Norbornene Monomer Exo Isomer Control for Polymer Yield
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Solution Overview
Problem
Current methods for producing norbornene monomers with a high exo isomer content are complex and inefficient, leading to lower polymerization yields and molecular weights due to the generation of excessive endo isomers, which affect the mechanical and optical properties of resulting polymers.
Innovation Solution
A method involving controlled reaction conditions such as temperature, time, and solvent addition without a catalyst to produce a norbornene monomer composition with 50 mol % or more exo isomer, using cyclopentadiene, dicyclopentadiene, and a compound represented by Formula 1, to enhance polymerization efficiency and optical film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a norbornene monomer with a polar functional group is used for addition polymerization, then the polymer has good transparency, thermal stability, and mechanical strength, but the polymerization yield and molecular weight are lower when the monomer contains endo isomer
Solution Approach 1:
The patent changes the stereochemical configuration parameter of the norbornene monomer from endo isomer to exo isomer. This parameter change resolves the contradiction by eliminating the chelate effect that occurs with endo isomer, where the polar functional group's unshared electron pairs bond to the metal catalyst, reducing catalytic activity. The exo isomer configuration prevents this interaction, thereby improving polymerization yield and molecular weight while maintaining the desired polymer quality.
2Productivity
If only exo isomer or high exo isomer content monomer is used to increase molecular weight and yield, then polymerization efficiency improves, but the complexity of controlling isomer ratio increases
Solution Approach 1:
The patent applies preliminary action by pre-selecting and using only the exo isomer of norbornene monomer in the polymerization reaction, rather than attempting to control the isomer ratio during the reaction process. This approach simplifies the overall process by eliminating the need for complex isomer ratio control mechanisms, while ensuring high polymerization efficiency and molecular weight from the outset.
3Ease of manufacture
If endo isomer is present in the norbornene monomer, then the monomer can be produced through conventional methods, but the unshared electron pairs of the polar functional group strongly bond to the metal catalyst, reducing catalytic activity
Solution Approach 1:
The patent changes the stereochemical parameter from endo isomer to exo isomer in the norbornene monomer structure. This parameter change resolves the contradiction by preventing the chelate effect where the polar functional group's unshared electron pairs would otherwise strongly bond to the metal catalyst. The exo isomer configuration spatially separates these interactions, maintaining high catalytic activity while still allowing for practical monomer production.
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 allows for the industrial production of norbornene polymers with improved yield and molecular weight, resulting in enhanced mechanical and optical properties of the resulting optical films.
Implementation Method 1
a thermoplastic norbornene addition polymer that includes a polar functional group
Implementation Method 2
in the case where the ratio of endo isomer is higher among exo and endo isomers of the ester-norbornene monomer, the polymerization yield and the molecular weight are lower
Implementation Method 3
a complex is stabilized and the unshared electron pairs of the oxygen atom partially provide electrons to the metal atom due to a chelate effect where an oxygen atom of a carbonyl group that is contained in the ester group is bonded to a metal catalyst
Data Source
AI summary
Disclosed is a method for producing a norbornene monomer composition, a norbornene polymer produced using the norbornene monomer composition, an optical film including the norbornene polymer, and a method for producing the norbornene polymer. The method includes reacting a reaction solution that contains cyclopentadiene, dicyclopentadiene, or a mixture of cyclopentadiene and dicyclopentadiene, an acetate compound, and a solvent so that a content of an exo isomer is 50 mol % or more. Variables such as a reaction temperature, a reaction time, a molar ratio between reactants, and addition of a solvent are controlled so that the exo isomer is contained in content of 50 mol % or more. Accordingly, it is possible to industrially produce an acetate norbornene addition polymer by using the acetate norbornene monomer composition containing the exo isomer in content of 50 mol % or more.