vinylidene fluoride with methyl 1,1‐dihydro‐4,7‐dioxaperfluoro‐5,8‐dimethyl non‐1‐enoate

The radical copolymerization in solution of vinylidene fluoride (VDF; or 1,1‐difluoroethylene) with methyl 1,1‐dihydro‐4,7‐dioxaperfluoro‐5,8‐dimethyl non‐1‐enoate (MDP) initiated by di‐tert‐butyl peroxide is presented. Six copolymerization reactions were investigated with initial [VDF]₀/[MDP]₀ molar ratios of 35/65 to 80/20. Both of these comonomers copolymerized in this range of copolymerization. Moreover, these comonomers homopolymerized separately under these conditions. The copolymer compositions of these random copolymers were calculated by means of ¹⁹F NMR spectroscopy, which allowed the quantification of the respective amounts of each monomeric unit in the copolymers. The Tidwell–Mortimer method was used for the assessment of the reactivity ratios (r_i) of both comonomers, which showed a higher incorporation of MDP in the copolymers (r_MDP = 2.41 ± 2.28 and r_VDF = 0.38 ± 0.21 at 120 °C). The Alfrey–Price Q and e values of the trifluoroallyl monomer MDP were calculated to be 0.024 (from Q_VDF = 0.008) or 0.046 (from Q_VDF = 0.015) and 0.70 (vs e_VDF = 0.40) or 0.80 (vs e_VDF = 0.50), respectively, indicating that MDP was an electron‐accepting monomer. The thermal properties of these fluorinated copolymers were also determined. Except for those containing a high amount of VDF, the copolymers were amorphous. Each showed one glass‐transition temperature (T_g) only, and with known laws of T_g's, T_g of the MDP homopolymer was assessed. It was compared to that obtained from the direct radical homopolymerization of MDP and discussed. Indeed, these two values were close (T_g = ?3 °C). Thermogravimetric analyses were performed, and they showed that the copolymers were rather thermostable because the thermal degradation occurred at 280 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3109–3121, 2003     

Reactivity ratios in conventional and nickel-mediated radical copolymerization of methyl methacrylate and functionalized methacrylate monomers

Copolymerization of an excess of methyl methacrylate (MMA) relative to 2-hydroxyethyl methacrylate (HEMA) was carried out in toluene at 80 °C according to both conventional and controlled Ni-mediated radical polymerizations. Reactivity ratios were derived from the copolymerization kinetics using the Jaacks method for MMA and integrated conversion equation for HEMA (r_MMA = 0.62 ± 0.04; r_HEMA = 2.03 ± 0.74). Poly(ethylene glycol) α-methyl ether, ω-methacrylate (PEGMA, M_n = 475 g mol⁻¹) was substituted for HEMA in the copolymerization experiments and reactivity ratios were also determined (r_MMA = 0.75 ± 0.07; r_PEGMA ∼ 1.33). Both the functionalized comonomers were consumed more rapidly than MMA indicating the preferred formation of heterogeneous bottle-brush copolymer structures with bristles constituted by the hydrophilic (macro)monomers. Reactivity ratios for nickel-mediated living radical polymerization were comparable with those obtained by conventional free radical copolymerization. Interactions between functional monomers and the catalyst (NiBr₂(PPh₃)₂) were observed by ¹H NMR spectroscopy.     

Iodine transfer copolymerization of vinylidene fluoride and α‐trifluoromethacrylic acid in emulsion process without any surfactants

