Sulfur-Modified Polyolefin Asphalt Binder for Rut Resistance
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Solution Overview
Problem
Current asphaltic concrete mixtures lack sufficient elasticity and resistance to permanent deformation, and existing polymer modifiers like SBS are expensive and prone to degradation, while olefinic polymers like PE and PP are immiscible with asphalt, limiting their effectiveness.
Innovation Solution
A homogeneous sulfur-modified polymer composition is created by pyrolyzing saturated hydrocarbon polymers to produce unsaturated hydrocarbon polymers, which are then reacted with elemental sulfur to achieve cross-linking, resulting in a composition with varying sulfur content, improving the rheological properties and stability of asphaltic concrete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unsaturated thermoplastic elastomers like SBS are used to enhance elasticity and resistance to permanent deformation, then the performance of asphalt is improved, but the cost increases significantly and the polymer is subject to degradation when exposed to atmospheric agents and mechanical stress
Solution Approach 1:
The patent replaces expensive SBS elastomers with cheaper polyolefin polymers (PE, PP) that can be used at higher concentrations (5-20% by weight). Although polyolefins have shorter service life and are more susceptible to degradation, their low cost allows using larger amounts to achieve the desired performance, effectively substituting quality with quantity while reducing overall material cost
Solution Approach 2:
The patent changes the concentration parameter of polymer additives from typical 1-3% for SBS to 5-20% for polyolefins. This parameter change compensates for the inferior performance per unit mass of polyolefins by using larger amounts, thereby achieving comparable or superior resistance to permanent deformation at lower cost
2Strength
If olefinic polymers like PE and PP are used to provide high rigidity and reduce deformations under traffic load, then the rigidity of asphalt is improved, but the polymers are almost completely immiscible with asphalt due to their non-polar nature, limiting their use
Solution Approach 1:
The patent modifies the local chemical properties of polyolefin polymers by introducing polar functional groups (carboxyl, hydroxyl, amine) at specific locations along the polymer chains. This creates a heterogeneous structure where non-polar segments maintain rigidity while polar segments provide compatibility with asphalt, resolving the immiscibility issue without sacrificing strength
Solution Approach 2:
The patent creates composite polymer structures combining polyolefin base chains with grafted polar functional groups. This composite approach integrates the rigidity-providing non-polar polyolefin backbone with asphalt-compatible polar side groups, achieving both high rigidity and good miscibility with asphalt binder
3Quantity of substance
If conventional asphalts are used, then the cost is reduced, but the asphalts do not retain sufficient elasticity in use and exhibit a plasticity range which is too narrow for use in many modern applications
Solution Approach 1:
The patent creates composite asphalt-polymer systems by blending modified polyolefin polymers with conventional asphalt binder. The polyolefin component provides elasticity and拓宽es the plasticity range, while the asphalt provides binding and structural properties, achieving enhanced performance without significantly increasing cost
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 sulfur-modified polymer composition enhances the rut resistance, elasticity, and high-temperature performance of asphaltic concrete, reducing emissions and costs, while maintaining desirable binder properties, thus addressing the limitations of existing modifiers.
Implementation Method 1
pyrolyzing the saturated hydrocarbon polymer to produce a unsaturated hydrocarbon polymer and acetic acid
Implementation Method 2
reacting the unsaturated hydrocarbon polymer with elemental sulfur such that cross-linking is achieved
Data Source
AI summary
The present invention relates to homogeneous sulfur-modified polymer compositions, methods related thereto and an asphaltic concrete mixture.