Thermoplastic Polymer Crosslinking Control via Chain Transfer
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Solution Overview
Problem
Regulating the degree of crosslinking in artificial elastomers is challenging due to various influencing factors such as starting materials, additives, reaction time, temperature, and branching, making it difficult to produce polymers with optimized mechanical properties while minimizing the use of chain transfer reagents.
Innovation Solution
A process involving the production of thermoplastic polymer compositions with a specific method of polymerizing monomer mixtures, including conjugated dienes, acrylates, styrene, and crosslinking monomers, followed by determining the degree of crosslinking using NMR relaxation measurements to adjust the polymerization process, reducing the need for chain transfer reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the degree of crosslinking is increased to improve mechanical properties and corrosion resistance, then strength and hardness increase, but brittleness increases and processability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the amount of chain transfer reagent (0.01-0.7 wt%) and crosslinking monomer (0-10 wt%) to optimize the degree of crosslinking. This allows achieving desired mechanical properties while maintaining processability, resolving the contradiction between strength and ease of manufacture.
2Manufacturing precision
If chain transfer reagents are used to control polymerization and achieve desired molecular weight, then polymerization control improves, but pollutant contamination and undesirable properties increase
Solution Approach 1:
The patent minimizes chain transfer reagent content to 0.01-0.7 wt% while using 0-10 wt% crosslinking monomer to achieve the desired degree of crosslinking. This reduces pollutant contamination while maintaining polymerization control, resolving the contradiction between manufacturing precision and harmful factors.
3Manufacturing precision
If multiple factors (starting materials, additives, reaction time, temperature, branching) are varied to optimize crosslinking, then degree of crosslinking control improves, but process complexity increases
Solution Approach 1:
The patent focuses on controlling key parameters (chain transfer reagent 0.01-0.7 wt%, crosslinking monomer 0-10 wt%) rather than varying all possible factors. This achieves precise degree of crosslinking control while simplifying the process, resolving the contradiction between manufacturing precision and device complexity.
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
This method allows for the production of polymers with optimized mechanical properties and reduced chain transfer reagent content, achieving precise control over crosslinking and improving the properties of thermoplastic polymer compositions.
Implementation Method 1
linking the individual polymer chains of the elastomer to one another using covalent bonds
Implementation Method 2
determining the degree of crosslinking using NMR relaxation measurements
Data Source
AI summary
A process produces a polymer composition (A) containing a styrene copolymer (a) and an impact modifier (b), comprising a copolymer (b1) as graft base and a graft (b2), where the steps of the process are: (1) providing a crosslinked copolymer (b1) made of: (b11) from 70 to 99.99% by weight of a conjugated diene or acrylate, (b12) from 0 to 29% by weight of another comonomer, (b13) from 0 to 10% by weight of crosslinking monomers, and (b14) from 0.01 to 0.7% by weight of a chain-transfer reagent; (2) applying, to the copolymer (b1), at least one graft (b2) comprising: (b21) from 65 to 95% by weight of a vinylaromatic monomer, (b22) from 5 to 35% by weight of acrylonitrile and/or methacrylonitrile, and (b23) from 0 to 30% by weight of monoethylenically unsaturated monomers, thus providing the impact modifier (b); (3) mixing the styrene copolymer (a) and the impact modifier (b), and thus leads to improved mechanical properties of the polymer composition (A).