Data from: Time-resolved, in situ MRI and NMR of polydiketoenamine (PDK) acidolysis
Data files
Feb 13, 2024 version files 19.66 GB
Abstract
Moving toward a circular plastics economy is a vital aspect of global resource management. Chemical recycling of plastics ensures high-value monomers can be recovered from depolymerized plastic waste, thus enabling circular manufacturing. However, to increase chemical recycling throughput in materials recovery facilities, the present understanding of polymer transport, diffusion, swelling, and heterogeneous deconstruction kinetics must be systematized to allow industrial-scale process design, spanning molecular to macroscopic regimes. To develop a framework for designing depolymerization processes, we examined acidolysis of circular polydiketoenamine (PDK) elastomers. We employed magnetic resonance to monitor spatially resolved observables in situ, then evaluated these data with a fractal method that treats nonlinear depolymerization kinetics. This approach delineated the roles played by network architecture and reaction medium on depolymerization outcomes, yielding parameters that facilitate comparisons between bulk processes. These streamlined methods to investigate polymer hydrolysis kinetics portend a general strategy for implementing chemical recycling on an industrial scale.
README: Time-resolved, in situ MRI and NMR of polydiketoenamine (PDK) acidolysis
https://doi.org/10.5061/dryad.k0p2ngfdw
This dataset includes time-resolved T2-weighted spin echo images, time-resolved pulsed gradient spin echoes (PGSEs) to report the apparent diffusion coefficient (ADC), and time-resolved CPMG echo train decays to report T2 for three crosslinker size variants of polydiketoenamine (PDK) (T403, T300, and T5000) in three different 5 M acids (HBr, HCl, and H2SO4). Images are taken in the axial orientation for 8 mm cylinders of PDK contained in a 10 mm NMR tube, with c.a. 1 cc of acid surrounding the polymer.
Description of the data and file structure
1. [in the folders with names starting with "PD_"] Imaging and diffusion were performed on a Pure Devices benchtop research instrument using the company's openMatlab software. Data for each unique sample (PDK variant/acid combination) is contained within a folder named GUI_PDK_XX_YY where "XX" denotes the crosslinker size of the PDK, and "YY" denotes the acid. Within each sample folder, time-resolved data from each experiment are grouped into folders titled by date/time_experiment name_XX_YY. The experiment name for T2-weighted spin echo images is"SpinEcho2DImage," and the experiment name for PGSEs is "ADC." Each experiment folder contains a .mat (Matlab) file containing a dataset structure with all relevant data and parameters from each experiment as provided via the openMATLAB interface from Pure Devices.
2. [in the folder with name starting with "MOUSE_"] CPMG data for time-resolved T2 was performed with a PM 25 NMR-MOUSE interfaced to a Kea II spectrometer using Magritek's Prospa software. This dataset includes the published T5000/H2SO4 combination. For this sample, experiments are contained in folders titled cpmg#, where the number denotes the experiment number in order. Within these folders, the raw echo train data and corresponding time vector are contained in a file named "data.csv"; the Prospa-generated Laplace inversion to yield the corresponding T2 distribution is contained in a file named "spectrum.csv."