Polylactide–Poly(3-Hydroxypropionate) Block Copolymer for Impact Strength

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Solution Overview

Problem

Polylactide resin exhibits limitations in impact resistance, heat resistance, and brittleness, with existing attempts to enhance its properties through compounding with biodegradable materials like PBS and PBAT leading to reduced tensile strength, while poly(3-hydroxypropionate) synthesized chemically has limited molecular weight increase potential.

Innovation Solution

A method involving ring-opening polymerization of lactide monomers using biosynthesized poly(3-hydroxypropionate) as an initiator, allowing for adjustable molecular weight and improved mechanical properties through biosynthesis, including hydrolysis to fine-tune molecular weight and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If polylactide resin is used to achieve biodegradability and environmental friendliness, then environmental affinity is improved, but impact resistance and heat resistance deteriorate

Engineering Contradiction:

Improveenvironmental affinityVSAvoidimpact resistance

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent creates a block copolymer composite material combining polylactide and poly(3-hydroxypropionate) segments. This composite structure allows the material to inherit biodegradability from polylactide while gaining improved mechanical properties including impact resistance from the poly(3-hydroxypropionate) blocks, thus resolving the contradiction between environmental affinity and impact resistance.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If polylactide resin is used to achieve biodegradability, then environmental affinity is improved, but elongation at break and brittleness deteriorate

Engineering Contradiction:

Improveenvironmental affinityVSAvoidelongation at break

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The block copolymer structure combines rigid polylactide blocks with flexible poly(3-hydroxypropionate) blocks. This composite architecture maintains the biodegradability of polylactide while the flexible segments provide excellent elongation properties, preventing brittleness and resolving the contradiction between environmental affinity and elongation at break.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If chemical synthesis method is used to increase molecular weight of poly(3-hydroxypropionate), then molecular weight is improved, but biodegradability and mechanical properties deteriorate

Engineering Contradiction:

Improvemolecular weightVSAvoidbiodegradability

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical synthesis methods with biosynthesis using engineered microorganisms. This biological approach enables the production of poly(3-hydroxypropionate) with controlled molecular weights while maintaining the polymer's biodegradability and mechanical properties, thus resolving the contradiction between molecular weight and biodegradability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Stability of the object's composition

If PBS or PBAT is compounded with polylactide to improve mechanical properties, then elongation is improved, but tensile strength deteriorates

Engineering Contradiction:

ImproveelongationVSAvoidtensile strength

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

Instead of compounding separate polymers (PBS/PBAT with polylactide), the patent creates a true block copolymer where poly(3-hydroxypropionate) blocks are covalently bonded within the polylactide matrix. This integrated structure allows the flexible blocks to provide elongation while the continuous polylactide phase maintains tensile strength, resolving the contradiction between elongation and tensile strength.

Inventive Principle:

Principle #40Composite materials

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 polylactide-poly(3-hydroxypropionate) block copolymer exhibits enhanced tensile modulus, tensile strength, elongation at break, and impact strength while maintaining biodegradability and environmental affinity, overcoming the limitations of conventional polylactide resin.

Implementation Method 1

subjecting a lactide monomer to a ring-opening polymerization in the presence of the poly(3-hydroxypropionate) initiator prepared in step (a) to prepare a polylactide-poly(3-hydroxypropionate) block copolymer

Methodology Applied

Scientific EffectRing-opening polymerization: Photopolymerisation

Implementation Method 2

subjecting the poly (3-hydroxypropionate) initiator biosynthesized in step (a) to hydrolysis or the like to adjust the molecular weight

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS12371720B2Method for preparing block copolymer

Publication Date: 2025.07.29 LG CHEM LTD

AI summary

Provided is a method for preparing a block copolymer including a step of subjecting a lactide monomer to ring-opening polymerization in the presence of a biosynthesized poly(3-hydroxypropionate) initiator to prepare a polylactide-poly(3-hydroxypropionate) block copolymer.