Testing of Thermoplastics

Report 60 Physical Testing of Thermoplastics, S.W. Hawley, Rapra Technology Ltd. 

Long-Term Strength Testing of Thermoplastic Piping Materials... 

Reference Leeveis, P. S. and Douglas, M., Notched Impact Testing of Thermoplastics A New Perspective, Limitations of Test Methods for Plastics,... 

Piston Cylinder (Extrusion). Pressure-driven piston cylinder capillary viscometers, ie, extmsion rheometers (Fig. 25), are used primarily to measure the melt viscosity of polymers and other viscous materials (21,47,49,50). A reservoir is connected to a capillary tube, and molten polymer or another material is extmded through the capillary by means of a piston to which a constant force is appHed. Viscosity can be determined from the volumetric flow rate and the pressure drop along the capillary. The basic method and test conditions for a number of thermoplastics are described in ASTM D1238. Melt viscoelasticity can influence the results (160). 

The method of obtaining creep data and their presentation have been described however, their application is limited to the exact same material, temperature use, stress level, atmospheric conditions, and type of test (tensile, compression, flexure) with a tolerance of 10%. Only rarely do product requirement conditions coincide with those of the test or, for that matter, are creep data available for all grades of material that may be selected by a designer. In those cases a creep test of relatively short duration such as 1000 h can be instigated, and the information can be extrapolated to the long-term needs. It should be noted that reinforced thermoplastics and thermosets display much higher resistance to creep (Chapter 2). 

St. Lawrence, S., Shinozaki, D.M., Puskas, J.E., Gerchcovich, M., and Myler, U. Micro-mechanical testing of polyisobutylene-polystyrene block-type thermoplastic elastomers. Rubber Chem. TechnoL, 74, 601-613, 2001. 

In initial tests to check the approach, sheet samples of thermoplastic ethylene tetra-fluoroethylene (ETFE) were used, with a permeation cup control test yielding a Q value of... 

At the request of an international petroleum company, a major manufacturer and supplier of down-hole equipment performed tests of the various elastomers commonly used in the construction of packers and other oil field tools. Seven of the nine most commonly used thermoplastic materials were found to be completely inert to TKPP solutions. The test included continual immersion in saturated TKPP for 21 days at 280°F. Only two elastomers, Vi-ton and Fluorel, showed any adverse reaction. O-rings made from these two elastomers showed minor cracking at the termination of the test. A listing of the elastomers that tested inert to TKPP solutions include nitrile, saturated nitrile (HNBR), Aflas, Kalrez, PEEK, Glass-filled Teflon, and Ryton. Several of these elastomers are attacked or degraded by conventional clear completion fluids containing calcium and zinc halides. The inertness of commonly employed elastomers to TKPP is an important advantage for TKPP fluids in normal operations. 

ASTM D1238-04c Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer, Book of Standards Vol. 08.011, ASTM International (formerly known as American Society for Testing and Materials), West Conshohocken, PA, USA. 

ISO 294-2 1996 Plastics - Injection moulding of test specimens of thermoplastic materials -Part 2 Small tensile bars... 

ASTM D1238-04c, Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer, (2004)... 

Mandell 3.F., Darwish, A.Y. and McGarry F.3. (1981). Fracture testing of injection-molded glass and carbon fiber-reinforced thermoplastics. In Testing Methods and Design Allowable for Fibrous Composites, ASTM STP 734 (C.C. Chamis ed.), ASTM, Philadelphia, PA, pp. 73 90. 

The degree of bonding analysis has been verified for both compression molding and online consolidation of thermoplastic composites. In these studies, composite test specimens were consolidated under controlled processing conditions. The most common types of tests performed to measure the interply bond strength were the interlaminar (short beam) shear test [21,25] or the lap shear test [12,21,26]. 

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