Liquid-Processible Diphthalonitrile Resins with Hydrophobic Siloxane Bridges
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Solution Overview
Problem
Existing phthalonitrile compounds exhibit poor moisture stability and are not suitable for liquid composite moulding techniques due to high viscosity and melting points, leading to defects in fibre-reinforced composites.
Innovation Solution
Development of diphthalonitrile compounds with bulky, hydrophobic silicon groups to stabilize the Si-O bonds, reducing melting points and enhancing processing characteristics, allowing for low-viscosity resin blends that can be cured at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phthalonitrile compounds are used to prepare resins, then thermal stability is improved, but viscosity becomes too high for liquid composite moulding techniques
Solution Approach 1:
The patent changes the chemical structure parameters of phthalonitrile compounds by introducing siloxane bridges and varying molecular weight, which alters the resin's viscosity and melting point parameters to achieve liquid processability while maintaining thermal stability
Solution Approach 2:
The patent creates composite resin systems by combining phthalonitrile compounds with siloxane bridges and other functional groups, resulting in materials that exhibit both thermal stability from the phthalonitrile core and improved processability from the siloxane modification
2Ease of manufacture
If phthalonitrile compounds are modified to decrease melting point and viscosity, then liquid processability is improved, but moisture stability deteriorates
Solution Approach 1:
The patent applies local modification by introducing hydrophobic siloxane groups specifically at the molecular level to protect against moisture while maintaining the low melting point and viscosity properties needed for liquid processability
Solution Approach 2:
The siloxane bridge acts as an intermediary structure that mediates between the conflicting requirements: it provides the necessary flexibility and low viscosity for processing while its hydrophobic character protects the phthalonitrile core from moisture degradation
3Ease of manufacture
If phthalonitrile compounds are used in liquid composite moulding, then fibre impregnation is improved, but curing temperature becomes too high
Solution Approach 1:
The patent modifies the curing chemistry parameters by introducing catalysts and functional groups that enable lower-temperature curing, allowing the resin to remain liquid at processing temperatures while curing at moderately elevated temperatures suitable for fibre impregnation
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 diphthalonitrile compounds and resins achieve moisture stability and low viscosity, enabling effective fibre impregnation and production of high-quality composite materials with improved thermal stability and mechanical properties.
Implementation Method 1
Development of diphthalonitrile compounds with bulky, hydrophobic silicon groups to stabilize the Si-O bonds, reducing melting points and enhancing processing characteristics
Implementation Method 2
diphthalonitrile compounds with bulky, hydrophobic silicon groups to stabilize the Si-O bonds
Implementation Method 3
allowing for low-viscosity resin blends that can be cured at lower temperatures
Data Source
AI summary
Diphthalonitrile compounds of formula I:Ar1(CN)2—O—Ar2—CH2—O—Si(R1)(R2)—O-[T-O—Si(R1)(R2)—O-]n—CH2—Ar3—O—Ar1(CN)2 (I)in free or salt or solvate form, wherein: Ar1 is a C6-C10-aryl group; Ar2 is a C6-C10-aryl group; R1 and R2 are independently C5-C10-alkyl; T is a C6-C10-aryl group; and n is 0, 1, 2, 3, 4 or 5, or a mixture thereof; Cured diphthalonitrile thermosets are provided by curing resin blends of such compounds.