Polylactic Acid Microsphere Emulsification With Solvent Recovery
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Solution Overview
Problem
Existing methods for preparing polylactic acid microspheres face challenges such as irregular morphology, agglomeration, wide size distribution, low yield, and environmental harm due to solvent evaporation, particularly in industrial production.
Innovation Solution
An apparatus and method involving a reactor system with a solvent recovery and distillation device, controlled parameters like volume ratios, stirring speeds, and temperature management to produce uniform polylactic acid microspheres efficiently and environmentally safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spray drying is used to prepare polylactic acid microspheres, then the solvent can be quickly evaporated and solid particles formed, but strict control of hot air temperature is required and the process is complex
Solution Approach 1:
The patent utilizes the phase transition of solvent from liquid to vapor through controlled heating. The solvent in the emulsion undergoes evaporation to form solid microspheres, leveraging the natural phase change process to simplify the drying system while maintaining controlled evaporation rates through temperature management of the water bath
Solution Approach 2:
The patent replaces the complex hot air temperature control system of spray drying with a simpler water bath heating system. By substituting the mechanical airflow control with thermal conduction through water, the system achieves solvent evaporation with reduced device complexity and easier temperature management
2Ease of manufacture
If phase separation is used to prepare polylactic acid microspheres, then the process is simple, but a large amount of organic solvent is consumed
Solution Approach 1:
The patent implements solvent recovery by collecting and reusing the organic solvent after the emulsion breaks and microspheres are formed. This allows the same solvent to be used multiple times, significantly reducing organic solvent consumption while maintaining the simplicity of the phase separation process
Solution Approach 2:
The patent optimizes the solvent-to-polymer ratio and controls the emulsification temperature to enhance solvent efficiency. By adjusting these parameters, the system achieves effective microsphere formation with reduced solvent requirements while maintaining process simplicity
3Ease of operation
If emulsification-solvent evaporation is used with uncontrolled conditions, then the operation is convenient and production can be expanded, but irregular morphology, agglomeration and wide size distribution occur
Solution Approach 1:
The patent incorporates continuous monitoring and adjustment of emulsification parameters including stirring speed, rotational speed, and temperature. This feedback control ensures consistent microsphere morphology and size distribution while maintaining the operational convenience of the emulsification process
Solution Approach 2:
The patent employs dynamic control of emulsification conditions by adjusting stirring and rotation speeds during the process. This dynamic adjustment allows the system to adapt to changing conditions, ensuring uniform microsphere formation while preserving the ease of operation and scalability of the process
4Manufacturing precision
If microfluidic apparatus is used to prepare polylactic acid microspheres, then uniform particle size is achieved, but the yield is low and industrial production is difficult
Solution Approach 1:
The patent uses a multi-nozzle emulsification system that divides the polymer solution into multiple streams, each forming microspheres independently. This segmentation approach maintains the uniformity benefits of microfluidic methods while scaling up production capacity through parallel microsphere formation
Solution Approach 2:
The patent transitions from single-point microfluidic droplet formation to a multi-dimensional emulsification field using rotating multi-nozzle assemblies. This dimensional expansion allows simultaneous formation of numerous microspheres with controlled size uniformity, achieving both precision and high yield suitable for industrial production
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 achieves polylactic acid microspheres with concentrated particle size distribution, high yield, and reduced solvent residue, ensuring biocompatibility and suitability for medical applications.
Implementation Method 1
supply heat to the reactor body in real time, whereby the solvent in the droplets of polylactic acid microspheres is evaporated
Implementation Method 2
cooling the evaporated solvent by the low-temperature circulating device in real time, and flowing the condensed solvent through the reflux head
Implementation Method 3
continuously shearing the reaction liquid by the emulsifying head driven by the emulsifying motor, to produce droplets of polylactic acid microspheres
Data Source
AI summary
Provided are an apparatus and a method for preparing polylactic acid microspheres. The apparatus includes a reactor body, a reactor cover, and a solvent distillation and recovery device. The method for preparing polylactic acid microspheres includes the following steps: adding a solution of polylactic acid in an organic solvent to an aqueous solution of polyvinyl alcohol; emulsifying, and heating the reaction liquid in real time, whereby the solvent in the droplets of polylactic acid microspheres is evaporated and the droplets are solidified into polylactic acid microspheres; and washing and drying the crude polylactic acid microspheres, to obtain finished polylactic acid microspheres. By using the apparatus and method for preparing polylactic acid microspheres according to the present invention, polylactic acid microspheres with concentrated particle size distribution is prepared, and the organic solvent is recovered and reused.