Composite materials history

Anisotropy in metals and composite materials is common as a result of manufacturing history. Anisotropic materials often display significantly different results when tested along different planes. This appHes to indentation hardness tests as well as any other test. 

Composites. The history of phenoHc resin composites goes back to the early development of phenoHc materials, when wood flour, minerals, and colorants were combined with phenoHc resins to produce mol ding compounds. In later appHcations, resin varnishes were developed for kraft paper and textile fabrics to make decorative and industrial laminates. Although phenoHcs have been well characterized in glass-reinforced composites, new developments continue in this area, such as new systems for Hquid-injection molding (LIM) and sheet-molding compounds (SMC). More compHcated composite systems are based on aramid and graphite fibers. 

The basic nature of composite materials was introduced in Chapter 1. An overall classification scheme was presented, and the mechanical behavior aspects of composite materials that differ from those of conventional materials were described in a qualitative fashion. The book was then restricted to laminated fiber-reinforced composite mafeffals. The basic definitions and how such materials are made were then treated. Finally, the current and potential advantages of composite materials were discussed along with some case histories that clearly reveal how composite materials are used in structures. 

It is known that the structures present in a polymer reflect the processing variables and that they greatly influence the physical and mechanical properties. Thus, the properties of polymeric materials are influenced by their chemical composition, process history, and the resulting morphology. Morphological study usually requires two preparatory steps prior to the study itself selection of instrumental techniques and development of specimen preparation techniques. Structural observations must be correlated with the properties of the material in order to develop an understanding and applications of the material. Figure 22.1 illustrates the types of optical microscope (OM) techniques commonly used to examine polymer specimens [2]. 

These compositional considerations necessitate attention to raw materials evaluation early in process research and development to (1) establish an in-depth knowledge of the principal raw material, including its composition and history of materials handling prior to arrival at the factory, (2) investigate the effects of seasonal variations and storage under various conditions on composition and on hydrolytic performance, and (3) explore alternative pretreatment processes for upgrading the composition and hydrolytic performance of available raw materials. The resource that is for sale is not pure cellulose it is a complex mixture containing cellulose caveat emptor. 

However, the technology of composite materials cannot be fully considered as a new chapter in the history of chemistry. Originally the term composite was used in conjunction with reinforced plastics. The US Society for Plastic Industries had a Reinforced Plastics Division which was renamed Reinforced Plastics and Composites Division, in 1967. [17] In France, a bi-monthly magazine entitled Plastique renforce/Verre textile published by the professional organization bearing the same name, started in 1963 and was rechristened in 1983 Composites with Plastique renforce/verre textile as a subtitle. The shift from reinforced plastics to composite... 

It is almost paradoxical that in the history of mankind composite materials were earlier used than their "homogeneous" rivals. The earliest "engineering materials" were bone, wood and clay. Wood is a composite of matrix lignin and a cellulosic reinforcement bone is a natural composite where fibres of hydroxyapatite reinforce the collagen matrix and the oldest building material was adobe clay as a matrix, reinforced by vegetable fibres. After the industrial revolution other composites were added reinforced rubber, reinforced concrete, reinforced asphalt, etc. 

The composition in the other bulb can be calculated from the material balance (Eq. 5.4.3). The results of similar calculations at other times are shown in the composition time histories shown in Figure 5.4 along with experimental data from the thesis of Duncan (1960). It can be seen that the agreement between theory and experiment is very good indeed. 

Borates (such as boric acid, borax, disodium octaborate tetrahydrate) have been used as broad-spectrum wood preservatives for over 50 years. Zinc borate has a shorter history as wood preservative, but it is well accepted in that capacity. There is a belief that, generally, zinc borate is more effective against fungal decay compared to mold inhibition, though systematic studies, using different composite materials, are apparently lacking. 

Fiberglass composite materials have a long history of proven performance. Several of the long term, documented case histories have been reviewed. The initial faith placed in these materials was well founded and this has resulted in a large and still growing industry with activity throughout the world. 

L. N. Johnson, Composite Resins as a Dental Restorative Material, /. Biomed. Mater. Res. Symp. 1, 207 (1971). History of use of polymers in tooth fillings. Description of composite materials for tooth fillings. Description of linear PMMA/crosslinked PMMA semi-II IPNs. 

Brent S A (2002), History of composite materials — Opportunities and necessities . Composites Manufacturing, 1-8. 

Setting up a pedigree material to be used repeatedly in order to calibrate each laboratory or field test is strongly recommended. This will ensure reproducibility of the test procedure. This material should be thoroughly characterized as to its chemical composition, process history, and microstructure. The size and shape of the reference material should reflect that of the candidate product forms being screened. 

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