The synthesis of poly(VDF‐co‐TFMA) copolymers (where VDF and TFMA stand for vinylidene fluoride and α‐trifluoromethacrylic acid, respectively) by iodine transfer polymerization without any surfactant is presented. First, the synthesis and the control of the copolymerization of VDF and TFMA were investigated in the presence of two chain transfer agents, 1‐perfluorohexyl iodide (C₆F₁₃I) and 1,4‐diodoperfluorobutane (IC₄F₈I). TFMA monomer was incorporated in the copolymer in good yields. Moreover, the molecular weights of the resulting poly(VDF‐co‐TFMA) copolymers were in good agreement with the theoretical values for feed of TFMA/VDF ratios that ranged from 50/50 to 0/100 mol %, showing that TFMA does not disturb the controlled radical polymerization of VDF. The microstructures of the produced copolymers were characterized by ¹H and ¹⁹F NMR to assess the amount of each comonomer, and the molecular weights and the end‐groups of the copolymers. The results on the control of the copolymerization were compared to those obtained with and without the presences of TFMA and surfactant. The addition of a low amount of TFMA improved the control of the polymerization of VDF without using any surfactant. Also, the size of particles, assessed by light scattering, was smaller than 200 nm. The addition of TFMA in low proportions, that is, 5 to 10 mol %, enabled us to stabilize the particle size and to decrease the size by one order of magnitude. The emulsifying behavior of TFMA (in low amount in the copolymer, that is, <10 mol %) was similar to those achieved when a surfactant was added. Indeed, neither sedimentation nor destabilization was observed after several days. The reactivity ratios for r_TFMA and r_VDF were 0 and 1.6 at 80 °C, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4710–4722, 2009     

VDF/TFE/PMVE三元共聚物的结构与性能研究

控制不同单体的起始组成合成了一系列偏氟乙烯 (VDF) 四氟乙烯 (TFE) 全氟甲基乙烯基醚 (PMVE)三元共聚物 ,通过1 9F NMR测定了这类三元共聚物的组成 ,结果与按竞聚率的计算结果吻合 .进一步分别用DSC和WAXD表征了玻璃化温度和结晶度 ,实验结果发现用这类三元共聚物制成的硫化胶的性能与其组成和微观结构密切相关     

全氟甲基乙烯基醚和其它含氟单体乳液共聚合的竞聚率测定

分别通过气相色谱法测定了全氟甲基乙烯基醚 (PMVE)与偏氟乙烯 (VDF)以及PMVE与四氟乙烯(TFE)二元乳液共聚反应中的气相单体组成和共聚物组成 ,然后用非线性回归法 (RREVM )计算得TFE PMVE及VDF PMVE乳液共聚合反应的表观竞聚率分别为γTFE =3 89和γPMVE =0 0 5以及γVDF =1 0 6和γPMVE =0 11.结合已经测定的TFE VDF二元乳液共聚的表观竞聚率 ,计算了由VDF TFE PMVE三元乳液共聚合反应合成的共聚物组成 ,后者与由1 9F NMR实测的共聚物组成吻合     

Synthesis and characterization of original alternated fluorinated copolymers bearing glycidyl carbonate side groups

A vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as ¹H, ¹⁹F, and ¹³C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol^?1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (T_d,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group. XII. Copolymerization of vinylidene fluoride with 2,3,3‐trifluoroprop‐2‐enol

An improved synthesis of 2,3,3‐trifluoroprop‐2‐enol (FA1) and its copolymerization in solution with vinylidene fluoride (VDF, or 1,1‐difluoroethylene) initiated by tert‐butyl peroxypivalate are presented. A new synthesis of FA1, with NaH and lithium diisopropylamine as bases, from 2,2,3,3‐tetrafluoropropanol is described. A series of nine copolymerization reactions were investigated from initial [VDF]₀/[FA1]₀ molar ratios of 9.1/90.9 to 94.2/5.8. The copolymer compositions were calculated via ¹⁹F NMR spectroscopy. From the Tidwell–Mortimer method, the reactivity ratios of both comonomers were determined (r_FA1 = 0.11 ± 0.22 and r_VDF = 0.83 ± 0.77 at 50°C), and they showed an azeotropic point. Alfrey and Price's Q and e values of FA1 were calculated to be 0.0178 (from Q_VDF = 0.008), 0.039 (from Q_VDF = 0.015), and 0.275 (from Q_VDF = 0.036) and 2.74 (vs e_VDF = 1.20), 2.04 (vs e_VDF = 0.50), and 1.94 (vs e_VDF = 0.4), respectively, and they indicated that FA1 is an electron‐accepting monomer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3634–3643, 2002     

