Nylon Microsphere Preparation via Segmented Polymerization
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Solution Overview
Problem
Conventional methods for preparing nylon microspheres are complex, costly, and inefficient, with issues such as irregular particle shapes and wide size distributions, making them unsuitable for industrial-scale production.
Innovation Solution
A method involving radical polymerization and anionic ring-opening polymerization in a continuous in-situ polymerization mode, using a lactam as solvent, to create a polymer alloy of free radical polymer/polyamide, allowing for controlled particle size and molecular weight through the ratio of free radical polymer to lactam monomer, and phase-reversal to achieve regular spherical nylon microspheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processes (solution precipitation, emulsion, direct polymerization) are used to prepare nylon particles, then nylon particles can be produced, but the processes suffer from technical complexity, high cost, high energy consumption, irregular powder shape, large particle size and wide distribution of particle size
Solution Approach 1:
The patent segments the polymerization process into two distinct stages: first free radical polymerization of vinyl monomer, then anionic ring-opening polymerization of lactam monomer. This segmentation allows each stage to be optimized independently, achieving precise particle size control (0.1-500 μm) and regular spherical shapes while simplifying the overall process compared to conventional single-stage methods
Solution Approach 2:
The patent utilizes parameter changes by controlling the ratio of free radical polymer to lactam monomer (10-50 weight%) and adjusting polymerization conditions to achieve phase reversal. This parameter control enables precise manipulation of particle morphology and size distribution, producing uniform microspheres with narrow size distribution while reducing process complexity
2Shape
If emulsion polymerization or interfacial polycondensation is used to make polyamide spherical particles, then spherical particles can be obtained, but the processes require a great deal of solvent and dispersant and have process complexity not suitable for industrial application
Solution Approach 1:
The patent extracts and eliminates the need for large quantities of solvents and dispersants by using a water-soluble polymer as a minimal continuous phase (1-10 weight%) that serves multiple functions: dispersing the dispersed phase, stabilizing emulsion, and facilitating phase reversal. This dramatically reduces substance consumption while maintaining spherical particle formation and enabling industrial scalability
Solution Approach 2:
The water-soluble polymer acts as an intermediary substance that mediates between the dispersed phase (polymer alloy) and the aqueous environment. This intermediary enables spherical particle formation and phase reversal with minimal quantity (1-10 weight%), replacing the need for excessive solvents and dispersants in conventional emulsion methods
3Ease of manufacture
If polyamide granules are mixed with water soluble polymer and water is used to remove the water soluble polymer, then polyamide powder can be obtained, but the preparation of polyamide powder requires consumption of a lot of energy
Solution Approach 1:
The patent performs preliminary action by incorporating the water-soluble polymer into the polymer alloy matrix during the polymerization process itself, rather than adding it separately afterward. The polymerization conditions are optimized to ensure proper dispersion and bonding, which simplifies the subsequent water washing step and reduces the energy required for granule preparation and processing
4Adaptability or versatility
If conventional methods are used to prepare nylon particles, then nylon particles can be produced, but they exhibit irregular powder shape and wide distribution of particle size rendering significant difficulty in practical application
Solution Approach 1:
The patent utilizes dynamics by controlling the phase reversal process during polymerization, where the dispersed phase and continuous phase dynamically exchange roles. This dynamic phase reversal, controlled by the ratio of free radical polymer to lactam monomer and water-soluble polymer content, produces uniform spherical particles with narrow size distribution (0.1-500 μm), enhancing adaptability for coatings and molding applications
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 method simplifies the production process, reduces energy consumption and costs, and enables precise control over particle size and molecular weight, producing nylon microspheres with regular shapes and controlled dimensions suitable for industrial applications.
Implementation Method 1
a free radical initiator is added, so that radical polymerization of the radically polymerizable monomer is carried out to give a mixture of a free radical polymer and the lactam monomer
Implementation Method 2
An initiator and an activator, used for anionic ring-opening polymerization of the lactam monomer, are added to the mixture obtained in step (1) wherein the remaining radically polymerizable monomer and water are removed, so that the anionic ring-opening polymerization of the lactam is carried out to give a polymer alloy of the free radical polymer/polyamide
Implementation Method 3
The free radical polymer in the polymer alloy obtained in step (2) is removed by dissolution, giving nylon microspheres
Data Source
Figure 1
AI summary
A method for preparing nylon microspheres is provided, said method comprising steps (1), (2) and (3) or steps (1'), (2) and (3) as follows: (1) a radically polymerizable monomer is dispersed in a molten lactam monomer, and a free radical initiator is added, so that radical polymerization of the radically polymerizable monomer is carried out, to give a mixture of a free radical polymer and the lactam monomer; or (1') a mixture of a free radical polymer and a molten lactam monomer is provided; and (2) an initiator and an activator, used for anionic ring-opening polymerization of the lactam monomer, are added to the mixture obtained in step (1) wherein the remaining radically polymerizable monomer and water are removed, or to the mixture obtained in step (1'), so that the anionic ring-opening polymerization of the lactam is carried out to give a polymer alloy of the free radical polymer/polyamide; and (3) the free radical polymer in the polymer alloy obtained in step (2) is removed by dissolution, giving nylon microspheres. Nylon microspheres are also provided, wherein the weight average molecular weight of the nylon lies in the range of 10000-300000, and the particle size of the nylon microspheres lies in the range of 0.1-500 µm.