Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Effect of reaction media on hydrogenolysis of polyethylene plastic waste: Polymer-surface interactions in small alkane/polymer blends

Journal Article · · Applied Catalysis. B, Environmental
 [1];  [2];  [2];  [2];  [2];  [2];  [2]
  1. University of Delaware, Newark, DE (United States); University of Delaware
  2. University of Delaware, Newark, DE (United States)

The polymer reaction media and its properties can be altered by recycling a fraction of liquid products or adding alkane solvents. Less clear is whether this strategy affects hydrogenolysis. Herein, we investigated the effect of short-chain alkanes Cn consisting of n carbons (n=8, 16, and 32) on the upcycling of high-density polyethylene (HDPE) plastic waste to lubricant-range products over Ru/TiO2 catalysts by multiscale simulations and experiments. First, we trained a force field for polymer/surface interactions on a Ru22 nanoparticle (NP) supported on TiO2. Using replica exchange molecular dynamics simulations, we studied the effect of small hydrocarbons on the adsorption of a surrogate polymer, C142, on the catalyst. We found segregation of long chains (C142) at the catalyst surface due to the enthalpy gained by adsorbing more C-C bonds of the long chains, compensating for entropic losses upon adsorption. Short-chain molecules decrease the adsorbed carbons of long chains on the Ru NP due to blocking Ru active sites. Compared to the bulk chains, competitive adsorption results in a broader, heavy-tailed distribution of end-to-end distance of adsorbed chains. Our experiments demonstrated that catalyst activity declines significantly beyond simple dilution due to changes in polymer adsorption, and tuning the reaction media by creating suitable blends impacts hydrogenolysis. Density distributions for a 50:50%wt mixture of PP and PE show that PE chains are segregated at the surface, so they are prone to C-C bond breaking much faster than PP chains. H/D exchange experiments show preferential deuteration of PE, while CH3 groups of PP remain undeuterated. Furthermore, this may be explained by the preferential sorption of PE over PP, leading to specific distribution in the polymer blend.

Research Organization:
University of Delaware, Newark, DE (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
Grant/Contract Number:
SC0021166
OSTI ID:
2324888
Alternate ID(s):
OSTI ID: 2340209
Journal Information:
Applied Catalysis. B, Environmental, Journal Name: Applied Catalysis. B, Environmental Vol. 351; ISSN 0926-3373
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (49)

