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1. Blocky Selective Postpolymerization C–H Functionalization of Polyolefins

   https://doi.org/10.1002/anie.202507687  

   Neidhart, Eliza K; Pomatto, Michelle E; Vasallo, Chris; Crater, Erin R; Alty, Jill W; Angelopoulou, Polyxeni P; Alexanian, Erik J; Kearney, Logan T; Moore, Robert B; Leibfarth, Frank A (June 2025, Angewandte Chemie International Edition)

   C–H functionalization of commodity polyolefins affords functional materials derived from a high‐volume, low‐cost resource. However, current postpolymerization modification strategies result in randomly distributed functionalization along the length of the polymer backbone, which has a negative impact on the crystallinity of the resultant polymers, and thus the thermomechanical properties. Here, we demonstrate an amidyl radical mediated C–H functionalization of polyolefins to access blocky microstructures, which exhibit a higher crystalline fraction, larger crystallite size, and improved mechanical properties compared to their randomly functionalized analogues. Taking inspiration from the site‐selective C–H functionalization of small molecules, we leverage the steric protection provided by crystallites and target polymer functionalization to amorphous domains in a semicrystalline polyolefin gel. The beneficial outcomes of blocky functionalization are independent of the identity of the pendant functional group that is installed through functionalization. The decoupling of functional group incorporation and crystallinity highlights the promise in accessing nonrandom microstructures through selective functionalization to circumvent traditional tradeoffs in postpolymerization modification, with potential impact in advanced materials and upcycling plastic waste. 

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2. Sparsity-promoting hierarchical Bayesian model for EIT with a blocky target

   https://doi.org/10.1016/j.jcp.2025.114255  

   Calvetti, D; Pragliola, M; Somersalo, E (October 2025, Journal of Computational Physics)
3. Origin of blocky aragonite cement in Cenozoic glaciomarine sediments, McMurdo Sound, Antarctica

   https://doi.org/10.1111/sed.12690  

   Yang, Mingyu; Frank, Tracy D.; Fielding, Christopher R.; Smith, Megan E.; Swart, Peter K.; Reijmer, ed., John (December 2019, Sedimentology)

   Abstract Inorganic aragonite occurs in a wide spectrum of depositional environments and its precipitation is controlled by complex physio‐chemical factors. This study investigates diagenetic conditions that led to aragonite cement precipitation in Cenozoic glaciomarine deposits of McMurdo Sound, Antarctica. A total of 42 sandstones that host intergranular cement were collected from theCIROS‐1 core, located proximal to the terminus of Ferrar Glacier. Standard petrography, Raman spectroscopy and electron microprobe analysis reveal a prominent aragonite cement phase that occurs as a pore‐filling blocky fabric throughout the core. Oxygen isotope compositions (δ¹⁸O = −30·0 to −8·6‰ Vienna Pee‐Dee Belemnite) and clumped isotope temperatures (TΔ₄₇ = 13·1 to 31·5°C) determined from the aragonite cements provide precise constraints on isotopic compositions (δ¹⁸O_w) of the parent fluid, which mostly range from −10·8 to −7·2‰ Vienna Standard Mean Ocean Water. The fluidδ¹⁸O_wvalues are consistent with those of pore water, previously identified as cryogenic brine in the nearbyAND‐2A core. Petrographic and geochemical data suggest that aragonite cement in theCIROS‐1 core precipitated from a similar brine. The brine likely formed and infiltrated sediments in flooded glacial valleys along the western margin of McMurdo Sound during the middle Miocene Climatic Transition, and subsequently flowed basinward in the subsurface. Consequently, the brine forms as a longstanding subsurface fluid that has saturated Cenozoic sediments below southern McMurdo Sound since at least the middle Miocene. Aragonite cementation in theCIROS‐1 core is interpreted to reflect its proximal position to sites of brine formation and greater likelihood of experiencing brines with sustained high carbonate saturation states and Mg/Ca ratios. This unusual occurrence expands the range of known natural occurrences of aragonite cement. Given the potential for cryogenic brine formation in glaciomarine settings, blocky aragonite, as the end member of the spectrum of aragonite cement morphology, may be more widespread in glaciomarine sediments than currently thought. 

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4. Blocky Ionomers via Sulfonation of Poly(ether ether ketone) in the Semicrystalline Gel State

   https://doi.org/10.1021/acs.macromol.8b01152  

   Anderson, Lindsey J.; Yuan, Xijing; Fahs, Gregory B.; Moore, Robert B. (August 2018, Macromolecules)
5. Blocky bromination of syndiotactic polystyrene via post-polymerization functionalization in the heterogeneous gel state

   https://doi.org/10.1039/c8py01008k  

   Noble, Kristen F.; Noble, Alexandria M.; Talley, Samantha J.; Moore, Robert B. (October 2018, Polymer Chemistry)

   This work demonstrates the successful blocky bromination of syndiotactic polystyrene (sPS- co -sPS-Br) copolymers containing 6–30 mol% p -bromostyrene units, using a post-polymerization functionalization method conducted in the heterogeneous gel state. For comparison, a matched set of randomly brominated sPS- co -sPS-Br copolymers was prepared using homogeneous (solution-state) reaction conditions. The degree of bromination and copolymer microstructure were evaluated using 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra of gel-state (Blocky) and solution-state (Random) copolymers exhibit strikingly different resonance frequencies and peak intensities above 6 mol% Br and provide direct evidence that functionalization in the gel state produces copolymers with non-random “blocky” microstructures. Quenched films of the Blocky copolymers, analyzed using ultra-small-angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS), show micro-phase separated morphologies, which further supports that the Blocky copolymers contain distinct segments of pure sPS and segments of randomly brominated sPS unlike their completely Random analogs. Crystallization behavior of the copolymers, examined using differential scanning calorimetry (DSC), demonstrates that the Blocky copolymers are more crystallizable and crystallize faster at lower supercooling compared to their Random analogs. Computer simulations of the blocky copolymers were developed based on the semicrystalline morphology of a 10 w/v% sPS/CCl 4 gel, to rationalize the effect of heterogeneous functionalization on copolymer microstructure and crystallization behavior. The simulations were found to agree with the microstructural analysis based on the NMR results and confirm that restricting the accessibility of the brominating reagent to monomers well removed from the crystalline fraction of the gel network produces copolymers with a greater prevalence of long, uninterrupted sPS homopolymer sequences. Thus, the blocky microstructure is advantageous for preserving desired crystallizability of the resulting blocky copolymers. 

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