Carbon Nanotube Masterbatch Dispersion in Cement Systems
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Solution Overview
Problem
Current methods for incorporating carbon nanotubes into cement-based materials face challenges such as instability of dispersions, safety concerns due to powdery nature, and difficulty in achieving homogeneous distribution, which affects mechanical strength and durability.
Innovation Solution
A process involving a masterbatch of carbon nanotubes and superplasticizer is used, where carbon nanotubes are mixed with a superplasticizer to form a stable and easily dispersible composition, which is then introduced into the cement system, allowing for improved mechanical properties and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon nanotubes are incorporated into cement-based materials to improve mechanical strength, then the mechanical properties are enhanced, but the dispersions become unstable and difficult to handle
Solution Approach 1:
The patent applies preliminary action by pre-dispersing carbon nanotubes in a superplasticizer solution before introducing them into the cement system. This preliminary dispersion step, performed using high-shear mixing or ultrasonic treatment, ensures that nanotubes are properly distributed and stabilized in the liquid medium before cement hydration occurs, preventing aggregation and maintaining dispersion stability throughout the mixing and setting process.
Solution Approach 2:
The superplasticizer acts as an intermediary substance between the carbon nanotubes and the cement system. The nanotubes are first dispersed in the superplasticizer solution, which provides steric and electrostatic stabilization. This intermediary approach allows easy handling and uniform distribution of nanotubes in the cement matrix without direct contact with the complex cement chemistry during mixing.
2Strength
If carbon nanotubes are used in powder form to reinforce cement, then mechanical reinforcement is achieved, but safety problems arise due to powdery nature and fine generation
Solution Approach 1:
The patent changes the physical state parameter of carbon nanotubes from dry powder to liquid dispersion form. By dispersing nanotubes in a superplasticizer solution, the material transitions from a hazardous powder that generates harmful dust to a liquid form that is safe to handle, transport, and incorporate into cement systems using standard liquid mixing equipment.
Solution Approach 2:
The superplasticizer solution serves as an intermediary carrier that eliminates safety hazards associated with dry nanotube powder. The liquid medium prevents dust generation, facilitates safe handling with conventional equipment, and enables controlled dosing, while still delivering the reinforcement function when the nanotubes are incorporated into the cement matrix.
3Manufacturing precision
If carbon nanotubes are dispersed using ultrasound in surfactant solution, then homogeneous distribution is achieved, but the process is complex and time-consuming
Solution Approach 1:
The superplasticizer serves multiple functions simultaneously: it acts as a dispersing agent for carbon nanotubes, a water-reducing admixture for cement, and a workability enhancer for the concrete. This multi-functionality eliminates the need for separate surfactant solutions and complex dispersion processes, allowing homogeneous distribution to be achieved through standard concrete mixing procedures.
Solution Approach 2:
The patent merges the dispersion function with the cement admixture function by incorporating carbon nanotubes into the superplasticizer solution. This combination integrates what would otherwise be separate processes (nanotube dispersion and cement mixing) into a single streamlined operation, reducing equipment complexity and processing time while maintaining homogeneous distribution.
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
This approach simplifies the distribution of carbon nanotubes, enhances mechanical strength, reduces cracking, and improves handling safety, while maintaining the existing manufacturing processes, resulting in denser and more durable materials.
Implementation Method 1
dispersing carbon nanotubes using ultrasound in a surfactant solution
Implementation Method 2
The carbon nanotubes used preferably have a diameter ranging from 20 to 40 nm and a length ranging from 10 to 100 μm. The surfactants are preferably polycarboxylate-based superplasticizers.
Implementation Method 3
dispersing carbon nanotubes using ultrasound
Implementation Method 4
dispersing carbon nanotubes using ultrasound in a surfactant solution
Implementation Method 5
the incorporation of carbon nanotubes into cements presents numerous advantages. Indeed, carbon nanotubes (or CNTs) confer improved mechanical properties
Implementation Method 6
their good mechanical properties and in particular resistance to elongation are linked in part to their very high aspect ratios (length/diameter)
Implementation Method 7
This study shows, however, that these CNT dispersions are not stable over time and must therefore be used quickly for the application of cement reinforcement
Data Source
Figure 1~2
AI summary
The invention relates to hardenable inorganic systems such as cements, plasters, ceramics or liquid silicates, usable for example in the building trade, construction industry or oil drilling industry. The invention more specifically relates to the insertion of carbonaceous nanofillers, such as carbon nanotubes, for reinforcing mechanical properties and improving such systems. The invention further relates to a method for producing a master mixture comprising at least one superplasticiser and carbonaceous nanofillers at a mass ratio of between 0.1 % and 25 %, preferably between 0.2 % and 20%, in relation to the total weight of the master mixture, and also to said master mixture thus obtained and to the use thereof in a hardenable inorganic system with a view to producing materials with improved properties. The invention applies to the construction industry, the building trade and the oil drilling industry.