Crosslinked Polylactone Elastomers via Dynamic Covalent Bonds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Crosslinked polymers, despite offering advantages like thermal stability and solvent resistance, are non-reprocessable and predominantly petroleum-based, leading to environmental concerns due to disposal issues and poor recyclability, with biodegradable alternatives often exhibiting undesirable properties such as low thermal stability and poor solvent resistance.
Innovation Solution
Development of biodegradable and renewable crosslinked polylactone elastomers through tandem copolymerization/crosslinking of lactone monomers with cyclic carbonates or crosslinking of linear lactone homopolymers using free-radical generators, allowing for chemical recycling and degradation under moderate conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If crosslinked polymers are used to achieve thermal stability and solvent resistance, then the material stability is improved, but the reprocessability and recyclability deteriorate
Solution Approach 1:
The patent applies parameter changes by transitioning from traditional permanent covalent crosslinks to reversible dynamic covalent bonds (vitrimers). The crosslinking density and bond reversibility are tuned through catalyst selection and processing temperature, enabling the material to exhibit both thermal stability and reprocessability. The vitrimer network allows stress relaxation and chain rearrangement above the glass transition temperature, facilitating reprocessing while maintaining structural integrity at service temperatures.
Solution Approach 2:
The patent implements dynamics by introducing dynamic covalent chemistry into the polymer network. The crosslinks are not static but can reversibly break and reform under specific conditions (temperature, catalyst presence). This dynamic behavior enables the material to flow and be reprocessed when heated, while maintaining dimensional stability and mechanical properties at lower temperatures. The exchange reactions allow the network to adapt its topology during processing.
2Duration of action of stationary object
If conventional crosslinked polymers are used to achieve durability, then the service life is improved, but the environmental impact worsens due to landfill disposal
Solution Approach 1:
The patent applies discarding and recovering by enabling the chemical recycling of crosslinked polymers through depolymerization. The vitrimer network can be selectively broken down using catalysts or specific conditions to regenerate the original monomers or oligomers, which can then be repolymerized to create new materials. This closed-loop approach allows near-complete recovery of valuable materials, eliminating the need for landfill disposal and reducing environmental impact.
Solution Approach 2:
The patent challenges the disposable nature of conventional crosslinked polymers by creating materials that are inherently recyclable. Instead of designing for single-use or landfill disposal, the vitrimers are designed with built-in recyclability through dynamic covalent bonds that can be reversibly broken and reformed. This extends the material lifecycle and reduces waste generation.
3Object-generated harmful factors
If biodegradable aliphatic polyesters are used to improve recyclability, then the degradability is improved, but the thermal stability and solvent resistance worsen
Solution Approach 1:
The patent applies composite materials by combining biodegradable polyester segments with crosslinking agents to create a network structure. The bulk polymer chains provide biodegradability through hydrolyzable ester bonds, while the crosslinks contribute thermal stability and mechanical strength. The synergistic combination allows the material to maintain structural integrity at elevated temperatures during use, yet degrade under composting conditions or controlled hydrolysis.
Solution Approach 2:
The patent applies local quality by creating heterogeneous structures where different regions have different properties. The polymer chains between crosslinks maintain the biodegradable polyester characteristics (hydrolyzability), while the crosslink junctions provide thermal stability and solvent resistance. This spatial differentiation of properties allows simultaneous achievement of degradability and stability.
4Adaptability or versatility
If biodegradable aliphatic polyesters are used to produce thermoplastic elastomers, then the renewability is improved, but the mechanical properties and stress resistance worsen due to Mullins effect
Solution Approach 1:
The patent applies preliminary action by pre-forming a crosslinked network structure before the material is put into service. The dynamic covalent crosslinks are established during processing, creating a stable gel network that prevents the stress softening (Mullins effect) observed in thermoplastic elastomers. This preliminary network formation ensures consistent mechanical properties and stress resistance throughout the material's lifecycle.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting polylactone elastomers exhibit excellent mechanical properties, including high thermal stability and elasticity, with the ability to be chemically recycled and degraded, making them suitable for various applications while minimizing environmental impact.
Implementation Method 1
reacting a lactone with a catalyst including a guanidyl moiety to form a lactone polymer
Implementation Method 2
crosslinking a linear lactone homopolymer with a free-radical generator
Implementation Method 3
reacting a polymer derived from a lactone with a cyclic carbonate compound comprising 2 to 5 cyclic carbonate moieties and a catalyst to form a crosslinked polylactone elastomer
Implementation Method 4
chemically recycled by depolymerizing to yield lactone monomer in high purity and yield of greater than about 80%
Data Source
AI summary
A method includes reacting a polymer derived from a lactone with a cyclic carbonate compound comprising 2 to 5 cyclic carbonate moieties and a catalyst to form a crosslinked polylactone elastomer.