The study on grafting comonomer of n-butyl acrylate and styrene onto poly(ethylene terephthalate) film by gamma-ray induced graft copolymerization

Poly(ethylene terephthalate) (PET) film was successfully grafted with n-butyl acrylate and styrene comonomer through gamma-ray induced graft copolymerization. The degree of grafting (DG) and the composition of grafted side chain were characterized by ¹H NMR. It was found that St can inhibit the homopolymerization of BA effectively and increase the DG when the concentration of comonomer mixture is kept constant. The proportion of St to BA in grafted side chain has a positive dependence on the feed ratio of St, which ultimately approaches the feed ratio. The thermal properties of poly(ethylene terephthalate)-graft-poly(n-butyl acrylate-co-styrene) (PET-g-P(BA-co-St)) films were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The T_g of PET decreases with the DG, indicating that the grafted P(BA-co-St) copolymer has good compatibility with PET backbone.     

THE MECHANISM OF THE COPOLYMERIZATION OF BF_3-COMPLEXED ETHYL ACRYLATE WITH PROPYLENE

The copolymerization of BF_2-omplexed ethyl acrylate with propylene in the presence ofAIBN at 25℃was investigated. It was found that the rate of the copolymerization was propor-tional to the square root of the initiator concentration. The chain transfer agent CCl_4 greatly af-fects the inherent viscosity of the resulting copolymer. The smaller the dielectric constant of thesolvent, the greater the rate of copolymerization is. The equal concentration of the two monomersgive the maximum copolymerization rate. The ~1H-NMR and ~(13)C-NMR analysis indicated, when[EA.BF_2]/[EA.BF_2]+[P]>0.5, the resulting copolymer was the acrylate-rich random copoly-mer. Through the kinetic experiments we suggest that copolymerization follows the mechanismof the random copolymerization of the ternary complex with binary complex. When [EA.BF_3]/[EA.BF_2]+[P]<0.5, the resulting copolymer is always strictly alternating, and the alternatingcopolymerization follows the mechanism of the ternary complex homopolymerization. Usingthe homolog of the propylene, 1-pentene, we found that BF_3-complexed ethyl acrylate can forma ternary complex with 1-pentene identified by UV spectroscopy. This is a strong evidence forthe mechanism of ternary complex homopolymerizetion.     

Radical copolymerization of cyclic diarsine with vinyl monomers

1,2,4,5‐Tetramethyltetrahydrodiarsenine ( 1 ), a cyclic diarsine compound, was stirred with styrene and a catalytic amount of 2,2′‐azobisisobutyronitrile (AIBN) as a radical initiator at 80 °C for 8 h in toluene to give a copolymer containing arsenic atoms in the backbone. The gel permeation chromatography (GPC) chromatogram of the copolymer showed a single peak. The number‐average molecular weight of the copolymer was estimated to be more than 10,000 by GPC analysis (CHCl₃, polystyrene standards). The structure of the copolymer was confirmed by the ¹H NMR and ¹³C NMR spectra. According to the integral ratio of peaks in the ¹H‐NMR spectrum, the content of 1 in the copolymer was smaller compared to the monomer feed ratio of 1 . Radical copolymerization of 1 with methyl methacrylate also provided the corresponding copolymer in the presence of AIBN, whereas copolymerization with vinyl acetate yielded no polymeric material. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3023–3028, 2004     

Soluble hyperbranched polymer through initiator-fragment incorporation radical copolymerization of ethylene glycol dimethacrylate and α-ethyl β-N-(α-methylbenzyl) itaconamate in benzene

