Reinforced thermoset composites materials

Thielemans, W. and Wool, R.P. (2004) Butyrated kraft lignin as compatibilizing agent for natural fiber reinforced thermoset composites. Composites Part A Applied Science and Manufacturing, 35,327-338. Satheesh Kumar, M.N., Mohanty, A.K., Erickson, L. and Misra, M. (2009) Lignin and its applications with polymers. Journal of Biobased Materials and Bioenergy, 3, 1-24. 

Polymer composites are plastics within which fibres are embedded. The plastic is known as the matrix (resin) and the fibres dispersed witbin it are known as the reinforcement Thermosetting matrix materials include polyester, vinyl ester and epoxy resins. For higher temperature and extreme environments, bismaleimlde, polyimide and phenolic resins are used. Composites can be used to replace metal parts but care must be taken during design. Most engineering materials have similar properties in any direction (called isotropic) where composites have not This can however be offset by arranging the reinforcement layers in varying directions. 

The interest in the use of raw materials derived from renewable sources, combined with the good properties that have been observed for these materials, have led to the perspective that composites based on bio-resins and lignocellulosic and/or cellulosic fibers will experience an impressive development in a near future. Furthermore, the coming years should see an increased number of investigations on nano-reinforced thermoset composites, including phenolic composites. 

In the early days nearly all thermosetting moulding materials were composites in that they contained fillers such as woodflour, mica, cellulose, etc to increase their strength. However, these were not generally regarded as reinforced materials in the sense that they did not contain fibres. 

There are a number of routes for recovering and reeyeling of materials from thermoset composites. With the exception of the ERCOM project none of these are particularly well developed. The most promising for development are innovative comminution techniques for the preparation of relatively uncontaminated forms of scrap as a reinforcement for development of high value... 

Laurence J Craigie, B S>Chem. Composite Resources, LLC industry consultant in regulatory, manufacturing, and business needs for the composite industry Member, American Society of Mechanical Engineers (Chairman RTP Corrosion Resistant Equipment Committee) Member, American Society of Testing and Materials Member, National Association of Corrosion Engineers International Member, Composite Fabricators of America (received President s Award) (Reinforced Thermosetting Plastie)... 

Inserts are often dedicated to specific plastic materials neat thermoplastics, neat and filled thermosets, reinforced plastics, composites, structural foams. .. 

Unlike ductile metals, composite laminates containing fiber-reinforced thermosetting polymers do not exhibit gross ductile yielding. However, they do not behave as classic brittle materials, either. Under a static tensile load, many of these laminates show nonlinear characteristics attributed to sequential ply failures. One of the difficulties, then, in designing with laminar composites is to determine whether the failure of the first ply constitutes material failure, termed first-ply failure (FPF), or if ultimate failure of the composite constitutes failure. In many laminar composites, ultimate failure occurs soon after first ply failure, so that an FPF design approach is justified, as illustrated for two common laminar composites in Table 8.9 (see Section 5.4.3 for information on the notations used for laminar composites). In fact, the FPF approach is used for many aerospace and aircraft applications. 

The manufacture of polymeric materials, reinforced or unreinforced, is not a single process rather, it is a sequence of processes. For example, the making of a thermoset composite in an... 

Pultrusion [PHENOLIC RESINS] (Vol 18) [PLASTIC PROCESSING] (Vol 19) [REINFORCED PLASTICS] (Vol 21) [COMPOSITEMATERIALS - SURVEY] (Vol 7) resin properties required for [COMPOSITE MATERIALS - POLYMER-MATRIX - THERMOSETS] (Vol 7)... 

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]. 

As mentioned earlier, suspensions of particulate rods or fibers are almost always non-Brownian. Such fiber suspensions are important precursors to composite materials that use fiber inclusions as mechanical reinforcement agents or as modifiers of thermal, electrical, or dielectrical properties. A common example is that of glass-fiber-reinforced composites, in which the matrix is a thermoplastic or a thermosetting polymer (Darlington et al. 1977). Fiber suspensions are also important in the pulp and paper industry. These materials are often molded, cast, or coated in the liquid suspension state, and the flow properties of the suspension are therefore relevant to the final composite properties. Especially important is the distribution of fiber orientations, which controls transport properties in the composite. There have been many experimental and theoretical studies of the flow properties of fibrous suspensions, which have been reviewed by Ganani and Powell (1985) and by Zimsak et al. (1994). 

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