DOI: 10.5061/dryad.k0p2ngfdw
title: Data from: Time-resolved, in situ MRI and NMR of polydiketoenamine (PDK) acidolysis

description: 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.
description: # Time-resolved, *in situ* MRI and NMR of polydiketoenamine (PDK)
 acidolysis This dataset
 includes time-resolved T<sub>2</sub>-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 T<sub>2</sub> for three crosslinker size
 variants of polydiketoenamine (PDK) (T403, T300, and T5000) in three
 different 5 M acids (HBr, HCl, and
 H<sub>2</sub>SO<sub>4</sub>). 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 T<sub>2</sub>-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 T<sub>2</sub> 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 T<sub>2</sub>
 distribution is contained in a file named "spectrum.csv."