Cement-Free Polymer Dispersion Stabilization
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Solution Overview
Problem
Existing cement-free aqueous dispersions of polymers and calcium silicate hydrates have a short shelf life due to gelling, coagulation, or viscosity increase, and lose their accelerating effect in the setting of mortars and concretes, requiring separate components for storage and handling, which is inconvenient.
Innovation Solution
A cement-free aqueous dispersion comprising particles of a polymer with a specific monomer composition and calcium silicate hydrate, with a polymer P having a number-average particle diameter of 10-1000 nm and a glass transition temperature of -55 to 30°C, and calcium silicate hydrate with a weight-average particle diameter of 0.1-100 nm, stabilized to maintain shelf life for at least 28 days at 23°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cement-free aqueous dispersions of polymers and calcium silicate hydrates are prepared, then the accelerating effect on setting of mortars and concretes is improved, but the shelf life is reduced due to gelling, coagulation, or viscosity increase
Solution Approach 1:
The invention segments the dispersion system into distinct functional components: polymer particles (10-1000 nm) providing stability and calcium silicate hydrate particles (0.1-100 nm) providing accelerating effect. This segmentation allows each component to perform its function independently while maintaining overall dispersion stability during storage.
Solution Approach 2:
The invention optimizes critical parameters including polymer particle size (10-1000 nm), calcium silicate hydrate particle size (0.1-100 nm), glass transition temperature (-55 to 30°C), and monomer composition ratios. These parameter changes ensure the dispersion remains stable during storage while maintaining accelerating effect for rapid setting.
2Speed
If dispersions of finely divided calcium silicate hydrates are used to obtain rapid setting and high early strength, then the setting speed is improved, but the dispersions tend toward agglomeration on storage
Solution Approach 1:
The invention introduces polymer particles as an intermediary substance that stabilizes the calcium silicate hydrate particles. The polymer acts as a protective colloid, preventing direct interaction between calcium silicate hydrate particles that would lead to agglomeration, while allowing the calcium silicate hydrate to maintain its accelerating effect.
Solution Approach 2:
The invention creates a composite dispersion system combining polymer particles and calcium silicate hydrate particles in specific size ranges and proportions. This composite structure leverages the stabilizing properties of the polymer matrix while incorporating the high-performance accelerating properties of calcium silicate hydrate, achieving both rapid setting and storage stability.
3Stability of the object's composition
If stabilizers and plasticizers are admixed to calcium silicate hydrate dispersions to reduce agglomeration, then the dispersion stability is improved, but the complexity of the system increases requiring separate components
Solution Approach 1:
The invention merges the stabilizer function directly into the polymer component of the dispersion system. The polymer particles themselves serve as the stabilizing agent, eliminating the need for separate stabilizer and plasticizer additives. This integration simplifies the system to a single-component dispersion that provides both stability and accelerating effect.
4Strength
If finely divided polymers are admixed to improve mechanical properties of mortars and concretes, then the mechanical strength is improved, but a retardant effect on setting behavior occurs
Solution Approach 1:
The invention uses calcium silicate hydrate particles that replicate the beneficial mechanical reinforcement effects of traditional polymer additives while avoiding their detrimental retardant effect on setting. The nanoscale calcium silicate hydrate particles provide mechanical strengthening through nucleation and reinforcement mechanisms similar to polymers but without interfering with the cement hydration process.
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 dispersion maintains stability and accelerating effect for mortars and concretes, allowing for a single-pot system with improved mechanical properties and rapid setting, reducing the need for separate components and storage complexity.
Implementation Method 1
the polymer P has a number-average particle diameter ≧10 and ≦1000 nm and a glass transition temperature in the range ≧−55 and ≦30° C.
Implementation Method 2
particles of a polymer P and particles of a calcium silicate hydrate, where the calcium silicate hydrate has a weight-average particle diameter ≧0.1 and ≦100 nm
Implementation Method 3
the accelerating effect in the setting of the mortars and concretes
Data Source
AI summary
Cement-free aqueous polymer dispersion comprising calcium silicate hydrate.