Monodisperse Polymer Particles with Grafted Diene Brush
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Solution Overview
Problem
Existing methods for producing monodisperse polymer particles with diameters above 1 μm, such as suspension, dispersion, and emulsion polymerization, face challenges in achieving optimal impact resistance and elastic recovery rates, particularly for use in conductive adhesives in electronic packaging like LCDs and OLEDs, where the monodisperse polystyrene particles produced by anion dispersion polymerization lack sufficient physical properties.
Innovation Solution
A method involving graft-polymerization of a conjugated diene based monomer onto the surface of monodisperse polymer particles using anion dispersion polymerization, with a brush formed by surface initiation polymerization, to enhance the elastic recovery rate and impact strength, specifically by regulating the graft efficiency and density of the brush on the polymer particle surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If anion dispersion polymerization is used to produce monodisperse polymer particles, then the particles have narrow size distribution and good monodispersity, but the physical properties including impact resistance and elastic recovery rate are insufficient
Solution Approach 1:
The patent applies composite materials by combining the monodisperse polymer particle core with a grafted brush layer composed of conjugated diene monomer. This creates a core-shell structure where the inner polystyrene core provides monodispersity and the outer brush layer provides impact resistance and elastic recovery, resolving the contradiction between manufacturing precision and strength.
Solution Approach 2:
The patent applies local quality by creating a surface-specific modification where the brush is grafted only on the surface of the monodisperse polymer particle. The core maintains its original monodisperse structure while the surface acquires enhanced mechanical properties through the brush layer, allowing different regions to serve different functions.
2Manufacturing precision
If conventional polymerization methods (suspension, dispersion, emulsion) are used to produce polymer particles of at least 1 μm, then the particles can be formed, but the process becomes complicated and reaction time is extended
Solution Approach 1:
The patent applies preliminary action by first forming the monodisperse polymer particle core through anion dispersion polymerization, then using surface initiation to graft the brush layer in a subsequent step. This two-stage approach allows precise control of particle size in the first stage and property enhancement in the second stage, avoiding the need for complex multi-stage polymerization processes.
3Strength
If the brush grafting is performed with high graft efficiency, then the physical properties are improved, but the brush molecular weight and density must be precisely controlled to avoid negative effects
Solution Approach 1:
The patent applies parameter changes by systematically varying the grafting conditions including monomer concentration, initiator amount, reaction temperature, and reaction time to achieve optimal brush density. By controlling these parameters, the patent achieves high graft efficiency for improved elastic recovery while preventing excessive brush density that would harm the properties, thus resolving the contradiction between strength 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
The approach results in polymer particles with improved impact strength and elastic recovery rates, making them suitable for use as conductive core particles in adhesives, with the brush's weight average molecular weight, graft efficiency, and density being critical factors in achieving these enhanced physical properties.
Implementation Method 1
a brush formed by the graft-polymerization of a conjugated diene based monomer onto the surface of a monodisperse polymer particle
Implementation Method 2
the monodisperse polymer is formed by the anion dispersion polymerization
Implementation Method 3
brush having softness on the surface of a monodisperse polymer particle
Data Source
AI summary
The present invention provides a method of preparing a polymer particle. More precisely, the invention provides a polymer particle having optimum impact strength and improved elastic recovery rate by forming the brush having softness on the surface of the monodisperse polymer particle by the anion dispersion polymerization using a conjugated diene monomer.