Bulk Depolymerization of Methacrylate Polymers via Pendent Group Activation.

In this study, we present an efficient approach for the depolymerization of poly(methyl methacrylate) (PMMA) copolymers synthesized via conventional radical polymerization. By incorporating low mol % phthalimide ester-containing monomers during the polymerization process, colorless and transparent polymers closely resembling unfunctionalized PMMA are obtained, which can achieve >95% reversion to methyl methacrylate (MMA). Notably, our catalyst-free bulk depolymerization method exhibits exceptional efficiency, even for high-molecular-weight polymers, including ultrahigh-molecular-weight (10-10 g/mol) PMMA, where near-quantitative depolymerization is achieved.

Inverse Miniemulsion Enables the Continuous-Flow Synthesis of Controlled Ultra-High Molecular Weight Polymers.

We report the controlled synthesis of ultra-high molecular weight (UHMW) polymers ( ≥ 10 g/mol) via continuous flow in a tubular reactor. At high monomer conversion, UHMW polymers in homogeneous batch polymerization exhibit high viscosities that pose challenges for employing continuous flow reactors. However, under heterogeneous inverse miniemulsion (IME) conditions, UHMW polymers can be produced within the dispersed phase, while the viscosity of the heterogeneous mixture remains approximately the same as the viscosity of the continuous phase.

Excitation Dependence in Photoiniferter Polymerization.

We report on a fundamental feature of photoiniferter polymerizations mediated with trithiocarbonates and xanthates. The polymerizations were found to be highly dependent on the activated electronic excitation of the iniferter. Enhanced rates of polymerization and greater control over molecular weights were observed for trithiocarbonate- and xanthate-mediated photoiniferter polymerizations when the n → π* transition of the iniferter was targeted compared to the polymerizations activating the π → π* transition.

Magnetic Properties of High-Nuclearity Fe-oxo ( = 7, 22, 24) Clusters Analyzed by a Multipronged Experimental, Computational, and Magnetostructural Correlation Approach.

The synthesis, structure, and magnetic properties of three related iron(III)-oxo clusters are reported, [FeO(OCPh)(mda)(HO)] (), [FeO(OH)(OCMe)(mda)](ClO) (), and [FeO(OH)(OEt)(OCMe)(mda)](ClO) (), where mdaH is -methyldiethanolamine. was prepared from the reaction of [FeO(OCPh)(HO)](NO) with mdaH in a 1:2 ratio in MeCN, whereas and were prepared from the reaction of FeCl/NaOCMe/mdaH in a 2:∼13:2 ratio and FeCl/NaOCMe/mdaH/pyridine in a 2:∼13:2:25 ratio, respectively, both in EtOH. The core of consists of a central octahedral Fe ion held within a nonplanar Fe loop by three μ-O and three μ-RO arms from the three mda chelates.