Nylon emerged as commercial thermoplastics after the Second World War following their remarkable wartime success in the textile field. The large scale production of Nylon plastics grew mainly from the adoption of conversion methods and equipment already used for other thermoplastics, together with the availability of relative cheep raw material for bulk manufacture of the polymers.
In this report an attempt has been made to present, a broad but balance picture of present day Nylon plastics technology. The topics follow the sequence adapted for monographs on plastic materials in this report and cover raw materials, polymerization techniques, and properties with an historical introduction and testing. While the emphasis is largely based on the effect of moisture on Nylon 6. In discussing properties necessitate is emphasized to obtain the reliable design data to exploit the unique combination of properties possessed by Nylon.
In compiling this report a large number of references were consulted, and those from which data were selected for inclusion are listed at the end of the report.
Moisture as a matter of fact affects the polymer in respect to their properties and other areas as well, as water molecules may enter the structure of polymer (hygroscopic materials) or may only settle on their surface (hydroscopic materials). In case of hygroscopic materials, as Nylon is, it is very significant to remove the water content from its molecules as they form a primary bond within the polymeric material and hence changes the performance and properties which were expected previously from the polymer. This state of affair raises problems in processing and design of component made from polyamides, for not only most important properties considerably are affected by the water absorption but also the dimensional changes may occur that can affect the functioning of components.
For Nylon it is very essential to maintain its likely properties since it was a new concept in plastics for several reasons because it provided a combination of toughness, rigidity, and lubrication free performance that lead to mechanical uses such as bearings and gears. Nylon required a reputation of a quality material by showing that a thermoplastic could be tough as well as stiff and can do some jobs better than metals. This performance capability gives Nylon the label ” ENGINEERING THERMOPLASTIC. “
The idea behind the subject is to compare the properties of dried and un-dried resin in order to support our subject. We choosed Nylon 6 as our primary object material to work and focus. The reason was simply the market value of Nylon6 as compared to other grades of Nylon available in market.
What most interest us about this subject and topic is to work on a highly demanded and esteemed engineering thermoplastic globally i.e. Nylon. Following a research to be made concerning its key dilemma, which would not only help in simplifying it’s processing attributes but also to achieve its expected end properties.
‘ May God Almighty Helps Us To Achieve Our Goals And Objectives. ‘
Since working on a report that needs to be prescribed and data well arranged, it is of outmost importance that we mention our working plan and strategy, which we would be following.
The report basically comprises of two sections, the first section gives a general description and literature survey on polyamides. The other section focuses on the object material chosen, Nylon 6 and all the work adopted practically in order to compare the properties of those dried and un-dried resin, which would satisfy our subject. The work plan followed is stated under the extent of below mentioned points
* Introduction to polyamides, including a short history, general conception and types of Nylon. Characterization of polyamides and methods for identification of type of Nylon.
* Polymerization techniques adopted and basics for different types of Nylon
* Processing conditions adopted for processing polyamides, material handling, control of moisture, and control of feed and drying.
* Processing variables and their effects, including tips for machining Nylon.
* Importance of drying resin, determining moisture content with references made to manufacturers of different drying equipment.
* Appropriate drying systems and method to be followed while drying polyamides.
* Mechanical properties of polyamides, general testing methods for calculating these mechanical properties and tables supportive to them.
* General point of view about Nylon 6 including its behavior and manufacturing technique.
* Work plan followed in order to carry practical research, includes the decision of choosing material grade, calculating and describing methods of moisture content determination and drying of resin.
* Mechanical test methods and theories against each of them and tables of test values carried for both dried and undried resin.
* Final approach to report with a matter of discussion, analysis and conclusions made.
The Moisture Absorbed By Polyamides, Brings About An Obvious Change Especially In Mechanical Properties Among Which Most Of Them Decreases (except of that impact strength) A Lot By A Great Margin.
INTRODUCTION TO NYLON
The first Nylon product to be marketed in 1938 was not a yarn but a continuous large diameter filament used as bristle for toothbrushes. Like the fiber, it depends for its utility on the enhancement of property realized by stretching the filament several fold, but large diameter monofilament is normally consider a plastic rather than fiber application (see table 1-1). This, then, was the origin of Nylon, the synthetic fiber industry, and a new concept in plastic.
Nylon was a new concept in plastics for several reasons: for one, it was the first crystalline plastic. Its crystallinity meant a sharp transition from solid to melt, unlike polystyrene or poly (methyl methacrylate); it also meant a much higher service temperature than previously known thermoplastic. Further, Nylon provided a combination of toughness, rigidity, and lubrication-free performance that led to mechanical uses such as bearing and gears, applications heretofore denied to plastics. Nylon required a reputation of a quality material by showing that a thermoplastic could be tough as well as stiff and could be some jobs better than metals.
Dupont first offered Nylon molding powder in 1941. Beginning in 1954 with the introduction by the Allied chemical Co. of extracted polycaprolactam, new to the American but not the European market, the number of United States manufacturer gradually grew.
The susceptibility of Nylon to modification was clear from the outset. Different acids and amines could be reacted to provide a variety of Nylons and Nylon copolymers. In 1948 Dupont’s line of Nylon molding and extrusion compounds included six products and twelve colors. In the next twenty years the Dupont line alone increased by an order of magnitude in both the number of formulations and the number of standard and service colors. It is not surprising that a 1964 article cited diversity as a key to Nylon and suggested that Nylon might actually be designed to meet the specific needs of an application of it were big enough.