Bulk Free‐Radical Co‐ and Terpolymerization of n‐Butyl Acrylate/2‐Ethylhexyl Acrylate/Methyl Methacrylate

n‐Butyl acrylate (BA), 2‐ethylhexyl acrylate (EHA), and methyl methacrylate (MMA) are commonly used monomers in pressure‐sensitive adhesive formulations. The bulk free‐radical copolymerizations of BA/EHA, MMA/EHA, and BA/MMA are studied at 60 °C to demonstrate the use of copolymer reactivity ratios for the prediction of BA/MMA/EHA terpolymer composition. The reactivity ratios for BA/EHA and MMA/EHA copolymer systems are determined using low conversion experiments; BA/MMA reactivity ratios are already known from the literature. The reactivity ratio estimates for the BA/EHA system are r _BA = 0.994 and r _EHA = 1.621 and the estimates for MMA/EHA are r _MMA = 1.496 and r _EHA = 0.315. High conversion experiments are conducted to validate the reactivity ratios. The copolymer reactivity ratios are shown to predict terpolymer composition of high conversion BA/MMA/EHA experiments.     

Synthesis and characterization of original functional polymers of tetrafluoroethylene and 4,5,5‐trifluoro‐4‐ene pentyl acetate

The bulk radical copolymerization of tetrafluoroethylene (TFE) with 4,5,5‐trifluoro‐4‐ene pentyl acetate (FAc), initiated by tert‐butyl peroxypivalate to synthesize original, functionalized fluorinated poly(TFE‐co‐FAc), was investigated. FAc monomer was prepared from a five‐step process. The copolymerization was carried out in batch at different initial monomer molar ratios ([TFE]_o/[FAc]_o ranging from 95/5 to 10/90 mol %) and at different initiator concentrations (ranging between 0.075 and 1.100 mol % about the monomers) at 70 °C. All the experiments revealed the production of fluorooligomers as evidenced by an allylic‐transfer reaction from FAc. The microstructure of these copolymers (i.e., the molar percentage of both monomers in the copolymers) was assessed by ¹⁹F NMR spectroscopy. From the kinetics of copolymerization, two key characteristics were determined. First, the reaction order to the initiator (being 1.07) and that of FAc monomer (0.85) showed a heterogeneous character of the copolymerization and monomolecular chain‐transfer reaction to FAc. Second, from the Tidwell and Mortimer method, the reactivity ratios of both comonomers were determined, showing a tendency to alternance in a wide range of initial monomeric ratios (30/70–70/30): r_FAc = 0.20 ± 0.26 and r_TFE = 0.18 ± 0.15. Alfrey and Price's Q and e values of FAc were calculated by Greenley's technique [Q_FAc = 0.098 (from Q_TFE = 0.032) and e_FAc = 1.23 (vs e_TFE = 1.63)], indicating that FAc is a strong electron‐withdrawing monomer as TFE. The normalized monomer‐diad and triad fractions as a function of the polymer composition were obtained from the comonomer sequence‐distribution procedure. The average molecular weights and molecular weight distributions as well as the thermal properties (glass‐transition temperature and decomposition temperature) of the fluorocopolymers were assessed and are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1693–1706, 2004     

An Error‐in‐Variables Method for Determining Reactivity Ratios by On‐Line Monitoring of Copolymerization Reactions

Summary: A new error‐in‐variables method was developed to estimate the reactivity ratios in copolymerization systems. It brings the power of automatic, continuous, on‐line monitoring of polymerization (ACOMP) to copolymerization calculations. In ACOMP systems, monomer and polymer concentrations are measured by the monitoring of two independent properties of the system. The reactivity ratios are found by taking into account errors in the monomer concentrations determined from measurements and from calibration of the instruments. All the error sources are taken into account according to the error‐in‐variables method, and their effects are reflected in determining the confidence intervals of the reactivity ratios by the usual error propagation technique.

Distribution of concentrations [a] and [b] for the simulated experiment I. Random errors are 1% of the initial value in both observed variables.     

