Polylactic Acid Decomposition Using Amine Salts
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Solution Overview
Problem
Polylactic acid is less susceptible to decomposition in anaerobic environments, such as methane fermentation, leading to inefficient decomposition and low lactic acid yield, which hinders resource recycling and energy recovery.
Innovation Solution
A method involving the use of an organic acid salt and/or inorganic acid salt of an amine compound, represented by Formula (I), to impregnate polylactic acid-containing organic materials and heat them above 40°C, enhancing decomposition efficiency and facilitating methane fermentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polylactic acid is subjected to methane fermentation in an anaerobic atmosphere, then biodegradation can occur, but the decomposition process takes a long time and efficiency is low
Solution Approach 1:
The patent applies preliminary action by treating polylactic acid with an alkaline solution before methane fermentation to hydrolyze the polymer into soluble oligomers and monomers. This pre-treatment step converts the recalcitrant polymer structure into more biodegradable forms, enabling faster subsequent fermentation and improving overall decomposition efficiency while reducing fermentation time.
Solution Approach 2:
The patent utilizes parameter changes by adjusting pH conditions - first using alkaline conditions (high pH) for hydrolysis, then transitioning to neutral or slightly acidic conditions for fermentation. This parameter transformation optimizes the chemical structure of polylactic acid at different stages, enabling efficient breakdown and subsequent microbial degradation.
2Quantity of substance
If polylactic acid is mixed with wastewater at 50-60°C to solubilize it, then some decomposition occurs, but the final lactic acid yield is low and treatment efficiency is insufficient
Solution Approach 1:
The patent applies parameter changes by using alkaline conditions to hydrolyze polylactic acid into soluble forms, then adjusting pH to optimize lactic acid recovery. This systematic parameter transformation ensures complete conversion of polymer to monomer form, maximizing lactic acid yield and treatment efficiency compared to simple temperature-based solubilization.
Solution Approach 2:
The patent replaces the mechanical/thermal solubilization method (heating at 50-60°C) with a chemical hydrolysis approach using alkaline solutions. This substitution enables more effective bond cleavage in the polymer structure, leading to complete decomposition and higher lactic acid recovery yields.
3Productivity
If polylactic acid is decomposed into lower molecular compounds, then it becomes more biodegradable, but polymers and oligomers remain and lactic acid recovery efficiency is reduced
Solution Approach 1:
The patent applies excessive action by using sufficient alkaline solution and extended hydrolysis time to ensure complete decomposition of polylactic acid into monomeric lactic acid, preventing the formation of intermediate oligomers. This thorough treatment maximizes both biodegradability and lactic acid recovery by driving the hydrolysis reaction to completion.
Solution Approach 2:
The patent uses parameter changes by controlling pH, temperature, and reaction time during hydrolysis to optimize the decomposition process. By maintaining alkaline conditions and adjusting parameters appropriately, the system ensures complete conversion to lactic acid monomers, enabling both high biodegradation and efficient recovery without oligomer intermediates.
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 significantly improves polylactic acid decomposition efficiency, allowing for high lactic acid recovery and energy recovery as biogas, reducing treatment costs and residue, and enabling efficient reuse of lactic acid as a starting material for polylactic acid synthesis.
Implementation Method 1
heating a polylactic acid-containing organic material and an organic acid salt and/or inorganic acid salt of an amine compound represented by Formula (I) to a temperature of greater than 40° C. to decompose the polylactic acid
Implementation Method 2
heating a polylactic acid-containing organic material and an organic acid salt and/or inorganic acid salt of an amine compound represented by Formula (I) to a temperature of greater than 40° C.
Implementation Method 3
subjecting the decomposition product obtained in step (a) to methane fermentation
Implementation Method 4
methane fermentation, which requires an anaerobic atmosphere
Data Source
AI summary
A primary object of the present invention is to provide a polylactic acid decomposition method that efficiently decomposes polylactic acid so that the polylactic acid can readily undergo degradation by a biological treatment such as methane fermentation. Specifically, the present invention provides a polylactic acid decomposition method involving a step of impregnating a polylactic acid-containing organic material with a treatment solution containing an organic acid salt and/or inorganic acid salt of an amine compound.