Stretched Polyurethane Valve Leaflets for Creep-Resistant Closure
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Solution Overview
Problem
Existing polymer materials used in valves face challenges in simultaneously achieving mechanical properties, biostability, and biocompatibility, leading to issues such as creep, incomplete closure, and regurgitation due to relative slippage between molecular chain segments, and fabric reinforcement results in thrombus calcification and notches at the free edge.
Innovation Solution
A polymer valve leaflet material made of polyurethane, stretched to a target dimension of 120% to 300% of its original size with controlled deformation in a perpendicular direction, enhancing tensile strength, elastic modulus, and softness, while forming micro-crystallization zones and hydrogen bonds to improve creep resistance and tear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polymer materials are used to achieve excellent mechanical properties, then tensile strength and elastic modulus are improved, but biostability and biocompatibility deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the stretching ratio (120%-300% of original size) and deformation parameters to achieve the desired balance between mechanical properties and biocompatibility. By precisely adjusting these parameters, the material achieves improved tensile strength while maintaining biostability and biocompatibility through controlled molecular chain orientation and micro-crystallization zone formation.
Solution Approach 2:
The patent creates a composite structure within the polyurethane material by forming micro-crystallization zones and hydrogen bonds during the stretching process. This internal composite structure combines the mechanical reinforcement from crystalline regions with the biocompatible polyurethane matrix, achieving both improved strength and maintained biostability without requiring external fabric reinforcement.
2Reliability
If polymer materials are used to achieve excellent biostability and biocompatibility, then biocompatibility is improved, but mechanical properties deteriorate
Solution Approach 1:
The patent applies preliminary action by performing the stretching process and forming micro-crystallization zones before the material is used in the valve. This pre-treatment prepares the material structure in advance to provide enhanced mechanical properties while maintaining biocompatibility, avoiding the need for subsequent fabric reinforcement that would compromise biostability.
3Strength
If fabric reinforcement is used to improve mechanical performance, then tensile strength and creep resistance are improved, but thrombus calcification and free edge notches occur
Solution Approach 1:
The patent extracts and eliminates the fabric reinforcement component from the valve construction, achieving mechanical performance through the stretched polyurethane material itself. By removing the fabric layer that causes thrombus calcification and free edge notches, the invention maintains mechanical strength through the stretched polymer's micro-crystallization zones and hydrogen bonds, thereby eliminating the harmful effects while preserving the beneficial mechanical properties.
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 stretched polyurethane material exhibits improved tensile strength, reduced permanent deformation, and enhanced fatigue resistance, preventing excessive elongation and regurgitation, with smoother valve operation and reduced risk of thrombus calcification.
Implementation Method 1
forming micro-crystallization zones and hydrogen bonds to improve creep resistance and tear resistance
Implementation Method 2
forming micro-crystallization zones and hydrogen bonds to improve creep resistance and tear resistance
Implementation Method 3
The stretched polyurethane material exhibits improved tensile strength, reduced permanent deformation, and enhanced fatigue resistance
Data Source
AI summary
Disclosed are a polymer valve leaflet material, a valve leaflet, a valve and a preparation method thereof. The polymer valve leaflet material is made of polyurethane and has a tensile strength in a range of 35 MPa to 60 MPa, an elastic modulus in a range of 15 MPa to 40 MPa, a softness in a range of 20° to 50°, and a thickness in a range of 0.10 mm to 0.20 mm.