Hexahydro-1,3,5-triazine Polar Additive for Styrene Block Control
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Solution Overview
Problem
Current methods for producing copolymers of vinylaromatic monomers and conjugated diene monomers struggle to achieve high vinylaromatic content with low vinyl content and low blockiness, often requiring complex two-stage processes or resulting in high vinyl content due to the use of standard randomizing agents.
Innovation Solution
Anionic polymerization of vinylaromatic and conjugated diene monomers in the presence of an organometallic initiator and a specific polar modifier, N,N′,N″-substituted hexahydro-1,3,5-triazine, which acts as a Lewis base to randomize styrene effectively without increasing vinyl content, allowing for controlled block styrene content and vinyl content between 8 to 45 weight percent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If standard randomizing agents are used to achieve high vinylaromatic content, then the copolymerization can proceed, but the block length of vinylaromatic repeating units decreases
Solution Approach 1:
The patent modifies the structural parameters of the randomizing agent to achieve optimal control over block length. The specific compounds of formula I and II provide the right balance between randomization and block formation, enabling vinylaromatic content of 30-80 wt% with controlled block lengths (0.01-32 wt% of blocks with more than 4 repeating units), thus resolving the contradiction between high vinylaromatic content and adequate block length.
2Stability of the object's composition
If the amount of polar additive is increased to promote randomization, then the randomization improves, but the vinylaromatic content and block length tend to decrease
Solution Approach 1:
The patent optimizes the dosage parameters of the polar additive by selecting compounds with specific molecular weights and structures (formulas I and II). The optimal amount is defined as 0.01-50 times the molar amount of initiator, which provides sufficient randomization while maintaining high vinylaromatic content and adequate block length, resolving the contradiction between randomization and vinylaromatic content.
3Device complexity
If a single-stage process is used to produce high vinylaromatic copolymers, then the process complexity is reduced, but it is difficult to achieve low vinyl content with controlled blockiness
Solution Approach 1:
The patent changes the chemical parameters of the randomizing agent to compounds with specific structures (formulas I and II) that provide enhanced control over polymerization kinetics and microstructure. This allows a single-stage process to achieve manufacturing precision comparable to or better than two-stage processes, with vinyl content of 8-45 wt% and controlled blockiness (0.01-32 wt% of blocks with more than 4 repeating units), thus resolving the contradiction between process simplicity and manufacturing precision.
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 production of high styrene, low vinyl copolymers with controllable styrene block content, improving tensile strengths and abrasion resistance without the need for complex two-stage processes, and reducing hysteresis issues associated with long block styrene content.
Implementation Method 1
anionic polymerization of vinylaromatic and conjugated diene monomers in the presence of an organometallic initiator
Implementation Method 2
a specific polar modifier, N,N′,N″-substituted hexahydro-1,3,5-triazine, which acts as a Lewis base to randomize styrene effectively
Data Source
AI summary
The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.