Invented by Dongsheng Mao, Zvi Yaniv, Applied Nanotech Holdings Inc
The Market For Method to Make Reinforced Polymer Matrix Composites
The market for reinforced polymer matrix composites focuses on using carbon fiber, glass fiber and natural fiber reinforcements in polymer matrices. These materials boast excellent material characteristics such as low cost per volume, high strength and specific stiffness.
These composites are environmentally friendly and recyclable. They have found applications in various end-use industries such as automotive, aerospace and sports.
Process
Reinforced polymer matrix composites can be manufactured through a range of manufacturing processes, such as resin injection molding (RIM), compression molding, vacuum molding or fusion. The selection of the process depends on the specific application as well as the reinforcing and matrix materials chosen.
The market for these types of products is growing as they offer the strength and stiffness that conventional materials lack without the weight or complexity of metals. Furthermore, these items can be tailored to a wide variety of applications.
These materials are commonly employed in structural applications, such as aerospace and automotive parts. Furthermore, they have other uses that demand high strength-to-weight ratios.
Composites can be constructed using thermoset and thermoplastic matrices that contain various polymers such as carbon, glass, ceramic, polypropylene, and epoxy. Depending on the type of polymer used in production, a composite may be classified as either fiber-embedded or particle-reinforced material.
A fiber-embedded composite requires precise alignment of its fibers for optimal mechanical properties. Similarly, particle reinforcement requires careful consideration when creating interfacial linkages.
Making a laminate with both reinforcement schemes is essentially the same, although fiber angles can be adjusted to meet application design needs such as stiffness and strength. Doing this results in higher yield strength and tensile modulus than using either one or the other alone would produce.
For instance, the mechanical properties of a laminate made with both carbon and glass fabrics were much better than those of solely carbon fibers. This is because the fabric-reinforced laminate can withstand more energy before it fractures.
Making composite materials requires extensive knowledge and expertise to develop the optimal laminate design for a particular use. As such, this industry faces fierce competition to stay abreast of new product demands and materials.
Reinforcement
Composite material refers to a mixture of two or more materials that retain their identity on the macroscopic level. It’s created by mixing a matrix or binding phase with reinforcement, such as polymers, metals, ceramics or wires.
When fabricating a composite, the type of reinforcing material used depends on properties like fracture toughness and tensile strength. In polymer matrix composites (PMCs), mechanical and physicochemical characteristics are determined by both phase ratios as well as the geometry and nature of interphase material – that is, what lies between polymer and reinforcement – that lies between them.
Additionally, the type of fiber used to reinforce a PMC has an impact on its tensile strength, stiffness and other properties. Most PMCs are reinforced with continuous reinforcing fibers like glass or graphite; however, some advanced composites use oriented polymers like DuPont’s Kevlar or Allied’s Spectra 900 as reinforcing materials.
These oriented polymers, composed of carbon or other molecules, possess higher specific stiffness and strength than today’s unidirectional fibers. This could enable the creation of a new class of reinforced composites with superior tensile and compressive strengths.
Residual stresses are another critical element in the tensile and compressive properties of polymer matrix composites. They are caused by deformation-related characteristics of the materials as well as production processes like compression molding or extrusion. Residual stresses can cause various defects in a composite, such as waviness, delamination, warping and dimensional imbalance.
One of the major issues confronting the aerospace industry is creep fracture, a phenomenon which occurs when materials subjected to sustained loading fail at stress levels lower than their static strengths. This issue could prove hazardous if left unrepaired; materials may not regain their original shape and form after such trauma.
Research is necessary to fully comprehend the effects of varying deformation-related properties and production conditions on residual stress generation in composites. This understanding is crucial for designing and manufacturing a resilient composite that will withstand cracking, delamination, warping or other defects.
Fibers
Composite materials are created by combining components with different physical and chemical characteristics to form a new material with distinct properties. Composites offer higher strength-to-weight ratios than metals or other engineering materials while being more durable overall.
Fibers are an integral part of a composite, providing its strength and stiffness. They can be made from materials like carbon fibre, glass, or Kevlar and usually embed into the matrix of either thermoset or thermoplastic polymers for extra reinforcement.
Fibre-reinforced polymer composites, commonly referred to as fibre matrix composites (FMC), are one of the most widespread types of composite materials. They can be produced using various techniques and formed into various shapes.
They are widely used in sports equipment, automotive parts and industrial equipment due to their superior strength and stiffness as well as design freedom. Furthermore, these composites are lightweight and easy to process or shape due to their light composition.
The choice of fibers used in a plying can affect both its mechanical performance and cost. Carbon fibers for instance can reduce weight by up to 70% in composite parts. Furthermore, properties within a composite are dependent on its reinforcement type as well as interphase composition.
