Biodegradable Polymer Particulates for Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing techniques face challenges with thermoplastic polymers used in powder bed fusion and selective laser sintering due to irregular particulate shapes and wide size distributions, leading to poor powder flow and packing efficiency, which result in structural and mechanical weaknesses in printed objects.
Innovation Solution
The use of polymer particulates formed through melt emulsification with biodegradable matrix polymers and biologically inspired emulsion stabilizers, such as cellulose or hydroxyapatite nanoparticles, which enhance particulate uniformity, flow properties, and biodegradability, reducing void formation and improving mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercial powder particulates are obtained by cryogenic grinding or precipitation processes, then polymer material can be produced, but irregular particulate shapes and wide particulate size distributions result, leading to poor powder flow performance and poor packing efficiency
Solution Approach 1:
The patent changes the fundamental parameters of the manufacturing process by using melt emulsification instead of cryogenic grinding or precipitation. This involves heating the polymer above its melting point, mixing with surfactant solution, homogenizing at controlled speeds and temperatures, and controlled cooling to achieve spherical particles with narrow size distribution (span < 1.5), whereas conventional methods produce irregular shapes and wide distributions
Solution Approach 2:
The patent exploits phase transitions of the polymer material - melting the polymer above its melting point to create a molten state for emulsification, then controlled cooling to solidify into spherical particles. This phase change approach enables uniform spherical morphology that cannot be achieved through mechanical grinding of solid polymer
2Ease of operation
If irregular-shaped powder particulates are used in additive manufacturing, then deposition can occur, but poor packing efficiency results, causing void formation and structural weak points in printed objects
Solution Approach 1:
The patent produces spherical polymer particles through controlled melt emulsification and phase transition. The spherical morphology enables superior packing efficiency during powder bed deposition, eliminating void formation and ensuring structural integrity of printed objects, whereas irregular shapes create packing defects and weak points
3Strength
If thermoplastic polymers with sharp melting points are used in selective laser sintering, then interlayer fusion can occur, but incomplete fusion may result, creating structural weak points
Solution Approach 1:
The patent replaces the mechanical mixing and grinding processes with a thermal-emulsification system. By controlling temperature, mixing speed, and emulsification parameters during melt processing, the patent achieves uniform spherical particles with consistent thermal properties that enable complete and reliable interlayer fusion during selective laser sintering, eliminating incomplete fusion defects
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 approach results in polymer particulates with improved sphericity, uniform size distribution, and enhanced flow performance, leading to higher structural and mechanical integrity in printed objects with reduced void formation and increased biodegradability.
Implementation Method 1
combining a matrix polymer and a plurality of emulsion stabilizers with a carrier fluid at a heating temperature at or above a melting point or softening temperature of the matrix polymer
Implementation Method 2
cooling the carrier fluid to at least a temperature at which a plurality of polymer particulates form from the liquefied droplets
Data Source
AI summary
Compositions include a plurality of polymer particulates comprising a matrix polymer and one or more types of nanoparticles selected from the group consisting of biopolymer nanoparticles, biomineral nanoparticles excluding biomineralized silica alone, and any combination thereof. Illustrative examples of such nanoparticles may include cellulose nanoparticles, hydroxyapatite nanoparticles, or any combination thereof associated with the matrix polymer. The polymer particulates may be prepared by melt emulsification. Methods include depositing such polymer particulates in a powder bed; and heating a portion of the powder bed to consolidate a portion of the polymer particulates into a consolidated part having a specified shape. The matrix polymer may be biodegradable and lose at least about 40% mass in six days in a phosphate buffer solution (0.2 M, pH 7.0) containing 0.2 mg/mL of lipase obtained from Pseudomonas cepacia (≥30 U/mg) and incubated at 37° C.