Thermoplastic Composite Recycling via Homogeneous Polyester Matrix
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Solution Overview
Problem
Current composite materials, especially thermoplastic composites, face challenges in recycling due to their heterogeneity and anisotropic properties, making it difficult and expensive to separate fibers from the matrix, which hinders efficient recycling and value creation from waste materials.
Innovation Solution
A thermoplastic composite is developed with a matrix and fibers made from a specific thermoplastic polyester composition that allows for easy recycling without separating the fibers from the matrix, utilizing a thermoplastic polymer matrix and fibers comprising 1,4:3,6-dianhydrohexitol, alicyclic diol, and terephthalic acid units, enabling transesterification reactions during heating to form a uniform, reusable thermoplastic material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite materials are used to improve mechanical properties, then strength and performance are enhanced, but recycling becomes difficult and expensive due to heterogeneity and anisotropic properties
Solution Approach 1:
The patent applies homogeneity by using a thermoplastic polyester matrix that has uniform chemical composition and properties throughout, making the entire composite material homogeneous in nature. This allows the composite to maintain mechanical strength while enabling easy recycling through melting and reprocessing, as the uniform thermoplastic matrix can be uniformly heated and reshaped without the complications of heterogeneous thermoset resins.
Solution Approach 2:
The patent utilizes parameter changes by selecting specific compositional parameters for the thermoplastic polyester matrix, including the molar ratio of 1,4:3,6-dianhydrohexitol units to alicyclic diol units (0.32-0.75), reduced viscosity (>50 ml/g), and specific monomer composition. These parameter changes enable the material to achieve both high mechanical performance and recyclability by controlling the crystallization behavior and melting properties of the polyester matrix.
2Loss of substance
If fiber-matrix separation techniques are used to recycle composites, then material recovery is possible, but the process becomes complex and costly
Solution Approach 1:
The patent applies the discarding and recovering principle by designing a composite material where the thermoplastic polyester matrix can be easily discarded (melted down) and recovered (reprocessed) without complex separation techniques. The entire composite, including fibers and matrix, can be ground together and remelted to produce new composite parts, eliminating the need for sophisticated fiber-matrix separation equipment and processes.
Solution Approach 2:
The patent effectively extracts the need for complex separation processes by using a thermoplastic matrix that can be uniformly removed through melting. The matrix is extracted from the composite structure through thermal processing, allowing fibers to be liberated and both components to be reprocessed together, simplifying the recycling operation to a single heating and remolding step rather than multiple separation stages.
3Strength
If thermoset composites are used, then mechanical properties are achieved, but the matrix cannot be melted and reformed, limiting recycling options
Solution Approach 1:
The patent applies inversion by reversing the fundamental chemical structure principle from thermoset to thermoplastic polymers. Instead of using crosslinked thermoset resins that set permanently, the patent uses linear or branched thermoplastic polyester chains that can be repeatedly melted and reformed. This inversion of the polymer structure principle enables the composite to maintain strength during use while providing versatile recycling options through multiple melt-processing cycles.
Solution Approach 2:
The patent applies dynamics by selecting a thermoplastic polyester matrix that exhibits dynamic behavior - it transitions from a rigid, strength-providing state during service to a fluid, reprocessable state during recycling. The matrix dynamically changes its physical properties based on temperature, allowing the composite to be strong at operating temperatures but easily reformable at elevated temperatures, providing adaptability for both performance and recycling 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
This approach enables efficient, cost-effective recycling of the composite materials into a uniform thermoplastic material, eliminating the need for fiber-matrix separation and allowing for multiple plastic applications, thus addressing the recycling challenges of existing composite materials.
Implementation Method 1
utilizing a thermoplastic polymer matrix and fibers comprising 1,4:3,6-dianhydrohexitol, alicyclic diol, and terephthalic acid units, enabling transesterification reactions during heating to form a uniform, reusable thermoplastic material
Data Source
AI summary
A thermoplastic composite comprising a thermoplastic polymer matrix comprising an amorphous polyester containing 1,4: 3,6-dianhydrohexitol units, an alicyclic diol and terephthalic acid, wherein diol component comprises 1,4:3,6-dianhydrohexitol and alicyclic diol in ratio from 0.32 to 0.75; and thermoplastic fibers comprising a semi-crystalline polyester containing 1,4: 3,6-dianhydrohexitol units, an alicyclic diol and terephthalic acid, wherein diol component comprises 1,4:3,6-dianhydrohexitol and alicyclic diol in ratio from 0.05 to 0.30 are disclosed. Methods for producing the polymer composite are also disclosed.