Homopolymer and copolymers of 4-nitro-3-methylphenyl methacrylate with glycidyl methacrylate: Synthesis, characterization, monomer reactivity ratios and thermal properties

The novel methacrylic monomer, 4-nitro-3-methylphenyl methacrylate (NMPM) was synthesized by reacting 4-nitro-3-methylphenol dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in the presence of triethylamine as a catalyst. The homopolymer and copolymers of NMPM with glycidyl methacrylate having different compositions were synthesized by free radical polymerization in EMK solution at 70 ± 1 °C using benzoyl peroxide as free radical initiator. The homopolymer and the copolymers were characterized by FT-IR, ¹H NMR and ¹³C NMR spectroscopic techniques. The solubility tests were tested in various polar and non-polar solvents. The molecular weight and polydispersity indices of the copolymers were determined using gel permeation chromatography. The glass transition temperature of the copolymers increases with increase in NMPM content. The thermogravimetric analysis of the polymers performed in air showed that the thermal stability of the copolymer increases with NMPM content. The copolymer composition was determined using ¹H NMR spectra. The monomer reactivity ratios were determined by the application of conventional linearization methods such Fineman-Ross (r₁ = 1.862, r₂ = 0.881), Kelen-Tudos (r₁ = 1.712, r₂ = 0.893) and extended Kelen-Tudos methods (r₁ = 1.889, r₂ = 0.884).     

Effect of nanoclay and macroinitiator on the kinetics of atom transfer radical homo- and copolymerization of styrene and methyl methacrylate initiated with CCl3-terminated poly (vinyl acetate) macroinitiator

Effect of nanoclay on the kinetics of atom transfer radical bulk homo- and copolymerization of styrene (St) and methyl methacrylate (MMA) initiated with CCl₃-terminated poly (vinyl acetate) macroinitiator at 90 °C was investigated. CuCl/PMDETA was used as a catalyst system. Results showed that nanoclay significantly enhances the homopolymerization rate of MMA. It was attributed to the activated conjugated CC bond of MMA monomer via interaction between the carbonyl group of MMA monomer and the hydroxyl moiety (AlOH) of nanoclay as well as to the effect of nanoclay on the dynamic equilibrium between the active (macro)radicals and dormant species. Homopolymerization rate of St (a noncoordinative monomer with nanoclay) decreased slightly in the presence of nanoclay. It could be explained by inserting of a portion of macroinitiator into the clay galleries, where no sufficient St monomer exists due to the low compatibility or interaction of St monomer with nanoclay to react with the macroinitiator. Controlled/living characteristic of all the reactions were confirmed by GPC results. More reliable reactivity ratios of the St and MMA in the presence of nanoclay were calculated by using the cumulative average copolymer composition at the moderate to high conversion to be r_St = 0.290 ± 0.082, r_MMA = 0.443 ± 0.093 (extended Kelen-Tudos method) and r_St = 0.293 ± 0.071, r_MMA = 0.447 ± 0.080 (Mao-Huglin method). Results indicated that the rate of incorporation of MMA comonomer into the copolymer increases in the presence of nanoclay, verifying the existence of interaction between the carbonyl group of MMA comonomer and the hydroxyl moiety of nanoclay. It was found that in the presence of nanoclay, tendency of the random copolymerization of St and MMA toward an alternating copolymerization increases.     

