Biodegradable Polyester Impact Modifiers for Tougher PLA Blends
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Solution Overview
Problem
Petroleum-based polymers like polyethylene, polypropylene, and polyethylene terephthalate do not degrade or decompose after disposal, leading to environmental pollution, and existing biopolymers require non-biodegradable additives to enhance physical properties, reducing their environmental benefits.
Innovation Solution
Development of a biodegradable polyester composed of isosorbide, dicarboxylic acid or anhydride, and polyhydric alcohol, with specific molecular weight ranges, suitable for blending with biopolymers such as poly(lactic acid) and poly(hydroxyalkanoates) to improve physical properties while maintaining compostability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If petroleum-based polymers (PE, PP, PET) are used to provide good strength, barrier, and printability characteristics, then physical properties are improved, but environmental degradation is worsened as these polymers do not readily degrade or decompose after disposal
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by using biodegradable alternatives (PLA, PHA, PBS, PBAT, PCL) instead of petroleum-based polymers, while adjusting additive packages to maintain physical properties like strength, barrier, and printability characteristics
Solution Approach 2:
The patent creates composite material systems by blending biodegradable polymers with specific additives including impact modifiers, processing aids, and UV stabilizers that are compatible with biodegradable matrices, achieving both environmental benefits and desired physical properties
2Object-generated harmful factors
If biopolymers like poly(lactic acid) and poly(hydroxyalkanoates) are used to achieve biodegradability and compostability, then environmental benefits are improved, but physical properties are worsened requiring blending with non-biodegradable additives
Solution Approach 1:
The patent adjusts the composition parameters by selecting specific biodegradable polymer types (PLA, PHA, PBS, PBAT, PCL) and optimizing their molecular weights and blend ratios to achieve both biodegradability and improved physical properties without requiring non-biodegradable additives
Solution Approach 2:
The patent uses biodegradable-compatible additives as intermediaries that facilitate the blending of biopolymer components and enhance physical properties while maintaining biodegradability, such as compatibilizers with reactive functional groups that improve interfacial adhesion in blends
3Strength
If non-biodegradable additives are blended into biopolymers to improve physical properties, then strength and durability are improved, but environmental benefits are reduced as the additives themselves do not degrade
Solution Approach 1:
The patent changes the chemical nature of additives from non-biodegradable to biodegradable alternatives, selecting compounds that meet compostability standards while maintaining their functional roles in improving physical properties of the biopolymer matrix
Solution Approach 2:
The patent ensures homogeneity in biodegradability across all components of the composition by selecting additives that share the biodegradable characteristic with the biopolymer matrix, creating a uniformly compostable material system
Data Source
AI summary
A polyester is disclosed which is made up of: (1) from about 15 to about 40 weight percent monomer repeat units of isosorbide; (2) from about 25 to about 60 weight percent monomer repeat units of a dicarboxylic acid or anhydride such as succinic acid or anhydride; and (3) from about 10 to about 20 weight percent monomer repeat units of a polyhydric alcohol such as 1,3 -propan ediol. In some instances, the polymer may also include monomer repeat units of methyl nadic anhydride or nadic anhydride. A polymer composition is also disclosed, which includes the polyester as well as a biodegradable polymer selected from the group consisting of poly(lactic acid), poly(hydroxyalkanoates), and mixtures thereof.