The copolymerizations of ethylene glycol dimethacrylate (EGDM) with α-ethyl β-N-(α^′-methylbenzyl) itaconamates (RS- and S-EMBIs) derived from (RS)- and (S)-α-methylbenzylamines were conducted at 70 and 80 °C in benzene using dimethyl 2,2^′-azobisisobutyrate (MAIB) of high concentration as initiator. The copolymerization of EGBM (0.20 mol/l) and RS-EMBI (0.50 mol/l) with MAIB (0.50 mol/l) proceeded homogeneously without any gelation in benzene to give benzene-soluble copolymer in a yield of 55% based on the total weight of EGDM, RS-EMBI and MAIB. The copolymer was soluble in acetone, ethyl acetate, chloroform, tetrahydrofuran (THF), toluene, N,N-dimethylformamide and insoluble in n-hexane, methanol, dimethyl sulfoxide, and water. The copolymerization system involved ESR-observable propagating radicals derived from EGDM and RS-EMBI, of which the total concentration increased with time in spite of the homogeneous system. The copolymer consisted of EGDM unit (25 mol%), RS-EMBI unit (45 mol%), and methoxycarbonylpropyl group as MAIB-fragment (30 mol%). Such a large number of initiator fragments were incorporated into the copolymer as terminal groups through initiation and primary radical termination, leading to a conclusion that the copolymer was of hyperbranched structure (initiator-fragment incorporation radical copolymerization). Radius of gyration (R_g) and M_w of the copolymer by light scattering measurements in THF were 17.8 nm and 7.7 × 10⁵, respectively. Comparison of these values with those (R_g=27.6 nm and M_w=2.9×10⁵) of linear polystyrene also supported the above conclusion. Reflecting the compact hyperbranched structure, the intrinsic viscosity ([η]) of the copolymer was very low, [η]=0.075 dl/g at 25 °C in THF. The individual copolymer molecules were observed as a nanoparticle by TEM. The copolymerization of EGDM and S-EMBI with MAIB in benzene also gave similar results.     

二烷基锡聚合物的研究——Ⅲ.顺丁烯二酸二丁基锡酯与丙烯酸甲酯、丙烯酸丁酯的共聚合

Benzoyl peroxide (BPO) was used for initiator in copolymerization of dibutyltin maleate (DBTM, M₂) with methyl acrylate (MA, M₁) in benzene and the reactivity ratios of copolymerization r1 and r2 were found to be 12.67 and 0.03, respectively. But in copolymerization of DBTM (M₂) with butyl acrylate (BA, M₁) r1 and r2 were 11.1 and 0> respectively. The cc-polymerization conditions, such as amount of initiator, ratios of monomers and addition method of initiator were examined. Copolymers were characterized by ¹H-NMR,IR,elemental and TG analyses. MA-DBTM copolymer is a white and brittle solid, while BA-DBTM copolymer is a transparent elastomer at room temperature.     

Alternating copolymerization of styrene and methyl α-chloroacrylate with diethylaluminum chloride

The alternating copolymerization of styrene and methyl α-chloroacrylate (MCA) with diethylaluminum chloride (Et₂AlCl) in benzene at 0°C has been investigated. The copolymer has an equimolar composition irrespective of the feed monomer composition, the copolymer yield and the amount of Et₂AlCl used. The copolymerization proceeds first very rapidly and then rather slowly after attaining a certain yield which varies proportionally to the amount of Et₂AlCl used. A maximum copolymer yield is observed at about 60% MCA feed composition. The ¹H-NMR analyses of dyad, triad, and pentad of the alternating deuterated α-d-St-MCA copolymer indicate that the configuration of this copolymer can be explained by a single parameter, coisotacticity σ(σ = 0.69). A favorable mechanism of the alternating propagation as well as of the stereoregularity control is discussed.     

Copolymers based on (<Emphasis Type="Italic">p</Emphasis>-vinylphenyl)cyclopropylmethyl chlorocinnamate and methyl methacrylate

Abstract—Copolymers of (p-vinylphenyl)cyclopropylmethyl chlorocinnamate with methyl methacrylate were prepared by radical copolymerization. The copolymerization constants were determined, and the Alfrey–Price Q–e parameters were calculated. The possibility of photochemical cross-linking of the copolymer via double bond conjugated with the carbonyl group in the chlorocinnamate moiety and via the cyclopropane ring was demonstrated. The copolymer obtained exhibits sufficiently high photosensitivity (54.5 cm² J^–1) and high refractive index (n _D ²⁰ 1.5890), which opens prospects for using it as a photosensitive base of negative photoresists and in optics.     

