Low-Mass PPF Polymer Synthesis for 3D Printing Resins
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Solution Overview
Problem
The existing methods for synthesizing poly(propylene fumarate) (PPF) polymers are inefficient, costly, and result in inconsistent molecular mass distribution, making it difficult to achieve predictable mechanical properties and regulatory approval for medical applications, particularly in 3D printing and implantable devices.
Innovation Solution
A method involving ring-opening polymerization of maleic anhydride and propylene oxide using magnesium ethoxide as an initiator, followed by isomerization, to produce low molecular weight PPF with controlled molecular mass distribution and viscosity, suitable for 3D printing and medical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional step-growth polymerization is used to synthesize PPF, then the polymer can be produced, but the molecular mass distribution is uncontrolled and high energy requirements are needed
Solution Approach 1:
The patent changes the fundamental polymerization mechanism from step-growth to chain-growth polymerization, and modifies reaction parameters including using chromium salen catalyst at low temperatures (-78°C to room temperature), controlling monomer ratios, and adjusting solvent conditions to achieve well-defined molecular mass distribution with low energy input
Solution Approach 2:
The patent replaces the traditional thermal step-growth polymerization mechanism with a catalyzed chain-growth mechanism using chromium salen complexes, substituting high-energy thermal activation with low-energy catalytic pathways that provide precise molecular weight control
2Productivity
If traditional polymerization methods are used, then PPF can be synthesized, but conversion rates are low and molecular weight control is poor
Solution Approach 1:
The patent introduces chromium salen complexes as intermediary catalysts that mediate the polymerization reaction between maleic anhydride and propylene oxide, enabling high conversion rates while maintaining precise molecular weight control through the catalyst's controlled radical mechanism
Solution Approach 2:
The patent applies local quality control by using specific chromium salen catalyst structures that create controlled reaction sites, where the catalyst's ligand environment locally controls the polymerization kinetics to achieve both high conversion and narrow molecular weight distribution
3Adaptability or versatility
If conventional synthesis methods are used, then PPF polymer is produced, but it is not suitable for 3D printing due to uncontrolled molecular properties
Solution Approach 1:
The patent optimizes molecular parameters including number average molecular weight (Mn = 1,500-5,000 Da), polydispersity index (PDI < 1.3), and end-group functionality to match the specific requirements for 3D printing applications, where controlled molecular properties enable proper rheological behavior and printability
Solution Approach 2:
The patent performs preliminary molecular weight control during synthesis by using chain-growth mechanism with controlled initiation and propagation, pre-establishing the molecular characteristics needed for 3D printing before the material is applied, rather than attempting post-synthesis modification
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 method produces PPF polymers with well-defined molecular properties, enabling predictable mechanical performance and resorption profiles, suitable for 3D printing and medical devices, and meets regulatory standards for safety and reproducibility.
Implementation Method 1
The polymerization of maleic anhydride and propylene oxide using a chain growth mechanism with chromium salen as a catalyst
Implementation Method 2
followed by isomerization with diethylamine, to produce PPF with controlled molecular weight and distribution
Data Source
Figure 1~2
Figure 3
Figure 4A
AI summary
The present invention provides a low molecular mass PPF polymer (and related methods) that is suitable for 3D printing and other polymer device fabrication modalities and can be made inexpensively in commercially reasonable quantities. These novel low molecular mass PPF polymers have a low molecular mass distribution (Đm) and a wide variety of potential uses, particularly as a component in resins for 3D printing of medical devices. The ability to produce low Đm PPF creates a new opportunity for reliable GMP production of PPF. It provides low cost synthesis and scalability of synthesis, blending of well-defined mass and viscosity PPF, and reduced reliance on solvents or heat to (a) achieve mixing of 3D printable resins or (b) and flowability during 3D printing. These PPF polymers are non-toxic, degradable, and resorbable and can be used in tissue scaffolds and medical devices that are implanted within a living organism.