Biodegradable Microcapsules via Controlled Crosslinking
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Solution Overview
Problem
Conventional controlled release microcapsules face challenges such as premature release of active agents in surfactant-containing solutions, poor environmental biodegradability, limited encapsulation breadth, mechanical instability, inadequate adhesion to substrates, and inefficient release profiles, particularly in rinse-off applications.
Innovation Solution
A modified biopolymer with a specific formula A-XY, where A is a polysaccharide, protein, or cellulose, and X is a moiety capable of free radical polymerization, is used to create controlled release particles with a high degree of crosslinking and environmental biodegradability, achieved through a method involving the sequential steps of preparing an oil phase and an aqueous phase, emulsifying the active ingredient, and adding structuring agents to form homogeneously suspended particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly crosslinked membranes are used to reduce swelling and solubility, then the membrane resistance to water and surfactants is improved, but the environmental biodegradability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the membrane by using biodegradable polymers with specific functional groups (carboxyl, hydroxyl, amine) and controlling the degree of crosslinking. This allows the membrane to achieve sufficient stability while maintaining biodegradability, as the crosslink density is optimized rather than maximized, and biodegradable crosslinkers are used.
Solution Approach 2:
The patent creates composite membrane structures by combining biodegradable polymers with crosslinking agents. The membrane comprises a matrix of biodegradable polymer chains with crosslinks formed by biodegradable crosslinkers, creating a composite material that exhibits both structural integrity and environmental degradability.
2Strength
If conventional synthetic polymers are used for microcapsule membranes, then the mechanical stability is improved, but the environmental biodegradability deteriorates
Solution Approach 1:
The patent changes the material composition parameter by selecting biodegradable polymers with appropriate molecular weights, functional group densities, and physical properties. This allows the membrane to achieve necessary mechanical strength while being composed entirely of biodegradable materials that can be broken down by environmental microbes.
Solution Approach 2:
The patent develops composite membrane materials combining biodegradable polymer matrices with biodegradable crosslinking structures. The composite structure provides mechanical stability through the crosslinked network while maintaining overall biodegradability since both the matrix and crosslinks are derived from biodegradable components.
3Reliability
If the degree of substitution of natural materials is increased to achieve high crosslink density, then the barrier properties are improved, but the environmental biodegradability deteriorates
Solution Approach 1:
The patent optimizes the degree of substitution parameter to a specific range that provides sufficient crosslinking for barrier properties while leaving enough of the natural polymer structure intact for biodegradability. The functional groups are attached at controlled densities rather than maximum possible densities, balancing performance and environmental compatibility.
Solution Approach 2:
The patent uses natural polymer structures as templates and attaches functional groups that enable crosslinking without fundamentally altering the biodegradable nature of the polymer backbone. The functional groups are added in a way that copies or enhances the natural structure's capabilities while maintaining its environmental compatibility.
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 modified biopolymer-based microcapsules effectively retain active ingredients in surfactant solutions, exhibit high environmental biodegradability, and improve adhesion to substrates during rinse-off applications, enabling controlled and sustained release of active agents.
Implementation Method 1
Y is a second moiety covalently bound to the first moiety X, capable of undergoing free radical polymerization
Implementation Method 2
An emulsion comprising the active material (dispersed phase) is stabilized in a continuous phase
Implementation Method 3
In one mode, a shell material is deposited from the continuous phase onto a dispersed phase via precipitation of the shell material
Data Source
AI summary
Disclosed is a modified biopolymer having the formula A-XY wherein: (a) A is a starting material selected from the group consisting of a polysaccharide, a protein and a cellulose; (b) X is a first moiety bearing a functionality co-reactive with A; (c) Y is a second moiety covalently bound to X, capable of undergoing free radical polymerization and bearing at least two ethylenically unsaturated functional groups; (d) the starting material A and the first moiety X are linked covalently through linkages selected from the group consisting of an ester, an amide, a urethane, a urea, a sulfonate ester, a phosphate ester and an ether; and (e) a degree of substitution of the starting material A with the first moiety X is less than 0.5 but more than 0.1. Compositions including the modified biopolymer and methods for making them are also disclosed.