PPF Copolymers for 3D Printing via ROCOP
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Solution Overview
Problem
Poly(propylene fumarate) (PPF) polymers have high viscosity due to their molecular weight, making them unsuitable for continuous digital light processing (cDLP) 3D printing applications, and their high absorbance at curing wavelengths prolongs printing times and increases energy consumption.
Innovation Solution
Copolymers of maleic anhydride and succinic anhydride with propylene oxide are synthesized using Mg(BHT)2(THF)2 as a catalyst, altering the order of reactive species addition to reduce viscosity and absorbance, resulting in PPF-based polymers with lower viscosities and absorbance values, allowing for faster curing and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PPF molecular weight is increased to maintain mechanical properties, then strength is improved, but viscosity increases making the material unsuitable for cDLP 3D printing
Solution Approach 1:
The patent changes the molecular weight parameter of PPF from high (>4000 Da) to low (400-2000 Da) to achieve printable viscosity while maintaining mechanical properties through optimized oligomer design and crosslinking density
Solution Approach 2:
The patent creates a composite resin system combining low molecular weight PPF oligomers with photoinitiators and crosslinking agents (diethyl fumarate, DMPA) to achieve both printability and mechanical strength through post-printing crosslinking
2Strength
If PPF molecular weight is increased to maintain mechanical properties, then strength is improved, but energy consumption increases due to prolonged printing times
Solution Approach 1:
The patent reduces printing time and energy consumption by using low molecular weight PPF oligomers with optimized photopolymerization characteristics that cure faster under cDLP UV irradiation
Solution Approach 2:
The patent optimizes the photopolymerization properties locally at the molecular level by selecting specific oligomer structures with appropriate functional groups that enhance light absorption and crosslinking efficiency
3Ease of operation
If PPF molecular weight is decreased to reduce viscosity for printing, then printability is improved, but mechanical strength may be compromised
Solution Approach 1:
The patent performs preliminary crosslinking preparation by incorporating photoinitiators and crosslinking agents into the resin formulation before printing, enabling strength development after the print is complete
Solution Approach 2:
The patent extends the useful action from just printing to include post-printing crosslinking and maturation processes that continue to develop mechanical strength after the initial print is complete
4Ease of operation
If PPF molecular weight is decreased to reduce viscosity for printing, then printability is improved, but the material becomes more difficult to handle and process
Solution Approach 1:
The patent optimizes the molecular weight parameter to a specific range (400-2000 Da) that balances viscosity for printing with ease of handling and processing during resin preparation and printing operations
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 resulting PPF-based copolymers have lower viscosities and absorbance, enabling efficient 3D printing with reduced diethyl fumarate usage and maintaining mechanical properties, thus enhancing the printability and energy efficiency of PPF-based resins.
Implementation Method 1
techniques for production of PPF by ring-opening copolymerization (ROCOP) of maleic anhydride and propylene oxide
Implementation Method 2
The resin also contains a photoinitiator such as 2,2-dimethoxy-2-phenylacetophenone (DMPA) or 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO)
Implementation Method 3
which upon exposure to UV or visible light generates radicals that initiate crosslinking of the polymer network
Implementation Method 4
PPF has an unsaturated double bond in its polymer back bone, which can be crosslinked post-polymerization in photochemical reactions
Data Source
AI summary
In various embodiments, the present invention is directed to a PPF-based copolymer for 3D printing applications and methods for its making and use. These copolymers have a viscosity in a printable viscosity range and allow light transmittance at curing wavelengths. In various embodiments, a lower viscosity copolymers are obtained by substitution of a portion of maleic anhydride with succinic anhydride and then forming a poly(propylene fumarate-co-succinate) copolymer by the copolymerization of maleic anhydride and succinic anhydride with propylene oxide via Mg(BHT)2(THF)2 catalyzed ring opening copolymerization (ROCOP). Because of their lower viscosities, these copolymers require less, if any, diethyl fumarate (DEF) to prepare the 3D printing resin, while the mechanical properties can still be adjusted as with a PPF polymer prepared without the succinic anhydride.