Synergy of Advanced Experimental and Modeling Tools to Underpin the Synthesis of Static Step-Growth-Based Networks Involving Polymeric Precursor Building Blocks

Abstract

The strength of combining experimental design and advanced kinetic Monte Carlo (kMC) modeling to understand step-growth network synthesis, commencing with a linear/star polymeric precursor, is illustrated considering three chemistries: (i) para-fluoro-thiol reaction (PFTR); (ii) nitrile imine-mediated tetrazole-ene cycloaddition (NITEC); and (iii) star poly­(ethylene oxide-stat-propylene oxide) (sPEG)-amine-epoxy click reaction. Chemical parameters are determined based on small-molecule systems (monofunctional analogues) and diffusion parameters based on literature data and higher-network-yield data. Overall model validation is performed considering molar mass and spectroscopic experimental data. As basic support, kMC modeling provides the evolution of the complete size exclusion chromatography trace for both the soluble and the insoluble fraction at any time. In more detail, kMC modeling allows one to construct, whenever desired, two-dimensional traces such as the distribution of species with a given molar mass and number of cross-linking points (CPs) of a given type (e.g., with at least three cross-links), still differentiating between the soluble and insoluble fractions. Ultimately, postprocessing of kMC modeling results allows one to calculate distributions regarding distances between specific functional groups and the molecular pore size distribution upon considering a three-dimensional representation of the molecular buildup of individual network molecules. Also, the (relative) importance of reaction pathways can be assessed. It is, for instance, shown that diffusional limitations on intermolecular reactions determine how far a polymer network yield can be pushed, with a strong effect due to an intrinsically fast maleimide incorporation step, specifically for NITEC. Too long linear precursor building blocks should be avoided as they induce too prominent diffusional limitations. Too short linear precursor building blocks promote intramolecular reactions. With the sPEG building blocks, a well-defined structure is obtained, as confirmed by the narrow distribution regarding the distances between dye molecules added in the polymerization recipe.

Synthesis and Characterization of New Polycarbonate-Based Poly(thiourethane-urethane)s

“…All these mechanisms change the amount and distribution of the HS and SS and lead to variation in the final properties [ 10 , 11 ]. This aspect of molar mass variation for polymeric network has been highlighted as well by De Keer et al [ 25 ].…”

Combining Chromatographic, Rheological, and Mechanical Analysis to Study the Manufacturing Potential of Acrylic Blends into Polyacrylic Casts

“…Cases 8 and 10, which correspond to the highest proportions of EGD and EGDA crosslinker, also developed temperatures that were high enough to ca cracking of the vials containing the reaction mixture upon quenching in liquid nitrog The occurrence of this cracking is shown by the crosses in the second and fourth row Table 2. To further understand this undesired phenomenon, the solid frozen content co be recovered in one piece and put in dichloromethane in preparation for GC analy Nonetheless, the samples with high crosslinking amounts could not be dissolved afte h, highlighting the sufficiently crosslinked nature of the polymer formed [94]. Hence ward the development of casting applications, care should be taken not to increase crosslinking amount too much.…”

“…To further understand this undesired phenomenon, the solid frozen content could be recovered in one piece and put in dichloromethane in preparation for GC analysis. Nonetheless, the samples with high crosslinking amounts could not be dissolved after 72 h, highlighting the sufficiently crosslinked nature of the polymer formed [94]. Hence, toward the development of casting applications, care should be taken not to increase the crosslinking amount too much.…”

Kinetic modeling of simultaneous polycondensation and free radical polymerization for polyurethane/poly(methyl methacrylate) interpenetrating polymer network

“…With the development of computer simulation, kinetic models have been widely used in modeling chain-growth polymerization such as free radical polymerization, [21][22][23][24][25][26][27] free radical-induced grafting and cross-linking, [28][29][30][31][32][33] and step-growth polymerization. [34][35][36][37] Unfortunately, few broadly applicable kinetic models to reveal competitive hybrid independent mechanisms are available in IPN synthesis.…”