Liquid Butadiene-Styrene Polymer Microstructure Control
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Solution Overview
Problem
The existing anionic solution polymerization process for producing liquid butadiene-styrene polymers faces challenges in stabilizing and controlling the microstructure, particularly for low-molecular-weight polymers, with high catalyst usage and temperature sensitivity, and difficulty in achieving fully random copolymerization of butadiene and styrene, affecting the polymer's performance.
Innovation Solution
An optimized anionic polymerization process involving a structure modifier comprising tertiary amines and alkali metal alkoxides, with a specific molar ratio, in an aliphatic heterocyclic solvent at controlled temperatures, to achieve a liquid butadiene-styrene polymer with defined structural unit content and cyclized 1,2-structural units, resulting in improved thermal expansion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If anionic solution polymerization process is used to prepare low-molecular-weight liquid butadiene-styrene polymer, then the polymer can be obtained with desired molecular weight, but the catalyst usage amount is high and catalyst removal is difficult
Solution Approach 1:
The patent changes the reaction parameters by conducting polymerization in bulk (without solvent) and using a two-stage temperature process (initially at lower temperature then raising to higher temperature). This parameter change enables effective catalyst removal through distillation while maintaining control over molecular weight, resolving the contradiction between obtaining desired molecular weight and ease of catalyst removal.
2Quantity of substance
If anionic solution polymerization process is used to prepare low-molecular-weight liquid butadiene-styrene polymer, then the polymer can be obtained with desired molecular weight, but the microstructure stability and controllability are poor
Solution Approach 1:
The patent employs parameter changes by implementing a two-stage temperature polymerization process and using specific catalyst systems. The initial lower temperature stage controls microstructure formation while the subsequent higher temperature stage ensures complete reaction and stabilizes the microstructure, achieving both desired molecular weight and microstructure stability.
Solution Approach 2:
The patent uses a specific catalyst system acting as an intermediary to control the polymerization process. The catalyst enables precise control over microstructure formation during the two-stage temperature process, ensuring stability and controllability while achieving the desired low molecular weight.
3Productivity
If anionic solution polymerization process is used, then polymerization can proceed, but the structure modifier's ability to adjust microstructure is temperature sensitive making stability and controllability difficult
Solution Approach 1:
The patent applies periodic action through a two-stage temperature process. The first stage operates at a lower temperature to allow the structure modifier to effectively control microstructure formation, while the second stage raises the temperature to complete the polymerization reaction. This periodic temperature variation resolves the temperature sensitivity issue and achieves both microstructure controllability and polymerization productivity.
4Productivity
If conventional anionic polymerization is used, then polymerization can occur, but achieving fully random copolymerization of butadiene and styrene is difficult due to large reactivity ratio difference
Solution Approach 1:
The patent changes the reaction parameters by implementing a two-stage temperature process with specific catalyst systems. The initial lower temperature stage allows for more controlled monomer incorporation according to reactivity ratios, while the subsequent higher temperature stage promotes random copolymerization. This parameter change enables achieving fully random copolymerization while maintaining polymerization productivity.
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 stabilizes the microstructure of the liquid butadiene-styrene polymer, enhancing its thermal expansion performance and peel strength, making it suitable for advanced communication technology applications.
Implementation Method 1
The liquid butadiene-styrene polymer generally adopts an anionic solution polymerization process
Implementation Method 2
the content of a cyclized 1,2-structural unit is 20-60 wt % based on the total amount of the 1,2-structural unit in the liquid butadiene-styrene polymer
Implementation Method 3
a coefficient of linear thermal expansion of the liquid butadiene-styrene polymer is (45-80)×10−6 m/m/° C.
Data Source
AI summary
A liquid butadiene-styrene polymer, a preparation method for same and an application of same, as well as a composition, a polymer coating, an adhesive and a cross-linking agent containing the same are provided. When the total weight of the liquid butadiene-styrene polymer is taken as a reference, in the liquid butadiene-styrene polymer, the content of a styrene structural unit is 15-30 wt %, the content of a butadiene structural unit is 70-85 wt %, and the content of a 1,2-structural unit is 60-80 wt %; when the total weight of the 1,2-structural unit in the liquid butadiene-styrene polymer is taken as a reference, the content of a cyclized 1,2-structural unit is 20-60 wt %. A coating formed by the liquid butadiene-styrene polymer not only has high peel strength for a substrate, but also has improved thermal expansion performance.