MMA bulk polymerization and its influence on <i>in situ</i> resin viscosity comparing several chemorheological models

Teyssandier, Fabien; Love, Brian J.

doi:10.1002/app.33214

Cited by 10 publications

(10 citation statements)

References 32 publications

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“…Any dip in viscosity is unaccounted for in the sigmoidal model. The value for, g ' is an extrapolation which we assigned as 1 3 10 5 Pa Á s, similar to other network structures we had analyzed earlier [17]. The physical significance of g ' is an open question, particularly because commonly accepted theories of gelation point to an infinite viscosity, whereas experimental measurements are limited particularly at high conversion due to the torque limit of each rheometer.…”

Section: Resultssupporting

confidence: 75%

“…The scarcity of higher viscosity measurements raises the potential that the g ' asymptote needs refinement. It's interesting to note that in earlier studies, logarithmic sigmoidal viscosity advancement models were more accurate for radical polymerization mechanisms using acrylates [12,17] as well as for epoxy resins [12,15]. The step polymerization from the monomer for the polyurethanes by Lipshitz and Macosko shows that, perhaps, the log sigmoidal is not as generic as a model for viscosity advancement.…”

Section: Resultsmentioning

confidence: 98%

“…We have found the modified Boltzmann sigmoidal model, shown in Eq. 2, represents viscosity advancement extremely well both for photopolymerized acrylates [12], thermally advanced acrylates [17], and also for epoxy resins formulated as chip under fill materials [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Cure advancement of urethane networks using a sigmoidal chemorheological model

Teyssandier

Love

2009

Polymer Engineering & Sci

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Archived measurements of urethane rheology undergoing crosslinking at 45, 55, and 65°C were reanalyzed by a sigmoidal mathematical model. The phenomenological sigmoidal model, with two kinetic parameters associated with cure advancement coupled with parameters for the initial viscosity and the terminal viscosity of the network, captures the nonlinearities in dynamic viscosity during polymerization and were similarly compared with a power law model. The interpretation of the gel time was determined using both models, with the sigmoidal model interpretation of the gel time being defined in terms of the other kinetic constants. The takeaway message is that there is very little difference in the quality of the fit between the power law model and the sigmoidal model and the experimental dynamic viscosity data. One would need a more comprehensive dataset to make a larger comparison as to which model actually represents viscosity more accurately. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

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Section: Resultssupporting

confidence: 75%

Section: Resultsmentioning

confidence: 98%

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Cure advancement of urethane networks using a sigmoidal chemorheological model

Teyssandier

Love

2009

Polymer Engineering & Sci

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“…The molecular weight and the viscosity of copolymer increased. The torque of the copolymer is proportional to the viscosity, which increased with time as the polymerization progressed 30,31 . Most the viscosity of the reaction mixture increase dramatically with consuming monomers (CL).…”

Section: Resultsmentioning

confidence: 99%

Solvent-free bulk polymerization of lignin-polycaprolactone (PCL) copolymer and its thermoplastic characteristics

Park

Sun

Kim

et al. 2019

Sci Rep

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The pristine lignin molecules contain multiple reactive hydroxyl [OH] groups, some of which undergo limited polymerization depending on their configuration (aromatic or aliphatic) or conformation. The key issue in lignin-polymerization is to quantify the number of hydroxyl groups in the pristine molecules for subsequent activation to specific lignin-polymer chain lengths or degree of grafting. In this study, using ε-caprolactone (CL) as a reactive solvent, we successfully polymerized CL on the [OH] sites in the kraft lignin macromonomers (LM, Mw = 1,520 g mol−1), which resulted in a thermoplastic lignin-polycaprolactone (PCL) grafted copolymer. We found that the average number of [OH] groups in the LM was 15.3 groups mol−1, and further detected 40–71% of the [OH] groups in the CL bulk polymerization. The degree of polymerization of PCL grown on each [OH] site ranged between 7 and 26 depending on the reaction conditions ([CL]/[OH] and reaction-time) corresponding to 4,780 and 32,600 g mol−1 of PCL chains per a LM. The thermoplastic characteristics of the synthesized lignin-PCL copolymers were established by the melt viscosity exhibiting a shear-thinning behavior, e.g., 921 Pa.s at 180 °C. The thermal stability was remarkable providing a Tid (2% of weight loss) of 230 °C of the copolymers, compared with 69 °C for the pristine lignin.

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“…Other nonlinear rheological models have been advanced based on parameters indicative of resin reactivity, thermodynamic models similar to the WLF model and other semi‐empirical models to describe time‐dependent viscosity including our work on the log‐Boltzmann sigmoidal model shown in Eqn (1):