Heat-Resistant PLA Foaming via EBH-g-ECA Chain Extension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polylactic acid foamed materials face limitations in heat resistance and industrial scalability due to low melt strength, narrow processing window, and high production costs, with existing solutions either sacrificing biodegradability or failing to achieve uniform cell size and mechanical properties.
Innovation Solution
The development of ethylene bis-12-hydroxystearamide grafted glycidyl citrate (EBH-g-ECA) as a multifunctional auxiliary agent that acts as both a chain extender and crystallization nucleating agent, enhancing melt strength and heat resistance while ensuring uniform cell size and low material density through continuous twin-screw extrusion and specific co-blowing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional continuous extrusion foaming technology is used for polylactic acid, then production efficiency is high, but the process is unsuitable due to low melt strength and narrow processing window
Solution Approach 1:
The patent modifies the chemical structure of polylactic acid by grafting ethylene bis-12-hydroxystearamide and glycidyl citrate, which changes the molecular weight and melt strength parameters. This enables the material to be processed using continuous extrusion foaming technology that would otherwise be unsuitable, thereby resolving the contradiction between high productivity and process suitability.
2Weight of stationary object
If polylactic acid is used as a foamed material, then density is reduced and weight is lowered, but heat resistance deteriorates with heat distortion temperature of only 55°C
Solution Approach 1:
The patent creates a composite modified polylactic acid system by incorporating ethylene bis-12-hydroxystearamide grafted glycidyl citrate. This composite structure simultaneously achieves light weight through foaming and high heat resistance with heat distortion temperature exceeding 115°C, resolving the contradiction between reduced weight and maintained heat resistance.
3Reliability
If batch foaming techniques are used for polylactic acid, then foaming can be achieved, but the molding process becomes complicated and the molding cycle is long
Solution Approach 1:
The patent extracts the foaming process from the complex batch molding procedure and integrates it into a continuous extrusion process. This separation of the foaming function from the complex batch process enables simple continuous production with short cycles, resolving the contradiction between achieving foaming and maintaining process simplicity.
4Strength
If chain extenders and crystallization nucleating agents are added separately to improve melt strength and heat resistance, then these properties are enhanced to a certain extent, but cell size becomes large and distribution is non-uniform
Solution Approach 1:
The patent merges the functions of chain extension and crystallization nucleation into a single grafted compound structure. The ethylene bis-12-hydroxystearamide grafted glycidyl citrate simultaneously provides chain extension for melt strength and nucleation for uniform crystallization, producing fine uniform cells while resolving the contradiction between improved strength and cell uniformity.
5Reliability
If polylactic acid is modified to improve foaming performance and heat resistance, then these properties are enhanced, but the cost increases and industrial production becomes difficult
Solution Approach 1:
The patent develops a multifunctional modifier that simultaneously provides chain extension, crystallization nucleation, and foaming stabilization. This single compound performs multiple functions that would otherwise require several different additives and complex processing steps, making the modified polylactic acid suitable for industrial continuous production while maintaining enhanced foaming performance and heat resistance.
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 EBH-g-ECA improves the heat distortion temperature of polylactic acid foamed materials to over 115°C, achieves a high foaming ratio, and ensures a uniform cell structure, making the material suitable for industrial production and reducing application costs while maintaining biodegradability.
Implementation Method 1
the use of a chain extender to increase the molecular weight
Implementation Method 2
the nucleating agent to change the process conditions
Implementation Method 3
Polylactic acid foamed products can effectively reduce the density and reduce the weight of individual products
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Disclosed in the present invention are an ethylene bis-12-hydroxystearamide grafted glycidyl citrate (EBH-g-ECA) and a preparation method thereof; the EBH-g-ECA can be used as a multifunctional auxiliary agent in a polymer material, and particularly has a chain extension and a crystal nucleation effect in a polyester polymer material. The present invention also provides a heat-resistant polylactic acid continuously-extruded foamed material containing EBH-g-ECA. The continuous foaming technology can be realized by using the heat-resistant polylactic acid foamed material, and the prepared foamed product has a high heat resistance, a uniform appearance, a low density, and complete biodegradation. Also disclosed in the present invention is polylactic acid foamed material preparation method for a heat-resistant, which is easy to be industrialized and has a great significance for realizing the large-scale replacement of petroleum-based plastic disposable foamed products such as PP and PS.