Graft copolymerization of methyl methacrylate onto lignosulfonate by H2O2–Fe(II) redox system. I. Preparation and characterization of the graft copolymer

Graft copolymerization of methyl methacrylate onto lignosulfonate in aqueous medium was investigated. It was found that the H₂O₂–Fe(II) redox system is very effective for the grafting (E_a = 4.4 kcal/mole). The H₂O₂/Fe²⁺ ratio was the most important factor in the graft copolymerization and characteristics of the resultant graft copolymers. In most cases, polymerization for 100 min at 30°C was enough to obtain 80% conversion and 50–60% grafting efficiency. The resultant polymer mixture was subjected to extraction alternately with acetone and water, and the graft copolymer was isolated free from homopolymer and unreacted lignosulfonate. With increasing H₂O₂/Fe²⁺ ratio, the grafting ratio showed a maximum at 4, whereas the yield of graft copolymer and number of poly(methyl methacrylate) branches for every building unit of lignosulfonate increased up to a ratio of 4, both values, however, remaining constant above 4. The graft copolymer obtained for the case H₂O₂/Fe²⁺ = 4 consisted of one part of lignosulfonate and five parts of poly(methyl methacrylate). The number of branches in the graft copolymer was 6 × 10^?3/OCH³ or one every 167 guaiacyl nuclei.     

Preparation and characterization of poly(butylene terephthalate)/poly(ethylene terephthalate) copolymers via solid‐state and melt polymerization

To increase the T_g in combination with a retained crystallization rate, bis(2‐hydroxyethyl)terephthalate (BHET) was incorporated into poly(butylene terephthalate) (PBT) via solid‐state copolymerization (SSP). The incorporated BHET fraction depends on the miscibility of BHET in the amorphous phase of PBT prior to SSP. DSC measurements showed that BHET is only partially miscible. During SSP, the miscible BHET fraction reacts via transesterification reactions with the mobile amorphous PBT segments. The immiscible BHET fraction reacts by self‐condensation, resulting in the formation of poly(ethylene terephthalate) (PET) homopolymer. ¹H‐NMR sequence distribution analysis showed that self‐condensation of BHET proceeded faster than the transesterification with PBT. SAXS measurements showed an increase in the long period with increasing fraction BHET present in the mixtures used for SSP followed by a decrease due to the formation of small PET crystals. DSC confirmed the presence of separate PET crystals. Furthermore, the incorporation of BHET via SSP resulted in PBT‐PET copolymers with an increased T_g compared to PBT. However, these copolymers showed a poorer crystallization behavior. The modified copolymer chain segments are apparently fully miscible with the unmodified PBT chains in the molten state. Consequently, the crystal growth process is retarded resulting in a decreased crystallization rate and crystallinity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 882–899, 2007.     

Mechanism of alternating copolymerization of 4-hydroxy-4′-vinylbiphenyl with α-chloromaleic anhydride

The copolymerization of 4-hydroxy-4′-vinylbiphenyl (HVB) with α-chloromaleic anhydride (CMAn) was investigated in THF, 1,4-dioxane, and acetonitrile. The formation of the 1:1 charge transfer complex between HVB and CMAn was confirmed spectroscopically, and the corresponding equilibrium constant (K_eq) was determined as follows: K_eq = 0.19, 0.11, and 0.058 mol/L in THF, 1,4-dioxane, and CH₃CN, respectively. The copolymer composition is affected by the solvent, i.e., the content of HVB in the copolymer obtained in THF or 1,4-dioxane is lower than 50 mol % whereas the copolymer obtained in CH₃CN has excess of HVB units. The maximum rate of copolymerization was observed at a 1:1 initial comonomer mole ratio, irrespective of the solvent polarity. Plots of R_p/[HVB] vs. [HVB] gave a straight line with a slope and an intercept for the copolymerization in THF whereas a straight line in CH₃CN has no slope. On the basis of these results and ¹³C-NMR spectra of the copolymers, the mechanism of the predominant formation of alternating copolymers is discussed.     

