Reinforcement, types

Carbon blacks are usually used as fillers. The semi-reinforcing types, such as PEP (Past Extmsion Pumace) and SRE (Semi-Reinforcing Pumace) give the best performance (see Carbon, carbonblack). To lower the cost and improve the processibiUty of light compounds, or to lower the cost of black compounds, calcined clay or fine-particle calcium carbonate are used. 

Carbon fibers are special reinforcement types having a carbon content of 92-99 wt%. They are prepared by controlled pyrolysis of organic materials in fibrous forms at temperatures ranging from 1,000-3,000°C. 

A hard-and-fast rule to be followed by all intending to use plastics is to design for plastics. As an example, for the same-size cross-section the strength of conventional plastics (not the high-performance reinforced types) is considerably less than that of most metals. The designer will thus find it necessary to increase thickness, introduce stiffening webs, and/or possibly use design inserts of various types of threads to secure the proposed product. The process will in some instances also require modification to the shape of the equipment used to produce the product. 

The reinforcement type and form chosen (woven, braided, chopped, etc.) will depend on the performance requirements and the method of processing the RP (Fig. 6-15). Fibers can be oriented in many different patterns to provide the directional properties desired. Depending on their packing arrangement, different reinforcement-to-plastic ratios are obtained (Appendix A. PLASTICS TOOLBOX). 

Composite mechanical performances according to the reinforcement type... 

Patents published in the year 2004 have been analysed by polymer type, reinforcement type, and material structure and process type see Figure 7.4 (a) and (b). 

Glass fiber reinforced types are known for a long time and are commercially available (32). Tradenames appearing in the references are shown in Table 10.8. 

ASTM Standard A 955-96, Standard Specification for Deformed and Plain Stainless Steel Bars for Concrete Reinforcement (Type 304, 304L, 316, 316L, 316 LN and duplex 2205)... 

There are a variety of silanes, titanates and zirconates used as coupling agents for the reinforcing type of filler. 

Figure 14.1 Composites classified according to reinforcement types.

TP Thermoplastic type GF Glass fiber reinforced type TS Thermosetting type... 

The mineral fillers are a large subclass of inorganic fillers comprised of ground rocks as well as natural, refined, or synthetic minerals. Commodity minerals are relatively inexpensive and are used mostly as additive extenders. Other fillers, so-called specialty minerals, are usually the reinforcing types. There are also inherently small particle size fillers such as talc and surface chemically modified fillers. The inert filler are those added to plastics to alter the properties of a product through physical rather than chemical means. 

Many combinations of resins and reinforcement types and weaves available for specific structural applications. Directional strength properties can be varied from unidirectional to orthotropic by choice of reinforcement type and laminate fabrication method. 

The initial step in the program is the development of a characterization project to assess the effect of a number of primary variables on the performance of laminates under irradiation and at 4 K. Typical variables are reinforcement type, resin system, and cure cycle. The materials will represent a cross section of the existing commercial laminate production. Several laminates will be specially fabricated to provide increased radiation resistance. They will utilize commercial, boron-free glass for reinforcement and epoxy systems cured with aromatic amines. All test laminates will be made by a commercial producer under conditions dupli-... 

FIGURE 19. CoF of different types of C/C-SiC composites [12] (Type I 2D reinforcement, Type II HM-fibies, Type III axial fibre orientation, Type IV high SiC-content)... 

Swelling and shrinkage of the subgrade material certainly negatively affect the performance of the rigid pavement, in particular the unreinforced or jointed reinforced type. 

For unreinforced and jointed reinforced type of concrete pavements, all types of joints are provided, while in the continuously reinforced pavements, only longitudinal (warping) joints are provided (see Figure 14.6). 

Figure 14.6 Schematic plant view of unreinforced, jointed reinforced and continuously reinforced type of rigid pavements, (a) Unreinforced rigid pavement with contraction and expansion joints (b) jointed reinforced rigid pavement with contraction and expansion joints (expansion joint is not shown in the plan view) and (c) continuously reinforced rigid pavement with longitudinal joint.

The inherent strength and resilience properties simplify the matching of the rubber to the application. Where optimum elastic properties are required, the rubber can be used in essentially unfilled (gum) vulcanizate form. If fillers are required non-reinforcing types can often be used, instead of the reinforcing fillers that are essential for low-strength rubbers. 

Non-reinforcing fillers, for a given increase in vulcanizate stiffness, generally give better permanent set, creep and dynamic properties than reinforcing types. The basic properties of natural rubber also show up to advantage in the fabrication of components. 

The reinforcement types which will be discussed are glass fibre, carbon fibre and aramid fibre. Each of these is not a single fibre type but more a family of fibres with a range of properties. Typical properties of a range of reinforcement fibres are given in Table 1.2 The strength and strain figures... 

The reinforcement used is generally a combination of uni directional roving and random mat (continuous filament mat). This combination provides a reasonably optimised set of properties in the longitudinal and the transverse directions respectively. Other reinforcement types may be used, including woven roving, chopped strand mat (nonsoluble binder), needled mat and multi-axial non-woven. 

The moulds are cleaned and prepared by the application of a suitable release agent. Previously prepared reinforcement, usually continuous strand mat but other reinforcement types may be used, is placed in the lower mould and the two mould halves are brought together and clamped. The reinforcement must fit the contours and perimeter of the mould accurately. Hence pre formed mat is often the preferred option. 

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