PLA Polymer Composition with In-Situ Urethane Impact Modifier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polylactic acid (PLA) is a brittle polymer that lacks impact strength, making it unsuitable for applications requiring toughness and resistance to cracking, such as engineering plastics and plastic films, due to its inherent brittleness.
Innovation Solution
A polymer composition is formed by blending a polyol with a dimer fatty residue into a polymeric matrix, followed by the addition of a polyisocyanate to react in situ and create urethane impact modifier particles, which enhances the impact strength of the PLA by forming phase-separated particles within the matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pure PLA polymer is used, then the polymer composition has good processability and chemical resistance, but it exhibits brittleness and lacks impact strength
Solution Approach 1:
The patent creates a composite material system by incorporating polyol particles containing dimer fatty acid residues into the PLA matrix. These particles form a secondary phase that acts as an impact modifier, absorbing impact energy through cavitation and shear band formation, thereby improving impact strength while maintaining the continuity and processability of the PLA matrix.
Solution Approach 2:
The impact modification is achieved by creating localized regions of polyol particles distributed within the PLA matrix. These localized modified regions provide toughness and impact resistance where needed, while the surrounding PLA matrix maintains its inherent properties such as chemical resistance and processability.
2Strength
If impact modifier particles are introduced into the polymeric matrix, then the impact strength is improved, but the polymer composition becomes more complex
Solution Approach 1:
The polyol is pre-formed with dimer fatty acid residues before being incorporated into the PLA matrix. This preliminary preparation of the polyol structure ensures that the phase separation and particle formation occur automatically during processing, eliminating the need for additional complex steps to create the impact modifier particles in-situ.
Solution Approach 2:
The polyol particles containing dimer fatty acid residues automatically phase separate from the PLA matrix during processing due to incompatibility, forming dispersed impact modifier particles without requiring external intervention. The system self-organizes into the desired composite structure through inherent thermodynamic principles.
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 resulting polymer composition exhibits improved elongation at break and unnotched impact strength, maintaining high elastic modulus while significantly increasing toughness, making it suitable for various applications without the brittleness of pure PLA.
Implementation Method 1
the low polarity of the polyol due to the dimer residue will cause the polyol to phase separate within the polymeric matrix. This phase separation may cause the polyol to form dispersed particles within a continuous polymeric matrix.
Implementation Method 2
A polyisocyanate added to the polymer composition will then react with the polyol particles to form urethane impact modifier particles in-situ within the polymeric matrix.
Data Source
AI summary
The present invention relates to a polymer composition comprising a polymeric matrix and particles of an impact modifier within the polymeric matrix, wherein the impact modifier comprises at least one urethane group and the impact modifier is obtainable by reacting in situ within the polymeric matrix a) a polyol comprising a dimer fatty residue; and b) a polyisocyanate. The invention also relates to a method of making the polymer composition.