Clash Berg temperature

The compounds were mixed on a two-roll mill at 320°F. for 8 minutes, then molded into test plaques at 340°F. and 1500 p.s.i. Samples for mechanical testing, hardness, compatibility, and Clash-Berg temperature were 0.075 inch thick while carbon black volatility and extractions were performed on 0.010 inch films. All testing was in accordance with ASTM specifications, and results are summarized in Tables II through V. 

The Clash-Berg temperature (ASTM Dl043-6IT) is the temperature at which the torsional modulus of a 0.075-inch sample equals 135,000 p.s.i. A constant torque of 0.5 inch-pound was applied and five-second readings were taken on a Tinius-Olsen instrument. 

Figure 3.7. Clash Berg temperature of PVC containing 50 phr plasticizer having variable number of carbon atoms in alcohol part and two different acids. [Data from Wickson, E. J., Handbook of Polyvinyl Chloride Formulating, John Wiley Sons, New York, 1993.]...

Some plasticizers contain chlorine. Its concentration determines their properties and behavior. The data included are in weight percent Clash Berg temperature... 

The brittle points generally range from -90°C up to -30°C. Clash-Berg stiffness temperatures are higher, from -50°Cup to -17°C. 

Creep testing was performed on a Clash-Berg Torsion Stiffness Tester. Silicone oil was used as the heat transfer medium. Temperatures were held constant to within + 1... 

Fire relstance,chemical composition by infrared (IR) and nuclear magnetic resonance (Mlffit) spectroscopy, thermal analyses, Clash-Berg moduli determination and dynamical mechanical analyses were determined. The fluorenone polyesters were spun as fibers from solution. They were blended with an acetylene terminated fluorenone monomer for plasticization and crosslinking at high temperatures to form an improved thermally stable product. 

Torsion modulus versus temperature Gehman torsion apparatus, Clash-Berg... 

Clash-Berg point n. The rising temperature at which the apparent modulus of rigidity of a specimen fells to 931 MPa, the end point of flexibility as defined by Clash and Berg in their studies of low-temperature flexibility. In a similar test described in ASTM D 1043, the deciding shear modulus is one-third the C-B value. 

See also brittleness temperature and clash-berg point. 

Low-Temperature Flexibility All plastics that are flexible at room temperature become less so as they are chilled, finally becoming brittle at some low temperature. This property is often measured by torsional tests over wide ranges of temperature, from which apparent moduli of elasticity are calculated. See also Brittleness Temperature and Clash-Berg Point. Some relevant ASTM tests are D 1043, D 3295, D 3296, D 3374 (Section 07.02), and D 1055 (Section 09.01). 

The addition of plasticizers to a PVC product extends the lower useful temperature limit of the finished product. Generally, the lower temperature performance is enhanced as the plasticizer concentration is increased. Some plasticizers are more efficient in providing low temperature flexibility than others. Aliphatic diesters of adipic, azelaic, and se-bacic acids are the preferred plasticizers for very low temperature requirements. In addition, the linear phthalates based on linear C9 alcohols, linear Cl 1 alcohols, and the linear C9/C11 blends offer enhanced low temperature performance over the corresponding branched esters. The low temperature flexibility as reported by the Clash-Berg (ASTM D1043) method for PVC plasticized with several esters is shown in Fig. 24.4. 

Figure 24.4 Low temperature performance as determined by the Clash-Berg 7, calculated [20].

Torsional Stiffness - Torsional stiffness tests measure the modulus of rigidity of an elastomer composition over a broad temperature range. Two widely-used tests are ASTM D-1043, which uses the Clash-Berg Tester, and the ASTM D-1053, which uses the Gehman Torsional Stiffness Tester. In both tests, the sample is chilled to a preset temperature, then twisted with a known force. The amount of twist is measured and related to the stiffness (modulus of rigidity) of the sample. The test temperature is then changed and the test is repeated, until a complete curve of stiffness vs. temperature is plotted. The temperature which produces a stiffness of 69 MPa (10000 psi) is sometimes taken as the Stiffness Temperature. 

Here the addition of 7 phr DINA to the formula will increase the lower temperature limit as reported by the Clash-Berg Tf method by almost 10 °C over the same formulation without DINA. 

Tensile strength at 50 phr Ultimate elongation at 50 phr Brittle temperature at 50 phr Clash-Berg at 50 phr Shore A hardness at 50 phr... 

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