Branching Polymerization of Cyanoacrylates via Chain-Transfer Agents

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Solution Overview

Problem

Current polymerization methods for cyanoacrylates are restricted by high monomer reactivity, requiring harsh conditions and resulting in linear polymers with limited control, making them unsuitable for advanced applications like fast-acting adhesives and biomedicine.

Innovation Solution

A method of branching polymerization using a cyanoacrylate composition with a comonomer containing chain-transfer functionality, allowing for rapid branching without harsh conditions, enabling high propagation rates and monomer conversions, and forming branched polymeric materials suitable for in-situ and surface-initiated polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If traditional polymerization methods are used for cyanoacrylates, then high monomer conversion is achieved, but harsh reaction conditions are required and control over polymerization is lost

Engineering Contradiction:
Improvemonomer conversionVSAvoidreaction conditions
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

A chain transfer agent (CTA) is introduced as an intermediary substance to mediate the polymerization process. The CTA controls the polymerization by providing chain transfer reactions that regulate chain growth, enabling high monomer conversion under mild conditions while maintaining control over the polymerization process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the polymerization mechanism from conventional free radical or anionic polymerization to chain transfer-mediated polymerization. By adjusting the type and concentration of chain transfer agents, the reaction conditions can be optimized to achieve high conversion under mild conditions without requiring harsh reagents or extreme temperatures.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If chain transfer agents are used to control polymerization, then polymerization control is improved, but branching structure is not achieved

Engineering Contradiction:
Improvepolymerization controlVSAvoidpolymer topology
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The chain transfer agent serves multiple functions simultaneously: it controls chain growth through chain transfer reactions (providing polymerization control) and introduces branching points through its multifunctional structure (creating branched topology). This multi-functionality resolves the contradiction between control and topology.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention uses a composite approach by combining cyanoacrylate monomers with multifunctional chain transfer agents. The resulting polymer system exhibits both controlled polymerization characteristics and branched structure, achieving a composite effect that satisfies both requirements.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If free-radical polymerization is used, then other polymer topologies can be synthesized, but stringent reaction conditions are required

Engineering Contradiction:
Improvepolymer topologyVSAvoidreaction conditions
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention substitutes the free-radical mechanism with a chain transfer-mediated ionic polymerization mechanism. This replacement eliminates the need for stringent conditions like inert atmospheres, metal catalysts, heat, or UV irradiation that are required for free-radical polymerization, while still enabling control over polymer topology including branching structures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If high monomer reactivity is suppressed to enable controlled polymerization, then polymerization control is improved, but propagation rate decreases

Engineering Contradiction:
Improvepolymerization controlVSAvoidpropagation rate
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The chain transfer agent dynamically regulates the polymerization process by continuously transferring chains between active and dormant states. This dynamic equilibrium allows the system to maintain high propagation rates while achieving control, as the CTA rapidly exchanges between chain transfer and propagation reactions without permanently deactivating the polymerization.

Inventive Principle:
Principle #15Dynamics

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

This approach enables the synthesis of branched polymeric materials with high monomer conversions and propagation rates under mild conditions, expanding the applicability of cyanoacrylates in various fields, including biomedicine and surface bonding, without the need for stringent reaction conditions.

Implementation Method 1

at least one chain-transfer functionality of the comonomer is deprotonated in a chain-transfer reaction, producing at least one more chain-growth site therefrom and converting the comonomer into a branching junction

Methodology Applied
Scientific EffectChain-transfer reaction: Chemical Bonding

Implementation Method 2

nucleophiles on surfaces initiate the polymerization and form covalent bonds between the surfaces and the polymerized adhesive film

Methodology Applied
Scientific EffectNucleophilic initiation: Chemical Bonding

Implementation Method 3

Cyanoacrylates are highly reactive monomers whose anionic polymerization is spontaneously initiated by nucleophiles, like water, amines, and bases, and progresses with high propagation rate and high monomer conversion

Methodology Applied
Scientific EffectAnionic polymerization: Chemical Bonding

Data Source

PatentUS20230383143A1Method of branching polymerization induced by chain-transfer reaction
Publication Date: 2023.11.30 THE HONG KONG UNIV OF SCI & TECH

AI summary

The subject invention pertains to a method of forming an adhesive material by a branching polymerization free of restrictive or harsh reaction conditions. A readily polymerizable composition includes a component comprises a chain-transfer functionality that can induce the formation of branches upon polymerization of the composition. The method enables in-situ polymerization and surface-initiated polymerization useful for rapid adhesive material formation on surfaces such as biological tissue.