New unsaturated polyesters as injectable drug carriers

New unsaturated polyesters of poly(fumaric acid-glycol-sebacic acid) copolymers and poly(maleic anhydride-glycol-sebacic acid) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: sebacic anhydride, fumaric acid or maleic anhydride and glycol. Methyl-methacrylate (MMA) was used as crosslinker and dimer acid was used as thinner.In vitro studies showed that those copolymers are degradable in phosphate buffer at 37 °C and poly(fumaric acid-glycol-sebacic acid) has proper drug release rate as drug carriers. The biocompatibility of poly(fumaric acid-glycol-sebacic acid) copolymers under mice skin was also evaluated; macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. The injected poly(fumaric acid-glycol-sebacic acid) [molar ratio M_{fumaric acid}:M_glycol:M_{sebacic acid} = 1.75:2.20:0.25] containing 5% adriamycin hydrochloride (ADM) in the mice bearing Sarcoma-180 tumor exhibited a good antitumor efficacy. The volume doubling time (VDT) (18 ± 2.5 days) of the tumor growth by this treatment was longer than that (7 ± 0.9 days) by the subcutaneous injection of ADM.     

Synthesis and properties of poly(aryl ether benzimidazole) copolymers for high-temperature fuel cell membranes

A series of poly(aryl ether benzimidazole) copolymers bearing different aryl ether linkage contents were synthesized by condensation polymerization in polyphosphoric acid (PPA) by varying the feed ratio of 4,4′-dicarboxydiphenyl ether (DCPE) to terephthalic acid (TA). As the ether unit content in the copolymer increased, the solubility of the copolymer in PPA and N,N′-dimethylacetamide/LiCl improved. For example 3–7 wt.% DMAc solution containing 2 wt.% of LiCl could be prepared from the copolymers. XRD studies revealed that the incorporation of flexible aryl ether linkages increased the chain d-spacings of the polymer backbones and decreased the crystallinity of the copolymers. Still, these copolymers having ether linkages showed reasonably good thermal/mechanical stability and high proton conductivity. For example, the copolymer with 30 mol% ether linkage had a tensile strength of 43 MPa (at 26 °C and 40% relative humidity) at an acid doping level of 7.5 mol H₃PO₄ and a proton conductivity of 0.098 S cm⁻¹ (at 180 °C and 0% relative humidity) at an acid doping level of 6.6 mol H₃PO₄.     

Synthesis and phase separation of amine-functional temperature responsive copolymers based on poly(N-isopropylacrylamide)

Free radical copolymerizations of N-isopropyl acrylamide (NIPAM) and cationic N-(3-aminopropyl) methacrylamide hydrochloride (APMH) were investigated to prepare amine-functional temperature responsive copolymers. The reactivity ratios for NIPAM and APMH were evaluated in media of different ionic strength (r_NIPAM = 0.7 and r_APMH = 0.7-1.2). Phase separation behavior of the random copolymers with only 5 mol% of the APMH was found to be suppressed in pure water at temperatures up to 45 °C due to electrostatic repulsion among the cationic amine groups randomly distributed along the copolymer chain. Alternate sequential addition of PNIPAM/APMH mixtures and pure NIPAM was used to provide increased control of the location of APMH units along the chain. Consequently (close to) homo-PNIPAM block(s) were formed as evidenced by its characteristic phase transition at 33 °C. The influences of the monomer feeding time and feeding interval time to the APMH distribution were investigated to prepare copolymers with thermo-induced phase separation under physiologically relevant temperature and to determine the extent of conjugation to poly(ethylene oxide).     

Synthesis and copolymerization of fluorinated monomers bearing a reactive lateral group. XX. Copolymerization of vinylidene fluoride with 4‐bromo‐1,1,2‐trifluorobut‐1‐ene

