An investigation into the technology of polymers

A polymer is a chemical substance made up of repea- Ling units, each unit being called a monomer.polymerisationmonomers---------> po1ymer .Proteins (animal origin) and cellulose (plant origin) arenatural polymers, [1]. Polymers have very large moleculescomprsing hundreds or thousands of a toms formed by successive linking of one or two, occasionally more,types of small molecules into cha Lu or network structures. Theconcept of the polymer is one of the great ideas of twentieth century chemistry. 1t emerged in the ]920s amid pro Iouged controversy and itsacceptance is closelyassociated with the name of Hermann Staudinger.The influence of the polymer (or macromolecule) concept spreadraqidIy into many areas of the natura Iscience and technology . In engineering a series of successes incommeri ca l polymer synthesis establ f shod a new sector ofthe lnternational chemical industry , devoted to producingand applying polymeric materials, notably plastics andrubbers coatings and adhesives. [2]Engineering design, whetherbuilding or of microelectronics, is very much a matter of exploiting theproperties of materials for practical ends.Early in the evolution of a design solution it consideres alternativematerials in broad terms: metal or non-metal. ceramic orpolymer, ferrous or non-ferrous metal. The choices are fromgeneral considerations of engineering properties includingcost and ease of processing and fabrication.1.2 Statement of the problemBecause of the advantage of fibre reinforced compositesin different applications, so the problem of determining theeffect of volume f r ac t ion for these reinforcement incomposites, as one of the main problems in production ofcomposites, Is intensively under investigations.Thisproblem aimed to be approached in the present work byproducing platesoffibre-glass/unsaturatedpolyester-composites, using fibre glass of E-chopped strand mat asreinforcement, with different volume fraction, and studyingits effect on some mechanical behaviours of composite specimens.