Polyamide Filament for Additive Manufacturing with High Glass Transition Temperature
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Solution Overview
Problem
The challenge in additive manufacturing is finding a polymeric composition that can be easily transformed into a filament with controlled diameter, exhibit high glass transition temperature for mechanical strength, suitable melting temperature for processability, and low water absorption to maintain mechanical properties, particularly for applications requiring high modulus at elevated temperatures.
Innovation Solution
A polymer composition comprising at least 50% polyamide (PA) formed from the polycondensation of a diamine component with bis(aminoalkyl)cyclohexane and a diacid component including terephthalic acid, which is processed into a filament with specific thermal properties and reinforced with glass fibers, enabling its use in Fused Filament Fabrication (FFF) technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If semi-aromatic polyamides are used to achieve high mechanical properties at elevated temperature, then the glass transition temperature is improved, but the processing temperature becomes too high for additive manufacturing processes
Solution Approach 1:
The invention modifies the chemical structure of the polyamide by incorporating specific cyclic diamine components ( formulas (I) and (II) ) and diacid components ( formulas (III) and (IV) ) with controlled ratios. This changes the molecular parameters to achieve a glass transition temperature of at least 120°C while maintaining a melting temperature below 290°C, enabling both high-temperature performance and additive manufacturing processability
Solution Approach 2:
The invention creates a composite polyamide structure by combining specific diamine and diacid monomers in defined proportions. The polyamide comprises recurring units from formulas (V) to (VIII) resulting from polycondensation of components (A) and (B), forming a composite material that integrates the beneficial properties of different molecular structures to simultaneously achieve high Tg and low Tm
2Ease of manufacture
If aliphatic polyamides are used for easy processing, then the processing temperature is reduced, but the glass transition temperature becomes too low for high-temperature applications
Solution Approach 1:
The invention introduces cyclic structures in the diamine components (cyclohexane rings in formula (I) and aromatic rings in formula (II)) which increase the glass transition temperature compared to purely aliphatic structures, while maintaining processing temperatures suitable for additive manufacturing through controlled monomer selection and ratios
3Strength
If polyamide composition is optimized for high glass transition temperature, then mechanical properties at elevated temperature are improved, but filament diameter control and processability deteriorate
Solution Approach 1:
The invention optimizes the molecular weight and molecular weight distribution of the polyamide through controlled polycondensation processes, and selects specific monomer combinations that provide both high-temperature mechanical properties and appropriate melt flow characteristics for precise filament extrusion and diameter control in additive manufacturing
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 polyamide filament provides excellent mechanical properties, thermal resistance, and chemical resistance, making it suitable for additive manufacturing while maintaining processability and retaining mechanical properties at elevated temperatures.
Implementation Method 1
a polyamide (PA) formed from the polycondensation of a diamine component with bis(aminoalkyl)cyclohexane and a diacid component including terephthalic acid
Implementation Method 2
a suitable melting temperature (Tm) to keep the polymer composition processable in the FFF technology
Data Source
AI summary
An additive manufacturing filament is provided, as are 3D manufacturing methods using the filament, and articles and composite materials made therefrom. The filament comprises a polymer composition, and the polymer composition comprises, in turn, at least 50 wt. % of a polyamide. The polyamide comprises recurring units R(PA1) from 30 mol % to 75 mol % recurring units R(PA1) according to formula (V′); and •from 25 mol % to 70 mol % of at least one of recurring units R(PA2), R(PA3) a and R(PA4), according to formulae (VI), (VII) and (VIII), respectively: •wherein ∘R1 and R2 are independently selected C1 to C3 alkyls; ∘Ri, at each location, is selected from the group consisting of an alkyl, an aryl, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, and a quaternary ammonium; ∘i is an integer from 0 to 10; ∘R3 is a C7-C16 alkyl, preferably a C7-C12 alkyl; ∘R4 is a C6 to C20 alkyl or a C6 to C20 aryl, preferably a C6 to C16 alkyl or a C6 to C16 aryl, more preferably a C6 to C12 alkyl or a C6 to C12 aryl; and ∘mol % is relative to the total moles of recurring units in the polyamide. The filament has a cylindrical geometry and a diameter between 0.5 mm and 5 mm.