Polyisoprene Latex Graphene Composite via pH-Adjusted Reduction

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Solution Overview

Problem

The challenge in producing a stable dispersion of graphene oxide in polyisoprene latex matrices and achieving effective interfacial adhesion between graphene oxide and polymer remains unresolved in conventional methods, which often rely on strong reducing agents and high-energy mixing processes.

Innovation Solution

A method involving the pH adjustment of graphene oxide to between 8 and 12, followed by slow agitation with curing agents at temperatures between 20°C to 80°C for 4 to 24 hours, allows for the reduction of graphene oxide without strong reducing agents and achieves stable dispersion and improved colloid stability in polyisoprene latex, enabling the production of elastomeric articles with enhanced mechanical properties and ageing resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical reduction of graphene oxide is performed using strong reducing agents, then reduced graphene oxide is produced, but the process becomes complex and requires additional chemicals and safety measures

Engineering Contradiction:
Improveproduction of reduced graphene oxideVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the curing agent itself to perform the reduction function, eliminating the need for separate reducing agents. The curing agent serves dual purposes: both curing the polymer and reducing graphene oxide, thereby simplifying the overall process while maintaining reliability of reduced graphene oxide production

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The curing agent is designed to perform multiple functions simultaneously: it acts as both a polymer curing agent and a reducing agent for graphene oxide. This multi-functionality resolves the contradiction by eliminating the need for separate reducing agents and their associated safety and complexity issues

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If high-energy mixing processes are used to achieve uniform dispersion of graphene oxide in polyisoprene latex, then dispersion homogeneity is improved, but energy consumption and process complexity increase

Engineering Contradiction:
Improvedispersion homogeneityVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent changes the surface charge parameter of graphene oxide by adjusting pH to between 8 and 12, which matches the charge characteristics of polyisoprene latex particles. This parameter change enables electrostatic stabilization and uniform dispersion without requiring high-energy mixing processes, thereby resolving the contradiction between dispersion homogeneity and energy consumption

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By matching the surface charge of graphene oxide to that of the latex particles through pH adjustment, the patent achieves homogeneous dispersion where the filler particles are uniformly distributed and electrostatically stabilized within the polymer matrix, eliminating the need for intensive mixing

Inventive Principle:
Principle #33Homogeneity

3Stability of the object's composition

If high-energy mixing processes are used to achieve uniform dispersion of graphene oxide in polyisoprene latex, then dispersion homogeneity is improved, but the process becomes more complex

Engineering Contradiction:
Improvedispersion homogeneityVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent changes the surface charge parameter of graphene oxide by adjusting pH to between 8 and 12, which matches the charge characteristics of polyisoprene latex particles. This parameter change enables electrostatic stabilization and uniform dispersion without requiring high-energy mixing processes, thereby resolving the contradiction between dispersion homogeneity and process complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The curing agent simultaneously performs both curing and reduction functions, simplifying the overall process while achieving uniform dispersion through pH-controlled electrostatic interactions rather than complex high-energy mixing protocols

Inventive Principle:
Principle #25Self-service

4Stability of the object's composition

If conventional methods are used to produce stable dispersion, then dispersion stability is achieved, but strong reducing agents and organic solvents are required

Engineering Contradiction:
Improvecolloid stabilityVSAvoiduse of strong reducing agents and organic solvents
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The curing agent serves dual purposes as both polymer curing agent and reducing agent for graphene oxide. This self-service approach eliminates the need for separate strong reducing agents and organic solvents while maintaining colloid stability of the dispersion

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pH-adjusted surface charge of graphene oxide acts as an intermediary mechanism that enables stable dispersion through electrostatic interactions with latex particles, replacing the need for harmful reducing agents and organic solvents typically used in conventional methods

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach results in a polyisoprene latex graphene composite with improved mechanical properties and ageing resistance, as evidenced by increased tensile strength and retention of properties after accelerated ageing, without the need for strong reducing agents or high-energy mixing.

Implementation Method 1

The reduction of graphene oxide is accomplished without the use of strong reducing agents... Chemical reduction of graphene oxide is normally achieved through addition of reducing agents

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

adjusting the pH of a graphene oxide composition to between about 8 and 12

Methodology Applied
Scientific EffectpH adjustment:

Implementation Method 3

incorporation of the reduced graphene oxide into polyisoprene latex is accomplished using room temperature latex mixing method or hot maturation

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3535317B1Polyisoprene latex graphene composites and methods of making them
Publication Date: 2024.07.17 KAREX HLDG SDN BHD
  • EP3535317B1 patent drawingFigure 1(A)~1(B)
  • EP3535317B1 patent drawing

AI summary

The present Invention' relates to a method of preparing reduced grapheme oxide, Incorporation of the adduced graphene oxide into polysioprene latex to provide a polyisoprene latex graphene composite and elastomerk articles prepared using the polyisoprene latex- graphene composite. In particular, the reduction of -graphene oxide is accomplished without the use of strong reducing agents and organic solvents and incorporation of die reduced graphene oxide into polyisoprene latex Is accomplished using room temperature latex mixing method or hot maturation. The resultant composite exhibits good colloid stability and. polyisoprene latex films produced from the composite exhibit good mechanical properties with improved ageing resistance.