Terpolymerization kinetics of amino acid N‐carboxy anhydrides

Based on their versatility with respect to amino acid type and sequence, polypeptides have become attractive for a number of biological applications such as drug delivery, biomineralization, and drugs. N‐carboxy anhydride (NCA) polymerization is a convenient way to rapidly prepare high‐molecular weight polypeptides with good control over molecular weight and polydispersity. However, the kinetics of the incorporation of NCA monomers into copolypeptides during random copolymerization are poorly understood. Here, kinetic data is presented that allows insight into the NCA polymerization of a terpolymer composed of three commercially relevant amino acids, namely, glutamic acid, lysine, and tyrosine. Furthermore, kinetic data and copolymerization parameters from the copolymerization of binary mixtures of these three amino acid NCAs is used to make predictions of the terpolymer composition. This study provides access to the information necessary to prepare functional copolypeptides with better‐defined sequence architecture that will be essential for the future development of polypeptide‐based materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1228–1236     

Reaction kinetics and gel effect on the polymerization of 2‐ethoxyethyl methacrylate and 2(2‐ethoxyethoxy) ethyl methacrylate

Polymerization kinetics at several temperatures of 2‐ethoxyethyl methacrylate (EEMA) and 2(2‐ethoxyethoxy) ethyl methacrylate (DEMA) in bulk and in dioxane solutions are described. The gel effect was never detected at monomer concentrations equal to or lower than 1 mol L^?1, although in the bulk polymerization both monomers display the gel effect at very low conversions. Because of the influence of the efficiency factor f on the polymerization rate, a theoretical kinetic interpretation of the changes in f with monomer and initiator concentrations and kinetic parameters was performed to achieve a better understanding of the mechanisms involved in radical polymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3987–4001, 2002     

Batch emulsion copolymerization of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose and butyl acrylate: Synthesis and properties of the sugar latices

To obtain new polymer latices based on sugar derivative, batch emulsion copolymerizations of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D ‐glucofuranose (3‐MDG) and n‐butyl acrylate (BA) were carried out at 70 °C, with potassium persulfate as the initiator. 3‐MDG polymerizes faster than BA because of its higher reactivity ratio, r_(3‐MDG) = 1.94 versus r_(BA) = 0.54. The effect of the initial monomer composition on the polymerization rate and the thermal properties of the end copolymers was investigated. The overall rate of polymerization increases by enhancing the sugar content in the initial monomer composition. The glass‐transition temperature is linearly related to the sugar content in the copolymer. The influence of the type of surfactant showed that the particle size increases by changing from ionic to nonionic surfactant. Furthermore, the effect of the added acrylic acid (AA) on the rheological properties suggests that the sugar latices exhibit different non‐Newtonian flows depending on the pH of the latex and on the AA concentration on the particle surface. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 788–803, 2003     

Fundamental investigations into the free‐radical copolymerization of N‐phenylmaleimide and norbornene

A fundamental investigation into the copolymerization of N‐phenylmaleimide and norbornene via conventional free‐radical polymerization techniques was conducted. Reaction conditions were optimized for molecular weight and percent yield by tuning overall concentration and initiator loading. The copolymerization kinetics were monitored using in‐situ, variable temperature nuclear magnetic resonance and first‐order behavior was observed with respect to each monomer. Although the related copolymerization of norbornene and maleic anhydride was well‐known to proceed in a perfectly alternating manner, the copolymerization of norbornene and N‐phenylmaleimide was found to deviate from strictly alternating copolymerization behavior, producing significant amounts of sequentially enchained N‐phenylmaleimide units within the polymeric backbone. This deviation from perfectly alternating behavior was confirmed by analysis of individual monomer conversion rates and by measurement of monomer reactivity ratios using the Mayo–Lewis graphical analysis method. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 985–991     

Penultimate Propagation Kinetics of Butyl Methacrylate,Butyl Acrylate,and Styrene Terpolymerization

The pulsed‐laser polymerization technique is used to determine the composition‐averaged free‐radical propagation rate coefficient (k_p,ter) for terpolymerization of butyl methacrylate, butyl acrylate, and styrene between 60 and 120 °C. A significant deviation from terminal model predictions is observed for the ternary system, indicating that penultimate kinetics are important at these industrially relevant temperatures. The implicit penultimate propagation model, with all the coefficients taken from previous studies of the binary systems, provides a good prediction of the experimental k_p,ter results.

