Engineering Thermoplastics A New Hope

SEMINAR ON THERMOPLASTICS AND ITS PROPERTIES

Thermoplastics are finding ever wider use in the production of orthopedic aids because of their special properties, such as quick and easy processing, minimum weight, excellent hygienic characteristics as well as outstanding strength, stiffness and shape retention. Thermoplastics can also be reshaped at any time. An ever-expanding range of materials is required with the growing number of applications for thermoplastics in the production of prosthetics and orthotics. At the same time, the development of increasingly high-quality plastics with extremely complex molecular structures allows for a wider variety of processing methods.

For plastics, the definition of ‘high temperature’ is taken to mean ‘any temperature above 135°C and it is true that the majority of available plastics are suitable only for use at temperatures below this value. These plastics are generally called the ‘commodity’ plastics and constitute by far the largest volume of plastics used in the world today.

Despite this, the last few years have seen a rise in the importance of ‘engineering’ plastics and these have significantly improved performance at temperatures above 135°C. The table at right gives the approximate upper limit for the service temperature of a range of plastics families and the engineering plastics show significant improvements in service temperature over the commodity plastics.

Assigning a "maximum service temperature" to any plastic should be undertaken with care. At high temperatures plastics not only soften but can also start to thermally degrade. A plastic that softens at a high temperature but which starts to degrade at a much lower temperature can only be considered for applications below the temperature at which it starts to degrade. Specifying the service temperature also requires knowledge of the thermal degradation performance of the material.

The physical ‘softening point’ of a plastic is defined largely by the type of plastic being used. For amorphous polymers (such as Ultem®, PMMA or PS) the important temperature is Tg – the glass transition temperature. For highly crystalline polymers (such as PTFE) the important temperature is Tm – the melting point. In either case the exact definition of the "softening point" will depend on the test method used

Click Here To Download Full Seminar Kit

Key:Thermoplastics ppt.Thermoplastics pdf,Seminar On Thermoplastics,Thermoplastics seminar report,Chemical engineering seminar topics,Chemical engineering seminar reports with ppt download,Free seminar reports and ppt,Engineering seminar reports,Production of thermoplastics,Engineering Thermoplastics ppt,Seminar Engineering Thermoplastics,Properties of thermoplastics,thermoplastics in automobiles,Thermoplastics in space applications,Use of thermoplastics