Glycolide Polyester Ring Opening Polymerization via Solution Precipitation
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Solution Overview
Problem
Current methods for producing glycolide polyesters through ring opening polymerization are energy-intensive, require high temperatures, and result in products with metal catalyst residues and difficulties in collection and processing, limiting their applications.
Innovation Solution
A method using metal-free catalysts and specific solvents to facilitate ring opening polymerization at low temperatures, allowing glycolide monomers and optional co-monomers to precipitate and be easily separated, enabling the production of glycolide homo- and copolymers with controlled particle size and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If melt polymerizing techniques are used at high temperatures, then ring opening polymerization of glycolide can be achieved, but the process becomes energy-intensive and requires equipment with tight temperature requirements
Solution Approach 1:
The patent changes the temperature parameter from high (melt polymerization above melting temperature) to low (below melting temperature) by using solution polymerization instead of melt polymerization, thereby reducing energy consumption while achieving effective polymerization
Solution Approach 2:
The patent introduces a solvent as an intermediary medium to enable polymerization at lower temperatures. The solvent dissolves the monomer and allows ring opening polymerization to proceed below the melting point of the polyester product, avoiding the energy-intensive melt process
2Reliability
If metal catalysts are used for ring opening polymerization, then polymerization can be catalyzed effectively, but metal catalyst residues remain in the product limiting applications
Solution Approach 1:
The patent uses organocatalysts (molecular sieves, acids, or bases) as temporary catalytic agents that can be easily removed or deactivated after polymerization, replacing persistent metal catalysts with short-lived organic catalysts that leave no harmful residues
Solution Approach 2:
The patent extracts metal catalysts from the system entirely and replaces them with organocatalysts. The organocatalysts can be removed through filtration (molecular sieves) or simple workup procedures, eliminating metal residue contamination from the final product
3Temperature
If solution ring opening polymerization is used, then polymerization can proceed at lower temperatures, but product recovery from polymer solute becomes costly and technically demanding
Solution Approach 1:
The patent exploits phase transition by selecting a solvent in which the polymer product is insoluble at the polymerization temperature. As polymerization proceeds, the polymer precipitates out of solution, automatically separating it from the solvent and simplifying recovery through filtration or decantation
Solution Approach 2:
The polymerization process itself serves the dual function of synthesis and purification. The insolubility of the polymer in the reaction solvent causes automatic precipitation during polymerization, so the product separates itself from the reaction medium without requiring additional complex recovery steps
4Productivity
If melt polymerizing techniques are used, then polymerization can be performed, but collection of produced polymers from reactor and further processing becomes difficult requiring pelletization
Solution Approach 1:
The patent uses phase separation where the polymer precipitates as a solid from the liquid reaction mixture. This automatic solidification during or after polymerization creates easily collectible solid polymer particles that can be separated by simple filtration or decantation, eliminating the need for complex pelletization equipment and 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
This method enables the rapid production of glycolide polyesters at low temperatures, resulting in a metal-free, colorless product with reduced energy consumption and improved handling, suitable for various applications, including pharmaceuticals and packaging materials.
Implementation Method 1
ring opening polymerization in the presence of a catalyst
Implementation Method 2
said solvent being selected so that said glycolide monomer and optional co-monomer(s), said dispersion stabilizer and said catalyst are soluble therein but resulting glycolide homopolymer or co-polymer is non-soluble
Implementation Method 3
resulting glycolide homopolymer or co-polymer is non-soluble
Data Source
AI summary
The present invention relates to a method for preparation a glycolide polyester by ring opening polymerization characterized in that glycolide monomer with optional co-monomer(s) of cyclic ester(s) is/are subjected to ring opening polymerization in the presence of a dispersion stabilizer and a catalyst, said catalyst being selected for precipitating glycolide homopolymer or copolymer from solvent, said solvent being selected so that the glycolide monomer and the optional co-monomer(s), the dispersion stabilizer and the catalyst are soluble therein but said glycolide homopolymer or copolymer is non-soluble. The present invention further relates to an in situ ring opening polymerizing process product, and to use of said glycolide polyester, and to further processing of said glycolide polyester.