However, it’s essential to remember that even though a composite is strong and tough, it is susceptible to fatigue due to factors like thermal expansion and residual stresses.
Residual stresses in polymer composites can arise during production or after curing, due to differences in component properties and manufacturing methods. If left unchecked, residual stresses may cause distortion and dimensional instability within the composite as well as matrix cracking.
Due to this, residual stresses in the composite industry have been extensively researched. Their effects on mechanical performance of a polymer composite are significant; several techniques have been devised to minimize their influence, such as fibre prestressing or adding an elastomer.
Matrix
Composite materials are created by combining constituent elements to achieve unique properties not possible individually. As a result, these composites boast an impressive strength-to-weight ratio and have become widely used as engineering materials in automotive and aerospace parts.
Composites typically consist of either thermoplastic or thermoset polymers, though ceramic and metal may also be utilized. They may also include fibers or particulates (natural or synthetic) for reinforcement.
At the design phase of a composite material, designers take into account its intended use. For instance, aerospace applications require high specific strengths and good fracture resistance properties; additionally, they strive to minimize material consumption in order to achieve desired performance.
Due to this, composites often feature an advanced polymer matrix reinforced with a high percentage of carbon fibers. This combination can give superior strength and stiffness to the polymer matrix itself while at the same time offering significant cost savings.
Composite material is widely used in structural and aerospace industries due to its superior strength, stiffness, freedom of design and easy processing and forming capabilities.
Another key advantage of composites is their resistance to environmental elements, as they do not absorb water and thus are immune from microbial and chemical attacks. Furthermore, their tensile strength is higher than most conventional metals, helping reduce wear-and-tear on mechanical components.
Composites offer other advantages due to their flexibility and ease of manufacturing. These characteristics enable them to be molded in various ways, such as solvent casting, blending, or in situ techniques.
In addition to its advantages in composite design, polymer matrixes can offer other useful properties like gas barrier and impact resistance. These properties may be achieved either through inclusions within the polymer matrix or by adding a special additive to the resin.
Compressive stresses in a composite matrix can be created either elastically or viscoelastically by applying load during curing and maintaining it throughout. This causes compressive stresses to develop within the material, helping reduce residual stress during cure and promoting solidification.
The Applied Nanotech Holdings Inc invention works as follows
Pre-treatment nanoparticles and pellets before melt compounding can improve the mechanical properties of clay or carbon nanotube-reinforced, polymer matrix nanocomposites. A milling process is used to coat the clay or CNTs onto the surfaces of polymer pellets. The nanoparticles are more stable and can be coated onto the polymer pellets by adding moisture to the mixture of nanoparticles.
Background for Method to make reinforced polymer matrix composites
Nanocomposites are composite materials containing particles with a range of sizes from 1-100 nanometers (nm). These materials allow for the use of submicron structural properties in molecules. These particles, including clay and carbon nanotubes, have excellent properties and a high aspect ratio. They also have a layered structure that maximises the bonding between polymers and particles. Adding a small quantity of these additives (0.5-5%) can increase many of the properties of polymer materials, including higher strength, greater rigidity, high heat resistance, higher UV resistance, lower water absorption rate, lower gas permeation rate, and other improved properties (see T. D. Formes, D. L. Hunter, and D. R. Paul, ?Nylon-6 nanocomposites from Alkylammonium-modified clay: The role of Alkyl tails on exfoliation,? Macromolecules 37, pp. Macromolecules 37, pp. 1793-1798 (2004). This is hereby included by reference.
However, it is important to disperse the nanoparticles in order to strengthen polymer matrix nanocomposites. This problem has led to nanoparticle dispersion in the polymer matrix. That is why those nanoparticle-reinforced nanocomposites have not achieved excellent properties as expected (see Shamal K. Mhetre, Yong K. Kim, Steven B. Warner, Prabir K. Patra, Phaneshwar Katangur, and Autumn Dhanote, ?Nanocomposites with functionalized carbon nanotubes,? Mat. Res. Soc. Symp. Proc. Vol. Vol. 788 (2004), which is herein incorporated by reference. Researchers claim that nanocomposites made from in-situ polymerization can increase the dispersion (see Werner E. van Zyl and Monserrat Garca, Bernard A. G. Schrauwen; Bart J. Kooi; Jeff Th. M. De Hosson and Henk Verweij.?Hybrid polyamide/Silica Nanocomposites Synthesis and Mechanical Testing. Macromol. Mater. Eng. Eng. The nanocomposites have better properties. In-situ polymerization has not been proven to be an acceptable manufacturing method for polymer production. Also used has been a melt compounding process, which is a more popular and manufacturable process to make nanoparticle-reinforced polymer nanocomposites (see Eric Devaux, Serge Bourbigot, Ahmida El Achari, ?Crystallization behavior of PA-6 clay nanocomposite Hybrid,? Journal of Applied Polymer Science Vol. 86, 2416-2423 (2002, which is hereby included by reference herein), but the results were not satisfactory.
