Light Curable Energetic Binder Process
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Solution Overview
Problem
Existing energetic polymers used in cast-cure explosive and propellant applications face challenges such as slow curing times, formation of voids due to moisture, and the use of toxic isocyanate curatives, which limit their application.
Innovation Solution
The development of light-curable energetic polymeric binders by modifying pre-polymers with alkyne, alkene, or acrylate moieties, allowing for curing at ambient temperatures without the need for toxic catalysts or nitrogen blanketing, and eliminating unwanted by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyisocyanate-based curatives are used for curing energetic pre-polymers, then the polymer formulation achieves crosslinked structure, but voids form due to carbon dioxide generation from moisture reaction
Solution Approach 1:
The patent changes the chemical parameters of the curative system by replacing polyisocyanate-based curatives with alternative curatives that do not generate carbon dioxide through moisture reaction. This parameter change eliminates the harmful void formation while maintaining the crosslinked structure necessary for polymer strength.
2Strength
If polyisocyanate-based curatives are used for curing, then crosslinking occurs, but toxic and carcinogenic substances are introduced into the formulation
Solution Approach 1:
The patent extracts and removes the harmful polyisocyanate-based curatives from the formulation while retaining the essential crosslinking function through alternative curative mechanisms. This extraction eliminates the toxic and carcinogenic substances while preserving the structural integrity of the cured polymer.
3Strength
If thermal curing with polyisocyanate curatives is employed, then crosslinking is achieved, but curing time becomes extremely slow limiting application
Solution Approach 1:
The patent changes the kinetic parameters of the curing process by substituting polyisocyanate-based curatives with alternative curatives that exhibit faster reaction kinetics. This parameter change dramatically reduces curing time from several hours or days to much shorter durations, enabling practical applications.
4Reliability
If traditional thermal cure methods are used, then polymerization occurs, but expensive nitrogen blanketing is required to prevent oxygen inhibition
Solution Approach 1:
The patent extracts and eliminates the requirement for nitrogen blanketing by using alternative curative systems that are not susceptible to oxygen inhibition. This removes the need for expensive nitrogen blanketing equipment and complex atmospheric control systems, simplifying the overall process while maintaining reliable 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
This approach significantly reduces curing time, minimizes moisture-related issues, and avoids the introduction of toxic reactants, enhancing the properties and safety of the final polymer formulations.
Implementation Method 1
combining a pre-polymer such as PGN or GAP having a terminal hydroxyl group in a solvent with a reactant
Implementation Method 2
The mixture is cooled below 0° C., and processed to recover the light curable energetic polymeric binder
Implementation Method 3
Such light curabable moiety can be either an alkene, alkyne or acrylate compound
Data Source
AI summary
The present invention is directed to a process for preparing light curable energetic polymeric binders. The process for preparing such binder comprises the steps of mixing a pre-polymer such as PGN or GAP having a terminal hydroxyl group with a solvent and adding reactants wherein the reactant has a light curable moiety and a pre-polymer reactive moiety. Catalysts such as carbodiimide and DMAP may be further added to the mixture.