Epoxy-Modified Styrenic Block Copolymer Impact Modifier for PPS
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Solution Overview
Problem
Polyarylene sulfide (PPS) polymers, used in high-performance applications, are inherently brittle and require impact modifiers to enhance toughness, but existing impact modifiers like SEBS and E-MA-GMA either fail to provide sufficient toughness or compromise processability.
Innovation Solution
A polyphenylene sulfide composition incorporating epoxy-grafted partially hydrogenated styrenic block copolymers as impact modifiers, which balances toughness, stiffness, and processability by adjusting the degree of epoxidation and hydrogenation levels, thereby improving the mechanical properties of PPS without significantly increasing viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SEBS or MA-g-SEBS is used as impact modifier, then processability is maintained, but toughness is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the impact modifier through epoxidation of the conjugated diene blocks. This transforms SEBS into e-SBC, changing the functional groups from simple hydrocarbon to epoxy-functionalized structures. This chemical parameter change enables both good processability and enhanced toughness, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite material system by combining PPS with epoxidized styrenic block copolymer. The e-SBC acts as a multi-functional additive that provides both processing assistance and toughness enhancement. The synergistic interaction between PPS and e-SBC creates a composite system that overcomes the limitations of using SEBS alone.
2Strength
If E-MA-GMA is used as impact modifier, then toughness is improved, but viscosity increases and processability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the impact modifier by using epoxidized styrenic block copolymer instead of ethylene-methyl acrylate-glycidyl methacrylate terpolymer. The e-SBC maintains lower viscosity compared to E-MA-GMA while providing comparable or superior toughness. This parameter change in polymer structure resolves the contradiction between impact strength and processability.
3Ease of operation
If PPS is used without impact modifier, then processability is good, but the material is inherently brittle
Solution Approach 1:
The patent introduces e-SBC as an intermediary substance that mediates between the PPS matrix and the requirements for toughness. The epoxidized styrenic block copolymer acts as a compatibilizer and impact modifier simultaneously, allowing the brittle PPS to achieve ductile behavior while maintaining its inherent processing advantages.
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 epoxy-grafted styrenic block copolymer composition enhances the notched Izod impact strength and maintains flexibility, providing a balanced set of properties that improve the overall performance of PPS in high-performance applications while minimizing the impact on processability.
Implementation Method 1
the styrenic block copolymer (SBC) precursor is hydrogenated to form a hydrogenated styrenic block copolymer precursor having a hydrogenation level of at least 97%
Implementation Method 2
the block B is epoxidized at aliphatic double bonds for the epoxidized styrenic block copolymer to have 1 to 35 wt.% of epoxy functional groups
Data Source
AI summary
The disclosure relates to an impact modified polyarylene sulfide composition containing epoxy functionalized styrenic block copolymer (e-SBC), for improved impact resistance with minimal impact on processability, wherein e-SBC is an epoxy functionalized unhydrogenated styrenic block copolymer (e-USBC), or an epoxy functionalized partially hydrogenated styrenic block copolymer (e-pHSBC), or an epoxy functionalized hydrogenated styrenic block copolymer (e-HSBC). The improved PPS composition can be used for making electronic components such as, but certainly not limited to, connectors, bobbins, coils, relays, etc.