Polymers depolymerizable by metathesis of a cleavable unit

Patent metadata

Field	Value
Publication number	US-11873367-B2
Application number	US-202117244012-A
Country	US
Kind code	B2
Filing date	Apr 29, 2021
Priority date	May 28, 2020
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

Novel polymers are depolymerizable by metathesis of a cleavable unit. As an example, a series of linear and crosslinked polyurethanes were prepared that can be selectively depolymerized under mild conditions. Two unique polyols were synthesized bearing unsaturated units in a configuration designed to favor ring-closing metathesis to five- and six-membered cycloalkenes. These polyols were co-polymerized with toluene diisocyanate to generate linear polyurethanes and trifunctional hexamethylene- and diphenylmethane-based isocyanates to generate crosslinked polyurethanes. The polyol design is such that the ring-closing metathesis reaction cleaves the backbone of the polymer chain. Upon exposure to dilute solutions of Grubbs' catalyst under ambient conditions, the polyurethanes were rapidly depolymerized to low molecular weight, soluble products bearing vinyl and cycloalkene functionalities. These functionalities enabled further re-polymerization by traditional strategies for polymerization of double bonds. This general approach can be expanded to develop a range of chemically recyclable condensation polymers that are readily depolymerized by orthogonal metathesis chemistry.

First claim

We claim:

1. A depolymerizable polymer, comprising a condensation polymer, wherein a monomeric unit of the condensation polymer is formed by reacting a functional group of a cleavable monomer, comprising two or more double bonds, at least one double bond placed in a main-chain configuration and at least one double bond placed in a side-chain configuration, with a different monomer, and wherein the cleavable monomer is cleavable by ring-closing metathesis.

2. The depolymerizable polymer of claim 1 , wherein the functional group of the cleavable monomer comprises a hydroxyl, amino, epoxide, isocyanate, aldehyde, anhydride, carboxyl group, or other non-vinyl species.

3. The depolymerizable polymer of claim 1 , wherein the condensation polymer comprises a polyurethane.

4. The depolymerizable polymer of claim 3 , wherein the cleavable monomer comprises 8-hydroxylinalool, (E)-nona-3,8-diene-1,5-diol, or (E)-deca-3,9-diene-1,5-diol.

5. The depolymerizable polymer of claim 1 , wherein the different monomer comprises an isocyanate.

6. The depolymerizable polymer of claim 5 , wherein the isocyanate comprises isophorone diisocyanate, methylene diphenyl diisocyanate, or hexamethylene diisocyanate.

7. The depolymerizable polymer of claim 1 , wherein the condensation polymer comprises a polymer formed from polycondensation of non-vinyl species.

8. The depolymerizable polymer of claim 7 , wherein the condensation polymer comprises a polyurethane, polyamide, or polyester.

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Jones Brad Howard
• Staiger Chad Lynn

Classifications

• C08G18/3206 Primary

  aliphatic · CPC title

• C07C6/04

  at a carbon-to-carbon double bond · CPC title

• C08G18/3212

  containing cycloaliphatic groups · CPC title

• C08G18/675

  Low-molecular-weight compounds · CPC title

• C08G18/725

  Combination of polyisocyanates of C08G18/78 with other polyisocyanates · CPC title