Bulk Free Radical Terpolymerization of Butyl Acrylate, 2-Methylene-1,3-Dioxepane and Vinyl Acetate: Terpolymer Reactivity Ratio Estimation

This investigation introduces the first estimation of ternary reactivity ratios for a butyl acrylate (BA), 2-methylene-1,3-dioxepane (MDO), and vinyl acetate (VAc) system at 50 °C, with an aim to develop biodegradable pressure-sensitive adhesives (PSAs). In this study, we applied the error-in-variables model (EVM) to estimate reactivity ratios. The ternary reactivity ratios were found to be r12 = 0.417, r21 = 0.071, r13 = 4.459, r31 = 0.198, r23 = 0.260, and r32 = 55.339 (BA/MDO/VAc 1/2/3), contrasting with their binary counterparts, which are significantly different, indicating the critical need for ternary system analysis to accurately model multicomponent polymerization systems. Through the application of a recast Alfrey-Goldfinger model, this investigation predicts the terpolymer's instantaneous and cumulative compositions at various conversion levels, based on the ternary reactivity ratios. These predictions not only provide crucial insights into the incorporation of MDO across different initial feed compositions but also offer estimates of the final terpolymer compositions and distributions, underscoring their potential in designing compostable or degradable polymers.

Film Formation of Iodinated Latex Dispersions and Its Role in Their Antimicrobial Activity

Waterborne coatings with intrinsic antibacterial attributes have attracted significant attention due to their potential in mitigating microbial contamination while simultaneously addressing the environmental drawbacks of their solvent-based counterparts. Typically, antimicrobial coatings are designed to resist and eliminate microbial threats, encompassing challenges such as biofilm formation, fungal contamination, and proliferation of black mold. Iodine, when solubilized using ethylene glycol and incorporated as a complex into waterborne latex dispersions, has shown remarkable antimicrobial activity. Here, we demonstrate the effect of the film formation process of these iodinated latex dispersions on their antimicrobial properties. The effect of iodine on the surface morphology and mechanical, adhesion, and antimicrobial properties of the generated films was investigated. Complete integration and uniform distribution of iodine in the films were confirmed through UV-vis spectrophotometry and a laser Raman imaging system (LRIS). In terms of properties, iodinated films showed improved mechanical strength and adhesion compared with blank films. Further, the presence of iodine rendered the films rougher, making them susceptible to bacterial adhesion, but interestingly provided enhanced antibiofilm activity. Moreover, thicker films had a lower surface roughness and reduced biofilm growth. These observations are elucidated through the complex interplay among film thickness, surface morphology, and iodine properties. The insights into the interlink between the film formation process and antimicrobial properties of iodinated latex dispersions will facilitate their enhanced application as sustainable alternatives to solvent-based coatings.

Degradation of a series of fluorinated acrylates and methacrylates initiated by OH radicals at different temperatures

Rate coefficients for the gas-phase reactions of OH radicals with a series of fluorinated acrylates and methacrylates have been measured for the first time as a function of temperature in the range 290–308 K.

Modeling of the Free Radical Copolymerization Kinetics of n-Butyl Acrylate, Methyl Methacrylate and 2-Ethylhexyl Acrylate Using PREDICI®

Kinetic modeling of the bulk free radical copolymerizations of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (EHA); methyl methacrylate (MMA) and EHA; as well as BA, MMA and EHA was performed using the software PREDICI®. Predicted results of conversion versus time, composition versus conversion, and molecular weight development are compared against experimental data at different feed compositions. Diffusion-controlled effects and backbiting for BA were incorporated into the model as they proved to be significant in these polymerizations. The set of estimated global parameters allows one to assess the performance of these copolymerization systems over a wide range of monomer compositions.

Arrhenius parameters for the OH-initiated degradation of methyl crotonate, methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate over the temperature range of 288–314 K

The relative-rate technique has been employed to obtain rate coefficients for the reactions of OH radicals with methyl crotonate, methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate between 288 and 314 K in 760 Torr of air.

Theoretical investigation of an atmospherically important reaction between methyl methacrylate and Cl atom: A mechanistic and kinetic approach

A theoretical investigation of the mechanism, kinetics and probable product analysis of the Cl -initiated oxidation reaction of methyl methacrylate (MMA) is presented in this paper. The major degradation pathway of MMA is the Cl -addition to the terminal carbon of the olefinic bond. Beside this, energetic and mechanism of other possible reaction pathways are discussed in detail. In addition, the mechanism for the secondary reactions in presence of O 2 and NO has also been presented. Cl -addition to the double bond takes place via formation of the pre-reactive complex as these reaction channel passes through negative activation barrier. Energetics and thermochemical analysis have been studied at the MP2=Full/6-311++g(d,p) level of theory. The rate constant of the Cl -addition reaction has been calculated using conventional transition state theory (CTST) at 1 atm pressure and 250–350 K temperature range.

Night-time atmospheric chemistry of methacrylates

BACKGROUND, AIM, AND SCOPE

Methacrylates are α, β-unsaturated esters that are widely used in the polymer plastics and resins production. Kinetic information of NO(3) radical reactions is especially scarce and a good understanding of all the atmospheric oxidation processes of these compounds is necessary in order to determine lifetimes in the atmosphere and to evaluate the impact of these reactions on the formation of ozone and other photooxidants.

MATERIALS AND METHODS

The experiments have been carried out using the relative technique in a static Teflon reactor at room temperature and atmospheric pressure (N(2) as bath gas) using gas chromatography (GC)-flame ionization detection (FID) as detection system. Products were analyzed using solid phase microextraction (SPME)-GC-mass spectrometry (MS) technique and Fourier transform infrared spectroscopy (FTIR) using air as bath gas.

RESULTS

The following rate coefficients were obtained (in cm(3) molecule(-1) s(-1)): methyl methacrylate + NO(3) = (3.55 ± 0.62) × 10(-15), ethyl methacrylate + NO(3) = (5.42 ± 1.90) × 10(-15), butyl methacrylate + NO(3) = (7.87 ± 3.86) × 10(-15). Methylpyruvate, ethylpyruvate, and butylpyruvate/butanol were identified as main degradation products respectively in the GC-MS analysis. Nitrates compounds were also identified in the FTIR study.

DISCUSSION

The reactivity increases with the substitution and with the chain of the alkyl group in -C(O)OR. An electrophilic addition mechanism is proposed as dominant degradation process. Estimations of the atmospheric lifetimes clearly indicate that the dominant atmospheric loss process for methacrylate esters is their daytime reaction with the hydroxyl radical. NO(3) and ozone are the main oxidants at night time.

RECOMMENDATIONS AND PERSPECTIVES

A detailed products analysis including quantification could elucidate the mechanism for butanol generation for butyl methacrylate reaction.