Biodegradable Hydrogels via Boric Acid Crosslinking
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Solution Overview
Problem
Current superabsorbent polymers face challenges in being biodegradable, hypoallergenic, and derived from renewable sources, with issues such as toxic crosslinking agents, imprecise crosslinking determination, and environmentally harmful production processes, particularly in large-scale applications.
Innovation Solution
A method involving an aqueous solution of alkylcellulose with boric acid or its derivatives at pH 7.5 or higher, allowing for crosslinking without pre-evaporation, using sodium hydrogen carbonate as both an alkalinizing agent and porogenic agent, which facilitates the formation of borate ions for crosslinking, resulting in biodegradable and environmentally friendly superabsorbent hydrogels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crosslinking agents (citric acid, epichlorhydrin, etc.) are used to produce superabsorbent polymers, then crosslinking efficiency is improved, but toxicity and environmental harm increase
Solution Approach 1:
The patent converts the traditionally harmful crosslinking process into a beneficial one by using boric acid, a non-toxic substance, as the crosslinking agent. This transforms the harmful chemical crosslinking into a safe, environmentally friendly process that maintains crosslinking efficiency while eliminating toxicity concerns.
Solution Approach 2:
The patent changes the chemical parameter of the crosslinking agent from conventional toxic substances (citric acid, epichlorhydrin) to boric acid, which has similar crosslinking capability but without the toxic side effects. This parameter substitution resolves the contradiction between crosslinking efficiency and toxicity.
2Reliability
If pre-evaporation and phase-inversion processes are used to produce superabsorbent polymers, then absorption performance is improved, but production time and energy consumption increase
Solution Approach 1:
The patent extracts and eliminates the time-consuming pre-evaporation and phase-inversion steps from the production process. By using boric acid crosslinking in aqueous solution, the method achieves high absorption performance without requiring these intermediate processing stages, thus significantly reducing production time.
Solution Approach 2:
The patent skips the traditional multi-step process (dissolution → pre-evaporation → phase-inversion → drying) and rushes through to a simplified process (dissolution → boric acid crosslinking → drying). This shortcut maintains product performance while dramatically reducing production time and energy consumption.
3Reliability
If conventional production methods are used, then absorption efficiency is achieved, but environmental pollution and resource depletion occur
Solution Approach 1:
The patent converts the environmentally harmful production process into a beneficial one by using renewable resources (cellulose from plants) and non-toxic crosslinking agents (boric acid). This transformation maintains absorption efficiency while eliminating environmental pollution and resource depletion issues.
Solution Approach 2:
The patent creates a composite material system combining cellulose (renewable polymer) with boric acid crosslinked network, forming a biodegradable superabsorbent polymer that achieves high absorption efficiency without environmental harm. This composite approach resolves the contradiction between performance and environmental sustainability.
4Reliability
If crosslinking agents with similar functional groups to substrate are used, then crosslinking reaction is facilitated, but analytical characterization becomes imprecise
Solution Approach 1:
The patent uses boron as a distinctive marker element that can be detected by various analytical techniques (XPS, FT-IR, SEM-EDX). This distinctive 'chemical color' or signature allows precise analytical characterization of the crosslinked product, resolving the issue of imprecise measurement when crosslinking agents have similar functional groups to the substrate.
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 method produces superabsorbent hydrogels that are biodegradable, hypoallergenic, and derived from renewable sources, with precise crosslinking assessment and reduced environmental impact, achieving high absorption efficiency and stability, suitable for various applications including hygienic, pharmaceutical, and food packaging uses.
Implementation Method 1
performing the crosslinking reaction obtaining a gel
Implementation Method 2
facilitates the formation of borate ions for crosslinking
Implementation Method 3
capable of absorbing and retain thereinside high amounts of aqueous solution
Implementation Method 4
the crosslinked structure lends itself to incorporate/release high amounts of solution via diffusive processes
Implementation Method 5
using sodium hydrogen carbonate as both an alkalinizing agent and porogenic agent, which facilitates the formation of borate ions
Implementation Method 6
drying the gel
Data Source
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AI summary
The present invention is directed to natural polymer-based biodegradable superabsorbent hydrogels and to methods for making them. These hydrogels can be employed in hygienic-health products, in the sector of food product packaging and in medical products.