Syntheses and characterizations of polypropene,polystyrene and their block copolymers with titanocene catalysts

Pentamethylcyclopentadienyltitanium tribenzyloxide, Cp^*Ti(OBz)₃, was used as the catalyst precursor for polymerizations of propene and styrene. The titanocene catalyst affords atactic polypropene and syndiotactic polystyrene with high activities in the presence of methylalumimoxane (MAO). Block copolymerization of propene and styrene was carried out in the presence of Cp^*Ti(OBz)₃/MAO catalyst system by the means of external addition of triisobutylaluminum (TIBA) and sequential monomer feed. The copolymerization product is mainly a mixture of atactic polypropene(aPP) and syndiotactic polystyrene(sPS) homopolymers and aPP-b-sPS block copolymers, which can be separated into fractions with successive extraction with boiling methylethyl ketone(MEK), heptane, tetrahydrofuran(THF), and chloroform. Studies on thermal properties showed that rubbery phases and crystalline regions both appear in the block copolymer at the room temperature and that aPP-b-sPS block copolymer has better toughness than sPS.     

Propagation Mechanism of Radical Copolymerization of Sulfur Dioxide and Vinyl Chloride

Radical copolymerization of sulfur dioxide and vinyl chloride (VC) has been studied by the comparison of the composition of copolymers obtaining from different reaction conditions, i.e., reaction temperatures, feed compositions, and total monomer concentrations. The composition of VC in copolymer is independent of comonomer composition except at high concentration of VC in feed; it increases with increasing reaction temperature or decreasing total monomer concentration. At lower temperature, the composition of copolymer becomes independent of total monomer concentration. The overall rate of polymerization is proportional to [VC]^1,7 and [SO₂]^0.5. These results were compared with those obtained in our previous study on the SO₂-styrene copolymerization. A propagation mechanism for radical copolymerization of SO₂ and VC is also proposed.     

Copolymerization behavior of direct polycondensation of AB2 and AB monomers that forms hyperbranched aromatic polyamide copolymers

The copolymerization behavior of the one‐step direct polycondensation of 3,5‐bis‐(4‐aminophenoxy)benzoic acid (AB₂ monomer) and 3‐(4‐aminophenoxy)benzoic acid (AB monomer) was investigated by IR and ¹³C NMR measurements. IR measurements revealed that the content of the AB₂ units in the polymer was higher in the early stages of polymerization. ¹³C NMR spectra of the polymers indicated that the number of dendritic units increased slowly with increasing reaction time. The stepwise copolymerization of the AB₂ and AB monomers was also carried out, and the structure was analyzed by ¹³C NMR measurements. Copolymer synthesized stepwise by adding AB₂ monomer first (polymer II ) had more dendritic units and less terminal units as compared with the one‐step copolymer (polymer I ). Copolymer synthesized stepwise by adding AB monomer first gave a resulting copolymer (polymer III ) composed of long AB chains. The solubility of the stepwise copolymers was low, and the inherent viscosity was high in comparison with the one‐step copolymer as a result of the difference in architecture of the copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3304–3310, 2001     

Structure and properties of the graft copolymer of starch and p‐hydroxybenzoic acid using horseradish peroxidase

A modified starch tannage was synthesized by free radical graft copolymerization of degraded starch with p‐hydroxybenzoic acid (pHA) using horseradish peroxidase/H₂O₂ as the initiator. In this study, the effects of the degree of degradation of the starch, dosage of pHA, polymerization temperature, system pH, and horseradish peroxidase content on the tanning properties of the graft copolymer were investigated. The shrinkage temperature of leather tanned by the graft copolymer was 78 °C. The thickness increment ratio of the retanned leather was 21.6%, and meanwhile the retanned leather showed better softness. The results indicate that the graft copolymer has excellent tanning and retanning properties. The structure of the graft copolymer was analyzed by Fourier Transform Infrared Spectroscopy (FTIR), ¹Hydrogen‐Nuclear Magnetic Resonance (¹H‐NMR), and ¹³Carbon‐Nuclear Magnetic Resonance (¹³ C‐NMR) and Gel Permeation Chromatography (GPC). Compared with conventional methods, we show that a “green” leather tannage could be achieved using a radical graft copolymerization of starch and phenols. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of grafted methyl methacrylate on the catalytic hydrogenation of natural rubber

The graft copolymerization of methyl methacrylate onto natural rubber was carried out by using a cumene hydroperoxide redox initiator. The graft copolymer was purified by extraction and then hydrogenated in the presence of OsHCl(CO)(O₂)(PCy₃)₂. The graft copolymer and hydrogenated product were characterized by proton nuclear magnetic resonance (¹H NMR). The rate of hydrogenation was investigated using a gas-uptake apparatus. The hydrogenation was observed to be inverse first-order with respect to rubber concentration. The addition of a small amount of poly(methyl methacrylate) demonstrated a beneficial effect on the hydrogenation of the grafted copolymer.     

