Ground Expanded Graphite Agglomerates for Polymer Composites
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Solution Overview
Problem
Expanded graphite's poor processability and dustiness make it difficult to handle and incorporate into polymer composites, leading to flow problems and reduced mechanical and thermal conductivity in final products.
Innovation Solution
Ground expanded graphite agglomerates in granular form are developed, which are soft and deagglomerate easily into finer particles during processing, improving handling and dispersion within polymers while maintaining thermal and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If expanded graphite is added to polymer mass to increase thermal conductivity, then thermal conductivity is improved, but processability and workability deteriorate due to difficult handling and flow problems
Solution Approach 1:
The expanded graphite is segmented into smaller particles with sizes between 0.1-2.0 mm through grinding and classification processes. This segmentation improves flow characteristics and feedability into extruders while maintaining the thermal conductivity benefits of expanded graphite structure.
Solution Approach 2:
The particle size parameter of expanded graphite is changed from larger flake forms to controlled smaller sizes (0.1-2.0 mm) through mechanical grinding and air classification. This parameter change resolves the contradiction by improving processability while preserving thermal conductivity through maintained expanded graphite morphology.
2Reliability
If expanded graphite is used as conductive filler, then electrical conductivity is improved, but dustiness increases making handling difficult
Solution Approach 1:
The expanded graphite is divided into controlled particle sizes (0.1-2.0 mm) through grinding and classification, which reduces excessive dust generation while maintaining electrical conductivity properties of the expanded graphite structure.
3Productivity
If expanded graphite particles are fed into extruder, then conductive composite is produced, but flow problems occur reducing productivity
Solution Approach 1:
The expanded graphite is segmented into optimal particle sizes (0.1-2.0 mm) that improve flow characteristics and feedability into extruders, directly resolving the feedability problem and enabling consistent extrusion processes with maintained productivity.
Solution Approach 2:
The expanded graphite undergoes preliminary grinding and air classification to achieve optimal particle size distribution before being fed into the extruder. This preliminary action prevents flow problems during extrusion and ensures smooth processing.
4Ease of operation
If ground expanded graphite is compacted into agglomerates, then handling properties improve, but particle hardness increases reducing deagglomeration
Solution Approach 1:
The compaction parameters are optimized to create agglomerates with controlled hardness that balance handling improvement with adequate deagglomeration capability during mixing. The particle strength parameter is carefully adjusted to resolve the contradiction between handling and deagglomeration.
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 ground expanded graphite agglomerates enhance the feedability and mechanical stability of conductive polymer composites, ensuring consistent thermal and electrical conductivity comparable to pristine expanded graphite, with improved handling and reduced dustiness.
Implementation Method 1
the agglomerates offer better handling properties as compared to unprocessed expanded graphite, which inter alia offers easier feeding of the graphite additive to the polymer during the production of the conductive polymer
Data Source
Figure 1~2a
Figure 2b~2c
Figure 3a~3b
AI summary
The present disclosure relates to ground expanded graphite agglomerate compositions, methods for making such agglomerates, their use as conductive additive, and conductive composites comprising such ground expanded graphite agglomerates. The disclosure also pertains to methods for making such composites and the use of such composites in preparing thermally conductive materials. The agglomerates are characterized by a certain softness allowing the agglomerates to dissolve, e.g., through shear forces applied during compounding, thereby leading to an improved feedability and a highly homogenous distribution of the expanded graphite material in the composite matrix.