Thermoplastic Polymer Mixture for Composite Impregnation
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Solution Overview
Problem
The challenge in using thermoplastic polymers for composite materials lies in impregnating fibrous materials due to high melt viscosity, especially for polymers with high Tg, which results in fragile composites with poor mechanical properties, and extending the manufacturing cycle time to achieve sufficient molar mass is counterproductive.
Innovation Solution
A composition comprising a mixture of non-reactive thermoplastic polymers with a Tg ≥40° C and reactive thermoplastic prepolymers, where the initial melt viscosity during impregnation is lower than without the prepolymer, and the ductility after in situ polymerization is equivalent or greater, enabling good and rapid impregnation and high-performance composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the molar mass of thermoplastic polymers is reduced to decrease melt viscosity for better impregnation, then the impregnation of fibrous material is improved, but the mechanical properties and ductility of the resulting composites deteriorate
Solution Approach 1:
The invention divides the polymer system into two distinct components: a non-reactive thermoplastic polymer that provides immediate low viscosity for impregnation, and a reactive thermoplastic prepolymer that contributes to final mechanical properties. This segmentation allows each component to fulfill its specific function without compromise
Solution Approach 2:
The invention changes the chemical state parameter of one component from non-reactive to reactive, transforming the prepolymer into a system that can undergo polymerization after impregnation. This parameter change enables the system to achieve both low initial viscosity and high final strength
2Strength
If the molar mass of thermoplastic polymers is increased to improve mechanical properties, then the strength and ductility of composites are improved, but the melt viscosity increases making impregnation difficult
Solution Approach 1:
The invention performs the impregnation action preliminarily using the non-reactive polymer at low viscosity, before the mechanical properties become critical. The reactive prepolymer then completes the system's development after impregnation is already established
Solution Approach 2:
The non-reactive thermoplastic polymer acts as an intermediary substance that facilitates the impregnation process. It temporarily performs the function of low-viscosity matrix material, enabling fiber saturation before being replaced/complemented by the polymerized prepolymer system
3Strength
If a reactive prepolymer is used alone to achieve both low viscosity and high final strength, then the mechanical properties are improved, but the cycle time for manufacturing must be extended to achieve sufficient molar mass
Solution Approach 1:
The invention merges two polymer systems with complementary characteristics into a single composite system. The non-reactive polymer provides immediate processing benefits while the reactive prepolymer delivers final performance, achieving both goals simultaneously without extended cycle times
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 allows for the production of high-performance composites with good mechanical properties by maintaining a lower initial melt viscosity and enhanced ductility, facilitating rapid and effective impregnation of fibrous materials.
Implementation Method 1
after in situ polymerization of said reactive thermoplastic prepolymer in said composition during the impregnation and after said impregnation
Data Source
AI summary
The use of a composition including a mixture of at least one non-reactive thermoplastic polymer of Tg >40° C., especially >100° C., in particular >120° C., and at least one reactive thermoplastic prepolymer, with a fibrous material, for the preparation of a fibrous material impregnated with the composition, the composition having an initial melt viscosity during the impregnation, as measured in plate-plate rheology under 1 Hz and 2% strain, at a temperature of 300° C., of less than the viscosity of the same composition devoid of reactive prepolymer, measured under the same conditions, and/or a ductility, after in situ polymerization of the reactive thermoplastic prepolymer in the composition during the impregnation and after the impregnation, that is at least equivalent to the ductility of the same composition devoid of non-reactive thermoplastic polymer, and of which said reactive thermoplastic prepolymer is polymerized to the same number-average molecular mass (Mn).