Polystyrene-Polyvinylpyrrolidone Filter Aid Extrusion
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Solution Overview
Problem
Existing methods for producing filter aids based on polystyrene and crosslinked polyvinylpyrrolidone face challenges with grindability, requiring high energy costs and being non-cost-effective on an industrial scale.
Innovation Solution
A process involving the extrusion of polystyrene and crosslinked water-insoluble polyvinylpyrrolidone popcorn polymers, with the addition of 0.1-10% water by weight, to create a blend that is suitable as a filter aid, allowing for improved grindability without affecting the morphology, using a twin-screw extruder with specific temperature and devolatilization zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filter aids are produced by compounding polystyrene with crosslinked polyvinylpyrrolidone in an extruder, then the filter aid can be used for filtration applications, but the grindability deteriorates requiring increased energy cost
Solution Approach 1:
The patent changes the processing parameters by introducing water (0.1-10% by weight) during extrusion, which modifies the morphology and grindability of the filter aid while maintaining filtration performance. This parameter change resolves the contradiction by making the material easier to grind without sacrificing filtration reliability
Solution Approach 2:
Water acts as an intermediary substance during the extrusion process, facilitating the formation of a porous structure that improves grindability. The water is temporarily present during processing but evaporates, leaving behind a structure that is both easy to grind and effective for filtration
2Ease of manufacture
If water is added to the extrusion mixture, then grindability is improved, but the stability of the polymer blend composition may be affected
Solution Approach 1:
The patent carefully controls the water content parameter (0.1-10% by weight) and processing conditions to achieve the desired morphology improvement without causing demixing of the polymer components. The specific range and controlled addition prevent composition instability while maintaining grindability benefits
Solution Approach 2:
The water is added locally during the extrusion process at specific zones, affecting only the morphology formation in the extrusion die area rather than causing widespread demixing throughout the entire polymer blend. This localized effect preserves overall composition stability
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 enables the production of filter aids with adjusted particle sizes at reduced energy costs, maintaining the morphology and preventing demixing of components, even when exposed to water, thus enhancing the filtration efficiency.
Implementation Method 1
melting polystyrene in an extruder and then treating it with the polyvinylpyrrolidone
Implementation Method 2
processing of the components in an extruder, which comprises melting polystyrene in an extruder and then treating it with the polyvinylpyrrolidone
Implementation Method 3
adding, to the mixture of the components, from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, of water
Data Source
AI summary
Process for production of polymer blends which are suitable as filter aids and are composed of polystyrene and of crosslinked water-insoluble polyvinylpyrrolidones via processing of the two components in an extruder, which comprises melting polystyrene in an extruder and then treating it with the polyvinylpyrrolidone, and adding, to the mixture of the components, from 0.1 to 10% by weight of water, based on the total amount of polystyrene and popcorn polymer, and extruding and comminuting the mixture.