Pp Association Studies Of The Physical Performance Test Data, The Iso And Astm Standards

Polypropylene is widely used everyday in various applications; including injection molded and extruded articles. There are numerous studies on its physical property testing. Nowadays, there are two major testing methods:ISO (International Organization for Standardization) and ASTM (American Society for Testing and Materials). Most countries also have their own independent testing methods, or methods based on ISO, such as JIS (Japanese Industrial Standards) in Japan, DIN (Deutsches Institut fur Normung) in Germany. China also has her own national standard-GB. Actually our country even has own industrial standard-HB. Due to its slight differences in specimen size and testing condition, the data cannot be compared directly. This causes a large waste in materials, time and other resources. It has gradually become a consensus to have a global unified testing method. Although ASTM and ISO are the most widely recognized and used testing methods, the comparison between these two methods is not straight forward and the data are not always interchangeable, because there are slight differences in specimen size and testing condition.One of the objectives of this thesis is to find an approximate relationship to bridge ASTM and ISO so that the data will be more useful in optimizing product quality and minimizing quality concerns during the production. Furthermore, the comparative studies in this thesis provide a deeper insight to the ASTM and ISO test methods and its possible conversion between their values.The thesis consists of four parts:1, Literature survey; 2, Some ISO and ASTM testing methods for Polypropylene; 3, ISO and ASTM testing data comparison; 4, Formula validation; 5, Conclusions.The experiments include ASTM and ISO tensile strength, flexural modulus, heat deflection temperature (HDT), MFR and density of 27 different polypropylene samples ranging in MFR from 1-36 g/10min. We use statistical software-Origin to regress a correlation between ASTM and ISO data. Key conclusions from these studies are summarized below:1, Density and MFR as measured by ASTM and ISO are identical2, ASTM and ISO tensile-strength is measured under almost identical conditions (even though the specimen dimensions are slightly different). There is a good correlation between ASTM and ISO methods. 3, Flexural modulus, by ISO methods is slightly higher than ASTM due to the following reasons.-Higher test speed in ISO leads to higher flexural modulus;-Higher span length in ISO method results in lower flexural modulus;-The lower ISO flexural modulus due to higher span is compensated by the higher test speed. So the flexural modulus by ISO is slightly higher vs. ASTM.4, The HDT by ASTM is measured on samples held edgewise, vs. samples held flatw-ise by ISO. There is lot of scatter in the data.5, It is not possible to correlate Izod impact strength by ASTM and ISO tests methods, for the following reasons.-The energy absorbed to propagate the fracture across the width of the ASTM specimen is reported as J/m or ft-lbs/in.-By ISO, the energy absorbed is measured per cross-sectional area of the specimen, and is expressed as KJ/m2.-There is no conversion factor between J/m and KJ/m2.The practical outcome of this thesis is a simplified conversion equation correlating tensile strength, flexural modulus and HDT. The results of this thesis would provide the theoretical basis as well as technical, experimental support for an enterprise to qualify raw materials. It helps to makes "zero stock inventory" come true.