Polyaryl ether ketone-polycarbonate copolymer blends for high-temperature load bearing
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Solution Overview
Problem
Crystalline polyaryl ether ketone (PAEK) resins have low glass transition temperatures, limiting their use at high temperatures under load, and the addition of reinforcements like glass fibers or mineral fillers improves some properties but adversely affects others, such as increasing weight and inducing anisotropy in molded parts.
Innovation Solution
A polymer composition comprising a mixture of polyaryl ether ketones and isoindolinone copolycarbonates, where the copolycarbonate units are derived from specific dihydroxy compounds, creating a phase-separated blend with two distinct glass transition temperatures, enhancing load-bearing capabilities and impact strength while maintaining melt processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass fiber, carbon fiber, or mineral filler is added to PAEK resins to improve high-temperature load bearing capability, then strength and stiffness are improved, but weight increases and anisotropy is induced in molded parts
Solution Approach 1:
The patent creates a composite material system by blending PAEK resin with polycarbonate to form a phase-separated mixture. This composite approach combines the high-temperature strength of crystalline PAEK with the toughness and processability of polycarbonate, achieving improved load-bearing capability without the weight penalty of traditional fiber reinforcements
Solution Approach 2:
The patent modifies the glass transition temperature parameter of the PAEK resin by blending it with polycarbonate. The resulting composition exhibits multiple glass transition temperatures (120-160°C and 170-280°C), which fundamentally changes the thermal-mechanical behavior and enables high-temperature load bearing without fibers
2Strength
If glass fiber, carbon fiber, or mineral filler is added to PAEK resins to improve high-temperature load bearing capability, then strength and stiffness are improved, but anisotropy is induced in molded parts
Solution Approach 1:
The phase-separated blend of PAEK and polycarbonate creates a homogeneous composite at the molecular level, eliminating the anisotropy inherent in fiber-reinforced composites. The mixture maintains uniform properties throughout the molded part while achieving superior high-temperature strength
Solution Approach 2:
The patent achieves homogeneous distribution of properties throughout the material by creating a phase-separated mixture at the microscopic level. This homogeneity prevents the anisotropy and warping that occur with fiber reinforcements, while still providing isotropic high-temperature load bearing capability
3Strength
If fiber additives are added to PAEK resins to improve strength, then load bearing capability is improved, but surface smoothness is adversely affected
Solution Approach 1:
The molecular-level composite of PAEK and polycarbonate phases eliminates surface defects caused by fiber additives. The blend maintains a smooth, uniform surface suitable for thin parts and films while providing enhanced load-bearing capability through the phase-separated structure
4Strength
If reinforcing filler is added to PAEK resins to improve strength, then load bearing capability is improved, but melt processability is reduced
Solution Approach 1:
The patent changes the thermal and rheological parameters of the PAEK resin by blending with polycarbonate. The resulting composition exhibits multiple glass transition temperatures and improved melt flow characteristics, enabling excellent processability for extrusion, injection molding, and film formation while maintaining high-temperature strength
Data Source
AI summary
A polymer composition comprising a mixture of a) a first resin component comprising a polyaryl ether ketone, a polyaryl ketone, a polyether ketone, a polyether ether ketone, or a combination of two or more of the foregoing, and b) a second resin component comprising a specific type of copolycarbonate, wherein the mixture has at least two glass transition temperatures, as measured by ASTM method D5418, wherein the first glass transition temperature is from 120 to 16OoC and the second glass transition temperature is from 170 to 28OoC is disclosed. The compositions have improved properties such as improved load bearing capability at high temperature, better impact strength, and a high crystallization temperature.