Chain Shuttling Agent for Multi-Block Copolymer Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing block copolymers, especially multi-block copolymers from ethylene, face challenges such as narrow molecular weight distribution, limited monomer types, and inefficient processes, including sequential monomer addition and batch processing, which hinder the production of polymers with desired physical properties like crystallinity and functionality.
Innovation Solution
A composition comprising a first and second olefin polymerization catalyst, capable of forming highly crystalline and branched polymers respectively, combined with a chain shuttling agent, allows for the continuous solution polymerization of ethylene to produce multi-block copolymers with controlled block lengths and properties, enabling high yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sequential monomer addition and batch processing are used, then block copolymers can be formed, but the process efficiency is poor and productivity is low
Solution Approach 1:
The patent employs continuous solution polymerization instead of batch processing, allowing the polymerization reaction to proceed continuously through a reactor system. This eliminates the downtime between batches and significantly improves productivity while maintaining the block copolymer formation capability through controlled monomer feed rates and residence time distribution.
Solution Approach 2:
The patent uses pre-formed catalyst systems that are prepared beforehand and then introduced into the continuous reactor. The catalysts are pre-activated and the polymerization conditions are pre-established, allowing the continuous process to start immediately without lengthy initialization periods, thus improving overall process efficiency.
2Ease of manufacture
If anionic polymerization is used, then block copolymers can be formed, but the molecular weight distribution becomes extremely narrow and monomer selection is limited
Solution Approach 1:
The patent changes the fundamental polymerization mechanism from anionic to coordination polymerization using metallocene and post-metallocene catalysts. This parameter change enables the use of diverse monomers including ethylene, propylene, and various dienes that are incompatible with anionic polymerization, while still achieving block copolymer formation through controlled catalyst deactivation and reactivation sequences.
Solution Approach 2:
The patent introduces organometallic catalysts as intermediaries that facilitate block copolymer formation through a different mechanism. These catalysts can be selectively deactivated and reactivated, allowing block formation without the stringent requirements of anionic polymerization, thus expanding monomer compatibility while maintaining block structure.
3Productivity
If chain transfer agents are used to control molecular weight, then polymerization speed increases, but the molecular weight distribution broadens and block structure is compromised
Solution Approach 1:
The patent extracts or eliminates the need for chain transfer agents by using catalyst systems that naturally control molecular weight through their deactivation mechanisms. The metallocene and post-metallocene catalysts can be deactivated by proton sources or other agents that do not act as chain transfer agents, thus maintaining narrow molecular weight distribution and block structure while still achieving controlled polymerization rates.
Solution Approach 2:
The patent substitutes the mechanical chain transfer mechanism with a chemical catalyst deactivation mechanism. Instead of using chain transfer agents that physically terminate chains, the system uses catalyst deactivation followed by controlled reactivation, which chemically controls block formation without broadening molecular weight distribution or compromising block structure.
4Manufacturing precision
If homogeneous coordination polymerization catalysts are used with suppressed chain transfer, then block-like structure can be formed, but the process requires low temperature and absence of chain transfer agents, reducing versatility
Solution Approach 1:
The patent introduces dynamic control of catalyst activity through sequential deactivation and reactivation. The catalyst system transitions between active and inactive states in a controlled manner, allowing block formation at various temperatures and with different monomers. This dynamic behavior provides flexibility in process conditions while maintaining block-like structure formation capability.
Solution Approach 2:
The patent develops universal catalyst systems that can form block copolymers with multiple monomer types under varied conditions. The metallocene and post-metallocene catalysts are designed to work with different monomers (ethylene, propylene, dienes) and can be deactivated/reactivated using different agents, providing multi-functionality and process flexibility while maintaining block structure formation.
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 process results in polymers with improved physical properties, including narrow molecular weight distribution and controlled block lengths, facilitating the production of high-density and elastomeric multi-block copolymers suitable for various applications.
Implementation Method 1
combining: (A) a first olefin polymerization catalyst, (B) a second olefin polymerization catalyst capable of preparing polymers differing in chemical or physical properties from the polymer prepared by catalyst (A) under equivalent polymerization conditions, at least one of catalyst (A) or catalyst (B) being capable of forming a branched polymer by means of chain walking or reincorporation of in situ formed olefinic polymer chains, and (C) a chain shuttling agent
Implementation Method 2
a first olefin polymerization catalyst capable of forming a highly crystalline ethylene homopolymers by ethylene polymerization
Implementation Method 3
a second olefin polymerization catalyst capable of forming a branched polymer upon polymerization by means of chain walking or reincorporation of in situ formed olefinic polymer chains
Data Source
AI summary
A composition for use in forming a multi-block copolymer from a single polymerizable monomer, said copolymer containing therein two or more segments or blocks differing in branching index, a polymerization process using the same, and the resulting polymers, wherein the composition comprises the admixture or reaction product resulting from combining: (A) a first olefin polymerization catalyst, (B) a second olefin polymerization catalyst capable of preparing polymers differing in chemical or physical properties from the polymer prepared by catalyst (A) under equivalent polymerization conditions, at least one of catalyst (A) or catalyst (B) being capable of forming a branched polymer by means of chain walking or reincorporation of in situ formed olefinic polymer chains, and (C) a chain shuttling agent.