Trithiocarbonate Transfer Agents for Aqueous Acrylic Acid Polymerization
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Solution Overview
Problem
Current RAFT polymerization processes for acrylic acid and its copolymers face challenges such as the use of organic solvents, which are hazardous and environmentally harmful, and the need for odorous xanthic salts, leading to inefficient conversion rates and polydispersity indices greater than 2.2, making it difficult to achieve controlled molecular weights and high conversion rates.
Innovation Solution
Development of compounds with a specific chemical structure, such as disodic trithiocarbonate or dipotassic trithiocarbonate, used in an aqueous solution to facilitate controlled radical polymerization of acrylic acid and its copolymers without organic solvents or odorous xanthic salts, resulting in polymers with a polydispersity index lower than 2.2 and high conversion rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional RAFT polymerization processes are used with organic solvents and xanthic salts, then polymerization can proceed, but the process becomes hazardous, environmentally harmful, and produces odorous byproducts
Solution Approach 1:
The patent changes the chemical parameters of the transfer agent from conventional xanthic salts to trithiocarbonate derivatives, and changes the solvent system from organic solvents to aqueous media. This parameter substitution eliminates hazardous and odorous components while maintaining polymerization functionality, directly resolving the contradiction between safety/environmental friendliness and process simplicity
Solution Approach 2:
The patent employs water as a safe, non-toxic, and inexpensive solvent替代 hazardous organic solvents. Water serves as an effective medium for the RAFT polymerization process without requiring special handling or disposal procedures, thus improving ease of manufacture while eliminating harmful factors
2Productivity
If conventional transfer agents are used, then polymerization can occur, but conversion rates remain inefficient and polydispersity indices exceed 2.2
Solution Approach 1:
The patent modifies the molecular structure of the transfer agent by using trithiocarbonate derivatives with specific R1 groups (alkyl with 2-10 carbons or aromatic with alkyl substitution). This structural parameter change optimizes the transfer agent's ability to control radical polymerization, achieving both high conversion rates and narrow polydispersity indices below 2.2
Solution Approach 2:
The patent creates a composite system combining trithiocarbonate derivatives with specific cations (sodium, potassium, ammonium, or amine salts) in aqueous media. This composite approach enhances the transfer agent's performance, enabling simultaneous achievement of high productivity and manufacturing precision that neither component could achieve alone
3Object-affected harmful factors
If aqueous solutions of trithiocarbonate derivatives are used as transfer agents, then hazardous solvents and odorous salts are avoided, but the process requires specific compound structures and manufacturing steps
Solution Approach 1:
The patent establishes specific parameter ranges for the trithiocarbonate derivative structure (R1 as alkyl with 2-10 carbons or aromatic with alkyl substitution) and cation selection (sodium, potassium, ammonium, or amine salts). These defined parameters create a systematic framework that, while requiring specific structures, provides clear guidance for synthesis and reduces overall process complexity
Solution Approach 2:
The patent performs preliminary synthesis of the trithiocarbonate derivative transfer agent with the desired R1 group and cation combination before the actual polymerization process. This preliminary preparation ensures the transfer agent has optimal structure for the intended application, simplifying the main polymerization step and reducing the need for complex in-process adjustments
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 process allows for the production of homopolymers and copolymers with controlled molecular weights and high conversion rates, serving as effective grinding and dispersion agents for mineral matter in aqueous suspensions and dispersions, while avoiding the use of hazardous solvents and odorous salts.
Implementation Method 1
The present invention concerns the field of processes for controlled radical polymerisation of the RAFT (Reversible Addition Fragmentation Transfer) type of homopolymers of acrylic acid and/or copolymers of acrylic acid with other water-soluble monomers
Implementation Method 2
The invention also concerns the use, as transfer agents in a process of controlled radical polymerisation of the RAFT type, in water, of homopolymers of acrylic acid and/or copolymers of acrylic acid with other water-soluble monomers, of compounds having the following formula (I′)
Implementation Method 3
The invention also concerns the use as dispersing agent of mineral matter in water, of the said homopolymers of acrylic acid and/or of the said copolymers of acrylic acid with other water-soluble monomers
Data Source
AI summary
The invention relates to novel sulphur compounds, to the production thereof by a method carried out in an aqueous medium and the use thereof in the form of transfer agents in a method for controlled radical polymerization of acrylic acid and/or acrylic acid with water-soluble monomers in water. The thus obtained polymers are usable in the form of dispersing agents or grinding aid agents and/or aid agents for combined grinding of mineral materials in an aqueous suspension and in the form of dispersing agents directly incorporated into aqueous formulations containing mineral materials.