Polymer-Modified Bitumen Crosslinking for Better Elastic Recovery
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Solution Overview
Problem
Existing polymer-modified bitumen formulations using dialkyl polysulfides with R=C6 to C16 exhibit inadequate elastic recovery and susceptibility to deforming forces, particularly under heavy traffic conditions.
Innovation Solution
Vulcanizing styrene-butadiene copolymers with C7-C8-dialkyl polysulfides, such as dioctyl pentasulfide, at specific mixing conditions to enhance crosslinking and improve elastic recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dialkyl polysulfides with R=C6 to C16 are used for crosslinking, then homogeneous distribution of sulfur is achieved, but elastic recovery is insufficient and susceptibility to deforming forces increases
Solution Approach 1:
The patent changes the carbon chain length parameter of the dialkyl polysulfide from C6-C16 to specifically C7-C8, which optimizes the balance between homogeneous distribution and elastic recovery properties
Solution Approach 2:
The patent creates a composite crosslinking system using specific C7-C8 dialkyl polysulfides combined with styrene-butadiene copolymers, achieving superior mechanical properties through the synergistic effect of optimized sulfur distribution and polymer matrix
2Stability of the object's composition
If dialkyl polysulfides with R=C6 to C16 are used for crosslinking, then crosslinking homogeneity is improved, but resistance to deforming forces decreases
Solution Approach 1:
The patent optimizes the alkyl chain length parameter to C7-C8, which provides the ideal balance between achieving homogeneous crosslinking distribution and maintaining high resistance to deforming forces in the asphalt blanket
3Object-generated harmful factors
If sulfur content is reduced, then emission of hydrogen sulfide is decreased, but elastic properties and crosslinking effectiveness are compromised
Solution Approach 1:
The patent changes the chemical structure parameter of the sulfur source to C7-C8 dialkyl polysulfides, which enable effective crosslinking at lower sulfur contents while reducing hydrogen sulfide emissions and improving elastic recovery
Solution Approach 2:
The patent converts the potentially harmful side reaction producing hydrogen sulfide into a beneficial process by using dialkyl polysulfides that crosslink more efficiently at lower concentrations, reducing emissions while enhancing elastic properties
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 process results in polymer-modified bitumen with improved elastic recovery and reduced susceptibility to deforming forces, as demonstrated by higher R-values and lower J-values in MSCR tests.
Implementation Method 1
Vulcanizing styrene-butadiene copolymers with C7-C8-dialkyl polysulfides, such as dioctyl pentasulfide, at specific mixing conditions to enhance crosslinking and improve elastic recovery
Data Source
AI summary
The present invention relates to polymer-modified bitumen, to a process for production thereof and to the use thereof for asphalt.