PMMA Microcapsule Synthesis via Organic-Solvent Free Process
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Solution Overview
Problem
Conventional methods for preparing phase change material microcapsules often involve organic solvents, leading to environmental issues due to solvent discharge during the manufacturing process.
Innovation Solution
A process that pre-polymerizes a polymer monomer to form Polymethyl methacrylate (PMMA) prepolymer in an organic-solvent free environment, followed by encapsulation and polymerization at an oil-water interface, using a stabilizer and cross-linking agents to form phase change material microcapsules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods using organic solvents are employed to prepare phase change material microcapsules, then the encapsulation process can be completed, but environmental pollution occurs due to solvent discharge
Solution Approach 1:
The invention extracts and removes the organic solvent component from the encapsulation process. By using water as the continuous phase and conducting polymerization in an aqueous environment, the harmful organic solvent is completely eliminated from the system, resolving the environmental pollution issue while maintaining the encapsulation functionality.
Solution Approach 2:
The invention changes the fundamental parameter of the reaction medium from organic solvent to water. This parameter change transforms the entire encapsulation system from an organic-based process to an aqueous-based process, eliminating environmental pollution while preserving the phase change material encapsulation capability.
2Device complexity
If direct polymerization of methyl methacrylate monomer is used to encapsulate phase change material, then the process is simpler, but the heat transfer efficiency is reduced due to thicker capsule walls
Solution Approach 1:
The invention applies preliminary action by first preparing PMMA prepolymer before the encapsulation step. This two-stage approach (prepolymerization followed by encapsulation polymerization) allows for better control of the capsule wall formation process, resulting in thinner and more uniform walls that improve heat transfer efficiency while maintaining process feasibility.
Solution Approach 2:
The invention segments the polymerization process into two distinct stages: (1) prepolymerization of methyl methacrylate to form PMMA prepolymer, and (2) encapsulation polymerization at the oil-water interface. This segmentation allows optimization of each stage independently, achieving both process simplicity and heat transfer efficiency.
3Ease of operation
If phase change material is applied directly without microencapsulation, then the application is simpler, but material loss during phase transition greatly affects the life of the material
Solution Approach 1:
The invention uses a thin polymer shell formed by controlled polymerization at the oil-water interface to encapsulate the phase change material. This thin film shell protects the material during phase transitions, preventing material loss and leakage, thereby extending material life while maintaining the simplicity of direct application through the microcapsule formulation.
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 effectively produces phase change material microcapsules without organic solvents, improving heat transfer and stability while minimizing environmental impact.
Implementation Method 1
a polymer monomer and an initiator are subject to pre-polymerization in water bath so as to form Polymethyl methacrylate (PMMA) prepolymers
Implementation Method 2
phase change material has the ability to change its physical state at a certain temperature, and absorbs or releases a large amount of latent heat in phase changing process
Implementation Method 3
encapsulation and polymerization at an oil-water interface
Data Source
AI summary
Phase change material microcapsules are obtained using a PMMA prepolymer and an organic-solvent free synthesis process. A polymer monomer and an initiator are subject to pre-polymerization in a water bath to form Polymethyl methacrylate (PMMA) prepolymer which is then prepared to be a stabilizer aqueous solution. A phase change material is added to the stabilizer aqueous solution and liquefied in advance, and stirred to form an emulsion by a homogenizing mixer. A starting agent, a cross-linking agent and a Polymethyl methacrylate methyl ester prepolymer are added to the emulsion containing the phase-change material. The emulsion is further stirred by the homogenizing mixer for micro-emulsification which then aggregates in water bath. In this way, the process may use organic-solvent free process to pre-polymerize the polymer monomer into a Polymethyl methacrylate prepolymer and carries out encapsulation and polymerization at an oil-water interface to achieve the preparation of phase change material microcapsules.