Free Radical Copolymerization of N‐(4‐Carboxyphenyl)maleimide with Hydropropyl Methacrylate

Abstract

The free radical copolymerization of N‐(4‐carboxyphenyl)maleimide (CPMI) (M₁) with hydropropyl methacrylate (HPMA) (M₂) was carried out with 2,2′‐azobis(isobutyronitrile) (AIBN) as an initiator in ethyl acetate at 75°C. The composition of copolymer prepared at low conversion was determined by elemental analysis. The monomer reactivity ratios were found to be r ₁?=?0.31 and r ₂?=?1.11 as determined by the YBR equation. The number‐average molecular weight and polydispersity were determined by gel permeation chromatography (GPC). Furthermore, the solvent effect on this copolymerization system was also investigated. The resulting copolymer was characterized by FTIR and ¹H‐NMR spectroscopy. The thermal stability of copolymers was determined by thermogravimetric analysis (TGA). It was found that the copolymer shows step‐by‐step degradation, the initial decomposition temperature (T _i), and final decomposition temperature (T _f) increased with increasing the component of CPMI in copolymer.     

Novel Copolymer of Diisopropyl Fumarate and Benzyl Acrylate Synthesized Under Microwave Energy and Quasielastic Light Scattering Measurements

Microwave assisted free radical copolymerization of diisopropyl fumarate (DIPF) and benzyl acrylate (BzA) with different copolymer compositions was performed using benzoyl peroxide as initiator. The effect of the reaction conditions on the macromolecular characteristics, monomer reactivity ratio and copolymer properties were studied. The monomer conversion and average molecular weights increase with the content of BzA units in the copolymer. The copolymers were characterized by IR, ¹H and ¹³C-NMR spectroscopies and the molecular weights were analyzed with size exclusion chromatography (SEC). The reactivity ratios obtained from an extended Kelen-Tüdös method under microwave irradiations are a factor which is double than those obtained by thermal copolymerization. The product r₁r₂ = 0.152 suggests a preference of both propagating macroradicals toward consecutive homopolymerization. The hydrodynamic and polydispersity size were measured in ethylacetate, tetrahydrofuran and methylethylketone with a quasi-elastic light scattering (QELS) technique showing that the quality of the solvents increases in the order: EA < THF < MEK.     

Kinetic study of copolymerization of linalool and methyl methacrylate initiated by selenonium ylide

Free radical copolymerization of an acyclic monoterpenoid linalool (LIN) and methyl methacrylate (MMA) in dioxan was carried out in dilatometer under an inert atmosphere of nitrogen for 90 min at 60 ± 1°C by using diphenyl selenonium 2,3,4,5‐tetraphenylcyclopentadienylide (selenonium ylide) as an initiator. The kinetic expression of the reaction is R_p ∝ [ylide]^0.5[MMA]^1.0[LIN]^1.0. The activation energy of copolymerization was estimated to be 43.7 kJ mol^?1. The formation of a functional copolymer is evidenced by spectral analysis. The copolymer was characterized by FTIR, ¹H NMR, ¹³C NMR, DSC, and TGA analysis. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 43–52, 2011     

Synthesis,Characterization, and Reactivity Ratios of Phenyl Methacrylate-N-vinyl-2-pyrrolidone Copolymers

Free radical solution copolymerization of phenyl methacrylate and N-vinyl-2-pyrrolidone was carried out using benzoyl peroxide in 2-butanone solution at 70°C. The composition of the copolymer was determined using ¹H-NMR spectra by comparing the intensities of aromatic protons to that of total protons. The results were used to calculaie the copolymerization reactivity ratios by both the Fineman-Ross (F-R) and Kelen-Tüdös (K-T) methods. The reactivity ratios are r ₁ = 4.49 ± 1.27 and r ₂ = 0.05 ± 0.09 as determined by the K-T method. These values are in good agreement with those determined by the F-R method. The FT-infrared and ¹³C-NMR spectra of the copolymer are discussed.