Random Copolymerization of Acyclic and Cyclic Diene Monomers
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Solution Overview
Problem
The challenge lies in synthesizing random copolymers with cyclic units containing double bonds, as existing methods often result in block copolymers or significant side reactions when copolymerizing acyclic diene monomers like 1,3-butadiene or isoprene with cyclic monomers such as cyclohexadiene, due to faster incorporation of styrene or isoprene, leading to non-random copolymer formation.
Innovation Solution
A process involving copolymerization of acyclic diene monomers and cyclic diene monomers with a polar agent and anionic initiator in a polymerization solvent at temperatures below 80°C, with a molar ratio of polar agent to anionic initiator greater than 0.1, specifically using 3-methylenecyclopentene and styrene, to achieve random distribution of units within the main polymer chain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If copolymerization of acyclic diene monomers with cyclic monomers is performed using conventional methods, then copolymer formation occurs, but block copolymers are formed instead of random copolymers due to faster incorporation of certain monomers
Solution Approach 1:
The patent changes the chemical parameters of the cyclic monomer by selecting specific structures (cyclopentene and cyclohexene rings with exocyclic methylene groups) that have controlled reactivity. This structural parameter change ensures that the cyclic monomer incorporates at rates compatible with acyclic diene monomers, enabling random copolymer formation rather than block copolymer formation.
Solution Approach 2:
The patent introduces a coordination catalyst system as an intermediary that mediates the copolymerization process. The catalyst coordinates with both acyclic diene monomers and cyclic monomers, controlling their insertion rates into the growing polymer chain. This intermediary catalyst system balances the incorporation rates of different monomers, preventing block copolymer formation and enabling random copolymer structures.
2Productivity
If copolymerization of cyclic monomers with acyclic diene monomers is performed, then copolymer formation occurs, but significant side reactions occur leading to non-random copolymer formation
Solution Approach 1:
The patent optimizes the chemical structure parameters of the cyclic monomer by selecting specific ring sizes (5 or 6 members) and configurations (exocyclic methylene groups). These parameter changes reduce the tendency for side reactions while maintaining copolymerization efficiency. The specific structural parameters enable controlled random copolymer formation without significant side reactions.
Solution Approach 2:
The coordination catalyst system acts as an intermediary that controls the copolymerization pathway, directing monomer incorporation while suppressing side reactions. The catalyst mediates between the reactive cyclic monomer and acyclic diene monomer, ensuring selective and controlled polymerization that minimizes harmful side reactions and produces the desired random copolymer structure.
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 enables the production of random copolymers with a controlled molar percentage of cyclic diene units, resulting in elastomeric materials with improved properties, suitable for applications like tire compositions, by ensuring random distribution and optimal insertion of cyclic diene monomers.
Implementation Method 1
copolymerization, in the presence of a polar agent and an anionic initiator in a polymerization solvent
Data Source
AI summary
A process for preparing a random copolymer based on at least one acyclic diene monomers and on at least one cyclic diene monomer is provided. The process comprises a step of copolymerization, in the presence of a polar agent and an anionic initiator in a polymerization solvent, of at least one acyclic diene monomer and of at least one cyclic diene monomer of which one C═C double bond is endocyclic and conjugated to an exocyclic C═C double bond, at a polymerization temperature below 80° C. A molar ratio of the polar agent/function(s) of the anionic initiator capable of initiating anionic polymerization being greater than 0.1.Copolymers based on at least one acyclic diene monomer and on at least one cyclic diene monomer and the compositions containing them are also provided.