The radical copolymerization of vinylidene fluoride (VDF) with 4‐bromo‐1,1,2‐trifluorobut‐1‐ene (C₄Br) was examined. This bromofluorinated alkene was synthesized in three steps, which started with the addition of bromine to chlorotrifluoroethylene. In contrast to the ethylenation of 1,1‐difluoro‐1,2‐dibromochlorethane, which failed, that of 2‐chloro‐1,1,2‐trifluoro‐1,2‐dibromoethane was optimized and led to 2‐chloro‐1,1,2‐trifluoro‐1,4‐dibromobutane. The kinetics of the copolymerization of VDF with this brominated monomer initiated by t‐butyl peroxypivalate led to an assessment of the reactivity ratios, r_VDF = 0.96 ± 0.67 and r_C4Br = 0.09 ± 0.63, at 50 °C. The suspension copolymerization was also carried out, and the chemical modifications of the resulting bromo‐containing poly(vinylidene fluoride)s were attempted and consisted mainly of elimination or nucleophilic substitution of the bromine. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 917–935, 2005     

Solvent effects on the copolymerization kinetics of ionic (AMPS) and non-ionic (HEAm) acrylamide derivatives

The free-radical copolymerization of two N-substituted acrylamide monomers, the ionic AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and the non-ionic HEAm (2-hydroxyethylacrylamide) is presented. Despite bearing similar polymerizable functionalities, HEAm is more reactive toward free-radical addition than AMPS in water. In a mixed aqueous solvent containing salt, (0.5 M LiNO₃, 50 wt%) and ethanol (50 wt%), the reactivity ratio was found to be r_AMPS = 0.53 and r_HEAm = 1.06 indicating that copolymers with a nearly random distribution of sulfonic and hydroxy functionalities can be prepared.     

Study of free-radical copolymerization of itaconic acid/2-acrylamido-2-methyl-1-propanesulfonic acid and their metal chelates

The monomer reactivity ratios for itaconic acid (IA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in N,N-dimethylformamide solution using the benzoyl peroxide (Bz₂O₂) as an initiator with different monomer-to-monomer ratios in the feed were investigated by studying the resulting copolymer composition via elemental analysis. Composition results were summarized and various methods were employed to estimate the monomer reactivity ratios including the use of the Error-in Variables-Model method using a computer program, RREVM. The estimates of the reactivity ratios from the EVM method are found to be r_IA = 0.4636 and r_AMPS = 0.0357. These values suggest that IA is more reactive than AMPS and the copolymer will be richer in IA units. Cu(II) and Ni(II) chelates of the copolymers were prepared and the formation constants of each complex were determined by the mole-ratio method using the UV-vis spectroscopy. UV-vis studies showed that the complex formation tendency increased in the followed order: Cu(II) > Ni(II). The copolymers and their metal chelates were characterized by FT-IR spectra and SEM analysis. Also, thermal stabilities of the copolymers and their metal chelates were investigated using TGA and DSC analysis.     

Reversible addition-fragmentation chain transfer radical copolymerization of β-pinene and methyl acrylate

The feasibility of radical copolymerization of β-pinene and methyl acrylate (MA) was clarified for the first time. The monomer reactivity ratios were evaluated by Fineman-Ross, Kelen-Tudos and non-linear methods, respectively. The obtained values were r_β-pinene ∼ 0 and r_MA ∼ 1.3, indicating that the copolymerization led to polymers rich in methyl acrylate units and randomly alternated by single β-pinene unit. The addition of Lewis acid Et₂AlCl to the AIBN-initiated copolymerization enhanced the incorporation of β-pinene. Furthermore, the possible controlled copolymerization of β-pinene and MA was then attempted via the reversible addition-fragmentation transfer (RAFT) technique. The copolymerization (f_β-pinene = 0.1) using 1-methoxycarbonyl ethyl dithiobenzoate (MEDB) as a RAFT agent gave copolymers with lower molecular weight and narrower molecular weight distribution. However, the presence of MEDB strongly retarded the copolymerization. Thus a new RAFT agent 1-methoxycarbonyl ethyl phenyldithioacetate (MEPD), which gives a less stable macroradical intermediate than MEDB, was synthesized and introduced to the copolymerization. As anticipated, a much smaller retardation was observed. Moreover, the copolymerization displayed a somewhat controlled features within a certain overall conversion (<∼40%).