Polydiorganosiloxane Polyamide Copolymers for Thermal Stability
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Solution Overview
Problem
Siloxane polymers lack tensile strength due to their inherent properties, and existing block copolymers with siloxane segments often have short segments and low weight fractions of polydiorganosiloxane, limiting their mechanical properties and thermal stability.
Innovation Solution
Development of polydiorganosiloxane polyamide copolymers with specific repeat units and amide end-capped organic soft segments, allowing for the tuning of surface and mechanical properties through reaction conditions, enabling higher polydiorganosiloxane segment incorporation and improved thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polydiorganosiloxane segments are incorporated into block copolymers to improve mechanical strength, then tensile strength increases, but thermal stability deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters by introducing amide end-capped organic soft segments with specific functional groups (carboxyl, hydroxyl, or amine) that can form hydrogen bonds. This modifies the intermolecular forces in the polymer chain, enabling the material to maintain both high tensile strength from the siloxane segments and improved thermal stability from the hydrogen-bonding amide end groups, resolving the contradiction between strength and thermal stability.
Solution Approach 2:
The patent creates a composite structure within the block copolymer by combining polydiorganosiloxane hard segments with amide end-capped organic soft segments. The siloxane segments provide mechanical strength while the amide-end capped organic segments provide thermal stability through hydrogen bonding. This composite approach allows simultaneous achievement of both properties that were previously mutually exclusive in siloxane-based polymers.
2Quantity of substance
If reaction conditions are optimized to increase polydiorganosiloxane segment incorporation, then weight fraction of polydiorganosiloxane increases, but manufacturing difficulty increases
Solution Approach 1:
The patent uses amide end-capped organic soft segments as intermediaries that facilitate the incorporation of polydiorganosiloxane segments. The amide end groups act as reactive intermediaries that can form hydrogen bonds with siloxane segments, enabling higher weight fractions of polydiorganosiloxane to be incorporated into the block copolymer structure without requiring extremely harsh reaction conditions, thus resolving the contradiction between quantity and ease of manufacture.
Solution Approach 2:
The patent modifies the reaction parameters by introducing hydrogen-bonding capable functional groups (carboxyl, hydroxyl, amine) at the ends of organic soft segments. This changes the intermolecular interaction parameters, allowing for more favorable reaction conditions that enable higher polydiorganosiloxane incorporation while maintaining reasonable manufacturing feasibility.
3Strength
If block copolymer structure is designed to enhance mechanical properties, then tensile strength improves, but solubility parameter compatibility deteriorates
Solution Approach 1:
The patent applies local quality by placing amide end-capped organic soft segments specifically at the ends of the polymer chains rather than throughout the entire structure. This localized modification allows the bulk of the polymer to maintain its siloxane-based structure for mechanical strength, while the end groups provide solubility parameter compatibility through hydrogen bonding, resolving the contradiction between mechanical properties and solubility compatibility.
Solution Approach 2:
The patent creates a composite structure where amide end-capped organic soft segments are combined with polydiorganosiloxane hard segments. The organic soft segments with amide end groups provide solubility parameter compatibility through hydrogen bonding, while the siloxane hard segments provide mechanical strength. This composite approach allows simultaneous optimization of both properties that were previously incompatible.
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 resulting copolymers exhibit enhanced mechanical strength, elastomeric properties, and thermal stability, making them suitable for various applications including adhesives, sealants, and medical uses while maintaining low refractive index and optical clarity.
Implementation Method 1
Polydiorganosiloxane polyamides have been prepared by condensation reactions of amino terminated silicones with short-chained dicarboxylic acids. Alternatively, these copolymers have been prepared by condensation reactions of carboxy terminated silicones with short-chained diamines.
Data Source
AI summary
Polydiorganosiloxane polyamide, block copolymers having organic soft segments and methods of making the copolymers are provided.