     

Synthesis,characterization, thermal properties,and antimicrobial activity of 4‐chloro‐3‐methyl phenyl methacrylate/8‐quinolinyl methacrylate copolymers

4‐Chloro‐3‐methyl phenyl methacrylate (CMPM) and 8‐quinolinyl methacrylate (8‐QMA) were synthesized through the reaction of 4‐chloro‐3‐methyl phenol and 8‐hydroxy quinoline, respectively, with methacryloyl chloride. The homopolymers and copolymers were prepared by free‐radical polymerization with azobisisobutyronitrile as the initiator at 70 °C. Copolymers of CMPM and 8‐QMA of different compositions were prepared. The monomers were characterized with IR spectroscopy and ¹H NMR techniques. The copolymers were characterized with IR spectroscopy. UV spectroscopy was used to obtain the compositions of the copolymers. The monomer reactivity ratios were calculated with the Fineman–Ross method. The molecular weights and polydispersity values of the copolymers were determined with gel permeation chromatography. The thermal stability of the polymers was evaluated with thermogravimetric analysis under a nitrogen atmosphere. The homopolymers and copolymers were tested for their antimicrobial activity againstbacteria, fungi, and yeast. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 157–167, 2005     

Kinetic study of the stable free‐radical copolymerization of styrene with butyl methacrylate

The radical copolymerization of styrene and n‐butyl methacrylate mediated by 1‐phenyl‐1‐(2′,2′,6′,6′‐tetramethyl‐1′‐piperidinyl‐oxy)ethane in bulk at 125 °C has been analyzed over a wide range of conversions and monomer feed compositions. Monomer reactivity ratios have been determined, and the Mayo–Lewis terminal model provides excellent predictions for the variations of the intermolecular structure over the entire conversion range. The kinetic analysis of this copolymerization system indicates an apparent propagation rate coefficient independent of the monomer feed composition as well as a limiting conversion that decreases as the styrene monomer feed decreases. This fact is attributed to side reactions leading to unsaturated end groups and the accumulation of nonactive adducts of n‐butyl methacrylate. The number‐average molecular weights linearly increase with conversion, and the copolymers present narrow molecular weight distributions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2750–2758, 2002     

Synthesis and properties of the polythiourethanes obtained by the cationic ring‐opening polymerization of cyclic thiourethanes

The cationic ring‐opening polymerization of a five‐membered thiourethane [3‐benzyl‐1,3‐oxazolidine‐2‐thione (BOT)] with boron trifluoride etherate afforded the corresponding polythiourethane with a narrow molecular weight distribution in an excellent yield. The molecular weight of the polymers could be controlled by the feed ratio of the monomer to the initiator. A kinetic study of the polymerization revealed that the polymerization rate of BOT (1.3 × 10^?2 L mol^?1 min^?1) was two times larger than that of the six‐membered thiourethane [3‐benzyltetrahydro‐1,3‐oxazolidine‐2‐thione (BTOT); 6.8 × 10^?3 L mol^?1 min^?1], and the monomer conversion obeyed the first‐order kinetic equation. These observations, along with the successful results in the two‐stage polymerization, supported the idea that this polymerization proceeded in a controlled manner. Block copolymerizations of BOT with BTOT were also carried out to afford the corresponding di‐ and triblock copolymers with narrow molecular weight distributions. The order of the 5% weight loss temperatures was as follows: poly(3‐benzyltetrahydro‐1,3‐oxazolidine‐2‐thione) [poly(BTOT)] > poly(BTOT₅₄‐b‐BOT₄₆) > poly(3‐benzyl‐1,3‐oxazolidine‐2‐thione) [poly(BOT)]. This indicated that an increase in the BTOT unit content raised the decomposition temperature. The order of the refractive indices was poly(BOT) > poly(BTOT₅₄‐b‐BOT₄₆) > poly(BTOT₅₄‐b‐BOT₄₆‐b‐BTOT₅₀) > poly(BTOT); this was in accord with the order of the sulfur content in the polymer chain. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4795–4803, 2006     

H‐transfer reaction during decomposition of N‐(2‐methylpropyl)‐ N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines

