Ethylene-Diene Copolymer Crystallinity Control
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Solution Overview
Problem
Ethylene-rich diene copolymers used in tire rubber compositions face issues with crystallinity and stiffness, leading to uncontrolled performance fluctuations due to temperature changes and unsuitability for certain applications.
Innovation Solution
A copolymer of ethylene and 1,3-diene with a composition of 50-95 mol% ethylene units and over 50 mol% 1,3-diene units in 1,2 and 3,4 configurations, synthesized using a metallocene and organomagnesium catalytic system, which reduces crystallinity and stiffness, is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the copolymer contains crystalline parts to improve mechanical strength, then the stiffness increases at low temperature, but the stiffness decreases uncontrollably when temperature reaches the melting point of crystalline parts
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific 1,3-diene units (isoprene, myrcene, piperylene) with controlled molar ratios (5-50 mol% of total units) alongside ethylene units (50-95 mol%). This compositional parameter change modifies the polymer's crystalline structure, reducing its melting point and controlling stiffness behavior across temperature ranges without complete loss of mechanical strength
Solution Approach 2:
The patent creates a composite polymer structure by combining ethylene units with specific 1,3-diene units (isoprene, myrcene, piperylene) in controlled proportions. This composite material approach allows the copolymer to exhibit both the strength benefits of crystalline regions and the temperature stability of amorphous regions, resolving the stiffness fluctuation problem
2Reliability
If the copolymer is made ethylene-rich to reduce oxidation sensitivity, then chemical stability improves, but crystallinity increases causing stiffness fluctuations
Solution Approach 1:
The patent optimizes the ethylene-to-1,3-diene ratio parameter, maintaining ethylene content at 50-95 mol% for oxidation resistance while incorporating 5-50 mol% of specific 1,3-diene units (isoprene, myrcene, piperylene) to control crystallinity. This parameter optimization achieves both chemical stability and mechanical stability across temperatures
3Stability of the object's composition
If the copolymer contains saturated 6-membered cyclic hydrocarbon motifs to reduce crystallinity, then temperature stability improves, but the stiffness becomes excessively high
Solution Approach 1:
The patent changes the structural composition by incorporating cyclic diene units (specifically 1,3-cyclohexadiene, 1,5-cyclooctadiene, or piperylene) at controlled levels (5-50 mol% of total units). This parameter change reduces crystallinity and improves temperature stability while the overall ethylene-rich composition (50-95 mol%) maintains adequate stiffness, avoiding excessive softness
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 copolymer maintains low crystallinity and stiffness, enhancing the performance stability of tire rubber compositions across temperature variations and expanding their application range.
Implementation Method 1
synthesized using a metallocene and organomagnesium catalytic system
Data Source
AI summary
A copolymer of ethylene and of a 1,3-diene of formula CH2═CR—CH═CH2 is provided. The ethylene units represent between 50 mol % and 95 mol % of the ethylene units and of the units of the 1,3-diene, and the units of the 1,3-diene of 1,2 and 3,4 configuration represent more than 50 mol % of the units of the 1,3-diene. The symbol R represents a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer exhibits an improved compromise between the degree of crystallinity and the stiffness and makes it possible to widen the field of application of ethylene-rich diene copolymers in rubber compositions.