Thionated Polymer Synthesis for Near-Infrared Transparency
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Solution Overview
Problem
Current methods for synthesizing thionated polymers with high sulfur content are labor-intensive, expensive, and result in materials that are not transparent in the near-infrared region due to impurities and lack desirable cross-linking and glass-transition temperatures.
Innovation Solution
The synthesis of thionated polymers involves oxidizing a monomer or oligomer with aromatic groups and then reducing the product with a sulfur source, resulting in materials that are transparent in the near-infrared region and have improved purity and durability, using fewer steps and lower-cost starting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copolymerization of sulfur and limonene is used to obtain copolymers with high sulfur content, then sulfur content is improved, but transparency in the near infrared region deteriorates due to alkyl fragments
Solution Approach 1:
The patent removes the problematic alkyl fragments from the polymer backbone by using aromatic monomers without such groups. The synthesis specifically targets the elimination of limonene-derived alkyl substituents that cause near-infrared absorption, while maintaining high sulfur content through alternative aromatic monomer structures.
Solution Approach 2:
The patent changes the chemical structure parameters of the polymer backbone by substituting aliphatic limonene units with aromatic monomers. This structural parameter change fundamentally alters the optical properties, eliminating near-infrared absorption while preserving the high sulfur content characteristic of the material.
2Quantity of substance
If cyclic arylenedisulfides and sulfur are used to synthesize polysulfide materials with high sulfur content, then sulfur content is improved, but manufacturing complexity worsens due to difficult separation of aromatic derivatives by-products
Solution Approach 1:
The patent eliminates the problematic aromatic derivatives by-products by changing the monomer structure to one that does not produce such by-products during polymerization. The selected aromatic monomers are designed to polymerize cleanly without generating separable aromatic by-products, thus simplifying the manufacturing process.
Solution Approach 2:
The patent achieves a more homogeneous polymer structure by using monomers that polymerize without producing by-products. This homogeneity eliminates the need for complex separation processes and simplifies manufacturing, while maintaining the desired high sulfur content through the polymer structure itself.
3Quantity of substance
If two consecutive stages are used in the synthesis process with copper salt catalyst, then sulfur content is improved, but productivity deteriorates due to labor and time consumption
Solution Approach 1:
The patent merges the polymerization and thionation steps into a single concurrent process. By using monomers with built-in thio groups that polymerize directly, the method combines what were previously two separate consecutive stages into one unified reaction process, eliminating the need for intermediate isolation and second-stage polymerization.
Solution Approach 2:
The patent segments the sulfur incorporation into the monomer structure itself rather than adding it in a separate stage. The thio-containing monomers are designed with sulfur already incorporated, allowing direct polymerization to high-sulfur polymers in one step, thus eliminating the multi-stage process requirement.
4Quantity of substance
If expensive reagents and multi-stage synthesis are used, then sulfur content is improved, but cost worsens
Solution Approach 1:
The patent employs inexpensive aromatic monomers that can be readily synthesized or obtained, replacing expensive specialized reagents. The monomers are designed to be simple, cost-effective starting materials that directly yield high-sulfur polymers without requiring expensive catalysts or multi-stage processing.
Solution Approach 2:
The patent segments the sulfur content into the monomer structure itself, allowing the use of simple, inexpensive aromatic compounds as starting materials. This approach eliminates the need for expensive reagents and complex synthesis sequences, achieving high sulfur content through straightforward monomer design and one-step polymerization.
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 resulting thionated polymers are highly transparent and durable, with reduced impurities and higher sulfur content, addressing the limitations of existing processes by achieving transparency in the near-infrared range and improved properties.
Implementation Method 1
oxidizing a monomer or oligomer comprising one or more aromatic groups
Implementation Method 2
reducing the product of step (a) with a sulfur source
Data Source
AI summary
Provided are thionated polymers comprising one or more aromatic groups and at least one Sx group, wherein x is 1-200, wherein the thionated polymer comprises about 50% by weight or less, based on the weight of the thionated polymer, of substituents on the backbone of the thionated polymer that absorb at a wavelength of about 700 to about 6200 nm. Also provided are substrates such as films, glass substrates, and optical devices comprising a thionated polymer and processes for preparing a thionated polymer described herein.