Modified PVDF Composite Pipes With Stronger Fiber-Matrix Bonding
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Solution Overview
Problem
Composites with a PVDF matrix suffer from inadequate fiber-matrix adhesion and excessive layer interfaces, leading to poor mechanical properties and increased material costs, particularly in thermoplastic composite pipes used in high-temperature and chemical-stress applications.
Innovation Solution
A composite comprising a polymer matrix with at least 80% low-viscosity PVDF and 1-50 parts by weight of an acrylate copolymer containing carboxylic anhydride units, combined with 10-80% continuous fibers, specifically carbon fibers with an epoxy size, to enhance fiber-matrix adhesion and reduce layer interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVDF matrix is used in composites, then flame retardancy and chemical stability are improved, but fiber-matrix adhesion deteriorates
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the PVDF matrix and glass fibers. This coupling agent contains both inorganic binding groups that bond to the glass fiber surface and organic functional groups that are compatible with PVDF, thereby mediating the adhesion interface and solving the poor bonding problem while maintaining PVDF's flame retardant properties
Solution Approach 2:
The patent creates a composite matrix system by combining PVDF with a silane-modified polymer matrix. This composite matrix structure integrates the flame retardant properties of PVDF with the enhanced adhesion capabilities of the silane-modified polymer, achieving both improved fiber-matrix bonding and maintained fire resistance
2Adaptability or versatility
If multiple layers are used in thermoplastic composite pipes, then functional requirements are met, but the number of layer interfaces increases leading to weaker bonding points
Solution Approach 1:
The patent merges the liner layer and reinforcement layer materials by using the same PVDF-based composite matrix for both layers. This material unification eliminates the interface between different materials, creating a homogeneous structure that maintains consistent bonding strength throughout while still fulfilling different functional requirements through structural design rather than material differentiation
3Strength
If conventional composite preparation methods are used with PVDF and unsaturated monomers, then fiber-matrix adhesion is improved, but production complexity and cost increase
Solution Approach 1:
The patent replaces complex, expensive radiation curing processes with a simple thermal curing approach using silane coupling agents. The silane-modified polymer matrix can be cured by conventional heating methods, eliminating the need for specialized radiation equipment and complex process control, thereby significantly reducing production complexity and cost while achieving adequate fiber-matrix adhesion
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 solution achieves improved mechanical properties, including higher interlaminar shear strength and reduced porosity, with enhanced fiber-matrix adhesion and reduced material costs, making it suitable for high-temperature and chemical-stress applications like thermoplastic composite pipes.
Implementation Method 1
adhesion between fiber and PVDF matrix is unsatisfactory
Implementation Method 2
carbon fibers with an epoxy size
Data Source
AI summary
The present invention is directed to continuous fiber-reinforced composites having a matrix of modified PVDF. The composite may be a semifinished product or a product or finished part manufactured therefrom. A product according to the invention is pelletized long-fiber material, while a finished part according to the invention is especially a thermoplastic composite pipe.