Silk Fiber Degumming Using Hydrogen Bubble Sericin Removal
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Solution Overview
Problem
Existing sericin removal methods for silk fibroin fibers are incomplete, time-consuming, labor-intensive, and damage the fiber structure, affecting the properties of silk fibroin.
Innovation Solution
A method involving immersion of silkworm cocoons in a sodium borohydride aqueous solution at room temperature for 1.5 to 26 hours, followed by washing and freeze-drying, to remove sericin without damaging the silk fibroin structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods (alkalies, soaps, urea, organic acids, ionic liquids, high temperature and high pressure, ultrasonic wave, microwave, enzymes) are used for sericin removal, then sericin removal can be achieved, but the process is time-consuming, labor-intensive, and causes serious damages to the structure of silk fibroin fiber
Solution Approach 1:
The patent changes the chemical parameters by using sodium borohydride as a reducing agent instead of traditional alkalies or enzymes. This chemical parameter change enables sericin removal at room temperature (17-25°C) rather than requiring high temperature and pressure, thereby reducing process time while maintaining complete sericin removal effectiveness
Solution Approach 2:
The patent replaces mechanical removal methods (ultrasonic wave, microwave) with a chemical reduction mechanism. Sodium borohydride chemically reduces sericin proteins, allowing removal without mechanical stress that would damage silk fibroin structure, thus achieving complete removal faster without time loss
2Reliability
If traditional methods are used for sericin removal, then sericin can be removed, but the structure of silk fibroin fiber is damaged
Solution Approach 1:
The patent converts the potentially harmful effect of strong chemicals into a beneficial process. Sodium borohydride, which could potentially damage proteins, is used in controlled conditions to specifically reduce sericin while leaving silk fibroin intact. The mild reducing conditions actually benefit the silk fibroin by preventing oxidative damage that would occur with traditional strong alkaline or enzymatic methods
Solution Approach 2:
The patent changes the chemical environment parameters to be mild and controlled (room temperature, neutral to slightly alkaline pH). This parameter change allows selective removal of sericin without damaging the sensitive silk fibroin structure, maintaining fiber integrity while achieving complete sericin removal
3Productivity
If high temperature methods are used for sericin removal, then sericin removal can be achieved, but the silk fibroin fiber turns yellow-brown and loses flexibility
Solution Approach 1:
The patent replaces thermal energy (heat) with chemical energy (sodium borohydride reduction). This substitution eliminates the need for high temperature processing that causes yellow-brown discoloration and loss of flexibility, while maintaining high sericin removal efficiency through chemical reduction mechanisms
Solution Approach 2:
The patent converts the potential harm of chemical reactions into a beneficial process. Instead of using strong oxidizing agents or high heat that would damage fiber color and flexibility, the mild reducing action of sodium borohydride removes sericin while preserving the natural white color and flexibility of silk fibroin fibers
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
Achieves a complete sericin removal with high efficiency, maintaining the flexibility and bright color of silk fibroin fibers, suitable for large-scale production.
Implementation Method 1
the sodium borohydride in a sodium borohydride aqueous solution reacts with water slowly to release hydrogen
Implementation Method 2
produce an upward pulling force to the sericin on a fiber surface along the silk fibers under the action of inertial force and surface tension
Implementation Method 3
produce an upward pulling force to the sericin on a fiber surface along the silk fibers under the action of inertial force and surface tension
Implementation Method 4
the drying is conducted by freeze-drying
Data Source
AI summary
The present disclosure provides a method for sericin removal. Since sodium borohydride has a high hydrogen storage performance, a convenient hydrogen release, and relatively-stable chemical properties, the sodium borohydride in a sodium borohydride aqueous solution reacts with water slowly to release hydrogen. A large number of accumulated hydrogen bubbles pass through silk fibers, and produce an upward pulling force to the sericin on a fiber surface along the silk fibers under the action of inertial force and surface tension, thereby achieving the sericin removal at room temperature. Moreover, the method for sericin removal has a simple process, a complete sericin removal effect, and no damage to the structure of silk fibroin fibers, and can prepare the silk fibroin fibers with high flexibility and bright color.