Tuning surface properties of melt blown polyester fibers by hydrolysis and solution grafting
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Solution Overview
Problem
Polybutylene terephthalate (PBT) nonwoven fibers' surface properties, such as wetting, biocompatibility, and adsorption, do not meet requirements for various applications, necessitating surface modification to enhance performance.
Innovation Solution
Alkaline hydrolysis of PBT fibers followed by solution grafting and fluorination to modify surface properties, achieving superhydrophilic or superhydrophobic surfaces, and adjusting fiber diameter distribution for improved functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface modification is applied to PBT nonwoven fibers to improve wetting properties, then surface wetting properties are enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies alkaline hydrolysis to modify the surface chemistry of PBT fibers by changing the chemical parameters of the fiber surface. This treatment introduces hydrophilic groups that enhance wetting properties without requiring complex equipment or multiple processing steps, thus improving reliability while maintaining manufacturing simplicity.
Solution Approach 2:
The patent replaces complex mechanical surface modification methods with chemical treatment (alkaline hydrolysis). This substitution achieves the desired surface property enhancement through chemical reactions rather than mechanical processes, simplifying the manufacturing approach while effectively improving wetting characteristics.
2Reliability
If alkaline hydrolysis is applied to PBT fibers to modify surface properties, then surface wetting improves, but fiber diameter is reduced
Solution Approach 1:
The alkaline hydrolysis treatment selectively modifies the surface properties of PBT fibers without significantly affecting the bulk fiber structure. By concentrating the chemical reaction at the fiber surface, the treatment enhances wetting properties locally while minimizing impact on overall fiber diameter, thus resolving the contradiction between surface improvement and dimensional stability.
3Reliability
If solution grafting and fluorination are applied to PBT fibers to achieve superhydrophobic surfaces, then surface wetting properties are enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent employs solution grafting as a preliminary step that prepares the fiber surface for subsequent fluorination. This preliminary action creates reactive sites on the fiber surface that facilitate the fluorination process, enabling superhydrophobic properties to be achieved through a systematic multi-step approach that remains manufacturable and does not require overly complex equipment or procedures.
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 process enhances surface wetting properties, reduces fiber diameter, and increases surface roughness, resulting in materials suitable for applications like crankcase ventilation coalescing and fuel filtration, with improved aerosol separation and extended filtration media life.
Implementation Method 1
subjecting said polyester fiber to alkaline hydrolysis
Implementation Method 2
functionalizing the polyester fiber by solution grafting
Data Source
AI summary
Described herein is a continuous process for modifying the properties of polyester and polyester based fibers, such as a poly(butylene terephthalate) (PBT) fiber, comprising subjecting the PBT fiber to alkaline hydrolysis, and optionally further comprising functionalizing the PBT fiber by solution grafting such as fluorination. The alkaline hydrolysis and optionally subsequent functionalization such as fluorination process can be continuous, following the melt blowing/spinning or spun-bonding process. Also described is a nonwoven PBT fiber mat obtained by the surface modification process. Further described is a filtration device comprising the nonwoven PBT fiber mat.