BRIEF DESCRIPTION DES DRAWINGS
FIG. “FIG.
FIG. “FIG.
FIG. 3 shows digital photos of (a) nylon 6 pellets and (b) a mixture MWNT (0.4% wt.). %)+nylon 6 pellets following a milling (without moisture (e.g. water)) and (c) a mixture MWNT (0.4% wt.). %)+nylon 6 pellets following a milling (with moisture (e.g. water )
FIG. “FIG. %)+nylon 6 pellets following a milling process without moisture (e.g. water ));”).
FIG. “FIG. %+nylon 6 pellets following a milling (with 10ml solvent);
FIG. “FIG. %)+nylon 6 pellets following a milling (with 45ml solvent);
FIG. “FIG. 6;
FIG. 8 is a digital photo of a cross-sectional view of the neat nylon 6-pellets (left), and 3.0 wt. “% MWNTs are coated onto the nylon 6 pellets’ surfaces (right);
FIG. 9 contains digital photos of (a) MWNT (3.0wt. %) reinforced nylon nanocomposite (no milling before melt compounding process) and (b). MWNT (3.0 Wt. %) reinforced nylon nanocomposite (no milling was done before melting compounding process) and (b) MWNT (3.0 wt.).
FIG. 10 is a digital photo of neat nylon 6 pellets (left), and 0.4 wt. “% DWNT was applied to the nylon 6 pellets’ surfaces (right).
Pre-treatment nanoparticles or polymer pellets before melt compounding can improve the mechanical properties of clay and carbon nanotube (CNT),-reinforced, polymer matrix nanocomposites. By milling the clay or CNTs onto the surface of the polymer pellets (e.g. using a ball mill, or an apparatus for performing an equivalent process), the clay is coated. FIG. FIG. 1 shows an example of a machine that can be used to perform a milling operation in accordance with the principles of the present invention. The nanoparticles are more likely to adhere to the surfaces of polymer pellets if they have been moistened. After the mixture has been ground for a time, the nanoparticle thin films are formed on the surfaces of the polymer beads. The term “ground” is used in this disclosure. The milling process will be referred to in this disclosure. Additionally, certain times, temperatures, and revolutions per minute are all permissible. While these parameters are used in the disclosed processes, the invention shouldn’t be restricted to them. It should be extended to other parameters that perform an equivalent function or produce a substantially identical result.
The milling process described in this article with added moisture:
Cases will be described in this section to demonstrate aspects of the invention. These examples used nylon 6 or nylon 11, and nanoclay or CNTs for the nanoparticles. You can also use other fillers like graphite, carbon fibers and fullerenes as well as carbon nanotubes, carbon nanotubes or ceramic particles. Metal particles, alloy particles, and any combination of them may also be used. You can also use other types of polymers such as thermoplastic and thermosetting polymers in addition to nylon 6 or 11. Thermoplastic polymers that may be used as described herein include, but are not limited to, polycarbonates, polyamides, polyesters (e.g., polybutylene terephthalate and polyethylene terephthalate), polyethers, thermoplastic polyurethanes, polyacetals, fluorinated polymers (e.g., polyvinylidene fluoride), polyethersulfones, polyolefins (e.g., polyethylene and polypropylene), polyimides, polyacrylates (polymethylmethacrylate), polyphenylene oxides, polyphenylene sulfides, polyether ketones, polyarylether ketones, styrene polymers (e.g., polystyrene), styrene copolymers (e.g., styrene acrylonitrile copolymers), acrylate rubbers, acrylonitrile-butadiene-styrene block copolymers, polyvinyl chloride, or any combination thereof. These thermosetting polymers can be used in the manner described herein, including phenolics and bismaleimides (BMIs), epoxies (CEs), polyimides or any combination thereof.
Case 1 – Nylon 6/Multiwall carbon Nanotube (MWNT), Nanocomposites
Nylon 6 pellets such as those available at UBE Co., Japan (product number: SF1018A), were used. The carbon nanotubes used here were MWNTs (commonly available from Bayer MaterialScience; product name: Baytubes, grade: C 150P). The MWNTs had a diameter of approximately 13 nanometers (nm), and a length between 5-20?m or micrometers.
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