Crosslinked Liquid-Crystalline Co-Polyimides for Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current additive manufacturing techniques, such as Fused Filament Fabrication (FFF) and Selective Laser Sintering (SLS), face limitations with thermoplastic materials that lack high-temperature stability and thermo-oxidative resistance, making them unsuitable for aerospace applications where higher service temperatures are required.
Innovation Solution
Development of low-molecular-weight, main-chain thermotropic liquid-crystalline co-polyimides (TLC-CoPI) using 1,3-bis[4-(4′-aminophenoxy)cumyl]benzene (BACB) and diphthalic dianhydrides with thermally reactive moieties, allowing for crosslinking at temperatures below 300°C, enhancing thermal stability and processibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic materials are used in additive manufacturing, then processability is improved, but thermal stability and thermo-oxidative resistance deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating aromatic groups (such as phthalic anhydride, isophthalic anhydride, terephthalic anhydride) and heteroatoms (sulfur, nitrogen, oxygen) into the polyimide structure. These compositional changes enable the material to achieve both thermoplastic processability and high-temperature stability, resolving the contradiction between ease of manufacture and thermal stability
Solution Approach 2:
The patent creates composite polyimide structures by combining multiple dianhydride components and diamine components with specific functional groups. The resulting composite material integrates the processability benefits of thermoplastics with the thermal stability of aromatic polyimides, allowing simultaneous achievement of both desired properties
2Temperature
If high service temperature is required for aerospace applications, then thermal stability is improved, but availability of suitable polyimide materials deteriorates
Solution Approach 1:
The patent systematically varies the compositional parameters by using different ratios of aromatic dianhydrides and diamines with heteroatoms, creating a series of polyimide compositions. This parameter optimization enables the development of materials specifically tailored for high-temperature aerospace applications while maintaining availability through controlled synthesis
Solution Approach 2:
The patent introduces local aromatic and heteroatom-containing functional groups at specific positions within the polyimide chain. These localized structural features provide high-temperature stability at critical sites while maintaining overall material processability and availability
3Reliability
If crosslinking is performed at high temperature, then thermal stability is improved, but processibility and LC temperature window deteriorate
Solution Approach 1:
The patent incorporates crosslinkable functional groups (epoxide, carboxyl, hydroxyl, isocyanate, acrylate, methacrylate) into the polyimide structure during synthesis. This preliminary incorporation of reactive groups allows crosslinking to occur at lower temperatures during or after processing, rather than requiring high-temperature post-processing that would compromise the LC temperature window and processibility
4Reliability
If aromatic groups and heteroatoms are incorporated into polyimide structure, then thermal stability is improved, but molecular weight and viscosity deteriorate
Solution Approach 1:
The patent optimizes the molecular weight parameters by controlling the stoichiometric ratios of dianhydride and diamine components during polymerization. By carefully adjusting these parameters, the patent achieves the desired balance between incorporating sufficient aromatic content for thermal stability and maintaining appropriate molecular weight for 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 new materials exhibit improved thermal stability, mechanical properties, and solvent resistance, enabling the use of thermotropic liquid-crystalline polymers in additive manufacturing for high-temperature applications, such as aerospace components, with a workable LC temperature window and controlled crosslinking.
Implementation Method 1
main-chain thermotropic liquid-crystalline co-polyimides (TLC-CoPI)... The LC transition temperatures of our TLCP-CoPI... are well below the that of high-molecular-weight thermotropic liquid-crystalline PMDA-BACB and the curing temperatures of thermosetting polyimides
Implementation Method 2
diphthalic dianhydride (DPA) that contains one or more thermally reactive and crosslinkable moieties... crosslinking at temperatures below 300°C... thermally crosslinkable TLCP-PI
Data Source
AI summary
A family of low-molecular-weight, main-chain thermotropic liquid-crystalline co-polyimides (TLC-CoPI) that are crosslinkable, and based on a unique, liquid-crystallinity (LC)-enabling diamine, namely, 1,3-bis[4-(4′-aminophenoxy)cumyl]benzene (BACB) and two or more mesogenic dianhydrides, at least one of which is a diphthalic dianhydride (DPA) that contains one or more thermally reactive and crosslinkable moieties similar to that of phenylethynyl (PE) is disclosed. Processes of making and using such low-molecular-weight, main-chain thermotropic liquid-crystalline co-polyimides are also provided.