Vitrimer ABS Composition for Extrudable Crosslinked 3D Printing
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Solution Overview
Problem
Crosslinked thermosets are not extrudable and thus not suitable for fused filament fabrication (FFF), limiting the recyclability and mechanical performance of commonly used thermoplastics like ABS, which are typically used in FFF processes.
Innovation Solution
Development of a crosslinked polymeric composition, known as a vitrimer, which incorporates dynamic covalent networks to create a recyclable and robust material that can be extruded and printed, enhancing mechanical strength and solvent resistance while allowing for recycling through reversible crosslinks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinked thermosets are used to improve mechanical strength and chemical resistance, then the material becomes non-extrudable and unsuitable for FFF printing
Solution Approach 1:
The patent applies dynamic covalent chemistry to create vitrimers with reversible crosslinks that can break and reform. At printing temperatures, the crosslinks dynamically exchange allowing the material to flow through the extruder, while at service temperatures the crosslinks remain intact providing thermoset-like mechanical strength and chemical resistance. This dynamic behavior resolves the contradiction between extrudability and strength.
Solution Approach 2:
The patent changes the physical and chemical parameters of the crosslinked network by introducing dynamic covalent bonds that are temperature-dependent. The material transitions from a rigid non-extrudable state at room temperature to an extrudable state at elevated temperatures, then returns to a strong solid state upon cooling, thereby achieving both extrudability and mechanical strength.
2Ease of manufacture
If traditional thermoplastics like ABS are used for FFF printing, then the material is extrudable and printable, but the mechanical performance and recyclability are limited
Solution Approach 1:
The patent creates a composite material system that combines the processability of thermoplastics with the enhanced mechanical properties of thermosets. The vitrimer incorporates dynamic crosslinked networks within a polymeric matrix, achieving a composite structure that exhibits both thermoplastic-like extrudability and thermoset-like mechanical performance.
Solution Approach 2:
The dynamic covalent crosslinks enable the material to exhibit thermoplastic-like behavior during processing (extrusion and printing) while maintaining thermoset-like mechanical properties in the final product. The reversible nature of the crosslinks allows the material to flow when needed and provide structural integrity when required.
3Reliability
If crosslinked networks are introduced to improve solvent resistance, then the material becomes more robust but loses processability and recyclability
Solution Approach 1:
The patent introduces dynamic covalent crosslinks that are reversible under certain conditions. These crosslinks provide solvent resistance at service temperatures while remaining exchangeable at processing temperatures, enabling both processability and recyclability. The dynamic nature allows the network to reconfigure during processing and heal defects, then provides stable solvent resistance in the final product.
Solution Approach 2:
The reversible crosslinks enable the material to be discarded and recovered through recycling processes. The dynamic bonds can be broken and reformed, allowing the material to be reprocessed multiple times while maintaining its mechanical properties and solvent resistance, thereby achieving circular economy goals.
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 vitrimer composition enables the production of stronger, tougher, and solvent-resistant 3D objects directly from recycled ABS, facilitating efficient recycling and upcycling of waste plastics, reducing carbon emissions by up to 65% compared to incineration.
Implementation Method 1
crosslinked polymeric composition, more particularly crosslinked ABS compositions... incorporates dynamic covalent networks to create a recyclable and robust material... reversible crosslinks
Data Source
AI summary
A crosslinked polymeric composition comprising a base polymer containing unconjugated carbon-carbon double bonds of the formula —CRa═CRb—, wherein a portion of said unconjugated carbon-carbon double bonds in said base polymer are interconnected by a crosslinker (L) as shown in the following structure:wherein: Ra and Rb are independently selected from hydrogen atom and hydrocarbon groups, wherein Ra and Rb may optionally interconnect to form a ring; x represents the molar percentage of segments that are linked with the linker L throughout the crosslinked polymeric composition; L is a crosslinker having the formula: —S—R1-La-R2-Lb-R1—S—; R1 and R2 are independently selected from hydrocarbon linking groups containing at least one carbon atom; La and Lb independently represent dynamic reversible crosslinking groups; and Za and Zb independently represent remaining portions of the base polymer.