Photopolymerizable Polyamic Diacrylate Resin for High-Temperature Polyimide 3D Printing
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Solution Overview
Problem
High-performance engineering thermoplastics with all-aromatic molecular structures face processing challenges due to their high thermal stability, limiting their application in additive manufacturing, as conventional melt processing is impossible and existing 3D printing methods are restricted to aliphatic polymers with lower thermal and glass transition temperatures.
Innovation Solution
Development of polymer resins suitable for stereolithographic 3D printing, specifically polyamic diacrylate esters with photocrosslinkable groups and a photoinitiator, which undergo thermal imidization to form high-temperature polyimides, enabling the creation of complex structures with improved thermal stability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional melt processing is used for high-performance engineering thermoplastics, then processing is possible, but the high thermal stability (Td > 500°C, Tg > 200°C) makes processing essentially impossible
Solution Approach 1:
The patent changes the processing parameters by using stereolithography (photopolymerization) instead of melt processing. This allows processing at room temperature or low temperatures, avoiding the need to heat high-thermal-stability polymers to extremely high temperatures for melting. The polymer is processed in a solid or semi-solid state through photopolymerization, then cured to achieve final properties.
Solution Approach 2:
The patent replaces the mechanical melt processing system with a photopolymerization system. Instead of using heat and mechanical force to melt and mold the polymer, the invention uses light energy to initiate polymerization and crosslinking reactions, fundamentally changing the processing mechanism from thermal-mechanical to photochemical.
2Ease of manufacture
If energy-intensive molding processes are used to improve processability, then processing is achieved, but resolution and complexity are limited
Solution Approach 1:
The patent replaces energy-intensive mechanical molding processes with stereolithography, which uses a UV laser to selectively cure photopolymer resin layer by layer. This photochemical approach enables much higher resolution and geometric complexity because the laser can precisely deposit material only where needed, avoiding the mold release requirements and dimensional limitations of conventional molding.
Solution Approach 2:
The patent adds the dimension of vertical layer-by-layer construction to the manufacturing process. Instead of forming the entire part simultaneously in a mold cavity, stereolithography builds the part incrementally in the Z-direction by curing thin layers of resin sequentially. This enables complex internal geometries and undercuts that would be impossible with conventional molding.
3Adaptability or versatility
If conventional 3D printing methods are used, then aliphatic polymers can be printed, but aromatic polymers with high thermal stability cannot be processed
Solution Approach 1:
The patent introduces a photoinitiator as an intermediary substance that enables aromatic polymers to undergo photopolymerization. The photoinitiator absorbs UV light and generates reactive species that initiate polymerization of the aromatic monomer or oligomer. This intermediary allows high-Thermal-stability aromatic polymers to be processed via stereolithography, which would otherwise require temperatures above their degradation point.
Solution Approach 2:
The patent changes the chemical parameters of the polymer system by using aromatic monomers or oligomers with photopolymerizable functional groups instead of conventional aliphatic polymers. This chemical modification allows the polymer to undergo photopolymerization at low temperatures while maintaining the high thermal stability characteristic of aromatic structures.
4Temperature
If high-temperature polyimides are synthesized conventionally, then thermal stability is achieved, but complex structures cannot be formed
Solution Approach 1:
The patent uses stereolithography to build complex three-dimensional structures layer by layer before thermal curing. The green (uncured) part can contain complex internal geometries, channels, and features that are impossible to achieve with conventional high-temperature processing methods. After printing, the part is heated to complete polyimide formation, combining structural complexity with high thermal stability.
Solution Approach 2:
The patent performs the shaping operation preliminarily during the stereolithography printing process, creating the complete complex geometry in the green state before thermal curing. This preliminary formation of complex structures avoids the need for post-processing or tooling that would be required if conventional high-temperature processing were used first.
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 solution allows for the 3D printing of high-temperature polyimides with thermal decomposition temperatures up to 700°C, overcoming processing barriers and achieving mechanical properties comparable to conventionally synthesized materials, while maintaining structural integrity and resolution.
Implementation Method 1
a photoinitiator suitable for initiating crosslinking of the photocrosslinkable groups when exposed to a light source of a suitable wavelength and intensity
Implementation Method 2
upon drying the resin and heating to a temperature of about 200° C. to 350° C. the polyamic diacrylate ester or salt thereof undergoes thermal imidization to form a polyimide
Data Source
AI summary
Polymer resins for the vat photopolymerization of thermoplastics are provided, in particular for the vat photopolymerization of thermoplastics with exception thermal stability and mechanical properties. In some aspects, the polymer resins are prepared by ring opening of an aromatic dianhydride with an alcohol containing an acrylate or methacrylate to produce a photocrosslinkable diacid monomer; conversion of the photocrosslinkable diacid monomer to a photocrosslinkable diacyl chloride; and polymerization of the photocrosslinkable diacyl chloride with an aromatic diamine to produce a photocrosslinkable precursor polymer. Upon crosslinking and drying, a thermal imidization can yield aromatic polyimide polymers with high yield and with micron-scale structural resolution.