PVDF-Rubber Bonding via Thiocyanate Surface Chemistry
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Solution Overview
Problem
PVDF, a semi-crystalline polymer used in various applications, exhibits poor adhesion properties to rubbers due to its low surface energy, which is a challenge in applications requiring strong bonding between PVDF and rubber components.
Innovation Solution
A method involving the introduction of oxygen-containing functional groups on the surface of PVDF followed by reaction with a compound containing thiocyanate groups, such as silane, to enhance the adhesion between PVDF and sulfur cross-linkable rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF is used for its piezoelectric properties and chemical stability, then reliability is improved, but adhesion to rubber deteriorates due to low surface energy
Solution Approach 1:
The patent applies local quality by treating only the surface of the PVDF polymer with oxygen plasma, creating a localized modification layer with oxygen-containing functional groups. This surface treatment enhances adhesion to rubber while preserving the bulk piezoelectric properties of the PVDF material.
Solution Approach 2:
The patent introduces an intermediary compound containing thiocyanate groups that reacts with oxygen-containing functional groups on the PVDF surface. This intermediary creates a chemical bridge between the PVDF surface and the rubber, enabling strong adhesion without altering the bulk properties of either material.
2Strength
If adhesive layers are used to bond PVDF to rubber, then adhesion is improved, but conductivity between piezoelectric layer and conductive layers deteriorates
Solution Approach 1:
The patent extracts and eliminates the adhesive layer from the system by creating direct chemical bonding between PVDF and rubber through surface treatment and thiocyanate compound reaction. This removes the insulating adhesive layer that would otherwise block electrical conductivity.
Solution Approach 2:
The patent merges the bonding function and electrical conductivity function into a single interface by creating direct chemical bonds between PVDF and rubber. This combination eliminates the need for separate adhesive layers and maintains electrical pathways.
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 method achieves high adhesive strength between PVDF and rubber without altering the internal structure of PVDF, effectively addressing the poor adhesion issue and improving the performance of PVDF-based piezoelectric devices.
Implementation Method 1
introducing oxygen-containing functional groups on the at least one surface of the piezoelectric polymer
Implementation Method 2
reacting the oxygen-containing functional groups with a compound comprising thiocyanate groups
Implementation Method 3
cross-linking
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a method for chemically adhering a diene rubber to a piezoelectric polymer, the method comprising the steps of: a) providing a piezoelectric polymer having at least one surface, b) providing a rubber component having at least one surface and comprising a sulfur cross-linkable rubber composition, c) introducing oxygen-containing functional groups on the at least one surface of the piezoelectric polymer, d) reacting the oxygen-containing functional groups with a compound comprising thiocyanate groups, and e) contacting the surface of the piezoelectric polymer obtained of step d) with the surface of the rubber component, and cross-linking.