Inorganic binder composition comprising surface-modified polyolefin fibres

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Solution Overview

Problem

Polyolefin fibers used in construction materials face limitations due to low pull-out strength and poor adhesion to cementitious matrices, which restricts their widespread use in high-performance concrete applications, particularly due to hydrophobicity and low wettability issues.

Innovation Solution

Surface-modified polyolefin fibers are produced through a process involving plasma treatment with an electrically excitable gas to introduce polar groups, followed by treatment with a gaseous siloxane or silazane compound, enhancing their bonding characteristics and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyolefin fibers are used as reinforcement in concrete, then cost is reduced and corrosion resistance is improved, but interfacial bonding strength and pull-out strength are insufficient

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidinterfacial bonding strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies plasma treatment to modify the surface parameters of polyolefin fibers, introducing polar groups that change the surface energy and wettability characteristics. This enables the hydrophobic polyolefin surface to become hydrophilic, improving interfacial bonding with the cementitious matrix while preserving the bulk material's corrosion resistance and cost advantages.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure at the fiber surface by combining polyolefin base material with plasma-introduced polar functional groups. This surface composite structure maintains the advantages of polyolefin (corrosion resistance, low cost) while adding the bonding characteristics needed for strong interfacial adhesion to cement matrix.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If polyolefin fibers are used as reinforcement, then weight is reduced compared to steel, but adhesion to cementitious matrix is poor due to hydrophobicity

Engineering Contradiction:
Improvefiber weightVSAvoidadhesion strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

Plasma treatment fundamentally changes the surface energy parameters of polyolefin fibers, transforming them from hydrophobic to hydrophilic. This parameter change enables proper wetting and adhesion to the cementitious matrix while preserving the lightweight characteristic of the polyolefin material.

Inventive Principle:
Principle #35Parameter changes

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 surface-modified polyolefin fibers exhibit significantly improved bonding and residual tensile strength, increasing the tensile strength of hydraulic binder compositions by 30-40% and enhancing the mechanical stability and ductility of reinforced concrete materials.

Implementation Method 1

a) a pretreatment of the polyolefin fibers by contacting the polyolefin fibers with an electrically excitable gas in a plasma reactor to obtain polyolefin fibers with polar groups on the surface

Methodology Applied
Scientific EffectPlasma treatment: Plasma

Implementation Method 2

b) plasma treatment of the polyolefin fibers in presence of a gaseous siloxane or silazane compound

Methodology Applied
Scientific EffectPlasma enhanced chemical vapour deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentEP3224405B1Inorganic binder composition comprising surface-modified polyolefin fibres
Publication Date: 2020.01.01 CONSTRUCTION RESEARCH & TECHNOLOGY GMBH
  • EP3224405B1 patent drawingFigure 1
  • EP3224405B1 patent drawingFigure 2
  • EP3224405B1 patent drawingFigure 3

AI summary

The present invention relates to surface-modified polyolefin fibers, the use of these fibers in hydraulic binder compositions, hydraulic binder compositions containing these fibers and a method for reinforcing hydraulic binder compositions.