Polymeric Part Flame-Retardant Modification via Supercritical Fluid
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Solution Overview
Problem
Existing methods for modifying polymeric parts to impart flame-retardant properties often result in surface treatments that do not penetrate the material deeply, leading to inadequate resistance over time and potential negative effects on the polymer's properties, especially when using fillers or impregnation with chemical agents.
Innovation Solution
A process involving the reaction of polymeric parts with a functional compound containing isocyanate and vinyl polymerizable groups, in the presence of supercritical fluids, to achieve deep chemical modification and covalent bonding, allowing for simultaneous surface and internal modification without the need for volatile organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impregnation with chemical agents is used to confer flame-retardant properties, then the targeted property is conferred on the surface, but the treatment does not penetrate deeply into the part and fixation is weak
Solution Approach 1:
The patent uses supercritical carbon dioxide (changing pressure and temperature parameters beyond critical point) to transform the fluid state of CO2, enabling deep penetration into the polymeric part while maintaining solvating power for chemical agents. This parameter change allows simultaneous achievement of deep penetration and strong fixation throughout the volume.
Solution Approach 2:
Supercritical carbon dioxide acts as an intermediary medium that carries flame-retardant chemical agents deep into the polymeric part. The supercritical fluid serves as a carrier that enables both deep penetration and uniform distribution of chemical agents throughout the material volume, resolving the contradiction between penetration depth and fixation strength.
2Reliability
If fillers are added to form composite material to improve flame-retardant properties, then flame resistance is enhanced, but the presence of fillers may have negative effects on other polymer properties
Solution Approach 1:
The patent extracts the harmful aspect of traditional filler addition by replacing solid fillers with a supercritical fluid-based chemical modification approach. This takes out the negative effects on polymer properties while retaining the beneficial flame-retardant function through covalent bonding of chemical agents.
Solution Approach 2:
The patent creates a composite structure at the molecular level by covalently bonding flame-retardant chemical agents to the polymeric matrix through supercritical fluid-mediated reactions. This molecular-level composite approach enhances flame resistance without compromising the macroscopic properties of the polymer.
3Productivity
If conventional impregnation is used to treat polymeric parts, then chemical agents can be applied, but the reaction kinetics are slow and large quantities of solvents and reagents are required
Solution Approach 1:
The patent changes the physical parameters of the carbon dioxide (pressure and temperature) to achieve a supercritical state, which dramatically enhances the solvating power and diffusion capability of the fluid. This parameter change accelerates reaction kinetics and reduces the quantity of reagents needed compared to conventional liquid-phase impregnation.
Solution Approach 2:
The patent utilizes the phase transition of carbon dioxide to supercritical state to achieve rapid penetration and reaction. The phase transition enables the fluid to achieve both liquid-like density (for solvating power) and gas-like diffusivity (for fast kinetics), significantly improving productivity while reducing reagent quantities.
4Reliability
If surface treatment is applied to polymeric parts, then flame-retardant properties can be conferred on the surface, but the treatment does not allow the part to be reached in depth
Solution Approach 1:
Supercritical carbon dioxide serves as an intermediary carrier that transports flame-retardant chemical agents from the surface deep into the bulk of the polymeric part. This intermediary enables uniform distribution of chemical agents throughout the entire volume, achieving both surface and internal flame-retardant protection simultaneously.
Solution Approach 2:
By changing to supercritical parameters (pressure and temperature), the fluid achieves enhanced penetration capability that allows it to reach deep into the polymeric part while maintaining the ability to carry and deposit chemical agents uniformly throughout the volume.
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 process enables thorough penetration and fixation of flame-retardant compounds within the polymeric part, enhancing its flame-retardant properties while minimizing environmental impact and reducing reagent usage, with improved reaction kinetics and industrial feasibility.
Implementation Method 1
the possibility of carrying the functional compound and the second compound deep into the polymeric part and thus allowing a chemical modification of the latter both on the surface and in depth and therefore in the whole of the part
Implementation Method 2
a significant solvating power, which makes it possible to give the reaction steps a much faster reaction kinetics compared to similar reactions, which would be carried out in a non-supercritical medium
Implementation Method 3
the isocyanate groups reacting, covalently with all or part of the amine groups and/or hydroxyl groups of the polymer(s), whereby a polymeric part covalently bonded to residues of the functional compound results
Implementation Method 4
from the polymerizable groups of the vinyl type of the residues of the functional compound, a step of polymerizing a second compound comprising at least one polymerizable group of the vinyl type and at least one group comprising at least one phosphorus atom
Data Source
Figure 1
AI summary
The invention relates to a process for chemically modifying a polymeric part in order to impart flame-retardant properties thereto or to improve said properties, said method comprising the following steps: - a step of reacting a polymeric part with at least one polymer comprising, as reactive groups, amine groups and/or hydroxyl groups, with a functional compound, referred to as the first compound, comprising at least one isocyanate group and at least one vinyl-type polymerizable group, wherein the isocyanate groups react in a covalent manner with part or all of the amine groups and/or hydroxyl groups of the at least one polymer, whereby a polymeric part is covalently bonded to residues of the functional compound; - from the vinyl-type polymerizable groups of the residues of the functional compound, a step of polymerizing a second compound comprising at least one vinyl-type polymerizable group and at least one group comprising at least one phosphorus atom, said reaction step and said polymerization step being carried out in the presence of at least one supercritical fluid.