Styrenic Block Copolymer Composition for Cure-Free Heat Resistance
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Solution Overview
Problem
Current rubbery materials require a costly curing process, generating non-recyclable products and side products, and lack suitable mechanical and thermal performance without it.
Innovation Solution
Development of styrenic block copolymers with specific molecular weight ranges and compositions, allowing for high temperature performance without the need for curing, through structures like A-B-A, (A-B-A)nX, and hydrogenated variants, which can be used in thermoplastic elastomer blends with various additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If curing process is used to achieve high temperature performance in rubbery materials, then thermal performance is improved, but process costs and manpower costs increase
Solution Approach 1:
The invention extracts and eliminates the curing step from the traditional rubber processing sequence. By designing thermoplastic block copolymers with specific microphase-separated structures (hard segments providing thermal stability, soft segments providing elasticity), the material achieves high temperature performance inherently without requiring external curing agents or crosslinking processes, thereby removing the associated costs and complexity.
Solution Approach 2:
The invention changes the fundamental parameter of polymer processability from chemically crosslinked (cured) to physically entangled (thermoplastic). By controlling block copolymer composition, molecular weight, and microphase morphology, the material achieves dimensional stability and mechanical strength at elevated temperatures through physical structure rather than chemical crosslinking, enabling cost-effective processing.
2Temperature
If curing process is used to achieve high temperature performance, then thermal performance is improved, but generation of non-recyclable finished products and side products occurs
Solution Approach 1:
The invention removes the curing reaction step entirely from the processing sequence. By relying on thermoplastic block copolymers that maintain structural integrity through physical microphase separation rather than chemical crosslinking, the material avoids generating non-recyclable cured networks and chemical side products, enabling straightforward recycling through melting and reprocessing.
Solution Approach 2:
The invention enables easy recovery and recycling of the polymer material. Since no irreversible chemical crosslinking occurs, worn or end-of-life products can be melted, reprocessed, and reused without degradation of fundamental properties, eliminating the generation of non-recyclable waste and supporting circular economy principles.
3Ease of manufacture
If traditional rubber materials are used without curing, then process costs are reduced, but mechanical and thermal performance is insufficient
Solution Approach 1:
The invention employs block copolymers composed of chemically distinct blocks (e.g., polystyrene hard segments and polydiene soft segments) that self-assemble into nanoscale composite structures. The hard segments form rigid domains providing thermal stability and strength, while soft segments provide elasticity and processability. This internal composite architecture delivers high performance without external curing.
Solution Approach 2:
The invention segments the polymer into functionally distinct blocks with different glass transition temperatures and mechanical properties. This segmentation creates microphase-separated morphologies where hard glassy or crystalline domains act as physical crosslinks and reinforcement, providing mechanical strength and thermal resistance without chemical curing, while maintaining overall material processability.
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 styrenic block copolymers provide excellent mechanical and thermal properties, enabling high temperature applications such as adhesives and vibration damping without the need for curing, maintaining cohesion and elasticity up to 130°C and beyond.
Implementation Method 1
which after hydrogenation has up to about 10 percent of the aromatic double bonds hydrogenated, and at least 80 percent of the 1,3-diene double bonds hydrogenated
Data Source
AI summary
A styrenic block copolymer is disclosed, having a formula, A-B-A, A-B-B-A, (A-B-A)nX, (A-B)nX or mixtures thereof, wherein n is from 2 to 30, and X is residue of a coupling agent. Each A block is independently a polystyrene having 10-63 wt. % 1,1-diphenylethylene, a GPC peak molecular weight from about 5-40 kg/mol, and forms 10-40 wt. % of the copolymer. Each B block is independently a poly(1,3-diene-co-styrene) comprising: (i) >90 wt. % of polymerized isoprene units relative to the weight of the polymerized 1,3-diene, where S is <40, and (S+V) is 18-75; (ii) >90 wt. % of polymerized butadiene units relative to the weight of the polymerized 1,3-diene, where S is <40, and (1.2*S+V) is 60-120; or combinations thereof “S” represents the polystyrene content, and “V” represents the 1,3-diene content having pendant 1,2- and/or 3,4-vinyl groups in the B block.