Comb Polymer Plasticizer for Concrete Workability
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Solution Overview
Problem
Existing polymers made from maleic acid or derivatives and allyl ethers used in concrete as plasticizers suffer from rapid decline in long-term workability, leading to poor workability of hydraulically setting compositions over time.
Innovation Solution
Development of polymers comprising specific structural units and prepared through free-radical polymerization at lower temperatures, which improve both long-term workability and water reduction in hydraulically setting compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional comb polymers are used as plasticizers in concrete, then water reduction is achieved, but long-term workability declines rapidly with time
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating vinyl acetate units (5-50 mol%) alongside maleic acid and allyl ether units. This compositional modification fundamentally alters the polymer's interaction with cement hydration products, maintaining workability without sacrificing water reduction capability. The specific ratio of these units creates a balanced plasticizer that addresses both requirements.
Solution Approach 2:
The invention creates a composite polymer structure combining three different structural units (maleic acid derivative, allyl ether, and vinyl acetate) into a single copolymer. This composite approach allows each unit to contribute its beneficial properties: maleic acid for water reduction, allyl ether for comb structure, and vinyl acetate for improved long-term workability retention.
2Ease of manufacture
If polymers are prepared at temperatures above 60°C, then generic comb polymers are produced, but long-term workability is poor
Solution Approach 1:
The patent changes the processing temperature parameter from conventional high temperatures (>60°C) to a lower range (10-50°C). This temperature modification prevents excessive polymerization that would compromise long-term workability while still enabling effective polymer formation. The lower temperature is compensated by optimizing initiator selection and reaction time to maintain manufacturing efficiency.
3Ease of operation
If conventional plasticizers are used, then initial workability is improved, but workability after short time is poor
Solution Approach 1:
The invention modifies the chemical parameters of the plasticizer by incorporating vinyl acetate units in specific proportions (5-50 mol%). This changes the polymer's molecular characteristics and its interaction with cement particles over time, maintaining ease of operation from initial mixing through extended working periods without the rapid workability loss seen in conventional plasticizers.
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 new polymers maintain excellent workability and water reduction properties in hydraulically setting compositions, with minimal decline in flow table spread even after extended periods, enhancing the stability and usability of concrete.
Implementation Method 1
The invention relates to a polymer P and to a method for preparing a polymer P. Especially preferred is a method for preparing a polymer P comprising the step of free-radical polymerization of: i) m′ mol % of at least one compound A′, which is maleic anhydride or a compound of the formula (IV)
Data Source
AI summary
The invention relates to comb polymers made from maleic acid or derivatives thereof, allyl ethers, and vinyl acetate, and the preparation thereof by free-radical polymerization at a reaction temperature of 10° C. to 50° C. The invention relates further to the use of such comb polymers to improve the workability of hydraulically setting compositions.