Thermal decomposition of four tertiary N‐(2‐methylpropyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines (SG1‐C(Me)₂‐C(O)‐OR, R = Me, tBu, Et, H) has been studied at different experimental conditions using ¹H and ³¹P NMR spectroscopies. This experiment represents the initiating step of methyl methacrylate polymerization. It has been shown that H‐transfer reaction occurs during the decomposition of three alkoxyamines in highly degassed solution, whereas no products of H‐transfer are detected during decomposition of SG1‐MAMA alkoxyamine. The value of the rate constant of H‐transfer for alkoxyamines 1 (SG1‐C(Me)₂‐C(O)‐OMe) and 2 ( SG1‐C(Me)₂‐C(O)‐OtBu) has been estimated as 1.7 × 10³ M^?1s^?1. The high influence of oxygen on decomposition mechanism is found. In particular, in poorly degassed solutions, nearly quantitative formation of oxidation product has been observed, whereas at residual pressure of 10^?5 mbar, the main products originate from H‐atom transfer reaction. The acidity of the reaction medium affects the decomposition mechanism suppressing the H‐atom transfer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

N‐vinylcaprolactam‐based microgels: Effect of the concentration and type of cross‐linker

New microgel particles produced by using N‐vinylcaprolactam (VCL) and poly(ethylene glycol) diacrylate (PEGDA) or N,N′‐methylenbisacrylamide (BA) were synthesized in a batch reactor. The influence of the concentration and type of crosslinker on polymerization kinetics and colloidal characteristics of such temperature‐sensitive particles was studied. The partial and total conversion evolutions of VCL, PEGDA, and BA were determined by quantitative ¹H NMR and the average diameters of microgel particles together with the swelling–deswelling behavior were analyzed by means of photon correlation spectroscopy (PCS). Partial and total conversions, final average diameters at collapsed state, and the swelling–deswelling behavior varied as a function of the type of crosslinker. These results were attributed to the higher solubility and stabilizing ability of PEGDA compared with that of BA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2766–2775, 2008     

The influence of N‐vinyl pyrrolidone on polymerization kinetics and thermo‐mechanical properties of crosslinked acrylate polymers

Polymerization of multifunctional acrylate monomers generates crosslinked polymers that are noted for their mechanical strength, thermal stability, and chemical resistance. A common reactive diluent to photopolymerizable formulations is N‐vinyl pyrrolidone (NVP), which is known to reduce the inhibition of free radical photopolymerization by atmospheric oxygen. In this work, the copolymerization behavior of NVP was examined in acrylate monomers with two to five functional groups. At concentrations as low as 2 wt %, NVP increases the polymerization rate in copolymerization with multifunctional acrylate monomer. The relative rate enhancement associated with adding NVP increases dramatically as the number of acrylate double bonds changes from two to five. The influence of NVP on polymerization kinetics is related to synergistic cross‐propagation between NVP and acrylate monomer, which becomes increasingly favorable with diffusion limitations. This synergy extends bimolecular termination into higher double bond conversion through reaction diffusion controlled termination. Copolymerizing concentrations of 5–30 DB% NVP with diacrylate or pentaacrylate monomer also increases Young's modulus and the glass transition temperature (T_g) in comparison to neat acrylate polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4062–4073, 2007     

Emulsion copolymerization of vinylidene chloride and methyl methacrylate. I. Effects of operating variables on the kinetic behavior

The effects of operating variables on the kinetic behavior of the emulsion copolymerization of vinylidene chloride (VDC) and methyl methacrylate (MMA) were examined at 50 °C with sodium lauryl sulfate as an emulsifier and potassium persulfate as an initiator, respectively. The number of polymer particles produced increased in proportion to the 1.0 power of the initial emulsifier concentration and to the 0.3 power of the initial initiator concentration and decreased with an increasing content of MMA in the initial monomer charge. The rate of copolymerization was proportional to the 0.4 power of the initial emulsifier concentration and to the 0.5 power of the initial initiator concentration and increased with an increasing content of MMA in the initial monomer charge. The molecular weight of copolymer produced decreased drastically with an increasing content of VDC in the initial monomer charge. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1275–1284, 2002