Molecular modeling of organic and biomolecular systems usingBOSS andMCPRO journal January 2005
Infrared spectra of crystalline and stereoregular polymers. II. Carbon—hydrogen and carbon—deuterium stretching frequencies of polypropylene and deuterated polypropylenes journal November 1960
The pressure-volume-temperature properties of polyethylene, poly(dimethyl siloxane), poly(ethylene glycol) and poly(propylene glycol) as a function of molecular weight journal January 1992
Replica-exchange molecular dynamics method for protein folding journal November 1999
A general strategy and a consolidated mechanism for low-methane hydrogenolysis of polyethylene over ruthenium journal December 2022
Ni/SiO2 catalysts for polyolefin deconstruction via the divergent hydrogenolysis mechanism journal March 2023
LAMMPS - a flexible simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales journal February 2022
Moltemplate: A Tool for Coarse-Grained Modeling of Complex Biological Matter and Soft Condensed Matter Physics journal May 2021
C 6 Coefficients and Dipole Polarizabilities for All Atoms and Many Ions in Rows 1–6 of the Periodic Table journal July 2016
Tinker 8: Software Tools for Molecular Design journal August 2018
Hydrogenolysis of Linear Low-Density Polyethylene during Heterogeneous Catalytic Hydrogen–Deuterium Exchange journal July 2020
Polypropylene Plastic Waste Conversion to Lubricants over Ru/TiO 2 Catalysts journal June 2021
UFF, a full periodic table force field for molecular mechanics and molecular dynamics simulations journal December 1992
Polyethylene Hydrogenolysis at Mild Conditions over Ruthenium on Tungstated Zirconia journal August 2021
Hydrogen-deuterium exchange for labeling polyethylene journal April 1989
Detailed Atomistic Simulation of a Polymer Melt/Solid Interface:  Structure, Density, and Conformation of a Thin Film of Polyethylene Melt Adsorbed on Graphite journal June 2005
Adsorption of Polymer Solutions onto a Flat Surface journal January 1996
Electronic modulation of metal-support interactions improves polypropylene hydrogenolysis over ruthenium catalysts journal September 2022
Catalytic upcycling of high-density polyethylene via a processive mechanism journal October 2020
Introducing DDEC6 atomic population analysis: part 1. Charge partitioning theory and methodology journal January 2016
Introducing DDEC6 atomic population analysis: part 2. Computed results for a wide range of periodic and nonperiodic materials journal January 2016
Introducing DDEC6 atomic population analysis: part 3. Comprehensive method to compute bond orders journal January 2017
Introducing DDEC6 atomic population analysis: part 4. Efficient parallel computation of net atomic charges, atomic spin moments, bond orders, and more journal January 2018
First principles characterisation of bio–nano interface journal January 2021
Polyolefin plastic waste hydroconversion to fuels, lubricants, and waxes: a comparative study journal December 2021
Conversion of plastic waste into high-value lubricants: techno-economic analysis and life cycle assessment journal January 2022
Antioxidant-induced transformations of a metal-acid hydrocracking catalyst in the deconstruction of polyethylene waste journal January 2022
Conformations of polyolefins on platinum catalysts control product distribution in plastics recycling journal January 2023
Parallel tempering: Theory, applications, and new perspectives journal January 2005
Multidimensional replica-exchange method for free-energy calculations journal October 2000
Adsorption of Polymer Molecules at Low Surface Coverage journal April 1965
Selection of temperature intervals for parallel-tempering simulations journal May 2005
Statistically optimal analysis of samples from multiple equilibrium states journal September 2008
A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu journal April 2010
A unified formulation of the constant temperature molecular dynamics methods journal July 1984
Surface segregation in polymer blends due to stiffness disparity journal March 1994
Diffusion in binary liquid n-alkane and alkane-polyethylene blends journal July 1999
Simplified TiO 2 force fields for studies of its interaction with biomolecules journal June 2015
How polarizabilities and C 6 coefficients actually vary with atomic volume journal August 2016
Molecular Dynamics Simulation of the Structural and Physical Properties of the Four Polymorphs of TiO 2 journal May 1991
Canonical dynamics: Equilibrium phase-space distributions journal March 1985
Projector augmented-wave method journal December 1994
Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals journal March 1999
Accurate Molecular Van Der Waals Interactions from Ground-State Electron Density and Free-Atom Reference Data journal February 2009
Entropy-driven surface segregation in block copolymer melts journal January 1993
Entropic and Enthalpic Surface Segregation from Blends of Branched and Linear Polymers journal March 1995
Complete Wetting from Polymer Mixtures journal November 1992
Exchange Monte Carlo Method and Application to Spin Glass Simulations journal June 1996
The Critical Role of Process Analysis in Chemical Recycling and Upcycling of Waste Plastics journal March 2022

Similar Records

Hydrogenolysis of Poly(Ethylene–co–Vinyl Alcohol) and Related Polymer Blends over Ruthenium Heterogeneous Catalysts
Journal Article · Fri Apr 12 00:00:00 EDT 2024 · ChemSusChem · OSTI ID:2338152

Ni/SiO2 catalysts for polyolefin deconstruction via the divergent hydrogenolysis mechanism
Journal Article · Wed Nov 02 00:00:00 EDT 2022 · Applied Catalysis. B, Environmental · OSTI ID:2421774

Direct Structural Evidence for Interfacial Gradients in Asymmetric Polymer Nanocomposite Blends
Journal Article · Thu Jul 22 00:00:00 EDT 2021 · ACS Applied Materials and Interfaces · OSTI ID:1870250