Solid-Solid Phase-Change PEEP Polymer Thermal Management
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Solution Overview
Problem
Existing solid-liquid phase-change materials face limitations such as the need for packaging, potential mass loss during thermal cycling, flammability, and aging effects that affect their reproducibility and symmetry in differential scanning calorimetry curves.
Innovation Solution
Development of polyester-epoxide polymer (PEEP) compositions as solid-solid phase-change materials, which involve a reaction product of a polyepoxide compound and a polyol composition. The PEEP compositions have a specific ratio of epoxy to hydroxyl equivalents and exhibit desirable properties such as a transition temperature range of -10°C to 70°C, latent heat values of 30 to 200 J/g, and minimal hysteresis or supercooling upon thermal cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If solid-liquid PCMs are used for thermal energy storage, then large amounts of energy can be stored at characteristic temperatures, but packaging is required to retain liquid phase and mass loss occurs after hundreds of melting and solidification cycles
Solution Approach 1:
The patent employs solid-solid phase transitions instead of solid-liquid transitions. The PEEP compositions undergo reversible phase changes between different solid crystalline states, eliminating the need for liquid containment packaging and preventing mass loss that occurs when materials are in liquid form during thermal cycling
Solution Approach 2:
The invention creates composite polymer systems by reacting polyepoxide compounds with polyol compositions to form PEEP materials. This composite structure integrates the phase-change functionality within a solid polymer matrix, maintaining dimensional integrity while enabling thermal energy storage without the drawbacks of traditional solid-liquid PCMs
2Use of energy by moving object
If solid-liquid PCMs are used, then thermal energy can be stored and released, but flammability issues arise (e.g., paraffins)
Solution Approach 1:
The patent changes the chemical composition parameters by using polyester and polyether polyol compositions with specific hydroxyl values and functionalities. These parameter changes result in PEEP materials with inherent fire resistance, eliminating the flammability problem associated with traditional PCM materials like paraffins while maintaining thermal energy storage capability
3Shape
If solid-solid PCMs are used to avoid packaging needs, then dimensional integrity is maintained, but most ssPCMs suffer from solubility in polyols or other reactants, supercooling, extractability, water solubility, flammability, material loss, or low thermal stability
Solution Approach 1:
The PEEP composition acts as an intermediary system where the crosslinked polymer network structure serves as a matrix that prevents solubility and extractability issues. The specific epoxy-to-hydroxyl equivalent ratio creates a stable intermediate state that resolves the contradiction between maintaining dimensional integrity and achieving chemical/thermal stability
Solution Approach 2:
By precisely controlling the epoxy equivalent weight (115-250 g/eq) and hydroxyl equivalent ratio (2:1 to 6:1), the patent optimizes the polymer network structure to achieve both dimensional integrity during phase transitions and high thermal stability (above 100°C) with resistance to solubility and extractability
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 PEEP compositions effectively function as solid-solid phase-change materials, offering enhanced thermal energy storage and release capabilities without dimensional changes, thus addressing the limitations of solid-liquid PCMs. They provide improved flexibility in product formulation, thermal management in electronics, and energy conservation in building materials and garments.
Implementation Method 1
the solid undergoes a transition while transforming from one solid phase (e.g., a rigid article) to another solid phase (e.g., a flexible solid) thereby avoiding the need for packaging or encapsulation
Implementation Method 2
PCMs are capable of storing or releasing large amounts of energy at a characteristic temperature, which typically corresponds to a phase change
Implementation Method 3
When the ambient temperature exceeds the transition temperature of the PCM, the PCM absorbs heat and stores the thermal energy
Implementation Method 4
The PEEP composition comprises a reaction product of a polyepoxide compound and a polyol composition
Data Source
Figure 1
AI summary
Polyether- or polyester-epoxide polymer (PEEP) compositions are disclosed. The compositions comprise reaction products of a polyepoxide compound and a polyol composition. The polyol composition has a melting point within the range of 20°C to 100°C and a hydroxyl number less than 35 mg KOH/g. The PEEP composition is a solid- solid phase-change material. As measured by differential scanning calorimetry (DSC) at a heating/cooling rate of 10°C/minute, the PEEP composition has a transition temperature within the range of -10°C to 70°C, a latent heat at the transition temperature within the range of 30 to 200 J/g, and little or no detectable hysteresis or supercooling upon thermal cycling over at least five heating/cooling cycles that encompass the transition temperature. The PEEP compositions should enable formulators to manage thermal energy changes in many practical applications, including automotive, marine or aircraft parts, building materials, appliance insulation, electronics, textiles, garments, and paints or coatings.