Sulfur Functional Prepolymers for Soluble Polyurethane Feedstocks
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Solution Overview
Problem
Elemental sulfur is difficult to process due to its brittle nature and limited solubility in polar organic solvents and aqueous media, limiting its utilization in various applications, particularly in the production of polyurethanes and other polymeric materials.
Innovation Solution
Development of sulfur-based prepolymers with reactive functional groups, such as alcohols and carboxylic acids, that are highly soluble in organic polar solvents, allowing for the purification and modification of these prepolymers into polyurethanes and block copolymers with increased thermal stability and tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If elemental sulfur is used in its original state, then it is available as a plentiful feedstock, but it has poor solution processing characteristics and limited solubility in polar organic solvents
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of sulfur through copolymerization with olefin co-monomers containing polar functional groups. This transforms elemental sulfur from an insoluble crystalline solid into copolymers with enhanced solubility in polar organic solvents and aqueous media, while maintaining sulfur's availability as a feedstock
Solution Approach 2:
The patent creates composite materials by synthesizing sulfur copolymers that combine sulfur monomers with olefin co-monomers having polar functional groups (hydroxyl or carboxylic acid groups). This composite structure provides both the desired solubility characteristics and the structural properties of sulfur, resolving the contradiction between feedstock availability and processability
2Adaptability or versatility
If sulfur copolymers are prepared from elemental sulfur and olefin co-monomers, then they can be produced with varied composition, but they have limited solubility in polar organic solvents and aqueous media
Solution Approach 1:
The patent systematically varies the composition parameters by using different olefin co-monomers with hydroxyl or carboxylic acid groups in different proportions. This parameter optimization achieves both composition variability and enhanced solubility in polar organic solvents, as the polar functional groups interact favorably with polar solvents
Solution Approach 2:
The patent introduces local quality by incorporating polar functional groups (hydroxyl or carboxylic acid groups) at specific locations within the copolymer structure. These localized polar regions provide the necessary solubility in polar organic solvents while the overall copolymer structure maintains composition variability for different applications
3Ease of manufacture
If polar functional groups are incorporated into sulfur copolymers, then solubility in polar organic solvents increases, but the complexity of the polymer structure increases
Solution Approach 1:
The patent manages structural complexity by controlling the parameters of copolymerization - specifically the ratio of sulfur to olefin co-monomer and the selection of specific co-monomers. This allows achieving desired solubility in polar organic solvents through parameter optimization rather than through complex multi-component structures
Solution Approach 2:
The patent applies segmentation by creating copolymers where sulfur segments are combined with olefin co-monomer segments containing polar functional groups. This segmented structure provides solubility in polar organic solvents through the polar segments while keeping each segment relatively simple, avoiding the need for highly complex overall structures
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-based prepolymers facilitate the production of polyurethanes with improved solubility, thermal stability, and tensile strength, enabling their use in a variety of applications including fire retardant compositions, coatings, and flexible foams.
Implementation Method 1
sulfur copolymers have been prepared from elemental sulfur and olefin co-monomers, such as vinylic co-monomers
Implementation Method 2
Such sulfur-based prepolymers are highly soluble in organic polar solvents, which allows for the purification of sulfur-based prepolymers that are suitable for use in the preparation of polymeric materials
Implementation Method 3
the sulfur-based prepolymers are reacted with isocyanates to provide polyurethanes
Data Source
AI summary
A composition includes a reaction product of a mixture of elemental sulfur and at least a first ethylenically unsaturated compound comprising a hydroxyl or carboxyl group.