Fibre-reinforced polymer materials matrix material

Subclass B2 is formed by the so-called structural composites, in which an outspoken mechanical reinforcement is given to the polymer. Subgroup B21 consists of blends of polymers with compatible anti-plasticizers subgroups B22 are the most important the fibre-reinforced polymer systems. The two components, the polymer matrix and the reinforcing fibbers or filaments (glass, ceramic, steel, textile, etc.) perform different functions the fibrous material carries the load, while the matrix distributes the load the fibbers act as crack stoppers, the matrix as impact-energy absorber and reinforcement connector. Interfacial bonding is the crucial problem. 

Fibre reinforced polymers (FRPs) are composed of a reinforcement material (glass, aramid or carbon fibres) surrounded and retained by a (thermoplastic or thermosetting) polymer matrix (unsaturated polyester, epoxy, vinyl ester, or polyurethane). FRPs were first used in the rehahiUtation of reinforced or pre-stressed concrete, but they have also been widely used in the reinforcement of timber structures. 

Almost as critical in commercial practice as the effects of reinforcement on proi>erties are the effects of reinforcement on the cost of the material and on its processing. The perceived effect of material cost depends on whether the decisive factor is cost per unit mass or cost per unit volume. Since the additive normally has a density considerably different from that of the po er matrix, the density of the composite differs from that of the polymer. Consider the fibre-reinforced polymer shown schematically in Figure 6.4. A mass m of composite occupies a volume u. It contains a mass of fibres occupying a volume and a mass of matrix occupying a... 

Composites are made up of individual materials these are referred to as constituent materials. The purpose of a composite is to create a material that combines its constituent parts in some beneficial way. The two main categories of constituent materials are the matrix and the reinforcement. The synthetic matrix materials are either thermoplastic or thermosetting resins. These polymers bind the reinforcement together and determine the physical in-service properties of the composite material. Polymers can also act as reinforcing material in composites Kevlar for instance, is a synthetic polymer fibre that is very strong and imparts toughness to a composite. 

Fibre-reinforced polymer (FRP) composites are among the increasingly used composites in the industry. FRPs are composite materials made of a polymer matrix reinforced with fibres. The polymer matrix is either a thermosetting or a thermoplastic resin while the fibres are usually fibreglass. 

Fibre-reinforced polymer (FRP) composites are composed of fibres and matrices, which are bonded through the interface to ensure that the composite system as a whole gives satisfactory performance. Part 1 deals with FRP composite matrix materials which provide the foundation for composite materials. Chapter 2 reviews the chemistry of phenolic resins together with their mechanical and thermal properties. Chapter 3 discusses polyester thermoset resins as matrix materials. An overview of the chemistry of vinylester resins, together with their mechanical and chemical properties, as well as their use as a matrix material in the construction industry, is provided in Chapter 4. The final chapter in Part 1 begins with a review of the epoxy resins commonly available on the market, and then focuses on the principal characteristics of epoxy resin composite systems and their practical applications. 

The strength and stiffness that can be obtained in short-fibre reinforced polymer matrix composites are well below that of long-fibre reinforced materials. Depending on the chosen processing route, the fibres can be oriented in loading direction or irregularly (see section 9.1.1). 

The same materials can be used as in long-fibre reinforced polymer matrix composites. Short-fibre reinforced polymers are useful in many applications where unreinforced polymers are not sufficient. The design of injection moulded components made of short-fibre reinforced polymers is complicated by the fact that the orientation of the fibre is determined by the fluid flow (see section 9.1.1) and can be irregular within the material. 

The performance of natural fibre reinforced polymer composites depends on several factors, including fibre chemical composition, cell dimensions, microfibrillar angle, defects, structure, physical and mechanical properties, and the interaction of a fibre with the polymeric matrix [28]. The knowledge about the characteristics of the fibre is essential in order to expand the effective use of lignocellulosic materials for polyethylene composites and to improve their performance. 

The generic thermosets are the epoxies and the polyesters (both widely used as matrix materials for fibre-reinforced polymers) and the formaldehyde-based plastics (widely used for moulding and hard surfacing). Other formaldehyde plastics, which now replace bakelite, are ureaformaldehyde (used for electrical fittings) and melamine-formaldehyde (used for tableware). 

PTFE is a unique polymer in the formulation of composites, since it may be either the material of the matrix or a friction-reducing filler. It is a very soft polymer, which in the absence of reinforcement will wear rapidly, and it will cold flow under load. As a matrix material it must therefore be effectively reinforced. As a friction-reducing filler it may be used in the form of particles or fibres. Table 12.6 shows the effect of different fillers on the properties of PTFE. Spengler et aP reported an... 

Research on the pyrolysis of thermoset plastics is less common than thermoplastic pyrolysis research. Thermosets are most often used in composite materials which contain many different components, mainly fibre reinforcement, fillers and the thermoset or polymer, which is the matrix or continuous phase. There has been interest in the application of the technology of pyrolysis to recycle composite plastics [25, 26]. Product yields of gas, oil/wax and char are complicated and misleading because of the wide variety of formulations used in the production of the composite. For example, a high amount of filler and fibre reinforcement results in a high solid residue and inevitably a reduced gas and oiFwax yield. Similarly, in many cases, the polymeric resin is a mixture of different thermosets and thermoplastics and for real-world samples, the formulation is proprietary information. Table 11.4 shows the product yield for the pyrolysis of polyurethane, polyester, polyamide and polycarbonate in a fluidized-bed pyrolysis reactor [9]. 

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